Derrycarhoon: A later Bronze Age copper mine in south-west Ireland 9781407359250, 9781407359267

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B A R I N T E R NAT I O NA L S E R I E S 3 0 6 9

Derrycarhoon A later Bronze Age copper mine in south-west Ireland WILLIAM O’BRIEN

2022

B A R I N T E R NAT I O NA L S E R I E S 3 0 6 9

Derrycarhoon A later Bronze Age copper mine in south-west Ireland WILLIAM O’BRIEN Contributors: Lena Grandin, Nick Hogan, Kevin Kearney, Simon O’Dwyer, Zofia Stos-Gale and Richard Unitt

2022

Published in 2022 by BAR Publishing, Oxford BAR International Series 3069 Derrycarhoon isbn isbn doi

978 1 4073 5925 0 paperback 978 1 4073 5926 7 e-format

https://doi.org/10.30861/9781407359250

A catalogue record for this book is available from the British Library © William O’Brien 2022 Bronze Age mine working at Derrycarhoon, Co. Cork, Ireland (photograph: William O’Brien) cover image

The Author’s moral rights under the 1988 UK Copyright, Designs and Patents Act, are hereby expressly asserted. All rights reserved. No part of this work may be copied, reproduced, stored, sold, distributed, scanned, saved in any form of digital format or transmitted in any form digitally, without the written permission of the Publisher. Links to third party websites are provided by BAR Publishing in good faith and for information only. BAR Publishing disclaims any responsibility for the materials contained in any third party website referenced in this work.

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Of Related Interest Forging Identities. The Mobility of Culture in Bronze Age Europe Report from a Marie Curie Project 2009-2012 with Concluding Conference at Aarhus University, Moesgaard 2012: Volume 1 Edited by Paulina Suchowska-Ducke, Samantha Scott Reiter, Helle Vandkilde Oxford, BAR Publishing, 2015

BAR International Series 2771

Forging Identities. The Mobility of Culture in Bronze Age Europe Report from a Marie Curie Project 2009-2012 with Concluding Conference at Aarhus University, Moesgaard 2012: Volume 2 Edited by Paulina Suchowska-Ducke, Samantha Scott Reiter, Helle Vandkilde Oxford, BAR Publishing, 2015

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Las Producciones Metálicas del III y II Milenio Cal ANE en el Suroeste de la Península Ibérica Manuel Eleazar Costa Caramé Oxford, BAR Publishing, 2010

BAR International Series 2106

Excavations on Copa Hill, Cwmystwyth (1986-1999) An Early Bronze Age copper mine within the uplands of Central Wales Simon Timberlake with contributions by T. Mighall, S. Clark, A. Caseldine, N. Nayling, D.M. Goodburn, B. Craddock, J. Ambers, A.E. Annel and R.A. Ixer BAR British Series 348

Oxford, BAR Publishing, 2003 Metals in Antiquity Edited by Suzanne M. M. Young, A. Mark Pollard, Paul Budd and Robert A. Ixer Oxford, BAR Publishing, 1999

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Acknowledgements The Derrycarhoon project was entirely funded by University College Cork, as part of our ongoing research on the archaeological heritage of the region. Many thanks to Nick Hogan, Joe Fenwick, Alan Hawkes, James O’Driscoll and Donal O’Brien for assistance with fieldwork, to Susan Lyons for wood identifications, Richard Unitt for geophysical survey and Simon O’Dwyer for discussion of the ‘Derrycarhoon Tube’. Thanks also to Lena Grandin and Zofia Stos-Gale for their important contribution to this work and support for the project. I am grateful to Professor Johan Ling (Gothenberg University) for including our metalwork analysis in his research project, Scandinavia’s role in the copper networks of Europe in the 2nd Millennium BC, financed by the Swedish Foundation for Humanities and Social Sciences (P14-0308:1). Thanks also to Ignacio Montero for assistance with lead isotope analysis in the University of the Basque Country; the Vegacenter facility at the Swedish Museum of Natural History for metal analyses, and the University of Groningen for radiocarbon dating. I wish to thank the National Museum of Ireland, Royal Irish Academy, Pitt Rivers Museum, Cork Public Museum, Geological Survey of Ireland, Eachtra Ltd, and Transport Infrastructure Ireland for use of illustrations. Special thanks to Nick Hogan (UCC) for survey work and producing many of the figures. This book could not have been done without his help. Thanks also to Madeline O’Brien who copyedited the text, the anonymous referees who offered useful comments and the editorial team at BAR Publishing for their watchful eye and support for the publication. This book is dedicated to George Eogan who sadly passed away in late 2021 before it was published. Professor Eogan was a pioneering researcher on the later Bronze Age in Ireland and the leading authority on its metalwork. His work continues to be of great importance in understanding the significance of metal during that important period of Irish prehistory.

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Contents List of Figures...................................................................................................................................................................... ix List of Tables...................................................................................................................................................................... xiv Abstract............................................................................................................................................................................... xv 1. Introduction..................................................................................................................................................................... 1 1.1 Prehistoric Copper Mining in Europe........................................................................................................................ 1 1.2 Metal in Bronze Age Ireland...................................................................................................................................... 7 1.3 Prehistoric Copper Mining in South-west Ireland..................................................................................................... 9 1.4 Derrycarhoon Mine Project...................................................................................................................................... 15 2. Discovery........................................................................................................................................................................ 17 2.1 Recent Mining at Derrycarhoon............................................................................................................................... 19 2.2 The ‘Danish Mine’ Revealed.................................................................................................................................... 19 2.3 ‘Curious Articles’ .................................................................................................................................................... 22 2.4 Later Visitors and Interpretations ............................................................................................................................ 25 3. The Mining Landscape................................................................................................................................................. 29 3.1 Geology and Mineralisation..................................................................................................................................... 30 3.2 Archaeological Survey (with Nick Hogan).............................................................................................................. 41 3.3 Geophysical Survey (Richard Unitt)........................................................................................................................ 48 3.4 The ‘Danish Mine’ Preserved................................................................................................................................... 52 4. Archaeological Excavation........................................................................................................................................... 55 4.1 Mine Excavation...................................................................................................................................................... 56 4.2 Surface Spoil Excavation......................................................................................................................................... 62 4.3 Excavation Finds...................................................................................................................................................... 66 4.4 Discussion................................................................................................................................................................ 77 5. Chronology.................................................................................................................................................................... 81 5.1 Historical Review..................................................................................................................................................... 81 5.2 Mining Technology ................................................................................................................................................. 82 5.3 Peat and Pollen......................................................................................................................................................... 85 5.4 Radiocarbon Dating................................................................................................................................................. 86 6. Palaeoecology................................................................................................................................................................. 91 6.1 Pollen Sampling and Analysis ................................................................................................................................. 91 6.2 Early Holocene Vegetation Change and Human Activity........................................................................................ 93 6.3 Mid-Holocene ‘Elm Decline’ and Neolithic Farming.............................................................................................. 96 6.4 Bronze Age Settlement and Environment in the Mizen Peninsula.......................................................................... 98 7. Cultural Landscape.................................................................................................................................................... 103 7.1 Environment and Settlement.................................................................................................................................. 103 7.2 The Early Prehistory of Mizen .............................................................................................................................. 106 7.3 Regional Context: Bronze Age Settlement in Cork............................................................................................... 115 7.4 Derrycarhoon and the ‘Stone Circle Complex’...................................................................................................... 125 8. Mine to Metal.............................................................................................................................................................. 145 8.1 Bronze Age Mining at Derrycarhoon .................................................................................................................... 145 8.2 Ore Beneficiation and Metal Production................................................................................................................ 152 8.3 Metal in the Landscape.......................................................................................................................................... 155 8.4 Derrycarhoon and the Supply of Copper in Bronze Age Ireland........................................................................... 160 9. The Wider Picture....................................................................................................................................................... 179 9.1 Derrycarhoon and Early Copper Production in Ireland......................................................................................... 179 vii

Derrycarhoon 9.2 Mining and Society................................................................................................................................................ 182 9.3 Bronze Age Trade and Hillfort Chiefdoms............................................................................................................ 188 9.4 The Significance of Derrycarhoon Mine and its Future......................................................................................... 192 Appendix 1. The Swanton–Windele correspondence 1846–7.......................................................................................... 195 Appendix 2. Derrycarhoon in the Mining Journal, 1847–1880........................................................................................ 197 References......................................................................................................................................................................... 201

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List of Figures Figure 1.1 Prehistoric copper mines in Europe..................................................................................................................... 2 Figure 1.2 Bronze Age trench copper mines at Chinflon, Huelva province, south-west Spain............................................ 3 Figure 1.3 Distribution of prehistoric copper mines in Britain and Ireland.......................................................................... 4 Figure 1.4 Bronze Age and later trench mining along the Engine Vein, Alderley Edge, Manchester, England................... 5 Figure 1.5 Bronze Age trench workings at the Great Orme copper mine, north Wales....................................................... 5 Figure 1.6 Prehistoric copper mines in south-west Ireland................................................................................................. 10 Figure 1.7 Chalcolithic/Beaker culture copper mine at Ross Island, Killarney, Co. Kerry................................................ 11 Figure 1.8 Bronze Age mining landscape on Mount Gabriel............................................................................................. 12 Figure 1.9 Bronze Age copper mine at Tooreen, Beara Peninsula, Co. Cork..................................................................... 14 Figure 2.1 Nineteenth-century industrial copper mines in the West Carbery district......................................................... 17 Figure 2.2 Section drawing sent in 1878 to the Inspector of Mines of an industrial copper mine (c.1814–78) at Ballycummisk, Ballydehob, 8km south of Derrycarhoon............................................................................................... 18 Figure 2.3 John Windele, Cork antiquarian, 1801–1865.................................................................................................... 21 Figure 2.4 Sketch of Derrycarhoon Tube sent 27th August, 1846, by Roger Downing, Bantry, to John Windele.............. 23 Figure 2.5 Historic sketch plans of Derrycarhoon mine made by Tom Duffy (top) and Adolf Mahr (centre right) during a visit in October 1929................................................................................................................................... 26 Figure 2.6. Interpretations of Derrycarhoon mine based on historical sources.................................................................. 28 Figure 3.1 Landscape setting of Derrycarhoon mine in the Mizen Peninsula of West Cork.............................................. 29 Figure 3.2 Aerial photo of Derrycarhoon mine, 1990......................................................................................................... 30 Figure 3.3 Aerial drone image of Derrycarhoon mine after felling of conifer plantation, 2014........................................ 31 Figure 3.4 Bedrock geology of Co. Cork............................................................................................................................ 32 Figure 3.5 Bedrock geology of Derrycarhoon area............................................................................................................ 33 Figure 3.6 Original plan of Derrycarhoon mine made by I.S. Thompson, Northfield Mines, December 1963................. 36 Figure 3.7 Geology and drilling of Derrycarboon mine showing location of drill-holes (D1–4), open-cut workings and underground levels, as recorded by I.S. Thompson, Northfield Mines........................................................ 37 Figure 3.8 Geological section for drill-hole D1, Derrycarhoon mine................................................................................. 39 Figure 3.9 Geological section for drill-hole D2, Derrycarhoon mine................................................................................. 40 Figure 3.10 Central mine area in forest clearing at Derrycarhoon in 2007........................................................................ 41 Figure 3.11 Surface survey of Derrycarhoon mine in 2007, showing location of early mine trenches (M1–6), nineteenth-century shafts (M7 and M8), spoil deposits and lengths of early modern stone walls....................... 42 Figure 3.12 Location of South Shaft infilled c.1920........................................................................................................... 42 Figure 3.13 Blocked underground level, North Shaft......................................................................................................... 43 Figure 3.14 Plan and section of c.1910 adit (M9) at Derrycarhoon dated 19 November 1962.......................................... 44 Figure 3.15 Partly infilled trench mine (M1), Derrycarhoon.............................................................................................. 44 Figure 3.16 Partly infilled trench mine (M2) marked by ranging pole, Derrycarhoon....................................................... 45 Figure 3.17 Partly infilled trench mine (M3), Derrycarhoon. Mount Gabriel in background............................................ 45 Figure 3.18 Partly infilled trench mine (M4a), Derrycarhoon............................................................................................ 46 ix

Derrycarhoon Figure 3.19 Partly infilled trench mine (M5a), Derrycarhoon............................................................................................ 46 Figure 3.20 Flooded trench mine (M6) after felling of forestry, 2015............................................................................... 47 Figure 3.21 Exposed mine spoil with rounded stone hammers, central mine area, Derrycarhoon.................................... 47 Figure 3.22 Electrical resistivity survey in progress at Derrycarhoon................................................................................ 48 Figure 3.23 Location of electrical resistivity survey lines across early trench mines at Derrycarhoon............................. 49 Figure 3.24 Electrical resistivity profile (Line 1) across Mine 6, Derrycarhoon................................................................ 50 Figure 3.25 Electrical resistivity profile (Line 2) across Mine 5b...................................................................................... 50 Figure 3.26 Electrical resistivity profile (Line 3) across Mine 4a...................................................................................... 50 Figure 3.27 Electrical resistivity profile (Line 4) across Mine 5a...................................................................................... 51 Figure 3.28 Electrical resistivity profile (Line 5) across Mine 1a...................................................................................... 51 Figure 3.29 Electrical resistivity profile (Line 6) across Mine 3b...................................................................................... 51 Figure 3.30 Geological setting of trench mines at Derrycarhoon....................................................................................... 52 Figure 3.31 Derrycarhoon mine after felling of forestry, 2015........................................................................................... 53 Figure 4.1 Plan of Derrycarhoon mine site, showing archaeological excavation trenches A, B, C (2010 season) and D (2011 season).................................................................................................................................... 55 Figure 4.2 Mine 5b looking east. The mine trench is mostly infilled, with a small opening visible (foreground) and the 2011 Mine 5b-1 excavation area in background............................................................................... 56 Figure 4.3 Excavation of Mine Trench 5b-1 in progress. Removal of peat infill (Layer 2)............................................... 57 Figure 4.4 Mine 5b-1 pit after excavation.......................................................................................................................... 57 Figure 4.5 Post-excavation plan and profiles of Mine 5b-1, Derrycarhoon........................................................................ 58 Figure 4.6 Remains of copper-bed with malachite staining on south wall of Mine 5b-1................................................... 59 Figure 4.7 Mine 5b-1 after excavation, looking up from floor........................................................................................... 59 Figure 4.8 East wall of Trench Mine 5b-1, with shallow recess at base............................................................................. 60 Figure 4.9 Recess at base of east wall of Trench Mine 5b-1.............................................................................................. 60 Figure 4.10 Foot-ledge on southern wall of Mine 5b-1...................................................................................................... 61 Figure 4.11 West wall of Mine 5b-1, showing stack of minor quartz veining.................................................................... 61 Figure 4.12 Laser scan image of Mine 5b-1, Derrycarhoon............................................................................................... 62 Figure 4.13 Archaeological stratification in Mine 5b-1, Derrycarhoon.............................................................................. 63 Figure 4.14 Shallow depression (Mine 5b-2) on south-west side of Trench Mine 5b-1.................................................... 63 Figure 4.15 South-facing section, Excavation Trench A, showing surface layer of mine spoil (with stone hammers) over peat layer above podzolised soil profile........................................................................................... 64 Figure 4.16 Shallow linear feature (right) in peat layer, Excavation Trench A.................................................................. 65 Figure 4.17 Deposit of mine spoil overlying brown peat layer in Excavation Trench B (looking north-east)................... 65 Figure 4.18 Stratification of Excavation Trenches A and B, central spoil area, Derrycarhoon.......................................... 66 Figure 4.19 General view of Excavation Trench C, showing build-up of mine spoil at southern (left) end of trench and Mine Trench 3b at western end (far right). Scale: 20cm divisions........................................................ 67 Figure 4.20 Build-up of mine spoil at southern end of Excavation Trench C.................................................................... 67 Figure 4.21 Stratification of Excavation Trench C on southern side of Mine 3b, Derrycarhoon....................................... 68 Figure 4.22 Selection of stone hammers excavated in Excavation Trenches A and B, central spoil area.......................... 69 Figure 4.23 Broken stone hammers from Mine 5b-1, Derrycarhoon. The side abrasion on the far left example is typical of the minimal haft modification of these cobbles................................................................................ 69 Figure 4.24 Antler pick, Mine 5b-1.................................................................................................................................... 74 x

List of Figures Figure 4.25 Fragments of twisted hazel withy (10E287:02) found under stone hammer in surface depression, Mine 5b-2......................................................................................................................................................... 75 Figure 4.26 Possible wooden wedge (10E287:03), Mine 5b-1........................................................................................... 76 Figure 4.27 Part of wooden handle (10E287:04) used to haft a stone hammer, Mine 5b-1, Derrycarhoon (right), with similar example from Mine 3, Mount Gabriel................................................................................................ 76 Figure 4.28 Broken step branch (10E287:05), Mine 5b-1.................................................................................................. 77 Figure 4.29 Broken step branch (10E287:06), Mine 5b-1, with (right) pencil-type tooling at end one end...................... 78 Figure 4.30 Hazel rods, Mine 5b-1..................................................................................................................................... 79 Figure 4.31 Selection of waterlogged wood fragments from Excavation Trench B........................................................... 79 Figure 4.32 Two fragments of twisted hazel (?) withy (right 10E287:01; left 10E287:02), Excavation Trench B............ 79 Figure 5.1 Photographs of Derrycarhoon tube.................................................................................................................... 83 Figure 5.2 Radiocarbon dating of the Derrycarhoon Tube (OxA-1184; 820±60 BP) and the Killeshandra, Co. Cavan horn (GrA-20477; 785±40 BP); calibration after OxCal v.4.4.3...................................................................... 84 Figure 5.3 The Killeshandra horn, Co. Cavan.................................................................................................................... 84 Figure 5.4 Monoxylous wooden ladder of Middle Bronze Age date, Owen’s and Bigg’s-Lot townland, Cashel, Co. Tipperary......................................................................................................................................................... 85 Figure 5.5. Schematic pollen diagram produced in 1947 by Frank Mitchell..................................................................... 87 Figure 5.6 Author probing peat infill in Mine Trench 5b using Russian auger, with peat sample (right) from a depth of 1.6m in this working................................................................................................................................. 88 Figure 5.7 Calibration of radiocarbon results from archaeological excavations at Derrycarhoon mine............................ 89 Figure 6.1 Pollen coring at Derrycarhoon, November 2018. Mound of mine spoil visible (centre background) in central mine area........................................................................................................................................ 91 Figure 6.2 Age-depth model of radiocarbon dates for the Derrycarhoon pollen core........................................................ 93 Figure 6.3 Pollen percentage and loss-on-ignition diagram for the Derrycarhoon pollen core.......................................... 94 Figure 6.4 Comparison between phases of woodland reduction and agricultural activity at Derrycarhoon and recent published pollen profiles from the Mizen Peninsula......................................................................................... 97 Figure 7.1 Physical environment of Mizen Peninsula and its hinterland, showing location of Mount Gabriel and Derrycarhoon copper mines.......................................................................................................................... 103 Figure 7.2 Satellite image of environs of Derrycarhoon mine, showing field patterns in areas of improved grassland, as well as conifer plantation in hilly areas of rock outrop .............................................................................. 104 Figure 7.3 Arderrawinny portal tomb, Mizen Peninsula................................................................................................... 106 Figure 7.4 Prehistoric rock art in Co. Cork....................................................................................................................... 107 Figure 7.5 Distribution of rock art and wedge tombs within 10km of Derrycarhoon mine............................................. 108 Figure 7.6 Rock art at Ballybane West (left) and Derreennaclogh (right), Ballydehob, Co. Cork................................... 109 Figure 7.7 Rock art at Glansallagh, 1.9km south-west of Derrycarhoon mine.................................................................111 Figure 7.8 Distribution of wedge tombs recorded in Co. Cork........................................................................................ 112 Figure 7.9 Altar wedge tomb, Mizen Peninsula, Co. Cork............................................................................................... 112 Figure 7.10 Toormore wedge tomb, Mizen Peninsula, Co. Cork. Arrow marks find-spot of bronze axe and copper ingots.............................................................................................................................................................. 113 Figure 7.11 Cappaghnacallee wedge tomb, Mizen Peninsula, Co. Cork.......................................................................... 114 Figure 7.12 Kilbronoge wedge tomb, Mizen Peninsula, Co. Cork................................................................................... 114 Figure 7.13 Gold disc found with a bronze armlet in a quarry at Sparrograda, Ballydehob, Co. Cork........................... 115 Figure 7.14 Bronze axehead and two copper ingots from Toormore wedge tomb, Mizen Peninsula, Co. Cork............. 115

