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At this point it is necessary to consider from such evidence as is available the physical conditions existing in Moore's place and the adjoining workings on the morning of the explosion, in order to determine whether the explosion was one of firedamp per se or one of firedamp originally and thereafter propagated through the workings by the aid of coal dust.

The place consisted of a bord about 12 feet wide by 6 feet high. It was in solid coal, of which the following is a section at the face

Coal	3 ft. 5 ins. to 3 ft. 7 ins.
Shale Band	8 ins.
Coal	2 ft. 0 ins. to 2 ft. 4 ins.

It was driven a distance of 52 yards beyond the last pillar and ventilated by means of brattice cloth, the air travelling in along the tub road and returning on the rise side of the road at the back of the cloth to the return air-course

There is no precise information as to how near to the face the ventilating current was conducted, but it was stated that the ventilation was good, and the Deputy's report showed that during the examination made before the men entered on the morning of the explosion the place was clear of firedamp, though on the previous day it had been laid idle through the presence of gas.

Although coal dust would be produced in the working of the coal, especially in view of the amount of blasting done, the place is said to have been wet; and there can be no doubt that water was made, for, during the investigation after the explosion, a pool some inches in depth was observed in the dip corner of the place. The face and sides of the bord were, however, comparatively dry, though it was said by several witnesses at the Inquest that the conditions were entirely changed by the heat of the explosion. Moreover, it was also stated that not only Moore's place, but all the workings as far outbye as the stone mine at the top of the engine plane were regarded as naturally wet throughout, and that pools of water existed here and there along the roadways. Some witnesses described the workings as "damp," others as "dampish" and wet. There was, however, no actual evidence to show the degree of dampness which existed in the dust that was inevitably made in working the coal and must have been deposited on the sides, floor, brattice cloth and roof supports; for it was admitted by the management that no tests were made to ascertain whether it contained 30 per cent. of moisture and thereby satisfied the requirements of the General Regulations of the 30th July, 1920. I shall return to this later on.

Meanwhile, to revert to what happened in Moore's place, I have already said that the explosion originated at a shot fired at the coal face. That shot was fired in the bottom coal, which had been previously "holed" in the shale above practically to the full length of the shot hole. It was charged with a "Permitted Explosive" — an explosive which has passed the Home Office test — and was fired electrically. The coal had been properly holed and the shot had done its work, Some of the witnesses, basing their opinion on the smallness of the pieces mto which the coal had been blown, considered that the hole had been rather overcharged. The usual charge for a hole in coal was four to six ounces, but the exact quantity used in this instance was not known. Permitted explosives are not flameless, and there can be no doubt that flame was produced by the shot and initiated an explosion of firedamp. The Explosives in Coal Mines Order provides that "No shot shall be fired unless the shot-firer has examined with a locked safety lamp or other apparatus approved for the purpose by the Secretary of State the place where the shot is to be fired and all contiguous accessible places within a radius of 20 yards from the place, and has found them clear of inflammable gas," and further that "the shot-firer shall make an examination immediately before the firing of each shot and shall not fire the shot unless he finds the place where the shot is to be fired and all contiguous accessible places within a radius of 20 yards free from gas and in all respects safe for firing." It must be assumed that an examination was made by the deceased Weightman prior to the firing of the shot, but it is possible that, owing to the use of a lamp that was fed at the middle ring, four inches or so from the lamp top, there was a layer of explosive mixture near the roof which he did not detect, and that similarly there was a small percentage of gas also undetected in the body of the air at the coal face. No one can definitely say whether this was the case or not, but it is evident that the shot may have opened up a feeder of firedamp of considerable pressure and in sufficient volume to create an explosive mixture.

This leads to the question whether the ignition and explosion of firedamp was by itself sufficient to account for all the loss of life and the damage to the workings. A reference to Plan No. 3 will show that the whole of No. 1 section was traversed by the effects of the explosion right to the top of the engine plane where Thos. Telford was thrown with empty tubs against the side of the main level. No less than sixteen bodies showed signs of extensive burning — notable instances of these were those of Weightman (charred) in No. 6 level; Thos. Haigh (charred) in No. 7 level; Thos. Moore in the main engine plane between Nos. 5 and 6 levels; Thos. McDowell in No. 1 level; J. Brewster in the air-course between No. 3 level and No. 1 level; and Win. Carter in the longwall workings to the rise of No. 8 gate longwall section.

In addition to this, coked dust was observed at different points in No. 6 level, and in the engine plane. It was also observed on props in No. 1, known as the wet level." It was also found in Brewster's place and in No. 8 gate. The evidence of flame and the coking were practically coincident with the lines of force and mainly traversed the main intake and main return airways.

The force generated appeared to have been cumulative. There was little disturbance in Moore's level except at its outbye end where there was a fall; but from that point outbye falls of roof' were general over the main engine plane, as indeed they were over practically the whole of the district. There was evidence of considerable force at the two air crossings, but further outbye little damage was done, although there was sufficient energy left in the blast to displace the boards covering the upcast shaft. The outbye end of the engine plane and the drift, from the junction with this engine plane to the shaft, had been treated with incombustible dust.

