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Mr. Kilpatrick, certificated Manager of the mine, was of opinion that it was a gas explosion in Moore's place, and, while admitting that there was evidence of coking in the roadways, he answered that the force of the explosion might carry coal off the sides — not exactly coal dust — and that that coal would be coked.
Dr. R. V. Wheeler, Professor of Fuel at Sheffield University and Director of the Mines Department Experimental Station,. who for many years has conducted important researches with reference to the explosibility of coal dust, gave learned and valuable evidence. In reply to Mr. Wilson, he said he thought that the greatest possibility lay in the ignition having occurred in Moore's place; that the probabilities were that, after the deputy had made his examination upon charging the shot, a feeder of gas had issued and produced an explosive mixture. He did not think that the explosive mixture extended much. beyond the end of the brattice, but it was an explosive mixture; that is to say, it was not a sudden outburst of gas but more a slow feeder of gas which had mixed with the ventilating current and produced an explosive mixture. He thought that the explosive mixture was ignited by the shot. At this point he had the gravest doubts, but he thought, weighing the probabilities, that it was the shot in Moore's place which caused the ignition. From then on, he was satisfied that the explosion was propagated by coal dust throughout the whole of its extent."
"Question: You have heard various witnesses describe this place as being naturally wet throughout?
"Answer: Yes.
"Question: From that it would not exclude from your mind the possibility of there being numerous dry places?
"Answer: I would not say that. I do not think that the dry, or what one might at first sight call damp places need he numerous; quite a small proportion of drier places than others would be capable of propagating that flame, as experiments which we have made have shown — that an explosion is capable of bridging over quite a long distance of thoroughly wet road, if over a certain portion of that. road quite a small section of sufficiently dry dust is present; but when I say sufficiently dry, the experiments have shown further that that dust can he in the nature of a thin mud, and yet he capable of propagating the flame.
"Question: Your experiments have proved that coal dust in the nature of even a thin mud would he sufficient to carry on an explosion?
"Answer: Yes.
"Question: Then if the management of this Colliery had believed that this place was sufficiently wet to prevent anything, as was said by Mr. Smith with reference to another witness apparently they have been living in a fool's paradise?
"Answer: I should say they have fallen into an error of judgment, an error of judgment, I may say, which it was very easy for them to fall into. It is difficult to believe, I agree, that dust which is in the form of fine mud could propagate an explosion, and it is certainly impossible to tell by merely looking at dust as to what is the proportion of water that is contained in it.
"Question: And the conditions you have described would exist throughout these workings?
"Answer: I have not been through the workings before the explosion. I can only judge from what has been said in the course of the evidence. By different witnesses statements were made as regards the dust being damp; some witnesses said it was dampish. Of course, these are only quite general terms, but I gather that it was not in some of the witnesses opinion swimming with water from end to end, and it is only that condition — swimming with water from end to end, brattice, floor, sides and roof — which would prevent the carrying on of this explosion by coal dust.
"Question: And I think there is not much doubt that in the minds of most people there has been an impression that if places were damp throughout an explosion could not he propagated?
"Answer: I think that is so. . . I have had that impression myself."
I have quoted the evidence of the experts at some length, because I consider that the question how this explosion was propagated is of such serious importance that the opinions which have been expressed should be widely known and brought to the knowledge of the persons responsible for the safety of mines in this country.
The theory put forward by Mr. Steel, the Agent and Works Manager, and Sir Richard Redmayne, who was called by the owners of the colliery, that the distillation of excrescences from the coal side was probably the cause of coking appears to ignore the fact that coal dust, even though damp, must have existed in the workings, and, even if the coal was distilled, the dust must also have played its part in propagating the explosion.
There was a divergence of opinion at the inquest, judging from the questions put by the miners' representatives, as to the starting point of the explosion I have already expressed my opinion about this, but whether that point was in Moore's place or in Osborne's, dust must equally have been an agent of propagation.
There is a very simple explanation of Sir Richard Redmayne's point that the explosion travelled the return road. It will he seen, from the plan of the workings, that several, in fact the majority, of the working places were on the return side of Moore's place, and it is my opinion, having regard to the conditions obtaining in the district as revealed by the evidence and especially to the great amount of blasting done in the coal, that the most coal dust would be made and deposited at and near the working faces and not in the main haulage road. Other things being equal, an explosion follows the path where most coal dust exists.
After listening carefully to all the evidence and giving much consideration to the whole matter, I have arrived at the conclusion that, while the explosion originated by the flame from a shot igniting firedamp, it was propagated by coal dust, which was believed by the management, by reason of its dampness, to be harmless, but which proved to be otherwise.
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