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Derrycarhoon Figure 7.15 Distribution of burnt mounds (fulachtaí fia) recorded in Co. Cork............................................................... 116 Figure 7.16 Burnt mound (fulacht fiadh) at Glanphuca (CO132-001001), 6km to the east/north-east of Derrycarhoon mine....................................................................................................................................................... 118 Figure 7.17 Bronze Age settlements excavated in Co. Cork............................................................................................ 118 Figure 7.18 Bronze Age roundhouses excavated on M8 road scheme at Mitchelstown (site 1), Co. Cork..................... 119 Figure 7.19 Bronze Age roundhouse on road scheme excavation at Ballynamona, Mitchelstown, Co. Cork................. 120 Figure 7.20 Bronze Age roundhouse from gas pipeline excavation at Curraheen (site 2), Co. Cork............................... 120 Figure 7.21 Excavation photographs and reconstruction of Bronze Age enclosures and roundhouses at Ballybrowney Lower (site 1), Rathcormack, Co. Cork.................................................................................................... 123 Figure 7.22 Bronze Age house enclosure at Carrigillihy, Glandore, Co. Cork................................................................. 124 Figure 7.23 Aerial view of Bronze Age hillfort at Clashanimud, Co. Cork..................................................................... 124 Figure 7.24 Partly reconstructed entrance to inner enclosure of Bronze Age hillfort at Clashanimud, Co. Cork............ 125 Figure 7.25 Distribution of stone circles recorded in Co. Cork........................................................................................ 126 Figure 7.26 Stone circle, stone pair and radial stone cairn at Kealkill, Co. Cork............................................................. 127 Figure 7.27 Distribution of stone circles, stone rows, stone pairs and boulder-burials within 10km of Derrycarhoon mine........................................................................................................................................................... 128 Figure 7.28 Multiple stone circle at Dunbeacon near Durrus, Co. Cork.......................................................................... 129 Figure 7.29 Selection of five-stone circles within 10km to north of Derrycarhoon mine................................................ 130 Figure 7.30 Distribution of stone rows and pairs recorded in Co. Cork........................................................................... 130 Figure 7.31 Selection of stone rows within 10km to north of Derrycarhoon mine.......................................................... 131 Figure 7.32 Selection of stone pairs within 10km of Derrycarhoon mine........................................................................ 133 Figure 7.33 Distribution of boulder-burials recorded in Co. Cork................................................................................... 135 Figure 7.34 Selection of boulder-burials within 10km of Derrycarhoon mine................................................................. 135 Figure 7.35 Larger of two boulder-burials at Cooradarrigan, Schull, Co. Cork............................................................... 136 Figure 7.36 Boulder-burial and stone pair at Ballycommane, Durrus, Co. Cork............................................................. 136 Figure 7.37 Plan and excavation of boulder-burial at Ballycommane, Durrus, Co. Cork................................................ 137 Figure 7.38 Excavation of northern stone of stone pair at Ballycommane, showing adjacent cist and an earlier cultivation furrow.................................................................................................................................................. 137 Figure 7.39 Distribution of single standing stones, along with stone circles, stone rows, stone pairs and boulder-burials, within 10km of Derrycarhoon mine....................................................................................................... 140 Figure 7.40 Prehistoric cairn in Skeagh townland, north-west of Skibbereen, Co. Cork................................................. 141 Figure 8.1 Exposure of copper-bed with malachite staining (inset), Arderrawinny, Mizen Peninsula, Co. Cork............ 146 Figure 8.2 Geological setting of Bronze Age copper mines, mid slope on Mount Gabriel, south-west Ireland.............. 147 Figure 8.3 Reconstruction of Derrycarhoon mining landscape, showing parallel trench mines on steeply inclined copper beds, with depiction of later peat growth................................................................................................ 148 Figure 8.4 Geo-engineering controls on Bronze Age mining on Mount Gabriel, Ireland................................................ 149 Figure 8.5 Methods used to haft stone mining hammers, with photograph of Chuquicamata hammer, Chile................. 150 Figure 8.6 Selection of mining implements dated 1700–1600 BC found in excavation of waterlogged Mine 3 on Mount Gabriel................................................................................................................................................. 151 Figure 8.7 Experimental hand-cobbing of copper minerals using stone hammers and anvil stones................................ 152 Figure 8.8 Early Bronze Age stone axe mould from Doonour on the north side of the Sheep’s Head Peninsula, c.14km west/north-west of Derrycarhoon mine.............................................................................................. 156 Figure 8.9 Undated stone ingot mould from Dunbeacon North (NMI 1970:14).............................................................. 156 xii

List of Figures Figure 8.10 Distribution of Early/Middle Bronze Age bronze axes and Mount Gabriel mines in Co. Cork................... 157 Figure 8.11 Middle and Late Bronze Age bronze metalwork from Mizen/Bantry area (not to scale)............................. 158 Figure 8.12 Upper: bronze spearhead from Lissaclarig East. Lower: Bronze Age stone row in adjacent townland....... 159 Figure 8.13 Bronze axeheads analysed in this project...................................................................................................... 161 Figure 8.14 Bronze axeheads analysed in this project...................................................................................................... 162 Figure 8.15 Lead isotope ratios to the non-radiogenic isotope 204Pb of the analysed ores from Ross Island, Mount Gabriel and Derrycarhoon mines, compared with a larger data-set for the Great Orme mine in Wales............... 165 Figure 8.16 Lead isotope ratios to the radiogenic isotope 206Pb of copper ores from Mount Gabriel and Derrycarhoon mines, showing the wide range of values created by the presence of the comparatively large amounts of uranium and thorium in the host rocks ................................................................................................. 166 Figure 8.17 Selection of lead isotope data for copper ores from Derrycarhoon compared with data for the Great Orme, Ross Island and Mount Gabriel mines, focussing on the non-radiogenic 208Pb/206Pb ratio......................... 167 Figure 8.18 Nickel-arsenic, nickel-silver, and antimony-silver plots in analysed samples of ores from Derrycarhoon, Mount Gabriel and Ross Island mines, compared with ores from the Great Orme mine......................... 169 Figure 8.19 Concentrations of Sn and Pb in the palstaves and socketed axeheads from Co. Cork analysed in this study........................................................................................................................................................ 170 Figure 8.20 Compositional patterns in three clusters identified in palstaves in this study, using values of Ni, As, Sb and Ag for classification with cluster analyses. See Table 4 for details...................................................... 171 Figure 8.21 Nickel-arsenic and antimony-silver plots for palstaves and socketed axeheads from Cork, compared to ore data from Bronze Age mines at Derrycarhoon, Mount Gabriel and Great Orme.................................. 172 Figure 8.22 Comparison of lead isotope ratios to 206Pb for copper ores from Bronze Age copper mines in southern Ireland and the Great Orme in Wales to LIA data for bronze axes from Cork analysed in this study............... 174 Figure 8.23 Comparison of lead isotope ratios to 204Pb for copper ores from the Bronze Age copper mines in southern Ireland and the Great Orme in Wales to LIA data for bronze axes from Co. Cork........................................ 175 Figure 8.24 Nickel-arsenic and antimony-silver plots for palstaves and socketed axeheads from Co. Cork, compared to ore data from Derrycarhoon, Mount Gabriel and Great Orme.................................................................... 176 Figure 8.25 Comparison of the lead isotope ratios of three bronze axes (UCC49, UCC51 and UCC55) from Co. Cork with ores from the Italian Alps and South Spain...................................................................................... 177 Figure 9.1 Correlation of patterns of mining and metal supply with hillfort chronology in Bronze Age Ireland............ 180 Figure 9.2. Distribution of Late Bronze Age goldwork in Co. Cork................................................................................ 185 Figure 9.3. The Cappeen gold hoard find of 1896, containing two bracelets, a twisted neck ornament, a coiled bar and a coiled strip........................................................................................................................................... 185 Figure 9.4. Gold bracelet found at Brahalish near Bantry................................................................................................ 186 Figure 9.5 Hoard of Late Bronze Age metalwork from Mountrivers, Co. Cork.............................................................. 187 Figure 9.6 Necklace of amber beads found after turf-cutting in the townland of Murrahin North, east of Ballydehob.................................................................................................................................................................... 187 Figure 9.7 Distribution of Class 2 hillforts in Ireland, including examples of confirmed or possible Neolithic or later Bronze Age date.................................................................................................................................... 189 Figure 9.8 Finds of Middle and Late Bronze Age spearheads and swords in Co. Cork, with location of Clashanimud hillfort..................................................................................................................................................... 190 Figure 9.9 Upper: Derrycarhoon mine in 2018 four years after felling of forestry. Lower: mine area in December 2021, with re-growth of conifers inside archaeological area designated for protection................................. 194

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List of Tables Table 3.1 Optical spectrographic analysis of two museum mineral samples from Derrycarhoon mine............................ 34 Table 3.2 Dimensions of trench mines recorded in 1846 and 2007 at Derrycarhoon mine................................................ 52 Table 4.1 Data for stone hammers excavated in Mine 5b-1, Derrycarhoon....................................................................... 70 Table 4.2 Data for stone hammers from surface spoil in central mine area, Derrycarhoon............................................... 74 Table 6.1 Radiocarbon dates from the Derrycarhoon pollen core...................................................................................... 92 Table 7.1 Rock art and wedge tombs within 10km of Derrycarhoon mine...................................................................... 110 Table 7.2 Burnt mounds (fulachtaí fia) recorded within 10km of Derrycarhoon mine.................................................... 117 Table 7.3 Bronze Age stone circles within 10km of Derrycarhoon mine......................................................................... 129 Table 7.4 Bronze Age stone rows and stone pairs within 10km of Derrycarhoon............................................................ 132 Table 7.5 Bronze Age boulder-burials within 10km of Derrycarhoon mine.................................................................... 134 Table 7.6 Single standing stones within 10km of Derrycarhoon mine............................................................................. 139 Table 7.7 Local concentrations of Stone Circle Complex monuments within 10km of Derrycarhoon mine................... 142 Table 8.1. Description of seven palstaves and two socketed axeheads from Co. Cork analysed in this project.............. 163 Table 8.2 Chemical data for bulk samples of copper ores from Derrycarhoon, analysed by ICP-AES and ICP-MS by ALS Minerals (No. PI16186614)............................................................................................................ 163 Table 8.3 Lead isotope data for copper ores from Derrycarhoon mine............................................................................ 164 Table 8.4 Chemical data for Bronze Age axes from Co. Cork, obtained by EPMA analyses (JEOL-JXA 8530F).......... 170 Table 8.5 Lead isotope data for Bronze Age axes from Co. Cork.................................................................................... 173 Table 8.6 Summary of characteristic features and suggested origin of copper in the analysed palstaves and socketed axeheads from Co. Cork.............................................................................................................................. 176

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Abstract As the name suggests, one of the distinctive features of the Bronze Age in Europe was a growing dependency on metal, with hundreds of thousands of copper and bronze objects recorded from the second millennium BC. That level of production was made possible by the mining of copper in some regions and its wider supply through trade and other exchanges. This publication presents an investigation of a prehistoric copper mine in south-west Ireland, the first example recorded there from the later Bronze Age, c.1300–1000 BC. The project, based in University College Cork, used approaches and information provided by geology, archaeology, history, and palaeoecology to examine the story of copper mining at Derrycarhoon in its cultural landscape setting. The recent history of mining and prospection at Derrycarhoon is considered, beginning with the discovery in 1846 of the so-called ‘Danish Mines’, of which ‘no previous tradition or suspicion had been entertained’. Later accounts of those finds are examined, as well as recent controversy concerning the antiquity of the mine. The landscape setting, bedrock geology and mineralisation of the mine are examined. Surface evidence of mining from different periods is recorded by archaeological and geophysical survey. This mapping also considered how the physical evidence of early mining was damaged by forestry and mineral exploration in modern times. The results of archaeological excavation undertaken in 2010–11 at Derrycarhoon are presented. This included the sampling of surface spoil and the excavation of an early mine working. The stratigraphic record of that excavation is supported by finds of early mine equipment. Samples of wood, charcoal, antler and peat were recovered from secure contexts for radiocarbon dating. The results have finally resolved controversy over many years around the early history of the mine. One of the 1846 finds is the ‘Derrycarhoon Tube’, a curved wooden object of later medieval date, which has been the subject of much speculation since its discovery. The object is reinterpreted as a musical instrument from that period with no connection to mining. The findings of a new palynological study provide an important insight into the vegetation record and farming history of the locality, and the limited environmental impact of the early mine. The study goes on to consider the technology and productivity of the mine at Derrycarhoon, from prospection to rock extraction and ore beneficiation. New data is presented on the chemistry and lead isotope signature of its copper mineralisation, in relation to a pilot programme of metalwork analysis for the region. The objective is to understand the circulation of copper from the mine and its wider significance for trade in later Bronze Age Ireland. The contemporary settlement landscape is examined, looking at late prehistoric sites and artifact finds within a 10km distance of the mine. Particular attention is paid to monuments of the Stone Circle Complex, as proxy indicators of a Bronze Age settlement landscape with a low archaeological visibility. The Derrycarhoon miners probably came from small farming communities in the general area. That cultural landscape setting is explored through the record of Middle and Late Bronze Age settlement in Co. Cork. The extraction and circulation of copper from Derrycarhoon may have been controlled by a hillfort chiefdom in that region, which emerged at a time of growing militarism and pressures on metal supply in Ireland. The project concludes by considering the importance of Derrycarhoon in the mining history of south-west Ireland and its broader significance for an understanding of Bronze Age trade. The conservation of mining heritage is also considered in relation to the history of interference with this site in the modern era.

xv

1 Introduction This monograph presents the results of archaeological investigation at a Bronze Age copper mine in south-west Ireland. The Cork and Kerry region was an important source of copper during the Chalcolithic and Bronze Age, with well-known mining centres at Ross Island and Mount Gabriel. There are other prehistoric mines in the region, including the focus of this study, namely Derrycarhoon in county Cork. This mine produced copper during the Middle to Late Bronze Age transition (c.1300–1000 BC), a period of significant metal use in Ireland and elsewhere in Europe.

Prehistoric copper mines are now recorded in many parts of Europe (Figure 1.1; reviewed by O’Brien 2015). The earliest known examples are in the Balkans, including Rudna Glava in eastern Serbia worked in the sixth and fifth millennia BC, and Aibunar in the Sredna Gora mountains of Bulgaria. In northern Italy, early copper mines are recorded in the Ligurian Alps, at Libiola dated to the later fourth millennium BC, and at Monte Loreto worked c.3500–2500 BC. The earliest copper mines in France are in the district of Cabrières-Peret of the Languedoc, where copper workings and production sites spanning the third millennium BC have been identified. In Spain, the earliest mines are in the Cantabrian mountain range, at El Aramo and El Milagro in Asturias, and La Profunda in León, which date from the mid-third millennium BC into the early centuries of the Bronze Age.

1.1 Prehistoric Copper Mining in Europe The vast quantity of copper and bronze objects recorded from late prehistoric Europe attests to the importance of metal for different culture groups across the continent. That dependency began slowly with an early use of copper and gold during the Copper Age (‘Chalcolithic’), which occurred in different regions between the sixth and third millennia BC. As demand grew across Europe, technical advances led to the widespread adoption of a new metal alloy by 2000 BC, or shortly afterwards. The Bronze Age that followed was marked by a growing dependency on tin-bronze for the production of tools, weapons and other types of metalwork. The mining of copper and tin in certain regions drove the wider supply of bronze along new trade networks that included other commodities. That allowed non-metalliferous regions, such as Denmark, and those where ore deposits could not be easily mined, such as Sweden, to develop sophisticated metalworking without being involved in primary production. That trade, driven by a phenomenal demand for bronze, had important social and economic implications for groups directly involved in copper mining during the second millennium BC.

Copper mining intensified in many parts of Bronze Age Europe during the second millennium BC. Major producers included the mines of the Troodos Mountains of central and western Cyprus, from where the word ‘copper’ derives. Other large mines are found in the eastern Alps, with Bronze Age copper production on an enormous scale in several parts of Austria. The most important sources were in the Salzach valley, including both the Mitterberg mountain area west of Bischofshofen (O’Brien 2015, fig. 7.6), the St Veit area to the south and the Glemmtal area to the west. Farther west, Bronze Age mining was undertaken in the Kelchalm and Schwaz-Brixlegg areas of north Tyrol, the Matrei area of east Tyrol, and in parts of eastern Austria, such as Eisenerz in Obersteiermark. The Austrian mines were worked at various times c.1800–700 BC, with near-industrial levels of production c.1500–1000 BC, supplying copper across Europe as far as Britain and Ireland. That mining extended into the southern Alps in northern Italy, with Chalcolithic and Late Bronze Age copper smelting recorded in the Trentino district of south Tyrol. In southern France, some copper mines in the Languedoc, and at St Véran in the Alps, were worked into the early centuries of the Bronze Age. Other early copper mines have been identified along the southwestern end of the Massif Central in southern France. These include mines at Bouco-Payrol in Aveyron, and possibly in the district of Seronais between St Girons and Foix in the south. Bronze Age mines have been identified in many parts of Spain, including the aforementioned examples in Cantabria, and a notable concentration in Huelva and surrounding provinces of the south-west region. Examples there include the mines at Chinflon and Cuchillares in Huelva (Figure 1.2), Potosí and Aznalcóllar in Sevilla, La Loba in Cordoba and Berrocal in Badajoz (ibid.).

Across Europe the first discoveries of ancient copper mines occurred when ‘old men’s workings’ with primitive tools were discovered during the industrial mining of recent centuries. That primitive technology, and the absence of historical records, suggested those mines were of considerable antiquity, dating to the Roman period or earlier. The earliest records are in mining literature of the eighteenth and nineteenth centuries, written mostly by engineers interested in the early history of their profession. Such reports led antiquarians to speculate on the significance of ancient mine discoveries as potential sources of metal in the Bronze Age. The first investigations were undertaken in Austria in the late nineteenth century. Over the next century early mine discoveries in other parts of Europe led to research projects where historical research combined with scientific fieldwork involving geoarchaeological survey and excavation.

1

Derrycarhoon

Figure 1.1 Prehistoric copper mines in Europe (O’Brien 2015; smaller mines in the same regions not shown).