Mr. Steel, the Agent of the Colliery, stated in his evidence that he had no doubt in his own mind that the explosion originated in Moore's place. "At the commencement it was a firedamp explosion . . . started from a shot ignited by the explosive." Firedamp must have been present in that place immediately before or at the time that the shot was fired. There must have been an explosive mixture, or it might not have been an explosive mixture, it might have been capable of being lit, capable of being burned, without causing an explosion. If the firedamp had been released from the coal . . . that, with the air coming into the place which was considerable, would create an explosive mixture. That exploded." He had known a gas explosion extend 800 yards without coal dust." He considered that a good outburst of gas would be carried, say, 400 or 500 yards as a gas explosion alone. . . . It has only come about 400 or 500 yards at the outside."

In answer to Dr. Wheeler, Mr. Steel added : "Well, it would partly develop into a coal dust explosion from these knobs and excrescences, as I have said, from the rough sides of the road." Further, he expressed the opinion that an explosive mixture was produced when the shot was fired, and his theory was that there was a small blower which made its way through the coal after Weightman had charged his shot, but between his charging the shot and going to fire the shot, and that that small blower created sufficient mixture to be ignited by the shot and then the blower caused by the shot formed a big flame afterwards. In reply. to Professor Poole, he also added that the coal (meaning the coal forming the roadsides) became distilled and gave off more gas and propagated the length of the explosion."

Mr. T. S. Durham, Mining Engineer to Lord Lonsdale, who visited the workings periodically prior to the explosion and assisted in the explorations afterwards, was asked whether he thought it likely that it was a dust explosion or was begun with gas and propagated through dust in the pit. He replied:

"Well, it is extremely difficult, I think, to define exactly what is a dust explosion, but to my mind what happened has been this, that there has been an ignition of firedamp in Moore's level, and, apart from a detonation, there has been an ignition of the gas, accompanied by a rolling flame, and added to by the gas coming off from the big blower; and I am satisfied that after that there has been a detonation, and it has been propagated through the district by something other than firedamp. Then I begin to get into difficulties as to what it is, and my own personal view, before hearing the views of anybody else, was that the wet dust about the place had been dried by this rolling flame and ignited by it. I have heard other views since and I have slightly modified my own views, but I think that is contributed to, to a considerable extent, by the propagation of the explosion." When cross-examined by Mr. Cape as to whether he "put much stress on the fact that this was a gas explosion and probably propagated with coal dust after that," he answered: "Yes, I do not say coal dust entirely as dust, but there is something other than gas has had a good deal to do with it. . . . It may he the dust dried by the flame and the heat and propagated in that way; it may have been the nodules of coal that Mr. Steel speaks of distilled and giving off gas. I do not know, but there has been something other than firedamp pure and simple." Later he added: "I think you could get a certain amount of dust put into suspension in the air by a rolling flame lasting some prolonged time," and in reply to Professor Poole he admitted that these replies implied that there must have been a certain amount of combustible material in the dust, and that when the water was driven out it would be capable of being burnt; also that 30 per cent. of moisture was not sufficient to stop the propagation of an explosion in a gassy mine.

Sir Richard Redmayne, in his evidence, said :—

"In my considered opinion the cause of the explosion is the ignition of a largish body of gas caused by an outburst traversing the return road to the greatest extent, instead of, as is characteristic in all coal dust explosions, the haulage road in which the fine and dangerous dust is chiefly observable. This explosion does not show a great violence in comparison with other explosions that I have examined.

"I say the chief lines of force are along the face, where water is most pronounced, and not along the road in which dampness is not so pronounced, and where if the mine had been, I will not say dry and dusty, but I would say less damp, you would. have expected to find the dangerous dust. . . . Flame had not, in my opinion, traversed that mine to a great extent, as I will presently show.

"In my opinion that outburst of gas existed in these threads and crevices in a state of pressure far beyond even 460 lbs. pressure to the square inch, which we know is not a normal pressure in ordinary conditions, and the wall protecting that gas from exit was being gradually weakened and the last straw Was. the shot; when that shot was fired, it did its work, but it lit up that gas which was followed by a very considerable quantity of gas.

"The result of all the coke we have seen in this disaster is the result of coking of fragments of coal, not coal dust, swept up by this explosion, carried through this volume of superheated airy steam and deposited on the walls in a plastic state against the props and other obstacles.

"This blast swept up everything in its passage, coal, stones, everything, as an explosion always does, and it would distil in that process a certain amount of light paraffin gases, which are the first to come off at a low temperature, and this would add — if an addition is needed to explain this explosion, and I do not think it is needed; in fact I am convinced it is not, the gas alone is sufficient — this would add to the volume of gas an additional force."

Questioned by Mr. Herbert Smith, he said that dust was "not at all attributable to this explosion," and "that in Moore's place (where the shot was fired), as it was the first shot to be fired, there had been no coal dust whatever in suspension."

In answer to Dr. Wheeler, Sir Richard added:

"You have a volume of gas and air exploding which is. sufficient to account for all the demonstrations of force in this district, and you have the atmosphere heated up to such a point of steam and heated gases as to account for all the coking we have found throughout the district.

"In every coal dust explosion that I have investigated the violence has been considerable and the area has been traversed to a much greater extent."

He would not regard 30 per cent. of moisture in the dust as sufficient to prevent propagation. He should think that the quantity of moisture throughout the pit was more than 30 per cent. "on the average," but he could not say "throughout." "The initial explosion would stir lip and create steam in that place, and we know there was steam created, and it would utterly prevent any explosion of coal dust. And it is for that reason that it has not traversed the intake to anything like the extent that one would have expected."