What caused the pike river mine tragedy?

Answer 1

The Pike River Mine disaster occurred on 19 November 2010, 50 kilometres northeast of Greymouth, in the West_Coast_Regionof New_Zealand'sSouth_Island. An explosion occurred in the mine at approximately 3:30 PM. At the time of the explosion 31 miners were present in the mine. Two miners managed to escape through a ventilation shaft; they were treated for moderate injuries and released from hospital later that day. The remaining miners were believed to be at least 1,500 metres (4,900 ft) from the mines entrance. Following a second explosion on 24 November at 2:37 PM NZDT, the 29 remaining miners are believed to be dead. Police Superintendent_(policeGary Knowles, the man in charge of the rescue operation, said he believed that "based on that explosion, no one survived". It is New Zealand's worst mining disaster in 96 years, and the nation's worst loss of life since the 1979 Air_New_Zealand_Flight_901.

Answer 2

a gas build up in the mine causing an explosion