Part of the summary from the official Inquiry Report for “Blantyre Colliery Explosion” of 1877. Transcribed by myself word for word for the first time appearing online, this particular detailed section summarises the source of the gas and ignition which caused the explosion:
SOURCE OF THE GAS AND IGNITION
“Various opinions were given as to where the gas came from which caused the explosion. There was the known accumulation at the Stoopings and the various places where gas had at times flashed off in the workings; Speir’s dook, which was most shattered by the explosion, being one of them. The shattering in Speir’s dook was especially noticed. Mr. Moore, the inspector of mines of the district, and his colleague Mr Wales and Mr. Willis, who at his request, you (the Secretary of State) had sent to assist him, inclined to the opinion that gas came either from the humph coal above, or out of the waste or labyrinth of the formed stoops.
“No gas sufficient to overpower the ventilation had, however, previously been known to come from the roof, and it was only on one occasion that gas had ever been found in this waste, and then only at a fall. Speir’s dook was one of the places yielding most gas. During three days in September last, when the furnace was being repaired, this dook was the only place where gas was found. The probability is, we think, that the gas at or near the Stoopings fired first, and that the suck or exhaust drew out an increasing quantity of gas from the working faces, bringing the already highly charged air up to the explosive point, and that it went off like powder. The general direction of the blast was from the Stoopings, but some of the indications were markedly upwards as well as downwards in Speirs’s dook, a large pulley wheel being driven or drawn upwards.
“The conflict in this dook may be explained either by the rope which was blown from the Stoopings towards No 2 shaft having drawn the pulley up or the gas at the Stoopings being too pure to fire wholly without a further admixture of fresh air, and having to spread out to get it, the explosion may have returned and been repeated in the dook. Or it may have been like that, this dook having been proved to be one of the most fiery parts of the pit, the gas sucked from the coal may have produced the effects found there. The mine being dry and dusty, and the dust being mixed with highly inflammable splint coal, would help to spread the flame and give force to the explosion.
“With the mine making gas, and the accumulated gas, the actual point of first ignition is unimportant, also whether the ignition resulted from a shot or an open light. An open lamp, it seems, found within about 10 yards of the Stoopings and a flask of powder unexploded close to them. These, however, may have been blown with the blast from elsewhere. Two shots were also expected to be fired that morning at the Stoopings. Two or three of the gauze safety lamps at the Stoopings had been known to have had the gauze pricked through with a pick, but no harm resulted, as the blow extinguished the light before the pick was withdrawn. The Davy lamp, it is known, fires through the gauze in an explosive current moving at the rate of about 690 feet per minute. With gauze lamps used at the Stoopings the gauze may have passed the flame. There were also open lights in use close to the workings which were ventilated by the return air from the Stoopings.
“During the replacing of Stoppings, bratticing etc in penetrating the mine, large quantities of firedamp had to be dislodged. The amount of ventilation as stated was then reduced by about three tenths, giving to that extent less air for diluting the gases. The explorations, however, only commenced in the inner workings on the fifth day after the explosion. During the time that had thus elapsed no new faces were being opened to give vent of fresh feeders of gas, the old ones would be pinning off and the suck of the explosion would have partially exhausted the whole. The quantity of gas coming into the mine, prior to the explosion would therefore be much more than during the exploration.
The gas which was found in various parts of the mine both before and after the explosion indicated a general and steady discharge of firedamp. No sudden outburst sufficient enough to overpower the ventilation appears to have been experienced or apprehended prior to the explosion. Indeed, with open lights in use at the time of the explosion in nearly every part of the pits, the gas if it came from a sudden outburst, would in all probability have got lighted before being mixed to the highly explosive state indicated by the explosion, and would have burned with less violent effects. The ordinary issue of gas was such that assuming the evidence which was given before us to be true, in the opinion of one coal master an interruption of the air current during about four hours might have sufficed for the explosion; and in the opinion of another upon the same assumption and with the previous opinion before him, would not have required many minutes.”
Illustration: AI for Blantyre Project