Outbursts of coal and gas occurred at the longwall faces in two collieries recently. From investigation into these outbursts, it became evident that the burst coals were from “Ganbai” (soot-like coal) of the upper band in the working seams and from “Hiki” (drag coal) along the faults. Samples of gas and coal taken from the burst coal seams were analyzed, and it has been found that the burst coals protruded into the faces and the solid coals left around the burst cavities indicated low atomic ratios of hydrogen-carbon and oxygen-carbon, and the compositions of gas were mostly methane and nitrogen. Such facts lead us to the consideration that some outbursts occurring at coal faces as well as at coal headings are possibly related to gases and vapour which had risen through faults from magma reservoir.