Britain was both a major producer and consumer of copper in the Bronze Age. The earliest copper used c.2500–2100 BC was arsenical metal sourced through Beaker culture exchanges with Ireland and the European mainland. The mining of local copper deposits began c.2200–2000 BC, at a time when bronze metallurgy was developed using tin sources discovered in Cornwall and Devon. Research in recent decades confirms there was intense copper mining activity in Wales and north-west England in the Early to Middle Bronze Age, c.2100–1400 BC (Figure 1.3). Copper mines in the mountains of central Wales include Cwmystwyth where mining commenced around 2100 BC at an altitude of 420m, and continued for the next 400 years

or so with open trench extraction of oxidised mineralisation to a depth of c.12m (Timberlake 2003). Other examples have been investigated at Nantyreira, Nantyrickets, Llancynfelin, Nantyrarian, Tyn y Fron, Ogof Wyddon and Erglodd (Timberlake 2009). Copper mines of similar age are recorded at Ecton in the Peak District of Staffordshire (Timberlake 2009), and at Alderley Edge near Manchester (Figure 1.4), where surface pits extracted secondary copper minerals from soft Triassic sandstones using fire-setting and stone hammers (Timberlake and Prag 2005). Bronze Age mining began along the north Wales coastline around 2000 BC, with workings at Parys Mountain on 2

Introduction

Figure 1.2 Bronze Age trench copper mines at Chinflon, Huelva province, south-west Spain (photograph: William O’Brien).

The archaeological record

Anglesey, and on the Great Orme, a limestone headland near Llandudno. The latter is one of the largest copper mines in Bronze Age Europe, worked more or less continuously from c.1700–800 BC (Dutton and Fasham 1994; Lewis 1994, 1998), with peak production in the Middle Bronze Age, c.1600–1400 BC (Williams and Le Carlier de Veslud 2019). That mining took the form of open-casts and trenches on exposures of oxidised mineralisation in rotted dolomitised lime­ stone (Figure 1.5). These surface workings continued underground to form an elaborate complex of tunnels approximately six kilometres in total length and up to 65m in depth. Stone hammers and bone gouges were used to tunnel the softer limestone, with fire-setting used on harder rock.

The archaeology of Bronze Age copper mining is distinctive to the activity itself and its geological environment. Much depends on the time and energy commitment to mining at a given location. That involved varying amounts of rock extraction, creating surface openings that may lead into underground workings. These mines vary in size and form depending on the geological setting, the technology employed and the scale of operation. They include surface pitting and trenching to varying depths, as well as underground mining accessed by tunnels and vertical or inclined shafts. The bedrock openings are generally accompanied at the surface by dumps of broken rock (‘spoil’) discarded by the miners, the size of which can be an indication of the scale of rock extraction. Other activity areas are not well exposed today, such as mining camps where hut shelters, hearths and cooking areas, equipment and fuel stores were located, as well as places where copper ore was smelted to metal in furnaces. The preservation of that archaeological evidence can vary considerably, depending on the geological environment, soil conditions, mine drainage, and disturbance caused by later mining and other activities. Many early copper mines in temperate Europe flooded soon after they were abandoned, resulting in waterlogged preservation of wood and other organic materials. There can also be excellent preservation of organic materials, particularly bone artifacts, where mining was carried out in calcareous geology.

In conclusion, the size of Bronze Age copper mines varied considerably across Europe, from small-scale production for mostly local needs, to larger sustained operations with near-industrial output. The latter were part of extensive trade networks, prominent examples being the mines of Cyprus and the Austrian Alps. Still greater were the copper mines of Kargaly in the southern Urals of Russia. Mining commenced there in the later fourth and early third millennia BC, reaching a peak in the second millennium BC with many thousands of individual mine operations. Some estimates suggest that up to two million tonnes of copper ore were extracted at Kargaly during the Bronze Age (O’Brien 2015, 187). 3

Derrycarhoon

Prehistoric Copper Mines (confirmed/likely)

Figure 1.3 Distribution of prehistoric copper mines in Britain and Ireland. South-west Ireland: 1 Ross Island; 2 Mount Gabriel; 3 Ballyrisode; 4 Toormore; 5 Boulysallagh; 6 Calaros Oughter; 7 Carrigacat; 8 Derrycarhoon; 9 Tooreen; 10 Canshanavoe; 11 Crumpane; 12 Reentrusk; 13 Coad Mountain. Wales: 14 Parys Mountain; 15 Great Orme; 16 Copa Hill, Cwmystwyth; 17 Nantyreira; 18 Nantyrarian; 19 Llancynfelin; 20 Ogof Wyddon; 21 Panteidal; 22 Pen Cerrig y Mwyn; 23 Llanymynech Ogof; 24 Tyn y From. England: 25 Alderley Edge; 26 Ecton (after O’Brien 2015).

4

Introduction

Figure 1.4 Bronze Age and later trench mining along the Engine Vein, Alderley Edge, Manchester, England (photograph: William O’Brien).

Figure 1.5 Bronze Age trench workings at the Great Orme copper mine, north Wales (photograph: William O’Brien).

5

Derrycarhoon Copper supply in prehistoric Europe

The recovery of this evidence mostly focuses on mine workings of a ‘primitive’ character, accompanied by spoil deposits with distinctive mining artifacts. Dating can be controversial, particularly for sites with several phases of mining where diagnostic material culture is absent. Prehistoric copper mines cannot generally be dated on surface features alone. While the technology used may indicate a certain antiquity, that must be critically assessed for different regions. For example, fire-setting was widely used in Bronze Age mining, however this method had an earlier history and continued to be used into early modern times in some parts of Europe. This need not be a difficulty as fire-setting leaves wood fuel residues that allow such mines to be dated by the radiocarbon method. The discovery of distinctive artifacts, such as pottery, can also indicate the age and cultural affinities of a mining group. Such finds are not common in Bronze Age mines, where specialized mining implements typically occur, including wooden and bone tools that can also be radio­ carbon dated. Stone tools are the most common finds in early copper mines, including cobble hammers or ‘mauls’, anvils and grinding stones. While caution is advisable in dating such basic implements, radiocarbon dating confirms they were widely used in prehistoric copper mining in Europe.

Broadly, there were three types of copper mining in Chalcolithic and Bronze Age Europe, based on the type of copper mineralisation exploited and the prevailing smelting technology. The extraction of native (pure) copper is not well recorded due to the rarity of its use in prehistoric Europe. The focus here is on copper ore, namely metallic minerals that occur in a concentrated form in an orebody and can be mined with prevailing technology. The earliest mining involved the extraction of secondary minerals, such as malachite and azurite, from surface zones of oxidation. These minerals are rich in copper and relatively easy to smelt using a primitive hearth or crucible technology. They were first mined in the Chalcolithic, and where locally available continued to be exploited in the Bronze Age, as recorded at Mount Gabriel-type mines in south-west Ireland, the Great Orme and other mines in Wales, and the mine at the centre of this study. The second type of mining involved the use of fahlore (‘grey copper ore’), namely complex sulfosalts of the tennantite–tetrahedrite series. These were rich in copper, with high levels of arsenic and/or antimony that added significantly to the quality of the smelted metal. Like the oxidised ores, fahlore can be smelted using a low temperature, non-slagging technology. Fahlore mining probably commenced in central Europe in the fourth millennium BC, and is particularly associated with the spread of Beaker culture metallurgy in western Europe in the third millennium BC. Examples include El Aramo in northern Spain, Cabrieres in southern France and Ross Island in Ireland. The use of fahlore declined significantly with the adoption of tin bronze around 2000 BC, but developed further in Austria during the Late Bronze Age, at mines such as Brixlegg and Mauk in North Tyrol.

The distribution of Bronze Age copper mines today reflects the survival and investigation of field evidence, and also the geological occurrence and accessibility of copper deposits. The latter do not occur evenly across Europe, which is partly why it took three millennia or so for copper metallurgy to spread across the continent. Not all copper deposits could be mined in the prehistoric period, as many occur at great depth in orebodies with low metal content and complex mineralogy and chemistry. Conversely, many locations where copper was extracted in the Bronze Age were not economically viable in historic times, which can contribute to the survival of early mines. Cultural preferences must also be considered, not least the efforts of some source regions to control metal supply by restricting the dissemination of mining and metallurgical knowledge. Other factors include perceived ‘ownership’ of the mineral resource, the motivation to invest time and energy in mining, and the value attached to the resulting metal. Not all regions with copper deposits responded in the same way to the opportunities presented by the new technology. Some were less receptive due perhaps to their cultural outlook and economic priorities, or an inability to mobilise the considerable resources required to engage in mining and metal production. Those regions with comparative advantages in other resources possibly chose to obtain metal through trade, as was necessary for regions with no natural sources of copper. Some groups exploited metal resources at a low level, embedded within economies where agriculture was a greater priority. For others, copper mining became a key economic activity that shaped the development of their societies over many centuries. Those mining traditions were determined by cultural choice and socio-economic background, as well as being contingent on historical and environmental circumstances.

A third type of prehistoric mining in Europe centred on the extraction of sulphide ores, particularly copper-iron sulphides such as bornite and chalcopyrite. Their first exploitation is not well dated, probably beginning in the Alpine zone during the Early Bronze Age. While sulphide ores can be reduced with primitive processes, the efficient recovery of metal requires an advanced furnace technology, which may have been first developed in Austria in the Early to Middle Bronze Age. On current knowledge, that technology was not present in Britain or Ireland during the prehistoric period. While Bronze Age mines produced smelted copper, recycling was also an important source of metal in that period. For many metalworking traditions the supply of bronze included primary metal coming directly or indirectly from a mine source, as well as secondary metal recycled from scrap over time. With recycling, the circulation of bronze could include mixtures of both types from the same or different mines, with obvious implications for understanding the final metal composition and its geological origin. 6

Introduction 1.2 Metal in Bronze Age Ireland

187–213). Bishopsland metalworking in Ireland produced specialised toolkits, with advances in bronze casting reflected in the use of clay moulds to make new object types such as the first bronze swords (Ballintober type). Novel types of gold ornament were also made, including a range of torcs, ear-rings, tress rings and bracelets. The appetite for fashion and innovation is clearly reflected in the great variety of bronze spearheads produced in the Middle Bronze Age.

Copper metallurgy was introduced to Ireland in the midthird millennium BC as part of the Beaker culture network of contacts across north-west Europe. The new technology was rapidly adopted, with copper objects in circulation across the island during a short-lived Chalcolithic (‘Copper Age’), c.2400–2100 BC. This was driven by the discovery of a major source of arsenicated copper at Ross Island, Killarney, Co. Kerry. The earliest use of tin-bronze occurred around 2100 BC, with widespread adoption of this metal across Ireland represented by large-scale production of Killaha series axeheads over the next two centuries (Harbison 1969). As the Early Bronze Age progressed the scale of production gradually increased, linked to new mine sources, recycling and a spreading knowledge of metalworking across Ireland. This is reflected in the large number of developed bronze axeheads, including many decorated examples, from the period c.2000–1600 BC (Harbison 1969a). That, together with early expertise in sheet gold (discs and lunulae) indicates a standard of metalworking on a par with many other regions of Europe.

With the beginning of the Late Bronze Age there was further intensification of bronze and gold production across Ireland, culminating in the metalworking of the Roscommon (c.1150–1000 BC) and Dowris (c.1000–700 BC) phases. Metalworking reached new heights in this period in terms of the scale of production, the great variety of metal products, and the technical accomplishment of the craft workers (Waddell 2010, 233–277). This was a time of conspicuous wealth in Ireland, most visibly expressed through largescale metal production hoarding, and the use of prestige metalwork. A wide variety of bronze implements were produced, with evidence of specialised tools used in different craft activities. This is illustrated by the eponymous hoard from Co. Offaly that originally contained over 200 bronze objects, including many new types for Ireland. Among the items represented are socketed axeheads, hammers, gouges and spearheads, as well as punches, razors, knives, swords, chapes, spear-butts, horns, hollow-cast pendants (crotals), cauldrons and buckets (Eogan 1983). The Dowris Phase is also known for the excellence of goldworking. A great variety of personal ornaments and prestige objects were made from solid bar and sheet gold, as well as from gold wire and foil, including gorgets, dress fasteners, lock-rings, penannular rings and types of bracelet.

The successful introduction of copper alloying to Ireland is all the more remarkable when the paucity of tin sources is considered. The first bronzes were made with copper from Ross Island mine mixed with metallic tin, but there are no sources of the latter in the south-west region. Of greater significance was the supply of tin from south-west England, with archaeological evidence the alluvial tin deposits of Cornwall and Devon were exploited in the Early Bronze Age. The discovery of Irish lunulae in Cornwall (Taylor 1980), as well as Irish-type bronze axeheads in stream tin workings in that region (Shell 1979; Penhallurick 1986), indicates trade in metals across the Irish Sea from around 2000 BC. This is supported by lead isotope analysis that points to south-west England as a potential source of early gold in Ireland (Standish et al. 2015). The supply of tin was likely to have been a constraint on primary bronze production in Ireland throughout the Bronze Age. It is difficult to know how connections with Cornwall were affected by the closure of Ross Island mine c.1900– 1800 BC, when attention may have turned to alternative sources in Ireland, such as the small alluvial deposits in Wicklow and the Mourne Mountains (Warner et al. 2010).

There was also a marked increase in the production of bronze weaponry during the Late Bronze Age. The first swords were introduced from southern England around the twelfth century BC. The earliest examples were the short Ballintober leaf-shaped type with organic handles riveted to projecting tangs (Eogan 1965; Waddell 2010). These were replaced by flange-hilted swords, imported or copied from Erbenheim and Hemigkofen swords on the Continent, coming in again through southern England. The use of these weapons in Ireland expanded significantly after 1000 BC, when a native form of the flange-hilted, leaf-shaped sword (Eogan’s class 4), known in Britain as the Ewart Park type, was produced in large numbers during the Dowris phase to around the eighth century BC. There are innovations in spearhead design during the same period. The side-looped, basal-looped and protected-looped varieties of the Middle Bronze Age were gradually replaced after 1100 BC by lunate and riveted forms during the Roscommon and Dowris phases. These were the weapons of a militarised society of competitive regional hillfort chiefdoms, where warrior-aristocrats commanded the services of specialist metalworkers (O’Brien and O’Driscoll 2017). The production of prestige weaponry and ornaments reveals a concern with ostentatious display in that period, with cult practices involving votive deposition of metalwork.

Wherever the tin came from, there was certainly a growing dependency on bronze to make weapons and work implements in Ireland from c.1600 BC (Ramsey 1995). Approximately 2500 bronze artifacts are recorded in Ireland for the period c.1600–1300 BC. These include the output of flanged axeheads and palstaves, dirks, rapiers and looped spearheads during the Killymaddy phase of the Middle Bronze Age (c.1550–1350 BC). Metal production intensified during the Bishopsland phase (c.1350– 1100  BC), when influences from Continental Europe channelled through the ‘ornament horizon’/Taunton metalworking of southern Britain led to the introduction of new metalworking techniques and a novel range of bronze and gold artifacts (Eogan 1964; 1994; Waddell 2010, 7

Derrycarhoon The proliferation of new tool, weapon and ornament types shows diverse influences from southern and western Britain, from northern and central Europe, Atlantic Europe and the west Mediterranean. In addition to external stylistic and technological influences, Irish metalwork was also exchanged widely in Britain and on the Continent in this period (Eogan 1995). The high level of craft specialisation in bronze and gold, and in exotic materials such as amber, is evident in the technical quality of the finished objects. Advances in metal fabrication include the widespread use of clay moulds in casting, the working of sheet bronze to make buckets, cauldrons and shields, the use of joining techniques such as riveting and soldering, and new metal compositions, such as leaded bronze and gold alloying.

graves in Bronze Age Ireland, which added to the amount of weaponry available where these were passed on through the generations. There were also significant levels of loss, through the conduct of war, the recycling of broken items, and the removal of weapons through votive deposition (Becker 2013). Unfortunately, the majority of these bronze objects do not have secure archaeological contexts or dating, with many found in bogs, lakes and rivers. A further problem is the limited record of metallurgical activity from settlement contexts. Bronze workshops have been identified in settlements of Late Bronze Age date, but there is little site evidence for earlier periods (see Ó Faoláin 2004 for a summary of the evidence). Returning to the question of where bronze came from, there is much evidence for trade in metal during the Middle to Late Bronze Age, including the acquisition of raw material and the exchange of finished objects. A lot of metal was sourced through recycling and foreign trade, with the discovery of scrap hoards suggesting this was a well-organised activity. Some primary (smelted) metal may have been imported from sources in Britain, where the only known copper mine in operation after 1400 BC is the Great Orme in north Wales. The circulation of copper from that mine is likely to have declined by 1000 BC (Williams 2019; Williams and Le Carlier de Veslud 2019). Trade links with the Continent led to new sources of copper (Northover 1982), with the most important supply possibly from the east Alpine mines in Austria. Irish metalwork was exchanged widely in Britain and the Continent during the Late Bronze Age, creating a network of contacts that supported the supply of metal.

During the seventh century  BC the first contacts were established with iron-using cultures in Britain and mainland Europe. Thus began a slow process of technological change, represented initially by Hallstatt C material in Ireland and culminating in the widespread adoption of iron metallurgy during a period of prolonged contact with La Tène groups from the third century BC (Raftery 1994). The processes by which iron was introduced to Ireland are much debated, as is the cultural context of this innovation. There is artifact evidence of Late Bronze Age metalworkers experimenting with iron in the centuries between 600– 300 BC (Scott 1990). This experimentation occurred against a background of contact with southern and western Britain, and France. Copper alloy metalworking continues in Ireland during the Iron Age (600/300 BC–400 AD), used mostly for the production of personal ornaments and prestige metalwork (see Raftery 1984). The supply of bronze

The archaeological evidence for importation of metal to Ireland is weak, with no ingot finds or shipwrecks comparable to Langdon Bay, Kent, or Salcombe, Devon (Needham et al. 2013). The importation of bronze is indicated by new tool, weapon and ornament types with stylistic and technical connections to southern and western Britain, and farther afield into northern, central and Atlantic Europe. This also involved exports, as Irish metalwork was exchanged widely in Britain and on the Continent in this period (Eogan 1995). The interpretation of goods in transit (’merchant hoards’) is problematic, though it is likely some hoards from the later Bronze Age were connected to supply networks. Metal analyses indicate a growing reliance on imported Continental metal during the Middle Bronze Age, with declining supply from British and Irish sources (Northover 1982, fig.7). It is likely that imported bronze from the Continent grew in importance during the Penard/Bishopsland phase, to eventually dominate copper supply during the Wilburton/Roscommon and Ewart Park/ Dowris phases of the insular Late Bronze Age (ibid., figs. 11 and 13).

As already mentioned, the amount of metal in circulation in Ireland increased steadily during the second millennium BC. This is indicated by the large number of bronze and gold finds, and by an increase in metal hoarding, with around 160 deposits known from the Late Bronze Age, most from the Dowris phase (Eogan 1983; 1994). For individual object types, an estimated 700 flanged axeheads and 400 palstaves are recorded from Early to Middle Bronze Age transition (Ramsey 1995), with 2000 or so socketed axeheads from the Late Bronze Age (Eogan 2000). The amount of bronze in circulation is also indicated by the massive output of specialized weaponry in the Middle and Late Bronze Age. An estimated 733 bronze swords are recorded in Ireland, a density of 8.7 finds per 1000 km2 one of the highest in Europe (Eogan 1965, revised by Colquhoun 2015). An estimated 1800 Middle and late Bronze Age spearheads are recorded in Ireland, including 45 end-looped, 827 sidelooped, 182 basal-looped, 56 protected-looped, 29 lunate, 7 basal-looped/riveted and 639 riveted leaf-shaped forms (Lineen 2017).

