A hole about 12 metres across has opened on land next to a primary school in Wales.
The BBC reports a smaller hole appeared on the same site near Ysgol Rhes-y-Cae on Halkyn Mountain last year.
It was capped, but a hole almost twice the size has now appeared. The school has asked parents and children to stay away from the area.
The landowner, who has to do the remedial work, has 24-hour monitoring in place.
Halkyn Council member Colin Legg said the area is known to contain disused mine shafts.
The BBC reports Halkyn has a lead mining history which dates back centuries. There is also an extensive cave system.
Mr Legg said other shafts have collapsed and opened on Halkyn Common in the past.
