Trent mine collapse drains lake 25 April 2013 Last updated at 08:09 A disused mine shaft has collapsed under a lake at a park in Stoke-on-Trent. People reported that the lake at Tunstall Park was rapidly draining on Wednesday evening, police said Fire crews and city council workers found a hole had opened up, caused by the collapse of a mine shaft, Staffordshire Fire and Rescue said. The area has been cordoned off and engineers from the Coal Authority are due to assess the damage later. Coal mining was a big industry in Stoke and there are numerous old shafts in the area.