The identification of specific mine sources during this period is complicated by the uniformity of bronze composition, which itself is partly a consequence of widespread recycling (Northover 1988). This has important implications for source provenancing of metalwork using

Allowing for survival and recovery variables, these finds represent a fraction of the total number of weapons produced. Swords and spears were rarely committed to 8

Introduction chemical or isotope analyses. It is likely that recycling made a significant contribution to metal circulation during the later Bronze Age in Ireland. That activity was well organised and included the use of secondary bronze from imported or older Irish sources. A number of scrap deposits (‘founders hoard’) containing broken/worn objects and/or ingots point to organised production and supply networks.

chronology have mostly been resolved by archaeological excavation and scientific dating undertaken by the author over the past four decades at nine ‘Danish Mine’ sites in Cork and Kerry (O’Brien 1987b; 1994; 2003). Ross Island As mentioned previously, copper metallurgy was introduced to Ireland in the twenty fifth century  BC, coinciding with the arrival of Beaker culture (Case 1966; Sheridan 1983). Those Beaker networks were critical in the transfer of mining expertise in Atlantic Europe, through coastal connections extending from northern Spain and western France to Ireland. The new technology was rapidly introduced, with a prolific output of axeheads, daggers and halberds over the following 400 years. These copper objects have distinctive arsenic content, connected to the mining of tennantite fahlore from one major source, Ross Island mine in Killarney, Co. Kerry. The extraction of fahlore copper began there around 2400 BC and continued through the Chalcolithic into the early centuries of the Bronze Age, ending around 1900 BC (O’Brien 1995).

While imported stock and recycling made a significant contribution to metal supply in Ireland during the Middle and late Bronze Age, the possibility of primary copper production must also be considered. This requires a review of the evidence of prehistoric mining to identify potential sources of smelted copper for that period. 1.3 Prehistoric Copper Mining in South-west Ireland Ireland has long been regarded as a significant producer of metal in the Bronze Age. This reflects the large quantities of Bronze Age metalwork in a part of Europe with abundant sources of copper. The Cork and Kerry region was an important centre of early copper production, with confirmed or likely prehistoric mines known at 15 locations (Figures 1.3 and 1.6; O’Brien 2015, 125). The earliest are those at Ross Island in Killarney, where Beaker culture groups produced arsenicated copper during the Chalcolithic and Early Bronze Age (c.2400–1900 BC). Farther south, there are seven copper mines dated to the Early-to-Middle Bronze Age (c.1800–1400 BC) in the peninsulas of west Cork. These, and other undated examples in West Cork and South Kerry, are known as Mount Gabriel-type mines, called after the largest concentration of such workings located on the eastern slopes of this mountain in the Mizen Peninsula of Co. Cork.

The early workings at Ross Island consisted of large cavelike openings on mineralised rock exposures (Figure 1.7; see O’Brien 2004 for full publication of the Ross Island research). The full extent of underground mining is uncertain as the early workings are no longer accessible due to flooding and roof collapse, problems the prehistoric miners may have faced. The copper mineral was extracted to depths of 10–12m, using simple, but effective, techniques. These included fire-setting, which left distinctive profiles on the mine walls as well as charcoal residues in adjacent spoil heaps. The heat-shattered rock face was pounded with stone cobble hammers, both hafted and hand-held. Thousands of broken examples are recorded close to the mine workings. Other tools included the shoulder-blade bones of cattle used as scoops, while a range of wooden equipment is likely to have been used.

The study of these prehistoric mines began during the late eighteenth/early nineteenth centuries, when mineral prospecting led to the discovery of primitive workings at several locations in south-west Ireland. Described as ‘Dane’s Workings’ or ‘Danish Mines’ in mining industry and antiquarian literature, these were associated with the use of fire-setting and stone hammers. Several examples were listed in 1929 by a geologist, Tom Duffy, who discovered the remarkable early mining landscape on Mount Gabriel (Duffy 1932). This was later mapped by another geologist, John Jackson, who brought the mountain to wider attention when he obtained a Bronze Age date from one of those workings (Jackson 1968), the first radiocarbon result obtained for a prehistoric copper mine in Europe. Jackson’s subsequent reviews highlighted the importance of south-west Ireland as a centre of prehistoric mining, arguing the ‘Danish Mines’ in that region were Bronze Age on the basis of the Mount Gabriel evidence (Jackson 1979; 1980). This was vigorously disputed over many years by an archaeologist, Stephen Briggs, who argued that Mount Gabriel and other ‘Danish Mines’ in south-west Ireland, including the example at the centre of this study, are early modern in date (Briggs 1983a, 1983b, 1984; for reply, see Jackson 1984). While Briggs remains to be convinced (e.g. Briggs 2003; 2004), questions around

A miner’s work camp was discovered adjacent to the early workings at Ross Island. This location was used for temporary habitation, with evidence of shelters, food consumption and the use of pottery. The foundation traces of several stake-built huts where the miners sheltered were identified. Food waste in the form of cattle and pig bones, and evidence of flint working, attest to other activities in the life of this mining camp. The animal bones indicate an important agricultural base supporting the mine operation, probably located within the environs of Killarney where copper and early bronze axes made with Ross Island metal have been found. The Beaker mine camp at Ross Island was mainly used for activities connected to the production of metal. That began with the crushing and hand-sorting of mineralised rock (ore) using stone hammers and anvils to extract high-grade tennantite, which was then ground down using basin-shaped querns. The ore concentrate was then smelted in shallow pit furnaces fuelled by charcoal. The 9

Derrycarhoon

Figure 1.6 Prehistoric copper mines in south-west Ireland, showing location of Ross Island, Mount Gabriel and Derrycarhoon mines, together with distribution of Mount Gabriel-type workings in the Mizen, Beara and Iveragh peninsulas (drawing: Nick Hogan).

process was primitive, but effective, with a significant amount of copper produced over time. This was due to the large amounts of tennantite ore in the mine, which could be easily extracted and beneficiated using those handcobbing and smelting techniques. The tennantite has a high copper (40–45%) and low iron (Sb>Ag) in the finished metalwork. Axeheads, daggers and other objects made with this arsenicated copper were widely exchanged across Ireland in the period 2400–1900 BC, with some products also reaching Britain (Northover 1982). The currency of this distinctive copper corresponds closely with a radiocarbon chronology for Ross Island, confirming that mine as the main source in Ireland. The same metal was recycled for several centuries following the closure of Ross Island mine, c.1900–1800 BC (Bray and Pollard 2012).

Excavation confirms that copper droplets produced in these pit furnaces were re-melted and converted into small slab ingots, one of which was found in the mine area. These ingots were transported from the mine to settlements around Killarney, where the metal was cast into axeheads and blades in workshop settings. The arsenic content of this 10

Introduction

Figure 1.7 Chalcolithic/Beaker culture copper mine at Ross Island, Killarney, Co. Kerry (photograph: William O’Brien).

The Ross Island mining was probably organised on a seasonal basis by miner/farmers, with the involvement of some full-time specialists. The food waste at the mine camp included cattle bone, which indicates contemporary farm settlement in Killarney, also confirmed in local pollen records. Excavation also uncovered approximately 450 sherds from at least 25 vessels of Beaker pottery. This ceramic can be directly associated with copper production in the mine during the period 2400–2000 BC. These wellmade vessels, decorated with horizontal cord and comb impressions, were used as drinking cups by the miners. They were also employed in a washing process to extract prills of copper metal from the furnace pits. The discovery of this pottery is an important connection with the culture group that introduced copper metallurgy to Ireland at the end of the Neolithic.

Ireland in the mid-third millennium BC. The transmission of this knowledge to Ireland must have occurred along exchange networks established by Beaker culture groups in Atlantic Europe. The technological background to Ross Island may be sought in contemporary mining activity in southern France or northern Spain and in the use of arsenical copper in Atlantic Europe (Ambert 2001). The mining of tetrahedrite fahlore at Cabrières provides an obvious source of knowledge, as do some of the mines of northern Spain. The stone mining hammers from Ross Island have parallels in the Cantabrian mines of El Aramo and El Milagro (e.g. Blas Cortina and Suárez Fernández 2010, fig. 22). Whether the Ross Island miners came from northern Spain or western France is unclear, but it is likely the new technology was introduced to Ireland from Atlantic Europe during the later 25th century BC.

On the basis of chronology and ore types, it is certain that Ross Island supplied arsenicated metal to make early copper axes in Ireland. The fact that the earliest axe forms (Castletownroche type) are made of the same type of copper places this mine close to the beginnings of Irish metallurgy. The background to this technology lies not in Britain but in mainland Europe, where the production of arsenicated copper from fahlore sources was part of a wider pattern of metal supply during the fourth and third millennia BC (Strahm 1994). The fahlore copper from Ross Island is likely to have been part of a Beaker metallurgical tradition that extended from Iberia and Atlantic France to

Mount Gabriel Ross Island continued to supply copper into the early centuries of the technological Bronze Age. The decline of this mine c.1900–1800 BC was followed by a new type of copper mining over the next four centuries or so across the peninsulas of West Cork and south Kerry. That involved the extraction of low-grade oxidised ore, principally malachite, from small drift mines located on exposures of sedimentary copper-beds. These mines are concentrated in the hilly interior of the peninsulas, at elevations of 60– 340m OD, usually within 5km of the coast. The largest 11

Derrycarhoon concentration occurs on the eastern slopes of Mount Gabriel (408m OD) in the Mizen Peninsula, Co. Cork, where 32 individual workings are recorded (Figure 1.8). Copper mining on this mountain c.1700–1400 BC was associated with fire-setting and the use of stone hammers (O’Brien 1994 for full publication of the Mount Gabriel research).

the largest archaeologically excavated examples worked to 11m (a few others may be deeper). The size of individual mines depended on the concentration of secondary copper minerals present and the difficulty of keeping inclined workings dry when fire-setting. Evidence of the latter technology is visible on the mine walls, which generally have a smooth concave profile. This, together with the discovery of large quantities of roundwood fuel and charcoal within and close to the workings, confirms the use of fire-setting in rock extraction. In a typical daily cycle, fires were burnt against the mineralised rock face for many hours causing thermal fracture, at which point it was pounded with stone hammers. The miner’s task was helped by micro-structures within the rock that allowed fragments to be prised out using fingers and wooden sticks. Experiments have shown that up to five centimetres of rock could be removed in this way before the next firing was necessary. On that basis, a single 10m deep mine on Mount Gabriel might have involved up to 200 fires over a period of several months. This would have consumed huge amounts of wood fuel. It is estimated that the extraction of approximately 4000 tonnes of rock from 32 recorded mines on the mountain required anything from 4000–14000 tonnes of roundwood fuel. The type of fuel used is confirmed by the discovery of a large quantity of branches in one of the waterlogged mines, many with axe tooling marks (O’Brien 1994, plates 37–9). Tree-ring analysis indicates organised collection to meet those enormous fuel requirements, while pollen

Mount Gabriel is one of the best preserved Bronze Age mining landscapes in Europe, located in a blanket bog environment with minimal disturbance from later mining or other activities. The Bronze Age workings are dispersed across the eastern and southern slopes of the mountain at elevations of 150–340m OD. They occur within a Late Devonian sedimentary geology consisting of thick sequences of purple mudrock and fine-grained sandstone, interbedded with thin grey-green units of coarser sandstone. The copper mineralisation occurs within the grey-green strata of this red-bed sequence. They are mostly small inclined openings driven into vertical rock faces where the green sandstone beds are exposed. The latter contain disseminated copper minerals, visible when the outcrop exposure is stained green by the copper carbonate mineral, malachite. The distribution of workings indicates a careful search for these copper-beds, as well as an empirical understanding of the geological factors controlling their exposure. The miners only extracted rock that might contain copper minerals, moving to other exposures once a particular working was exhausted. Some workings were abandoned after less than one metre, with

Figure 1.8 Bronze Age mining landscape on Mount Gabriel, Mizen Peninsula, Co. Cork. Inset: Mine 3, radiocarbon dated 1700–1660 BC (photograph: William O’Brien).

12

Introduction studies in the locality point to some form of woodland management (Mighall et al. 2000). Oak and hazel were mainly used, however species such as alder, ash, birch, pine and willow were also collected. Examples of wooden equipment include shovels carved from alder, twisted withies of hazel and willow for stone hammer handles, oak planks used as steps inside the mines, as well as splints of resinous pine used in torches.

exposures was exhausted. Similar mine workings of the same period, occurring either individually or in small clusters, are known from five other locations in the Mizen peninsula to the west of Mount Gabriel. One of these is on Ballyrisode Hill, Co. Cork, where in 1854 a hoard of twelve polished stone axes was discovered in a small fireset working radiocarbon dated 1853–1619 BC. A Mount Gabriel-type stone hammer was discovered at infilled mine workings at nearby Toormore, an area where an important votive deposit of Early Bronze Age copper was discovered (O’Brien, Northover and Cameron 1989/90). Similar mines are also recorded at Boulysallagh in the Goleen area at the western end of the Mizen Peninsula, where 4–5 infilled workings and surface spoil containing stone hammers are visible today. This mine is radiocarbon dated 1883–1691 BC. Two other Mount Gabriel-type workings in the same area, Callaros Oughter and Carrigacat, are dated 1879–1531 BC and 2009–1693 BC respectively (O’Brien 2003).

Once rock was extracted, the next task was to separate the copper minerals to prepare an ore concentrate that could be smelted to metal. Ore beneficiation began with the coarse crushing of rock extract using stone hammers and anvil stones, with continuous hand-sorting of visibly mineralised fragments. This produced low mounds of crushed rock spoil near the mine entrances, containing large amounts of charcoal and broken stone hammers (‘mauls’). The latter are rounded cobbles gathered from local beach deposits for use, either hand-held or hafted, at the mine face or in surface concentration of copper ore. They broke easily being of similar geology to the mine rock, which explains why many thousands of those implements were used over three centuries or so of mining on the mountain.

Farther north, four Mount Gabriel-type copper mines have been identified in the Beara Peninsula of Co. Cork (Figure 1.6; O’Brien 2015, 134). They include an undated example at Tooreen in the mountains above Glengarriff, where there is a large cavernous opening with surface spoil deposits (Figure 1.9). Another example has been discovered at Canshanavoe in the mountains north of Adrigole village, Co. Cork. There are at least two areas of copper-bed extraction at this location, one of which contains three fire-set workings and a large spoil deposit with charcoal dated 1600–1430 BC. Other examples in this peninsula include Crumpane on the mountain ridge overlooking Eyeries, worked in the period 1700–1500 BC (O’Brien 2009), and an undated mine at Reentrusk in the Allihies area. Finally, there are two Mount Gabrieltype mines recorded on the southern side of the Iveragh Peninsula, Co. Kerry. The mines at Staigue near Sneem, and Lambs Head, Caherdaniel, are not dated, nor is a fireset working (‘St Crohane’s Cave’) on a quartz-sulphide vein on nearby Coad Mountain (O’Brien 1987a (vol. 2), 272–292).

The Mount Gabriel mines were short-lived operations, probably undertaken on a seasonal basis due to the demands of the agricultural year. Mine flooding would have hindered fire-setting and may have caused the early abandonment of many workings. For that reason, it is likely individual mines were worked over a short period, with the extraction cycle at different outcrops overlapping to provide for continuous output during the mining season. This was probably organised around a diurnal fire-setting cycle, which allowed miners time to rest, process copper ore and engage in ancillary activities. Some individuals were engaged in underground rock extraction and surface ore concentration, while others supported the mining effort by collecting fuel from local woodland or hauling stone cobbles from beach sources up to 4km away. Food supply was probably organised from local farms where the miners lived. Those settlements have not been discovered, but their general location can be inferred from the occurrence of Bronze Age ritual monuments in the vicinity of the mountain.

Compared to Ross Island with its rich copper deposit, the Mount Gabriel-type mines represent a different approach to metal sourcing in the Bronze Age. The mining strategy was designed to maximise returns from low-grade mineralisation by extensive exploitation of small copperbed exposures in the landscape. The proliferation of surface workings represents a limited investment of time and resources by small groups working on a seasonal or sporadic basis. That is indicative of the social context in which this small-scale mining was undertaken (O’Brien 2000).

On present evidence, the mining on Mount Gabriel concluded with the preparation of crushed ore concentrates ready for the smelting furnace. No evidence of smelting is recorded on the mountain, partly because those processes were non-slagging, with any furnace remains likely to be concealed by the later growth of blanket peat. The amount of copper ore extracted on Mount Gabriel was small, certainly when compared to the Ross Island mine. Current estimates suggest that these mines may have yielded as little as 15–20 kg of metal a year, enough to make 40–50 bronze axeheads for local needs and exchange into the wider region (O’Brien 1994, table 12).

What came next? By 1400 BC primary copper production involving organised mining was declining in both Britain and Ireland. This is the picture presented by radiocarbon data from twenty or so early copper mines sampled in south-west

Copper mining ended on Mount Gabriel around 1400 BC, probably when the supply of malachite from copper-bed 13

Derrycarhoon

Figure 1.9 Bronze Age copper mine at Tooreen, Beara Peninsula, Co. Cork (photograph: William O’Brien).

Ireland, mid and north Wales and the English midlands (O’Brien 1994; 2003; 2004; Timberlake and Marshall 2019). The decline of copper mining in the later Bronze Age was a wider phenomenon across Atlantic Europe, coinciding with a growing demand for metal in societies with expanding trade connections.

particularly if there were significant changes in mining technology. The replacement of fire-setting would remove distinctive wallrock patterns, while reducing the sample material available for radiocarbon dating. The use of large numbers of stone hammers in earlier copper mines is also relevant, as their replacement by specialised bronze tools would remove an important surface indicator of this activity. With no evidence the latter were used for mining in Atlantic Europe during the later Bronze Age, there may have been few options but to continue with the older technology.

Several theories can be advanced to explain the absence of insular copper mines during the later second millennium BC. One possibility is that mines did exist, but have not survived or cannot be easily recognised today. The former might be connected to a change in the type of ores extracted, possibly involving deeper mining of mineral deposits that were intensively worked in later periods. Against this, is the very notable absence in Ireland and Britain of slags connected to the smelting of copperiron sulphide ores. This means that any indigenous mining after 1400 BC continued to rely on surface occurrences of oxidised mineralisation. The depletion of those accessible and easily smelted copper ores, combined with an inability to process copper-iron sulphides, may have been significant factors in the decline of mining during the Middle Bronze Age.

The rise and fall of different mining regions can be understood in terms of boom/bust cycles, however the abandonment of established mines in the Bronze Age was not driven by economic forces alone. The closure of individual mines and a decline in mining at a regional level must also be understood in relation to the sociopolitical context of these ventures. This is a complex issue with many variables, such as technological constraints and alternatives to metal supply, such as recycling and longdistance trade. Some of these questions can be explored in relation to a recent discovery in south-west Ireland, which provides an insight into the final stages of copper mining there during the Bronze Age. The mine at Derrycarhoon provides the first evidence of continued supply of primary copper from an Irish mine during the Middle/Late Bronze Age transition.

