A sinkhole has developed near the Galmoy mine in Co. Kilkenny.
The hole was first spotted by the mine operators on Saturday, some 300 metres from the nearest building.
The Department of Energy and Natural Resources says there are no public safety issues involved.
However the mining company is maintaining 24-hour security at the scene and a nearby road has been closed as a precaution.
Officials from Kilkenny County Council and the Environmental Protection Agency (EPA) are now liaising with the Department to work out what follow-up action to take.
County Manager Joe Crockett says it is not clear whether the event is connected with recent weather conditions, adding that there does not appear to be any risk to public safety or to the public water supply.
