ANNUAL REVIEW 2021
Historic Mines:
Bunmahon Shaft Collapse
by Eoin McGrath, Geological Survey Ireland and Laurena Leacy, Geoscience Policy Division There are many historic mine sites around Ireland. The responsibility of each site lies with either the private mineral owner / landowner or the State where the minerals are State-owned. Under the Minerals Development Acts 1940-1999, the Minister for the Environment, Climate and Communications may carry out works to make safe openings into underground workings, such as shaft and adits, where State-owned minerals have been extracted. The Minister may also prepare a plan for the long-term rehabilitation of a former mine site, regardless of whether the minerals extracted were State owned or privately owned under the Part 9 of the Energy Miscellaneous Act 2006. Examples of the rehabilitation of old mines sites are Avoca, Co. Wicklow and Silvermines, Co. Tipperary. Following an internal Departmental reorganisation, the responsibility for managing works at old mine sites moved from the Exploration and Mining Division to the Geoscience Policy Division in the Department of the Environment, Climate and Communications. Since 2013, the
Collapsed shaft in Bunmahon showing the extent of damage to the overlying concrete slab and adjacent wall.
Office of Public Works has undertaken minor works at old mines sites on behalf of the Department.
COPPER COAST COLLAPSE In February of 2021, the Geoscience Policy Division received notification of a potential shaft collapse in the vicinity of the historic
mines that form the centrepiece of the Copper Coast UNESCO Global Geopark. In conjunction with Geological Survey Ireland, a site visit and inspection was organised to assess the collapse and the potential risk to the general public. The shaft collapse occurred in a farmyard in the Knockmahon area of the Copper Coast. Situated within 100m of a previous collapsed feature, the area is known to have multiple underground features associated with the historic mines. Comparison with the mine plans and sections identified this shaft as “Carew’s Shaft” which accessed the Stages Lode. This orebody originally outcropped at Stages Cove from where the ore for the entire area was loaded onto ships, hence the name of the lode. It continues inland for several kilometres and is accessed by over 30 shafts along its length, many of which have been infilled since the cessation of mining.
The shaft was identified as Carew’s shaft accessing the Stages Lode mineralisation.
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The surface feature was characterised by the original shaft, with a broad collapse feature immediately above it. The area had been covered in concrete for use as a livestock pen and this concrete slab had fallen into the shaft and was additionally badly undercut by the broader collapse
