On 20 September 1975 at approximately 5 pm, an explosion occurred in the underground areas of the Kianga No 1 mine in central Queensland. Thirteen people working in the No. 4 North Section of the mine at the time of the explosion were killed.

In accordance with section 74 of the Coal Mining Act (1925) an inquiry was held to investigate the incident, with emphasis on determining the reasons for the disaster. The inquiry commenced on 10 November 1975 and closed on 24 November. Evidence presented to the inquiry showed the mine worked on a board and pillar system. This area was not extracted to the required height, thus coal was susceptible to spontaneous combustion. The inquiry found that the explosion was initiated by a spontaneous combustion source which ignited inflammable gas and was propagated by the existence of coal dust.