Fiona O'Loughlin (Kildare South, Fianna Fail)
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872. To ask the Minister for Communications, Climate Action and Environment the position regarding the identification and monitoring of potential sinkholes; and if he will make a statement on the matter. [54402/18]

Seán Canney (Galway East, Independent)
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Identification and monitoring of potential sink holes is a broad and complex topic involving various potential formational mechanisms, both natural and induced. The vast majority of sinkholes are natural occurrences formed from the dissolution and erosion of soluble bedrock, such as limestone and gypsum units. Until sinkholes reach the near surface, they are very difficult to identify, let alone monitor. Features, resembling sinkholes, may occasionally develop above shallow underground mine workings. These features are specifically referred to as crown holes. The majority of abandoned mines in Ireland are not the legal responsibility of the State. As a result, the State does not undertake monitoring at these sites. At all current underground mining operations and recently-closed underground mines, subsidence monitoring is undertaken by the licensee or former mining operator. The results of monitoring at current mines and some closed mines are normally reviewed on a biannual basis by the Department of Communications, Climate Action and Environment. However, detailed subsidence monitoring provides no certainty that potential crown hole development will be identified. Crown holes, like sinkholes, are difficult to identify until the cavity breaks the surface.

Mining subsidence events, including crown holes, have recently occurred at the Drumgoosat gypsum mine in Co. Monaghan, which closed in 1989. Monitoring of this site, including subsidence monitoring, has been occurring since the 1980s. The three relevant authorities, Monaghan County Council, the Environmental Protection Agency and the Department of Communications, Climate Action and Environment, are working together to ensure that the company carries out the necessary investigations to understand the development of the recent subsidence events and that all appropriate actions are taken to ensure the health and safety of the local community.