The destruction of mining evidence is certainly relevant, but is unlikely to be the entire explanation as Late Bronze Age mines are well known in other parts of Europe (O’Brien 2015). Archaeological visibility may be relevant, 14

Introduction 1.4 Derrycarhoon Mine Project

Objectives:

This small copper mine lies in hilly terrain, 5km north of the village of Ballydehob on the north-east side of the Mizen Peninsula, Co. Cork (Figure 1.6). The discovery there in 1846 of ‘Danish Mines’, consisting of narrow trench workings ‘…smothered up by a growth of peat, over fourteen feet deep’ (Kinahen 1886, 202), received much attention in antiquarian and mining circles in the late nineteenth century. Jackson (1980) interpreted this as representing six Mount Gabriel-type drift mines and a large open-cast, all of Bronze Age date. That interpretation was challenged by Briggs (1984) who rejected the possibility of Bronze Age mining at the site, proposing instead the 1846 discoveries are post-medieval in date. This was dismissed by Jackson (1984) on the basis of dates for the Mount Gabriel mines, which he argued were of similar type and technology to those at Derrycarhoon.

1a. Review published sources and mineral exploration data on the bedrock geology and mineralisation of the mine. 1b. Sampling of copper minerals for chemical and lead isotope analysis. 1c. Visualisation of surface features using ground and aerial survey methods, with geophysical imaging of the trench mines. Aim 2 (Mining history) Reconstruct the history and chronology of copper mining at Derrycarhoon. Objectives: 2a. Review published and archival sources for the history of mining and mineral exploration at Derrycarhoon.

Around that time, the author reviewed those arguments and supporting historical information, but was unable to resolve the issue of Bronze Age copper mining (O’Brien 1989). No further research was undertaken at the site until 2007, with investigations of the Mount Gabriel and Ross Island mines pursued in the intervening years (O’Brien 1994; 2004). Work resumed at Derrycarhoon in 2007 with the first detailed survey of the archaeological area (O’Brien 2007a), undertaken to advise the National Monuments Service in advance of the felling of this forestry in 2014. In 2010 the author carried out sample excavation of surface spoil at Derrycarhoon, with one of the early trench mines excavated the following year (O’Brien 2010; 2011). Radiocarbon dates from both contexts confirmed copper mining at this location in the Middle to Late Bronze Age transition, c.1300–1000 BC. The results of this survey and excavation at Derrycarhoon were then published (O’Brien and Hogan 2012; O’Brien 2013; O’Brien 2019).

2b. Conduct excavation of an early mine working and surface spoil to obtain cultural material and stratified samples for radiocarbon dating. 2c. Carry out a detailed study of the ‘Derrycarhoon Tube’ using archival and other sources. Aim 3 (Technology) Examine the approach to mining and prospecting, and the technology in different periods. Objectives: 3a. Archaeological and geophysical survey of surface workings and other mining features.

In 2018 a new stage of research began, with further survey and sampling at the site. The cultural landscape of the Bronze Age mine was explored at a local and regional level. The environmental setting and impact of this mining was examined through pollen analysis, details of which were recently published (Kearney and O’Brien 2021). Isotopic and chemical analysis was undertaken to examine whether the Derycarhoon ore deposit correlates with Middle and Late Bronze Age metalwork in the region and farther afield. The results of these and other studies are presented in this monograph.

3b. Sample excavation to examine the size and form of the early trench mines. 3c. The recovery and analysis of mining tools used in the working of this mine. Aim 4 (Environment) Understand the palaeoecology and environmental impact of mining at Derrycarhoon

Research design

Objectives:

This project has four broad aims, designed to examine the geological setting, mining history, technology, and wider context of Derrycarhoon mine. These aims and accompanying research objectives may be listed as follows:

4a. Review historical records of peat growth at the mine site, with coring to identify surviving deposits. 4b. Conduct a new palynological study to reconstruct the vegetational history of Derrycarhoon

Aim 1 (Geology)

4c. Use pollen data to assess the environmental impact of Bronze Age mining at Derrycarhoon and other anthropogenic impacts on local vegetation in that period.

Understand the physical setting of the mine, its bedrock geology, mineralisation and landform setting. 15

Derrycarhoon antiquity. Chapter 3 examines the geology of Derrycarhoon and how the mining landscape was created. The surface evidence of mining is recorded by archaeological and geophysical survey, which also examines the extent to which this archaeology was damaged by recent conifer plantation and other activities.

Aim 5 (Wider Context) Explore the settlement background and cultural affinities of Derrycarhoon mine and its contribution to the circulation of metal in the Irish Bronze Age. Objectives:

Chapter 4 presents the results of archaeological excavation undertaken in 2010–11 at Derrycarhoon. This includes the sampling of surface spoil and the full excavation of an early mine working. The stratigraphic record is supported by details of early mine equipment and items of worked/unworked wood. The excavation recovered organic samples (wood, charcoal, antler and peat) from secure contexts for radiocarbon dating, the results of which are discussed in Chapter 5. The chapter also considers the ‘Derrycarhoon Tube’, a curved wooden object of later medieval date that has been the subject of much speculation since its discovery in 1846 at the mine. This study will advance a new interpretation of this object, which is now held in the collections of the Pitt-River Museum, Oxford, where it was not available for study in 2020–21 due to covid pandemic restrictions.

5a. Investigate Bronze Age archaeology within a 10km distance to identify settlement locales connected to the mine. 5b. Examine a possible connection between the Derrycarhoon miners and culture groups of the ‘Stone Circle Complex’ in the region. 5c. Conduct a pilot programme of chemical and lead isotope analysis of Middle and Late Bronze Age axeheads from the Cork region to assess the potential circulation of the copper produced at Derrycarhoon copper in that period. Thanks to the support of Professor Johan Ling, the Derrycarhoon project was included in the ‘Moving Metals’ project based in the University of Gothenburg. That project examined the role of Bronze Age warrior elites in Scandinavia in trade networks across Atlantic Europe (Ling et al. 2013; 2014; 2019; Ling, Earle and Kristiansen 2018). Ore samples from Derrycarhoon and samples of contemporary metalwork were submitted to the project for lead isotope and chemical analysis. The aim was to examine the potential contribution this Irish mine made to the supply of copper in the Atlantic Bronze Age.

Chapter 6 presents the results of a palynological study at the mine undertaken for this project. This provides an important insight into the vegetation record and environmental impact of the Bronze Age mine in a local setting. Chapter 7 explores the contemporary settlement landscape of the Bronze Age mine at Derrycarhoon. This involves analysis of all late prehistoric sites and artifact finds within a 10km distance of the mine. Particular attention is paid to monuments of the Stone Circle Complex, as proxy indicators of settlement in a Bronze Age landscape with generally low archaeological visibility and survival. This local study is expanded to consider the record of Middle to Late Bronze Age settlement in the Cork region.

Finally, as already mentioned, this research began under a cloud of controversy concerning the chronology of Derrycarhoon mine. The project has been able to resolve that issue through historical research and scientific dating. This was the first geo-archaeological fieldwork undertaken at the site. While the scale of investigation is small, there is important new information on geological setting and palaeoenvironment, and on the mining strategies and technology employed in different periods. This provides a new understanding of the history of a small mining landscape from the Bronze Age to the present day. Through this research it is hoped to promote awareness and appreciation of that mining heritage, in an effort to protect the site from further damage caused by forestry and mineral exploration.

Chapter 8 examines the technology and operation of the Bronze Age mine, from prospection to rock extraction and ore beneficiation. New data is presented on the chemistry and lead isotope signature of the copper mineralisation at Derrycarhoon, in relation to a pilot programme of metalwork analysis for the region. The objective there is to understand the circulation of metal from this mine during the later Bronze Age. The study concludes in Chapter 9 by examining the significance of Derrycarhoon in the mining history of south-west Ireland, and the contribution it made to metal supply in Ireland and the wider Atlantic zone during the Middle and Late Bronze Age. Finally, the conservation of mining heritage at Derrycarhoon is considered in relation to the history of the site in the modern era and the lessons that might be learned.

Layout of this book Having introduced the subject matter, Chapter 2 looks at the recent history of mining at Derrycarhoon, and the discovery in 1846 of ‘Danish Mines’ and primitive tools of which ‘no previous tradition or suspicion had been entertained’ (Mining Journal 1847, 70). This is supported by two appendices to the book that document those contemporary accounts. Later interpretations of the finds are examined, as well as recent commentary on their 16

2 Discovery Derrycarhoon is located in the West Carbery mining district in West Cork, an area covering the medieval barony of that name, and parts of the adjacent baronies of East Carbery and Bantry (Figure 2.1). This includes the Mizen and Sheep’s Head peninsulas, the hinterland of Bantry town, and the southern coastline from Skibbereen to Clonakilty. A number of early medieval texts refer to copper miners in the region, such as the Síl mBuinne or the Cerdrige of Bérre (Ó Corráin 1974), but these groups cannot be connected to specific mining locations. There was very limited mining of metal ores by local Gaelic lordships during the later medieval period. There are references to a silver mine on Dursey Island and a copper mine at ‘Bannentrie’ [Bantry] within Berehaven, both dating AD 1497 (Hamner Papers in Addenda to Calendar of State Papers Ireland 1601–03), and a sixteenth-century copper mine at ‘Ghynyboig’ near Bantry (Harleian ms 286, 182–3, in Cowman and Reilly 1988, 142). The region was not subjugated by the English until the early seventeenth century, and it was not until the later eighteenth century that the political climate, improved communications and an assured military presence created conditions for speculative investment to promote industrial mining ventures.

metal during the Industrial Revolution. During the early nineteenth century there was considerable interest in the mineral wealth of the West Carbery district. This began in 1811 with the enterprising Colonel Robert Hall, who worked a copper mine at Ross Island in Killarney in the preceding years. From 1811–22 Hall opened at least six copper mines in West Carbery (Cowman and Reilly 1988, table 2), along with the important Allihies mine in the Beara Peninsula (Williams 1991). Thus began a period of intensified mineral exploration, sustained by Irish and British investment capital raised through joint-stock companies. The main emphasis was on copper mining, with some exploration for lead-silver and iron-manganese, followed by bartyes production in the later nineteenth century (Cowman and Reilly 1988). Numerous small copper mines and trials were opened in the Mizen peninsula from 1810–50 (Figure 2.1). These included operations to the east of Schull at Ballydehob, Cappagh, Ballycummisk (Figure 2.2), Horse Island and Coosheen. There were also ventures at the western end of the peninsula, with mines south of Goleen village at Crookhaven, Brow Head and Mizen Head, and at Dhurode to the north. While significant ore returns were made in some instances, production was mostly sporadic and poorly financed. Cowman and Reilly (1988) reviewed the commercial history of these 19th-century mines, including many ventures operated by so-called ‘bubble companies’

Mineral exploration in the Clonakilty area in the mideighteenth century (Smith 1750; Pococke 1758 in Ó Maidín 1958; Townsend 1810) marks the beginnings of an industry that expanded with an increasing demand for

Figure 2.1 Nineteenth-century industrial copper mines in the West Carbery district (drawing: Nick Hogan).

17

Derrycarhoon

Figure 2.2 Section drawing sent in 1878 to the Inspector of Mines of an industrial copper mine (c.1814–78) at Ballycummisk, Ballydehob, 8km south of Derrycarhoon (open access online publication, Geological Survey of Ireland).

in 1850–55, when up to twenty speculative ventures were promoted in West Carbery (see also Hodnett 2010).

geologist observed, ‘the south-western part of the county of Cork is a district which, perhaps more than any other, requires great caution as well as skill and prudence to mine with profit’ (J.B. Jukes in Jukes et al. 1861, 27–8). Those copper deposits fall into two styles of mineralisation. There are numerous exposures of sedimentary ‘copper-beds’ along the rocky coastline and hilly interior. The copper minerals occur as disseminations in grey-green sandstone units, within red-bed sequences of the late Devonian (Old Red Sandstone) geology. These are low tonnage deposits with an average copper concentration of less than 10%wt (Snodin 1972). Minor quartz veins that intersect these

By 1880 all copper mines in the West Carbery district had closed, though barytes production continued at some mines in the early twentieth century. The decline of copper mining may be explained by trends in world metal markets, and the poor reputation of this district following many decades of speculative investment. The geological setting contributed to the mixed fortunes of these ventures, in an area with numerous surface showings of copper mineralisation, but few deposits proven at depth. As one 18

Discovery copper-beds may carry copper mineralisation. The second style of mineralisation comprises a small number of major quartz-sulphide veins with higher ore grades and larger tonnage (Reilly 1986). These were the focus of 19thcentury mining at larger mines such as Ballycummisk, Coosheen, Crookhaven and Dhurode.

This was not a success, with no production recorded in a venture that ‘seems to have been conducted more for stock-market purposes rather than for potential mining profits’ (Murphy 1962). Derrycarhoon was included in a catalogue of Irish metal mines published in 1922 by the Geological Survey of Ireland (confused with neighbouring townland of Derreennaclogh). This brief note mentions some work there in 1852, but no details are provided (Cole 1922, 55). There was also a report on this mineral deposit in 1917 by H.J. Daly for the Department for the Development of Mineral Resources (Cole 1922, 55). That interest continued with State-licensed mineral exploration at Derrycarhoon at various times over the past half century. This began with prospection in 1962–4 by a Canadian company, Northfield Mines Inc, reports of which are published online by the Geological Survey of Ireland (see below). In 1962 Northfield conducted geophysical survey (induced polarisation/resistivity) and soil geochemical survey in the area, as well as underground exploration and chip sampling in the accessible workings at Derrycarhoon, and also at a nineteenth-century copper mine in the neighbouring townland of Shronagree. The results from Derrycarhoon were sufficiently encouraging to commence drilling from December 1963 to January 1964, when four holes were bored to a combined depth of 784 feet (239m). The copper mineralisation encountered was not of sufficient grade or tonnage to warrant further exploration, and the work was then suspended.

2.1 Recent Mining at Derrycarhoon There are no historical records of mining at Derrycarhoon prior to 1846, with no workings depicted on the 1842 Ordnance Survey mapping (Cork six-inch sheet 131). The site is not included in lists of mines published for southwest Ireland in the early nineteenth century (e.g. Townsend 1810; Wakefield 1812; Weaver 1838; Kane 1845), nor in earlier sources. The earliest documented mining at Derrycarhoon dates to 1846 and 1847, when a wellknown miner in the West Carbery region, Captain Charles Thomas, cleared some old workings at the site. Thomas was a respected mining engineer of Cornish background who, along with his brothers Henry and William, was prominent in mineral exploration in West Cork during the mid-to-late nineteenth century (Cadogan 2002, 238–42). Charles Thomas conducted ‘superficial trials’ at Derrycarhoon to reveal ‘several parallel lodes near each other containing rich grey and purple copper ore and large deposits of carbonate of copper...’ (Mining Journal 1880, 585). He sent 46 tons of ore to the Swansea smelters in June 1848 where it sold for £180 (Mining Journal 1848, 303; recorded as ‘between 30 and 40 tons of rich grey copper ore’ in Mining Journal 1875, 900; see also William Thomas comments on a ‘cargo of ore’, Mining Journal 1880, 585). The venture seems to have been short-lived, with no other records available. The mine location is not recorded on the Geological Survey of Ireland field maps of 1854, but is mentioned (‘Danish or Old Men’s Workings’, about a mile west of Ballybane’) in a commentary on mines in the accompanying memoir (Kinahen in Jukes et al. 1861, 25).

There was further mineral exploration in the Derrycarhoon area in the 1970s, undertaken by Dresser Minerals, and in the late 1980s by Conroy Petroleum and Natural Resources PLC. This involved soil, stream and rock chip sampling for geochemical analysis, and some geophysical survey, conducted over a wide area. Work at the mine itself was confined to sampling of surface spoil. The results of the Dresser and Conroy exploration did not lead to any further work at Derrycarhoon. Also relevant are a number of student research projects that included the mine, including a stream geochemistry survey undertaken by Keele (1969) and a review of copper mineralisation by Snodin (1972) and Wen Ni (1991).

The next recorded mining at ‘Derry Cahoonie’ was in 1856 when one ton of 3% copper was sold to the Swansea smelters for £2-9/0 (Hunt 1857; Mining Journal 1856, 208). There are no details of that venture. In the Mineral Statistics lists of working mines, Derrycarhoon is listed as a mine owned 1862–73 by Swanton and Co (Hunt 1863 et seq.). Other sources suggest that by 1860 the mining lease was held by John Abraham Jayoe (Mining Journal 1880, 585). There is no record it was worked during that period. There was a brief resumption of mining around 1906 when a venture led by a Mr McArthur of Glasgow drained the south shaft and drove an adit level from the northern side of the hill to intersect and drain the old workings (Duffy 1932). Published lists of mines for those years record that McArthur was the lease owner, with a David Simpson acting as agent (List of Mines in the United Kingdom of Great Britain and Ireland 1906–09). The record for 1906 lists six men working underground, seven the following year, with six underground and one on the surface in 1908.

2.2 The ‘Danish Mine’ Revealed The discovery in 1846 of primitive mine workings and equipment in Derrycarhoon townland, of which ‘no previous tradition or suspicion had been entertained’ (Mining Journal 1847, 70), was publicised in antiquarian and mining circles in that period. The primary record is a series of eleven letters sent by a local landowner, Thomas Swanton, to the Cork antiquarian, John Windele (Figure 2.3). Swanton was in contact with Charles Thomas and visited the mine at the time of the discoveries. These letters, dated March 1846 to October 1847, some of which were published by Briggs (1984), are in the Windele manuscripts held by the Royal Irish Academy (Appendix 1; no record survives of Windele’s letters to Swanton). 19

Derrycarhoon Two of the Swanton letters contain important detail on the Derrycarhoon discovery:

rubbish, and at top with bog-stuff, the upper part of which was solid bog, apparently of natural formation. The bogstuff extended in some places 14 feet deep but it was not all solid, part was mixed with rubbish. Q. 5. Any articles found, and of what kind? That curved tube. A ladder formed of a single piece of black oak, with stepping places cut into it all at one side of the stick, length of ladder 18 feet, but some was broken off or decayed before it was found; the number of steps is 13. A few slender sticks pointed. A great number of stones fit for paving all considerably battered as if they had been used in place of sledge-hammers, weight from 3 to 7 lbs. Q.6. What metals do these mine produce? Copper. Q.7. Do the holes appear to have been much worked and whether skilfully or otherwise? They were worked to a greater depth than is yet ascertained. They were worked skilfully. They left arches of rock uncut to keep the walls of the lode from closing. Q.8. What are the traditions of the people about them? The people have no traditions about them. I may mention as, perhaps, a help to arrive at some conclusion as to the date of these works, that there is a stratum of whitish slime (such as runs off in the washing of copper) lying between two strata of bog, the upper of which is 3 ½ ft. thick. The bog in which this appears lies a few yards lower down the hill than the mouths of the mines. These works are half way up the south side of the range of mountains which separate the parish of Skull (Sgoil) from the parish of Durrus (Dúb-rus). As I am not sure when I must go to Cork I would wish to send you that tube and some old sticks found in the mines. Please do let me know the place at which you wish to have them left for you…Thomas Swanton.’ (RIA Ms 12.L.10, 103–5).

