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81. Summarising the results of the Inquiry, I consider it established that :–

(1) The explosion originated with the firing of a charge of sheathed permitted explosive in a shot-hole drilled in the roof and directed towards the waste behind and immediately contiguous to the No. 2 Dip longwall machine-cut conveyor face in the Six Quarters Seam.

(2) Before the shot-hole was charged it had not been examined for breaks running along or across, contrary to the requirements of Clause 6 (d) of Part II of the principal Explosives in Coal Mines Order.

(3) The shot-hole passed through a roof break or breaks and the inner end of the hole either made contact with, or was in very dose proximity to, a bed-separation cavity containing inflammable gas which was continuous with an accumulation of explosive gas in the contiguous waste or goaf.

(4) The firing of the shot ignited the gas in the bed-separation cavity.

(5) The gas in the cavity burned for a short interval of time and the flame travelled along the cavity until it reached the explosive mixture in the waste, causing a firedamp explosion.

(6) The flame of the explosion traversed several working faces and nearly 2,000 yards of roadway, including several inbye conveyor roads, about 60 yards of the main return airway and nearly half a mile of the main intake haulage road.

(7) The explosion was marked by few signs of extreme violence.

(8) The initial explosion was almost certainly one of firedamp only. The blast from this initial explosion raised a dust cloud ahead of it and as the explosion travelled on its path the nature of the combustible mixture gradually changed from firedamp-and-air through firedamp-coal-dust-and-air to practically coal-dust-and-air alone, before the flame was finally extinguished by excess of stone dust in the dust cloud.

(9) The excess of coal-dust in the dust cloud was mainly derived from under the roadway conveyor structures and from the recently deposited top layer along the whole length of the inbye conveyor roads, while the stone dust was mainly derived from the main intake haulage road. This stone dust was projected ahead of the coal dust blown from the inbye conveyor roads and did not contribute to the extinction of the explosion until the flame had travelled nearly half a mile outbye along the haulage road.