‘There’s gold in them thar hills’ and apparently it’s still there! The Clogau gold mine, 6.5 km north west of Dolgellau, was last worked in 1998 when the cost of extraction exceeded the income from the gold produced. New and more stringent environmental management requirements were also a factor. Now that the economics have changed and the environmental management of mines are better understood, the extraction of gold is once again an attractive proposition. Gold Mines of Wales (GMoW) is taking steps to explore the possibilities with a view to re-opening this mine and a number of others in the Dolgellau Gold Belt.
Since its closure, the Clogau Mine has become a haven for a number swarming and hibernating bats, which means that GMoW has had to apply for a European Protected Species (EPS) license for temporary planned works, to rehabilitate and make the mine safe. Specifically, the works set out to clear a rockfall near the entrance to one of the adits, repair floors and install safety handrails and create a second means of egress for safety. This will enable stockpiled rock and targeted drill sampling to support estimates of the amount of gold available as well as waste rock and water sampling. These works are required to develop an operational plan for the mine compliant with the Mine Regulations 2014 and provide sufficient information to complete an Environmental Impact Assessment prior to the submission of a planning application for the future operation of the mine.
Environment Systems’ team of Ecologists was commissioned to carry out bat surveys in 2018 and 2019 to identify the use of the planned work zones by bats and to design mitigation measures as necessary. This included swarming surveys using harp traps, mist nets, automated detectors and hibernation surveys. During the hibernation surveys lesser horseshoe bats and Natterer’s bats were detected and swarming bats surveys detected several other species. It was evident that the planned works would result in the disturbance of roosting bats. The mitigation measures put forward will be beneficial, in the long-term, to the bat species encountered on site by retaining flight routes to underground hibernation areas and retaining habitat above ground to support swarming.
As well as the swarming and hibernation surveys, a Preliminary Ecological Appraisal (PEA) which included an Extended Phase 1 Habitat Survey was undertaken of the land surrounding the mine which consists predominantly of livestock pasture, coniferous timber plantations and natural woodland. Marshy grassland and wetlands associated with the nearby Mawddach estuary also come into play. This mosaic of habitats provides a range of places for bats and other protected and priority wildlife to shelter, breed and feed. The mine itself is likely to be part of the ecological network that supports bats. For this reason, open spatial data were used to carry out an assessment of connectivity resilience between known breeding roost sites and the mine.
The application for the EPS license was successful and, at the time of writing, the preliminary repair work is underway with GMoW complying with the Mine Regulations 2014 and HSE health and safety requirements for working the mine. Works are specifically planned to avoid the period when bats are expected to be found using the mine for hibernating with a review of the gold and rock sampling results to guide the next steps.