Cranliath, 1st May, 1846 ‘…I promised Captain C. Thomas to let you know that they had not yet reached bottom, I have broken my word. He will assist in making out the replies but he says he cannot say much until at least one of the excavations is cleared out. There are four or five of them, they are filled on the top with bog naturally formed without stones or hard pieces of turf. I shall tell you in my next how many feet the bog goes down, under it there are stones, pieces of timber and rubbish, which I suppose were thrown in when the works were deserted. There are a good many river stones of a very hard quality battered at one end which Capt. C T. supposes were used as hammers, they are about 2 or 3 lbs each. He says these mines were worked judiciously, there are pieces of rock left uncut to keep the sides from closing. They have cleared out about 45 feet in depth. These are not holes. They are long narrow cuts (how long I shall tell soon). The best thing since the crooked tube is the discovery of a ladder 18 feet long, not with rungs on two sides but the steps are cut in a solid tree. I have not yet seen it but hope to have that pleasure on Saturday. I just heard yesterday that a piece of an Irish harp was found. Yours sincerely, Thomas Swanton’ (RIA Ms 12.C.6, 295-8). Around that time, Windele sent Swanton a questionnaire, to which the following reply was made: Cranliath, 9th May, 1846 ‘Dear Sir Captain Charles Thomas accompanied me to the old mines and very politely gave every assistance. I shall now endeavour to answer your queries. Q. 1 Their number? Six. Q. 2. Names? Danish Mines of Derrycarhoon Drineceathanain, they lie North by east from Ballidahob at a distance of about 3 miles English. Q.3. Character of the excavations, extent depth etc? They are all parallel lodes worked without powder. No 1. Partly re-opened, length 10 fathoms, average breadth 8 feet, depth already cleared 10 ft. No 2. Now nearly cleared, length 30 fathoms, breadth 10 feet, depth cleared 43 feet. It dips towards the west where its depth is not yet known. No 3. Not opened, probable length 16 fathoms, breadth 6 feet. No 4. Not opened, length 7 fathoms, average breadth 5 feet. No 5. Not opened, length 6 fathoms, breadth 5 feet. No 6. Not opened, length 4 fathoms, breadth 3 feet. The length and breadth of those not reopened is known from a hollow on the surface of the mountain. Q.4. When last opened, appearance then? Never reopened until now. They were found filled at bottom with

The other letters mostly relay Swanton’s intention to send Windele ‘the old affairs found in the mines’. Eventually, the tube was sent to Windele, who exhibited it at a meeting of the Cork Cuverian Society in late 1846, of which the following account survives: ‘Mr John Humphrey for Mr Windele read a paper on the wooden tube exhibited in November. In searching in the early part of the year [1846] for indications of ore in the west of the county near Ballydehob, no less than 6 old mineholes were discovered, 3 miles NE of it, of which nothing previously was known. They were all parallel lodes, one was 30 fathoms long, and 10 feet broad. They were found filled at bottom with rubbish and at top overlaid with bog stuff in some places to a depth of 14 feet. The tube now exhibited, a ladder 18 feet long, formed of a single piece of black oak, with 13 stepping places cut into it on one side, and a no. of the stones called Danish hammers were found. The meas. of the tube was 2.8 feet long, 2½ inches diameter at large end and a 1½ inch diameter at smaller, it consists of 2 parts, the smaller 5 inches long fits into the larger portion, and the extremity of this seems to have been an as bound round with a ferrule. In front the tube is open for a length of 15 inches and 7–8 inches in breadth, where 20

Discovery one side of the timber, and a number of stones, weighing from 3lbs to 7 lbs each, similar to those found in the old mines at Mucross, and there called Danes’ hammers, were also found. These old shafts had been worked with considerable skill. Arches of rock uncut had been left by the miners to keep the walls of the lodes from closing. “I may mention (says my informant, T. Swanton, Esq., of Cranliath, near Ballydehob) as, perhaps, a help to arrive at some conclusion as to the date of these works, that there is a stratum of whitish slime (such as runs off in the washing of copper) lying between two strata of bog, the upper of which is 3 ½ ft. thick; the bog in which this appears lies a few yards lower down the hill than the mouth of the mines.” If further evidence of the extreme antiquity of mining operations in Ireland were necessary, beyond those remains of old works here slightly adverted to, we might refer with confidence to the enormous quantities of bronze weapons, for warlike and domestic use, which have been continually dug up for the last two centuries in every part of Ireland, and in situations admitting of no doubt as to the remoteness of their era...[goes on to mention moulds and bronze objects]. The measurement of this tube is: - Length, 2 ft. 8 ½ in.; diameter at larger end, 2 ½ in.; ditto at lesser, 1 ¼ in. It consists of two parts: the smaller, which is only 5 in. long, fits into the larger portion; and the extremity of this last seems to have been formerly bound round with a ferule of binding. In front the tube is open for a length of 15 in., and by a breadth of 7/8 ths of an inch, where broadest. What was the object or purpose of this article, I confess my total disability to tell. It is to me, and to all who have looked at it, a mystery, and incomprehensible. In form, it resembles some of our old brazen trumpets; but, beyond this, I suspect it has no other resemblance to those instruments. The longitudinal opening baffles every conjecture. The timber appears to be yew.’ (Mining Journal 13th February, 1847, 17, 70).

Figure 2.3 John Windele, Cork antiquarian, 1801–1865 (courtesy Cork Historical and Archaeological Society).

broadest. What was its object or purpose, neither I or any other person who have seen it imagine. The longitudinal opening baffles every conjecture.’ (January 1847 entry, Minute Book of Cork Cuverian Society, p.339; Boole Library, University College Cork). An expanded report was published the following month in the weekly trade publication, the Mining Journal, in an article titled ‘Ancient Mining in Ireland’, as follows:

Other reports on Derrycarhoon appeared in the Mining Journal up to 1880 (listed in Appendix 2). Most of these referred to the Danish Mines, suggesting the promotional value of highlighting the discovery of ancient mining at an ore prospect. Two of those commentaries were provided by the mine captain, William Thomas, brother of the Derrycarhoon captain, including the following published in 1853:

‘Mr Windele exhibited, at one of the late meetings of the Cork Cuverian Society, an antique wooden tube, considerably curved and partly open in front, found in the shaft of an ancient mine, recently discovered near Ballydehob…In searching in the early part of the present year, for indications of ore in the mountain district neighbouring to Ballydehob, in the west of this county, under the direction of Capt. Thomas, of Cornwall, no less than six old mineholes were discovered on the lands of Derricarhoon, three miles north-east of the village above named. Of these no previous tradition or suspicion had been entertained. They were all parallel lodes; one was about 30 fms in length and 10 ft broad, but its breadth at the time when I received information of the discovery was not fully known. They were found filled at the bottom with rubbish, and at the top were overlaid with bog stuff (peat), in some places to a depth of 14ft. The tube now exhibited, a ladder 18 ft in length, formed of a single piece of black oak, with 13 stepping places cut into it, on

Mines of Ireland, No. III. By Capt. Wm Thomas. ‘Four miles north of Ballydehob, in the Derrycarhoon Mountain, which from its shape signifies in English “the butt of the thigh”, some extensive excavations have been found, which no doubt were made at a very remote period, as they are invariably designated by the country people Danes’ or Danish Works, but whether these ancient works were carried on or not by the Danes is not easy to determine; it is, however, an historical fact, that the Danes visited Ireland many hundreds of years ago. One of those singular excavations at Derrycarhoon was a few years since cleared of water and rubbish; it 21

Derrycarhoon Geological Survey memoir (Kinahen in Jukes et al. 1861). He also included the discovery in a review of Irish metal mining published by the Royal Dublin Society, where with some prescience he speculated the mine must be at least 3000 years old, based on the depth of peat in those ‘Danes Mines’ (Kinahen 1886, 202).

was found to be 60 ft. deep, and about 120 ft. in length; there was not the least trace visible of any iron implement being employed in cutting the rock, which is light blue compact clay slate; and the lode or vein appears to have been literally pounded away by stone hammers, a great many of which were found in the old works and which were evidently brought from a considerable distance, there being no rock of the same character within many miles. Notched pieces of oak were also found, evidently used as ladders, and several articles of great antiquity, but for what purpose it is now hard to determine. Numbers of similar excavations, but of smaller dimensions, are to be found in then Derrycarhoon and Shronagree (which signifies the “Hare’s Nose”) Mountains; and the ancients or workers in the olden time were certainly good miners, having hit upon and scooped out many rich deposits of copper ore, which much clearly have been the case, as not an atom of the debris from former workings are to be found. To the antiquary it would, no doubt, be an interesting subject of investigation to ascertain in what manner or by what process the Danes reduced the ore to a metallic state? No trace of smelting is to be found in the vicinity of the works. Query: was the ore removed to some foreign country, if so, to what country, to be smelted? There are a number of veins of rich grey ore running through these mountains, in an east and west direction; and from frequent observations, I am inclined to the opinion, that by tracing the veins, and scoping out the rich deposits of ore, and, in fact, following the modus operandi of the ancients – leaving deeper workings for those who prefer them – considerable profits might be made. Those mineral veins are traceable from Shronagree to Dreenalom, a mountain range of several miles in length. I omitted to remark that in one of the Danes Works at Derrycarhoon, which in the course of ages had become full of peat, and the surface quarry, like any other part of the mountain which was cleared out, I have seen the fibres of the peat completely precipitated or formed into pure copper, like so many beautiful hairs or fine threads – in fact, many lumps of peat I have seen thoroughly impregnated with pure copper, one of which I assayed and it gave 90% of pure copper. Probably this may be accounted for by the action of the acid contained in the peat on the copper exuding from the lode, and held in solution in the water.’ (Mining Journal 21st May, 1853, vol. 23, page 312).

These nineteenth-century sources do not contain plans or other illustrations of Derrycarhoon mine. One of the trench mines cleared by Captain Thomas in 1846 is likely to be depicted on the 1:2500 Ordnance Survey mapping of 1890 (Cork sheet 131/10). This depicts an irregular trench, measuring c.27m by 3m, with spoil dumps in an area of c.900m2 (base map, Figure 2.5 upper). 2.3 ‘Curious Articles’ The above accounts record that Charles Thomas’ exploration of Derrycarhoon in 1846 led to the discovery of stone and wooden equipment, then regarded to be of some antiquity. The original source refers to wooden objects, including a ‘crooked tube’, a ladder where ‘the steps are cut in a solid tree’, ‘a few slender sticks pointed’, and ‘a piece of an Irish harp’, as well as numerous hammers comprised of ‘river stones of a very hard quality battered at one end’ (Swanton letters to John Windele, 1st and 9th May, 1846). The ‘Derrycarhoon Tube’ The earliest mention of this find is contained in a letter from Thomas Swanton to John Windele, dated 27th March 1846. The tube is mentioned in their subsequent correspondence to October 1847 (Appendix 1). The Windele manuscripts also contain a letter dated 27th August 1846, sent to Windele by a local antiquarian, Roger Downing of Bantry, who speculated the tube was a ‘musical instrument’. The letter contains the earliest known illustration of the object, provided by a Mr Doyle, Controller of Customs. Two sketch drawings record the curved length of the tube as about 3 ½ feet long and 2 inches diameter (Figure 2.4). The Downing letter makes no mention of cylindrical fittings found with the tube (see below), but does record that it was found with a wooden ladder (RIA Ms 12L10, 132–4). As detailed above, the tube was exhibited in January 1847 at a meeting of the Cork Cuverian Society. Windele returned the object to Swanton in July 1847, and it was eventually acquired by J.W. Clarke of Skibbereen. In October that year this object and the ladder were given to a visitor from Dublin University, named by Swanton as a ‘Professor of Geology’, but possibly George James Allman, Professor of Botany (1844–56) in Trinity College Dublin, whose family background was in West Cork. In January 1848, Allman exhibited the tube at the Royal Irish Academy in Dublin, with the following description published in their Proceedings:

These accounts of the Derrycarhoon discoveries in the Mining Journal essentially derive from the Swanton– Windele correspondence, and probably Captain Thomas’ conversations with his brother. Windele published a summary of the discovery in a paper on ancient Irish gold (Windele 1861), a report that contributed to other antiquarian commentaries (e.g. Rolt Brash 1871; Macalister 1921; 1928). Despite this publicity, Derrycarhoon was omitted from some later lists of mines in the region, including those published in 1853, 1854 and 1862 by the geologist, Sir Richard Griffith (see Morris 2001; Wyse Jackson 2002). Another geologist of that period, George Henry Kinahen, was aware of the find, mentioning the ‘Danish or Old Men’s workings’ west of Ballybane in the

‘Dr. Allman exhibited and described a singular implement discovered in an ancient copper mine in the parish of Skull, Co. Cork. It consists of a tube formed of yew 22

Discovery

Figure 2.4 Sketch of Derrycarhoon Tube sent 27th August, 1846, by Roger Downing, Bantry, to John Windele (by permission of the Royal Irish Academy).

timber, gradually increasing in diameter towards one end, and bent in the manner of a siphon at an angle of about 80°, the point of flexure being nearer to the narrower end. A slit nearly half an inch in width extends for about the middle third of the concave side through the thickness of the walls, and at the narrower end are indications of wear, as if the implement had been fitted into a collar or tube of greater diameter. It presents the following dimensions: Length of the longer leg….17 inches Length of the shorter leg…13 inches Diameter at small end….1½ inches Diameter at large end….2¼ inches Another implement, constructed also of yew timber, and evidently related to that just described, was found along with the latter, and also exhibited by Dr. Allman. It resembles a funnel formed of two cylinders of different diameters, the wider constituting the mouth, and the narrower the neck, the whole being scooped out of a single piece. The neck of the funnel fits accurately into the wider end of the siphon. The following are the measurements: Length of wider cylinder….2¾ inches Length of narrower cylinder…2 inches

Diameter of wider cylinder….2½ inches Diameter of narrower cylinder….1½ inches The mine in which the implements just described were found is one of several vertical cuttings recently discovered near Ballydehob, in the parish of Skull, and apparently of very great antiquity. The cuttings, when discovered, were filled to the surface with the rubbish of the ancient workings, and when this was removed there were found, lying on the bottom, the subjects of the present communication, along with a great number of rolled stones, almost all of which exhibited marks of attrition, as if they had been used instead of hammers. A beam of oak timber, about twenty feet in length, and notched along the sides, in such a way as to suggest its use as an ancient ladder, was also found in the same place. Some idea of the antiquity of these singular mining operations may be formed from the fact of some of the old rubbish being now found near the mouth of the cuttings, with a covering of more than two feet of apparently naturally formed peat. The implements exhibited are the property of J. W. Clerke Esq. of Skibbereen.’ (Allman 1848, 64–5). 23

Derrycarhoon The tube (but possibly not the ladder) returned to Clarke who exhibited it at a National Exhibition of 1852 held in Cork City. The exhibition catalogue contains the following description:

to suggest that it may have been part of an early suction pump (Davies 1933–4, 24), used for draining the deep trench mines at Derrycarhoon. It was later identified as a horn used for shot powder in the mine (Briggs 1984, 37), a possibility also entertained by the Pitt Rivers Museum.

‘Ballydehob Tube

The Derrycarhoon ladder

A singular trumpet-shaped wooden tube, contributed to the Exhibition by J. W. Clarke, Esq,. of Skibbereen, excited much speculation as to its use, although there could be but little doubt as to its remote era. It measured about three feet, and consisted of two joints, a larger and a smaller, the latter being only about three inches in length. It was formed of yew, hollowed throughout, and had an open slit, extending down the inner curve, for about two-thirds of its length. It was discovered in the shaft of an ancient copper-mine, near Ballydehob, of whose working there is no record. On re-opening the shaft, in 1846, it was found filled with the rubbish of the original operations, and the upper surface was covered over with some feet of turf. At the bottom of the cutting, stone hammers were discovered, and the remains of a primative (sic) ladder, about twenty feet in length, formed, out of the solid oak, and notched, so as to constitute rude steps. The whole have been referred to the period of the Phoenician intercourse with Ireland’ (Maguire 1853, 357–8).

The clearance in 1846 of two trench mines at Derrycarhoon led to the discovery of… ‘A ladder formed of a single piece of black oak, with stepping places cut into it all at one side of the stick, length of ladder 18 feet, but some was broken off or decayed before it was found; the number of steps is 13’ (Swanton letter 9th May, 1846). There is no additional detail in the Windele correspondence, apart from mentioning that the ladder was given to a ‘Professor of Geology’ in Dublin University (Swanton letter, October 1847). The ladder is mentioned in accounts of the mine in the Mining Journal (1847, 70; 1849, 199; 1850, 285; 1853, 312; 1860, 648; 1875, 900; 1880, 585; see Appendix 2). Some later descriptions mention a ladder length of 20 feet with 14 steps (Allman 1848; Maguire 1853; Rolt Brash 1871), Downing said it was 26 feet long (see above), while others mention more than one ladder (Mining Journal 1850, 285; 1853, 312).

The tube subsequently came into the possession of Colonel Lane Fox, the famous English archaeologist later known as General Pitt-Rivers. This probably occurred during a period of military service in Cork c.1862–1865, when he was active in local antiquarian circles, and was an acquaintance of Windele (Twohig 1987). Lane Fox exhibited the tube at a meeting of the Society of Antiquaries of London on 30th November 1871. He gave the dimensions as follows: ‘The length of the longer leg is 17 inches, of the shorter 13 inches. The diameter at the small end 1 ½ inch, at the large end, where a terminal piece is inserted, 2 ¼ inches’. The report has a drawing of the tube and its collar attachment (Proceedings of the Society of Antiquaries of London 5, 223). Both objects were displayed at Bethnal Green Museum at that time, and in 1884 were donated to the Pitt Rivers Museum in Oxford, where they remain today (PRM museum catalogue 1884.117.28.1–2). The museum gives the combined dimensions of the two objects as 64mm maximum height; 540mm max. length; 330mm max. width; 62mm max. diameter. The larger object has a max. height of 60mm, max. length of 475mm; max. width of 330mm and max. diameter of 55mm. The smaller cylindrical fitting has a max. length of 121mm; and max. diameter of 62mm.

The use of monoxlyous ladders at Derrycarhoon can be explained by the near-vertical profile of the early trench mines discovered in 1846. Sadly, the later history of this ladder is unknown. Swanton records it was taken to ‘Dublin University’ (RIA ms 4.B.7, 339–41), possibly by Professor Allman, or else Samuel Haughton, who was then Professor of Geology in Trinity College Dublin. The Dublin University Museum catalogues for 1846 and 1847 have no records of an acquisition. The Museum was broken into smaller museums in the 1850s, including a Geological Museum, but again there are no records of the ladder (information: Patrick Wyse Jackson, TCD). There is no record either in the National Museum of Ireland. Given its size and possibly waterlogged condition, it is likely the ladder was disposed of during that period. Other wooden finds from the 1846 exploration include ‘a few sticks pointed’ and ‘a piece of an Irish harp’ (Swanton letter, 9th May 1846), none of which survive. The status of the latter is unknown, but a possible connection to a musical instrument has a new relevance in relation to the Derrycarhoon tube (see Chapter 5). The pointed sticks may represent prise-sticks used in mining or roundwood used as fuel in the mine site, among other possibilities.

