On 31 July 1972 at 2:47am, an explosion occurred in the number five shaft at the Box Flat Colliery, the result of spontaneous heating of fallen coal. Reduced airflow due to fan stoppage also contributed to the heat increase.

The heating resulted in the development of a large fire developed approximately 300 metres underground. Efforts to contain or extinguish the fire were unsuccessful. Gases generated by the fire as well as coal dust caused explosions throughout the mine.

Seventeen men were killed instantly in the explosion – 14 underground and three at the surface. Among the fatalities were nine officials and employees of the mine and eight men from the mine's rescue station. A further 17 were injured.