There are occasional references to the tube and other Derrycarhoon finds in short articles published in the Mining Journal (see Appendix 2) and by geologists (Kinahen 1886; Cole 1922). The find is also mentioned in antiquarian and early archaeology publications (e.g. Windele 1861; Rolt-Brash 1871; Macalister 1921, 1928, 1948). Opinion was divided as to the function of this object. An early interpretation suggested a ‘musical instrument’ (Downing 1848 above), but this was not well received. The mining historian, Oliver Davies, was the first

Dane’s hammers A large number of stone cobble hammers were discovered in the 1849 exploration at Derrycarhoon. These are described as ‘…a good many river stones of a very hard quality battered at one end which Capt. C T. supposes were used as hammers, they are about 2 or 3 lbs each’ (Swanton letter, 1st May 1846; RIA Ms 12.C.6 fols 296–8; his letter 24

Discovery a week later gives a weight range of 37 lbs). These are also mentioned in accounts of the mine published in the Mining Journal (1847, 70; 1849, 199; 1850, 285; 1853, 312; 1858, 807; 1860, 648; 1875, 900; 1880, 585; see Appendix B). One of those entries was written by William Thomas, who observed that ‘…the lode or vein appears to have been literally pounded away by stone hammers, a great many of which were found in the old works and which were evidently brought from a considerable distance, there being no rock of the same character within many miles’ (Mining Journal 1853, 312). Later antiquarian discussion compared these ‘mauls’ to examples from the Killarney mines (Windele 1861; Rolt Brash 1871).

water to a depth of 50 feet (15.2m) until they were filled in by the landowner c.1920. The South Shaft was pumped dry in 1912, measuring 12 ft. by 8 ft. on the exposed bottom. In his sketch, Mahr says the infilled North Shaft is called the ‘Dane’s Hole’. These two shafts provided access to a series of six underground tunnels on either the 50 ft. or 100 ft. level. Four tunnels trending north-east/south-west were driven in the central mine area. These include (north to south) a tunnel accessed from the North Shaft at the 50 ft. level, a second tunnel at the 50 ft. level accessed from a cross-cutting tunnel (see below), and two others accessed from the South Shaft at the 50 ft. and 100 ft. level respectively (latter depicted on A–B section in Mahr sketch survey). In addition, there were two cross-cutting tunnels trending north-west/south at the 50 ft. level, the first extending northwards from close to the North Shaft, and a second connecting the western ends of the two north-east/south-west levels connected to the two shafts.

2.4 Later Visitors and Interpretations In 1929 Derrycarhoon was visited by Tom Duffy of the Geological Survey of Ireland. This was part of a survey of copper deposits in south-west Ireland (Duffy 1932), which also led to the discovery of the Mount Gabriel mines (O’Brien 1994, 48–9). Duffy’s unpublished report contains the following entry on Derrycarhoon:

Duffy (1932) recorded the location of an ‘adit recently driven’ (c.1906–8) c.196m north/north-west of the North Shaft, which he says reached the northern cross-cut at a depth of about 45 ft. (13.7m). He also recorded seven ‘shallow trial openings’ in beds of cupriferous sandstone on the northern side of the mine area (Figure 2.5). These include two short rows of three and two workings respectively directly north of the North Shaft, as well as a ‘shallow trial opening’ c.70m to the west/north-west, and an ‘old trial opening’ c.190m to the north-west. No details were provided on the size, form or age of those surface workings.

‘Near the Western boundary of this townland are situated the Derrycarhoon pre-historic copper mines. These mines were opened in beds of grey grits and slates traversed by quartz strings. According to Mr John Martin who owns the land two shafts were open until about 12 years ago [1920] when he filled them in for safety. The shafts were then about 100 feet deep and were filled with water up to about 50 feet below surface. The south shaft was pumped dry by Mr MacArthur of Scotland about 20 years ago [1912]. The shaft was then about 12’ x 8’ on the bottom, or at least on the floor of loose stones. The true bottom was not then seen. About 200 yards north-west of the site of the old shaft (north) an adit was started and driven towards the old mine about 20 years ago. The driving reached the north driving of the old mine at a depth of about 45’ – not sufficiently deep to dry the old workings. A small lode which appears at the surface was cut in this driving. All of the above information supplied by Mr. Martin. In the old dumps at the mine coper carbonate and some pyrites are seen in a gangue of quartz mixed with country rock and occasionally some calcite’ (Duffy 1932, 27; the text is accompanied by ‘a sketch drawing of the old mine according to John Martin’; reproduced in O’Brien 1989, fig. 2).

The Duffy and Mahr sketch plans record a large spread of broken rock spoil in the central mine area. This spoil is likely to derive from the clearance of two old trench mines in 1846–7, and from subsequent shaft-and-gallery mining in the nineteenth century. The following observation on surface evidence of early mine spoil is of interest in relation to the possibility of cut-and-fill mining in the trench workings: ‘It is a singular fact that not a vestige of this produce of the excavation was to be seen on the surface, so that it may be inferred that the vein stuff was not only valuable but removed to a distance for smelting, there being no trace of smelting operations on the spot’ (Mining Journal 1875, 900). Ó Ríordáin and Mitchell On the 25th January, 1938, the mine was visited by Professor Séan P. Ó Ríordáin, then Professor of Archaeology in University College Cork, in the company of the landowner, John Martin. The latter had previously filled in some of the old workings, which he recalls were supported by ‘heavy baulks of timber and stone walling’. Ó Ríordáin noted the presence of a large number of ‘Danes hammers’ in the surface spoil, as well as some stone walling there, and ‘what appears to be a stone hut 21 ft. distant’ (topographical files, Department of Archaeology, UCC). The same records contain a letter to Ó Ríordáin dated 10th May 1939, sent by a local historian, Claude Chevasse, who met an ‘old miner’ in the area who had some memory of the Derrycarhoon finds.

Duffy has also left a plan of the mine on the 1:2500 map of this area (Figure 2.5). He re-visited the site on 4th October 1929, in the company of Adolf Mahr, then Keeper of Irish Antiquities in the National Museum of Ireland, and subsequently its director. Mahr did not publish any details of the visit, but there is a sketch plan with his notes in the Museum records (Figure 2.5). The Duffy and Mahr surveys confirm the presence of underground shaft-and-gallery mining of post-1846 date in the same area as the trench mines discovered by Charles Thomas. Duffy’s plan and report shows two vertical shafts, estimated to have been 100 feet deep (30.5m) and filled with 25

Derrycarhoon

Figure 2.5 Historic sketch plans of Derrycarhoon mine made by Tom Duffy (top) and Adolf Mahr (centre right) during a visit in October 1929. Also included (bottom) is schematic plan of the nineteenth-century copper mine based on these records (drawing: Nick Hogan, with historic plans courtesy National Museum of Ireland and the Geological Survey of Ireland).

26

Discovery Ó Ríordáin returned to Derrycarhoon in 1947 in the company of the botanist and Quaternary scientist, Frank Mitchell, Trinity College Dublin, also visiting the Mount Gabriel mines on that occasion. Mitchell took peat samples for pollen analysis, summary results of which were published by Jackson (1984a, 47; 1984b, 376), including the following profile from a peat exposure in the mine:

controversy that followed (Figure 2.6; Jackson 1968; 1979; 1980; 1984a; 1984b; 1984c). This was based on documentary sources, mainly secondary accounts of the 1846 discoveries and the Duffy (1932) survey, with no indication that Jackson visited the mine. He cited the discovery of an ‘old and unusually extensive mine together with six drifts similar to the mines on Mount Gabriel … under some 14’ (4.27m) of peat during peat-cutting operations.’ (Jackson 1968, 100). Applying a broad peat accumulation rate, he suggested the mine may be as old as 1616 BC, supporting an earlier estimate of at least 3000 years old (Kinahen 1886, 202; 1889, 2). Acknowledging the limitations of this approach, he also suggested the mine must pre-date 500 BC, based on information then available on when blanket bogs began to develop in the west of Ireland (Jackson 1968, 101).

Base of late tip-heap (19th century).............— Peat in primary position..............................0.45m Grey-green sandy clay (Swanton’s slime) with broken maul in situ...................0.13m Peat with pine wood....................................0.40–0.98m Rock............................................................— In later years Professor Mitchell kindly sent the author his field notes (sadly, not very legible), as well as a sketch pollen diagram reproduced in Chapter 5 (Figure 5.5 below).

In a later paper, Jackson suggested the style of mineralisation at Derrycarhoon is different than that at Mount Gabriel, namely a discordant mineral vein as opposed to the stratiform copper-beds of the latter (Jackson 1979, 111–2). He estimated the amount of metal from the ‘open-cast’ using Kinahen’s measurement of 18.29m long by 18.29m deep by 1.2m wide for that working to estimate a volume of 407.69m3, equivalent to 1084.45 tonnes of rock extract. He suggested this contained 182.65 tonnes of mineralised rock (ore) potentially smelted to produce 60.88 tonnes of copper. He applied similar calculations to the ‘six drivings similar to those on Mount Gabriel’, assuming a production of 20 tonnes of metal for each of those mines. Combining these estimates, Jackson proposed that 180.88 tonnes of copper may have been produced from those seven Bronze Age workings at Derrycarhoon (Jackson 1979, table 2). Jackson subsequently revised these estimates, reducing the early Derrycarhoon production to 55.77 tonnes of smelted copper (Jackson 1980, table 3). He also produced a plan of the mine based on his interpretation of the Duffy record (Figure 2.6).

Despite their respective visits, there was no mention of Derrycarhoon in Mahr’s Presidential Address to the Prehistoric Society (Mahr 1937), nor in Ó Ríordáin’s review of recent discoveries from Irish prehistory to the same learned body a decade later (Ó Ríordáin 1946). Similarly, there is no reference to the mine in Raftery’s (1951) Prehistoric Ireland, but it does feature in the second edition of The Archaeology of Ireland (Macalister 1949), having been mentioned in passing in the first edition (Macalister 1928, 54): ‘At Derrycarhoon, near Schull (Cork), six copper-mine shafts were found, which are (too briefly) described by Thomas Swanton of Cranley. Besides the usual stone mauls, a ladder was found in one of these mines, 18 feet in length, consisting of a board of black oak with thirteen steps cut in its edge (after the manner of saw teeth); this mine is sufficiently old for a natural growth of peat, 2 feet thick, to have accumulated over part of the spoil-heap at its mouth. It also contained an object to which it is difficult (impossible rather) to assign a specific use; it was lying, along with some of the mauls, at the bottom of one of the shafts, covered with what appeared to be the debris from another shaft, opened after the abandonment of the first; and may thus be described. A tube of yew wood, tapering in external diameter from 2 ¼ to 1 ½ inches, “elbowed” with a sharp bend – the longer (and broader) branch being 17 inches, the shorter 13 inches in length. A slot nearly ½ inch wide was cut in the concave side, and what we may call a movable “mouthpiece” was provided, in the shape of two cylinders with their axis in line, the narrower cylinder being an exact fit in the broader end of the tube. Without a knowledge of the purpose of this object it would be futile to conjecture its age, and whether its connexion with then mine was intrinsic or accidental’ (Macalister 1949, 127–8).

In the 1980s the Derrycarhoon evidence was reviewed by British archaeologist, Stephen Briggs, as part of a broader critique of the Bronze Age date attributed to early copper mines in south-west Ireland (Briggs 1983a, 320–1; 1983b, 48–52; 1984). Like Jackson, there is no evidence Briggs visited the mine, as his discussion does not contain field observations. He did publish the first accounts of the Swanton-Windele correspondence on the 1846 discoveries, and also had the Derrycarhoon tube examined in the PittRivers Museum (Briggs 1984, 33–6). Briggs went on to locate the trench mines recorded by Swanton on Jackson’s published plan of the Duffy survey (Figure 2.6). He then considered the dating of this site, focusing on the style of mining, and the age of the equipment found in 1846. He concluded the wooden artifacts are post-medieval in date, associated with trench mines he argued were worked with steel tools. He suggested the six shallow drivings identified by Jackson as Mount Gabriel-type mines are more likely to be nineteenth-century trials (ibid. 378). In an earlier paper he suggested the peat found in these pre1846 workings was a rubbish infill, and so not indicative of their antiquity (Briggs 1983a, 320, 328).

Recent research The discoveries at Derrycarhoon were considered by the geologist, John Jackson, in a series of articles dealing with his study of the Mount Gabriel mines and the dating 27

Derrycarhoon

Figure 2.6. Interpretations of Derrycarhoon mine based on historical sources (left: Jackson 1980, fig. 7; right: Briggs 1984, fig. 2; compiled by Nick Hogan).

Jackson replied to these criticisms, providing details of Mitchell’s study of a peat profile at Derrycarhoon, as outlined above (Jackson 1984a; 1984b; 1984c). Mitchell recorded mine sediment (‘Swanton’s slime’) with a stone hammer underneath a growth of peat where pine pollen was shown to be present (Jackson 1984a, 47). Jackson regarded the latter as significant, because ‘since pine died out in Southwest Ireland in about 1140 BC, this peat must be older than that, and the underlying mine waste older still’ (Jackson 1984c, 8). Jackson also rejected Briggs’ assertion that peat does not grow at a predictable rate, citing data from Cashelkeelty, Co. Kerry (Jackson 1984a, table 2) in support of his estimates at Derrycarhoon.

in a Bronze Age date for Derrycarhoon, where similar stone mining hammers were found and where mines were also filled with peat. It was noted that Briggs confused the 1846 record of six parallel trench mines with the shaft-and-gallery system of later nineteenth-century date (O’Brien 1989, 9–10, fig. 2). He had correlated the six trench mines recorded in 1846 to the 50 ft. and 100 ft levels recorded on Duffy’s map (Figure 2.6). It is clear from Duffy’s (1932) description, and his 1:2500 field map (Figure 2.5) that those levels represent underground tunnels at depths of either 50 ft or 100 ft. This is confirmed by Mahr’s sketch plan, which provides a sectional profile showing the relationship of two of these tunnels to the South Shaft (Figure 2.5).

Subsequent publications by Briggs reiterated his view that the 1846 discoveries at Derrycarhoon relate to copper mining during the post-medieval period. In 1986, with the support of the University of Oxford, he secured a radiocarbon date for the Derrycarhoon tube, which places the object in the late medieval period (in Hedges et al. 1988). Briggs regarded the 1846 discovery as representing six trench mines of post-medieval date, one of these being Jackson’s ‘open-cast’. He also rejected Jackson’s interpretation of Duffy’s six ‘shallow trial workings’ as Mount Gabriel-type mines, suggesting those ‘…were probably trials for copper made around, or shortly after the re-discovery of the trenches’ (Briggs 1984, 38).

The 1989 review also considered the significance of a radiocarbon date for the Derrycarhoon tube (Hedges 1988), in relation to the trench mines where it was supposedly found, and other finds from the site. The possibility of three periods of mining (prehistoric, later medieval and nineteenth century) was considered. That could not be confirmed in the absence of supporting evidence. Radiocarbon dating of the tube did confirm activity during the later medieval period, but could not constitute a priori evidence of mining as the purpose of that object was unclear (O’Brien 1989, 16–17). The 1989 publication concluded the history of this mine could only be clarified by detailed survey, archaeological excavation and radiocarbon dating. For various reasons this was not undertaken until 2007, when the site was surveyed in detail, with sample excavation in 2010 and 2011 (O’Brien 2013; O’Brien and Hogan 2012). Further work was undertaken in 2013 with a geophysical survey of the trench mines, followed by a palynological study in 2018. The results of this work are presented here, beginning with an understanding of the mine landscape, its geological setting and archaeological features.

The author first considered the 1846 finds at Derrycarhoon as part of a doctoral thesis on prehistoric copper mining in south-west Ireland (O’Brien 1987a, vol. 2, 199–226). This was based largely on a review of documentary sources, followed by a first visit to the mine in 1984 when no detailed fieldwork was undertaken. The publication of that study (O’Brien 1989) examined the question of dating in light of recent excavation results from nearby Mount Gabriel (O’Brien 1987b; O’Brien 1990; O’Brien 1994). The results from Mount Gabriel supported Jackson’s belief 28

3 The Mining Landscape Derrycarhoon mine is located on the north-east side of the Mizen Peninsula in West Cork (Figure 3.1). This is the most southerly of the peninsulas of south-west Ireland, approximately 12km across on its eastern side, tapering to 4–5km wide at the south-west end, where Mizen Head and Brow Head are the southerly points of mainland Ireland. It is bounded to the north by Dunmanus Bay and the ridge-like Sheep’s Head peninsula, beyond which is Bantry Bay and the mountainous Beara Peninsula. To the south lies Roaringwater Bay, with its indented coastline and archipelago of small islands (‘Carbery of a Hundred Isles’). The maritime environment is influenced to a great extent by the North Atlantic drift, contributing to a mild temperate climate with high rainfall. The coastline is highly erosional in the face of Atlantic waves, while the interior is a low-energy environment, with many streams but few large rivers.

summit to 216m OD at Knocknageeha at its western end. That rugged interior is formed by Late Devonian (Old Red Sandstone) geology, with progressively younger rocks of the Lower Carboniferous along the coastal margins and adjacent bays. The basic landform was created during the Variscan (Hercynian) mountain-building period, roughly 300 million years ago, which left a folded structure of near east–west parallel ridges and valleys. Those landforms were subsequently moulded by Tertiary erosion and Quaternary glaciation, the latter leaving drift deposits as parent material for acidic soils with varying degrees of podzolisation today. There are extensive tracts of blanket bog in hill and lowland settings, the product of a longestablished climatic regime with high rainfall. Derrycarhoon mine is located at 165m OD on the southern slopes of a hill ridge (the Knocknamaddree Anticline) that extends east from Mt. Corin (288m OD) to Mt. Kid (298m OD). Mount Gabriel (408m OD) is clearly visible from the site, 8km to the south-west. The area is drained by the stream tributaries of the Bawnaknockane River that flows south into Ballydehob harbour. The mine is c.500m west

Mizen is considerably less mountainous than the other Cork/Kerry peninsulas, with a hilly spine at elevations of 200–400m OD (Figure 3.1). The highest relief is formed along the Mount Gabriel ridge, from 408m OD at the

Figure 3.1 Landscape setting of Derrycarhoon mine in the Mizen Peninsula of West Cork (drawing: Nick Hogan).

29

Derrycarhoon of the overlying Castlehaven Formation, consisting mainly of purple mudrocks with subordinate sandstones (Figure 3.5). Reilly and Graham (1976) interpreted the sandstones as channel deposits and the mudrocks as overbank alluvial plain deposits.

of the main Ballydehob–Bantry road. Historic mapping suggests this was an area of marginal farmland during the nineteenth century, with clusters of small fields of improved grassland in an landscape of coarse hill grazing, blanket bog and intermittent rock outcrop. The townland name suggests the area was wooded in earlier times (Dhoire Ceathrún –‘oakwood of the quarterland’; source: logainm.ie). Until recent years the mine was exposed within a c.2000m2 clearing in dense conifer plantation planted possibly in the 1980s (Figure 3.2). Prior to felling, a forest track led into a clearing where a large spread of broken rock spoil and some mine workings were visible. That forest was clear-felled in 2014 (Figure 3.3), and is currently being re-planted.

Towards the top of this sequence, there is a rapid loss of red colouring with the overlying Toe Head Formation of late upper Devonian age comprised mostly of grey and green sandstones and mudrocks. These rocks outcrop along the northern side of the Mizen peninsula and along the southern coastline. The Toe Head Formation accumulated in a low-lying coastal plain. An ensuing marine transgression resulted in the deposition of shallow water mudstones and sandstones, to form the overlying Old Head Sandstone Formation. The latter outcrops on the north side of the peninsula and to the west of Ballydehob Bay, as the first geology to show marine influence in the area. It is overlain by the fine-grained Kinsale Formation, which was deposited in a shallow sub-tidal environment that represents the encroachment of the Carboniferous sea. The Kinsale Formation outcrops on the north side of the peninsula and inland from Roaringwater Bay to Skibbereen.

3.1 Geology and Mineralisation The geology of south Munster consists mainly of sedimentary rocks of Devonian (Old Red Sandstone) and Carboniferous age (Figure 3.4). These were deposited to a thickness of approximately 7km in a flood plain environment, within what is known as the ‘South Munster Basin’ during the upper part of the Palaeozoic era, 400–300 million years ago. The geology of the Mizen peninsula is typical of the basin margin sequence (Pracht and Sleeman 2002; MacCarthy 2007). The oldest rocks are those of the Sherkin Formation which are of late middle Devonian (Givetian) or early upper Devonian (Frasnian) age. These outcrop mostly on the southern side of Roaringwater Bay, from Clear Island to Sherkin and inland from Baltimore. The core of the peninsula is formed by non-marine rocks

As already mentioned, these sedimentary rocks were subjected to the intense earth movements of the Variscan orogeny. South-west Ireland is located at the western end of a continental fold belt that extends east from Dingle Bay in Co. Kerry to Dungarvan, Co. Waterford. That mountainbuilding period left its imprint in the formation of hills and

Figure 3.2 Aerial photo of Derrycarhoon mine, 1990 (photograph: William O’Brien).

30

The Mining Landscape

Figure 3.3 Aerial drone image of Derrycarhoon mine after felling of conifer plantation, 2014. Spoil heaps of central mine area visible left of centre. (photograph: Nick Hogan).

mountains, and in the coastal landscape of peninsulas, rias and offshore islands. The major fold axes extend southwest to form the anticlinal Old Red Sandstone peninsulas and inland ridges separated by bays and valleys floored with rocks of the lower Carboniferous. The Mizen peninsula is a major anticlinal fold structure, on which an alternating sequence of second order fold structures are superimposed. These include the Mount Gabriel syncline that runs down the centre of the peninsula to create the highest ground on that ridge (Figure 3.1). This is bordered to the north and south by the Knocknamaddree and Ballydehob anticlines, beyond which there are further synclinal structures. This folding extends south into Roaringwater Bay, to produce an east–west lineament of small islands separated by shallow bays. Local landforms and outcrop are influenced by minor folding, fault structures and joint planes in siliciclastic rocks with strong cleavage development.

Major quartz-sulphide veins, with higher grades of copper mineralisation of more varied types, along with other metals in minor or trace amounts.

As discussed in Chapter 2, there are numerous occurrences of copper minerals in the Mizen Peninsula, many of which were worked at various times (Figure 2.1). This copper mineralisation is hosted in rocks of the upper Devonian, which were altered by low-grade metamorphism during the Variscan orogeny (c.300 mya). Three broad styles of mineralisation are recorded (Snodin 1972; Reilly 1986; Ni Wen et al. 1999):

The most common copper minerals are chalcocitedjurleite (Cu2S), bornite (Cu5FeS4) and chalcopyrite (CuFeS2), with malachite (Cu2CO3(OH)2) and occasionally azurite (Cu3(CO3)2(OH)2) in the oxidation zone. These occur as small, scattered, rather ill-defined and irregular disseminations, visible at outcrop as lightto-heavy copper carbonate smear, mainly the bright green colour of malachite, or as finely disseminated and irregular monomineralic or composite blebs of grey or yellow copper sulphides, six centimetres to less than ten microns in size (Snodin 1972). They also occur as irregular to rounded patches and lenticles less than 0.15m in maximum diameter, and as sulphide strings up to one metre in length. The concentration (‘grade’) of metal present varies considerably given the disseminated nature

The first type, copper-bed mineralisation, is widespread across the upper Devonian geology of south-west Ireland (reviewed by Snodin 1972, with studies by Ni Wen 1991 and Ixer 1994). In Mizen, copper-beds occur as green-grey bedded sandstone units within thicker purple mudrock sequences in the upper part of the Castlehaven Formation into the lower part of the overlying Toe Head Formation (Figure 3.5). These can extend up to 350m in length, with the copper minerals concentrated over strike and dip lengths of less than three metres. The mineralisation was most likely mobilised from these ‘red-beds’ and concentrated within channel sandstone units of higher porosity by diagenetic processes.

1. Sedimentary mineralisation where stratiform deposits (‘copper-beds’) have low-grade disseminations of copper sulphides and copper-iron sulphides, with secondary oxidation minerals. 2. Minor quartz-calcite-chlorite veins with similar mineralisation to the copper-beds. 31

Derrycarhoon

Figure 3.4 Bedrock geology of Co. Cork (drawing: Nick Hogan, based on 1:500,000 solid bedrock mapping, Geological Survey of Ireland).

of this mineralisation. Snodin recorded copper values of 0.4–6.4%, which is probably representative of the higher grades over distances of one metre or less.

or ‘pipes’ several metres thick. Quartz lodes of varying size were mined at some 30 locations in West Carbery during the nineteenth-century, with large operations at Cappaghglass, Coosheen, Crookhaven, Ballycummisk and Ballydehob on the southern coastline of the Mizen peninsula (Cowman and Reilly 1988). While many ventures were not successful, others yielded significant amounts of copper, such as the 6000 tonnes of ore raised at Ballycummisk c.1857–1877. This was still a small mine compared to an estimated 300,000 tonnes of copper ore mined in that period from larger quartz-sulphide lodes at Allihies, at the western end of the Beara Peninsula (Williams 1991).

The copper-beds are often intersected by minor quartzcalcite veins containing chlorite, which occur widely in the upper Devonian geology of south-west Ireland. These were formed within compressive fractures by remobilization of country rock during the Variscan orogeny (Snodin 1972). They are often barren, but can carry some mineralisation where they intersect the cupriferous strata. The nineteenthcentury geologist, Henry Kinahen, noted these ‘flying veins of quartz’ form ‘bunches of ore’ where they intersect the copper-beds (in Jukes et al. 1861, 20). They can vary 0.01–0.3m in thickness and usually pinch out along strike and dip over distances of less than 20m. They are generally concordant with the bedding of the country rock, and may branch into smaller strings and zones of parallel veins. Where mineralised, these veins tend to have the same minerals as the stratiform copper-beds, suggesting the metal was mobilised from that source.

The geology of Derrycarhoon This mine lies on the boundary of the Castlehaven Formation and Toe Head Formation of Palaeozoic/Upper Devonian age (Figure 3.5). The former is comprised mostly of purple and minor green mudstone and siltstone, with thin green beds of fine sandstone (Pracht and Sleeman 2002, 12). The Toe Head Formation consists of mostly green channel sandstones and siltstones, with thin laminae of finer purple mudstone (ibid. 13). The Geological Survey of Ireland placed the mine within the non-marine Castlehaven Formation (MacCarthy, Pracht and Sleeman 2002), whereas later mapping shows it inside the marinetransition Toe Head Formation (MacCarthy 2007). While that boundary is gradational, the start of the Toe Head Formation is regarded by some as the first appearance of

The most important copper deposits in economic terms in West Carbery are the major quartz-sulphide veins (‘lodes’). These orebodies have a varied mineralogy of copper sulphides, copper-iron sulphides and some fahlore minerals, as well as iron-manganese, lead and silver, and a number that were mined for barytes in the later nineteenth century. These veins are generally less than one metre in thickness, but laterally extensive, swelling to oreshoots 32

The Mining Landscape

Figure 3.5 Bedrock geology of Derrycarhoon area (drawing: Nick Hogan based on MacCarthy, Pracht and Sleeman 2002).

33

Derrycarhoon a sandstone bed over 1m in thickness. This is recorded at Derrycarhoon, placing the mine just inside that formation (Unitt pers. comm.). In structural terms, Derrycarhoon occurs on the northern limb of the Knocknamaddree Anticline, steeply dipping to the north-west (Figure 3.5; Pracht and Sleeman 2002, fig. 10).

Duffy’s 1929 survey records sedimentary copper-beds at Derrycarhoon, where green channel sandstones, as well as calcareous conglomerates (‘cornstones’) carry small disseminations of copper sulphide and copperiron sulphide minerals with secondary malachite (Figure 2.5; Duffy 1932). While the copper deposit has not been studied in detail, there is some unpublished mineralogy for surface spoil in the mine (Keele 1969; Snodin 1972; Ni Wen 1991; Ni Wen et al. 1999). This confirms the presence of disseminated copper sulphides (chalcocite Cu2S and the closely related djurleite Cu31S16) and copper-iron sulphides (bornite Cu5FeS4 and chalcopyrite CuFeS2), as well as secondary carbonate minerals, principally malachite Cu2(CO3)(OH)2. References in the Mining Journal to ‘purple copper ore’ is probably bornite, while the ‘grey ore’ probably refers to chalcocite (djurleite), which has a similar grey-black colour and metallic luster in low-grade hand specimen to fahlore minerals of the tetrahedrite (copper-antimony)–tennantite (copper-arsenic) group. An exploration drill log in 1963 suggested the ‘tetrahedrite’ in quartz vein at Derrycarhoon may be specular hematite (see below). Furthermore, the presence of fahlore is not confirmed in chemical analysis of the Derrycarhoon mineralisation (see below Chapter 8.4).

The early trench mines at Derrycarhoon followed thin concordant bands of grey-green sandstone with disseminated copper minerals, interbedded within a sequence of fine purple rock, mostly siltstone and mudstone. The Bronze Age miners extracted the hydroxycarbonate mineral, malachite, produced by surface oxidation of lowgrade copper sulphide minerals. Quartz veins parallel or at a high angle along strike to the copper-beds are also likely to have been a source of copper. Nineteenth-century sources for the mine record ‘several parallel lodes near each other containing rich grey and purple copper ore and large deposits of carbonate of copper were laid open by surface trials in 1846–7…’ (William Thomas, Mining Journal 1880, 585). In 1929 the geologist, T.J. Duffy noted ‘these mines were opened in beds of grey grits and slates’ in a sequence of purple slate and flaggy grits (Figure 2.5; Duffy 1932, 26). He identified four separate ‘beds of grey grits (sandstone) traversed by quartz strings and stained by green carbonate of copper (malachite). These include the 1.8m wide South Shaft lode and the 3m wide North Shaft lode, separated by c.24m of purple mudrock. The geological strike of these beds is west/south-west and they dip very steeply to the north. Duffy also recorded two parallel lodes in the northern mine area, consisting of thin beds of ‘soft grey grits showing green carbonate of copper’, in which six ‘trial’ workings were located.

An early analysis of two museum samples of quartz vein from the mine spoil at Derrycarhoon revealed copper concentrations in excess of 35% (Table 3.1; Butler in Coghlan et al. 1963). This suggests that some of the Derrycarhoon ore was quite rich, even if most was of the lower grades typical of the copper-bed mineralisation. The richer ore is likely to have come from small bunches (pipes) in quartz veins concordant with those copperbeds. This would account for the 46 tons of copper ore sent to the Swansea smelters in June 1848 (Mining Journal 1848, 303; recorded as ‘between 30 and 40 tons of rich grey copper ore’, Mining Journal 1875, 900). There is also a record of one ton of 3% copper sent in 1856 from Derrycarhoon to Swansea (Mining Journal 1856, 208).

Some nineteenth-century reports mention ‘veins of rich grey ore running through these mountains’ (Mining Journal 23, 312; 28, 807). At the mine itself there are reports of ‘rich grey ore and carbonate of copper’ (Mining Journal 45, 900) and ‘several parallel lodes near each other containing rich grey and purple copper ore and large deposits of carbonate of copper..’ (Mining Journal 50, 585). There are also records of copper-bed mineralisation in the neighbouring townland of Shronagree, c.1km east of Derrycarhoon mine, where mining trials were conducted in the nineteenth century (Jukes et al. 1861; Cole 1922). Geological Survey of Ireland mapping in the nineteenth century, and modern stream geochemistry (Keele 1969), confirm the occurrence of copper beds there and in the adjacent townland of Ballybane West.

The presence of quartz-carbonate vein material in surface spoil at Derrycarhoon, together with the exposure of quartz veinlets in the trench mines, as well as the aforementioned records of nineteenth-century production, indicates the importance of minor quartz lodes at Derrycarhoon. The early mines trenches extracted oxidised copper minerals from steeply dipping copper beds and associated strike veining.

Table 3.1 Optical spectrographic analysis of two museum mineral samples from Derrycarhoon mine (details in Butler in Coghlan et al. 1963). All ppm except where percentage concentrations are given. The GSI-19 sample was identified as bornite and malachite, while the GSI-20 sample is given as tetrahedrite , malachite and calcite. The following elements were also analysed in both samples but not detected: zinc, lead, arsenic, molybdenum, cadmium, and antimony. The absence of antimony questions the identification of tetrahedrite in GSI-20, suggesting the copper mineral present was chalcocite. Ref.

Cu

Fe

V

Cr

Mn

Co

Ni

Zn

Ag

Sn

Pb

Bi

GSI-19

35%+

2–4%

150

100

270

10

10

1000

1700

150

220

350

GSI-20

15–20%

3–5%

250

100

>0.5%

30

5

400

500

nd

100

nd

34

The Mining Landscape Recent mineral exploration at Derrycarhoon

and striking between 075° and 080° magnetic. Bedding was very rarely detected and where seen, dips were northwards at 35–65 degrees’ (Murphy 1962b).

The most detailed information on the geology of this mine comes from mineral exploration in the modern era. That prospecting was undertaken prior to the plantation of conifer forestry in the 1980s, when there was greater exposure of bedrock and mine features at the site. From 1962–4 Derrycarhoon was prospected by a Canadian exploration company, Northfield Mines Inc., part of a larger concern, the Lower Limestone Syndicate. Northfield conducted surface and underground sampling, as well as geophysical and geochemical survey of the mine environs, culminating in a drilling programme there in 1964. The results are available in open-access files of the Geological Survey of Ireland (secure.dccae.gov.ie/goldmine/index. html). These unpublished reports, dated from 24 July 1962 to 15 June 1964, contain much detail on the underground workings, geology and mineralisation of the mine.

In terms of mining potential, the October 1962 report concluded: ‘A disappointing – though intriguing – feature of both “veins” is the virtual absence of present-day evidence as to why these sites were selected for mining operations. Apart from a small rupture or schistosity-slip in the No.2 vein (as seen in the open stope), the writer has seen no significantly strong geological structure which might have localised mineralisation along these veins, nor evidence of any distinctive host rock. Signs of mineralisation are extremely meagre in the roof and walls of the open stope, and in outcrops closely adjoining the worked ground in the area of Nos. 2 and 3 veins. Presumably the mineral shoot was very localised and worked out in toto. Some mineralisation can be seen in the drift at the south end of the adit (= No. 2 vein), confined for the most part to a width of less than 2 ft. on the south (H.W.) side of the drift. Economically, however, this mineralised section is unimpressive, consisting of 2 or 3 discontinuous and thin (less than ½ inch) veins of chalcocite along the nearvertical schistosity, with rare blebs or ‘nests’ of mineral and/ or a very fine dissemination in some of the green and grey compact siltstones or fine grits, and patchy malachite staining in some of the intercalated grey-green to dark grey shales. The latter are in places rather strongly sheared over widths of up to 18” or so – as seen in various parts of the old workings – but the mineralisation is not simply a function of the degree of sheering, but rather it would seem to the neighbouring presence of more massive beds containing disseminated chalcocite. The drift here was probably driven not so much because a good ore-shoot had been cut, as because some mineral had been encountered, just before they breached the old x-cut, so they drove along the No. 1 vein as they could do so just above water level without pumping’ (Murphy 1962b).

The Northfield prospecting licence was taken up in February 1962, with a geophysical survey (induced polarization/ resistivity) over 1115m2 undertaken by McPhar Ltd (Hallof 1962). This revealed a significant anomaly north of the mine, with a recommendation for geochemical survey and possibly drilling, which the company did not pursue for licensing reasons. The geophysical survey did not identify any significant mineralisation, though geochemical soil sampling revealed some continuity of low-grade copper over a distance of 300m along strike from the mine workings (Murphy 1962a). A progress report in October that year (Murphy 1962b) records efforts to drain the underground workings. The company encountered significant flooding and pumping problems, as well as infill that did not permit access to the main stope. An inspection of around 400ft (122m) of accessible levels and cross-cuts did not identify significant mineralisation. The following observations were made: ‘The rocks out by the old workings are the normal ones occupying much if not most of the Derrycarhoon concession, viz., silty shales, fine siltstones, shales, and very fine grits – in that order of abundance – of purple, green, and grey colour, with some intermediate types. In general, the coarser beds are green or grey rather than purple, and are sometimes strongly, though finely, micaceous. For the most part, the copper mineralisation consists of a fine dissemination of chalcocite, less frequently of small “clots” of chalcocite, and more rarely of thin veins or stringers of the same mineral generally running parallel with the schistosity. The disseminated type seems from visual examination, to be restricted to the green, or greygreen, more gritty beds, and seems to be absent in all the purple rocks. A dissemination is sometimes present in the green shaly beds, but the mineral is much more noticeably seen as malachite staining on schistosity surfaces, or less obviously as veinlets concordant with the schistosity. This, in the old workings, is near-vertical (80–90 degrees), typically dipping south, though sometimes to the north,

The Northfield records contain a surface survey of the mine landscape (Figure 3.6). A report on the first year of prospecting at Derrycarhoon concluded ‘…that any new mineralised zones would be limited in horizontal and vertical extent (i.e. small pods)’ (Thompson 1963). There is also a plan of the old mines at Derrycarhoon and nearby Shronagree, with details of back-sampling locations in those workings (Murphy 1962c). This drawing has the following annotation on the geology of the mines: ‘The rocks in all these old workings [Derrycarhoon and Shronagree] belong to the same suite, viz.: interbedded, weakly to moderately schistose, siltstones, silty shales and fine grits – in diminishing order of abundance. The rock colours are light purple, purplish-grey, green, greenishgrey, and dull grey – again listed in order of decreasing abundance. Copper mineralisation occurs as 1) chalcocite in the form of scattered specks, and less frequently as tiny “clots” and small veinlets or stringers running 35

Derrycarhoon

Figure 3.6 Original plan of Derrycarhoon mine made by I.S. Thompson, Northfield Mines, December 1963 (compiled by Nick Hogan based on open-source record, Geological Survey of Ireland).

concordantly with the schistosity (at least as seen in places). The chalcocite disseminated mineralisation seems to be restricted to the more massive and coarser textured greenish beds, and is suggestive of either selective replacement in this rock type, or else a syngenetic mineralisation in the greenish grits and coarser siltstones, followed by remobilisation and localised re-distribution of the chalcocite, either within parts of the gritty or silty beds, or else along planes of schistosity or shear adjoining these mineralised beds; 2) megascopic copper mineralisation also as films or stains of malachite (rarely azurite) on various surfaces: joint, schistosity, minor shears and slips etc. Malachite staining may be found in all the abovementioned rock-types, but is very rarely found in the purplish beds’ (Murphy 1962c).

The rocks in the 1910–11 adit are listed as ‘…purple and purplish-grey, with dull grey, siltstones and silty shales alternating with a very subsidiary development of green and green grey siltstones and fine grits. Copper staining in this x-cut is nowhere in evidence. A schistosity or close fracture cleavage is generally present with steep dips (70–90°) usually to the south, though very locally to the north’ (ibid.) The 1910–11 adit breached end of ‘old x-cut (driven northwards from the old stope about the year 1865)’. Another note says: ‘Same rock types occur in [old] x-cut as in the 1910 adit, but chalcocite specks and local malachite staining are to be seen over sampled stretches’. The drawing records the southern end of 1865 ‘old crosscut’ is blocked off from old open stope by fill. It was noted that ‘from sound effects, the old open stope accessible from ground surface would seem to be 75–120 ft. distance away from the fill at the south end of the x-cut’ (ibid.)

The plan for Derrycarhoon also listed assay results for chip and muck samples from the underground drift and cross-cut. These mostly range