ORIGIN OF THE EXPLOSION.

The point of origin of an explosion must be referred to some cause within the area directly affected by the explosion. This must be flame of some kind. Within that area in this case there were the following lights carried by workmen or near the shafts, viz., the safety lamps of Elliott, Bloomfield, Maddison, and Dixon, with the possible inclusion of the incandescent electric lights near the shafts. The electric lights were, however, probably not in use as the under-manager had given orders that they were not to be turned on during the night, and when the master-shifter left the shaft they were not in use.

We are compelled to reject all these lights except that carried by Maddison, because it was clear the explosion travelled to them and not from them.

Metcalfe, the only person in the Low Main seam who carried a naked light, a glass hand lamp, was last seen alive before the explosion by a man named H. McGonnel, who was one of the party of four led by Wm. Peat who were found alive in the 1st East way on the evening of the day following the explosion. McGonnel stated that he left Metcalfe on the engine plane on the 2nd East way, after they had travelled in-bye together. Metcalfe went no farther than his place of work, a sump by the side of the engine plane, where he had to bail water, while McGonnel proceeded further in-bye to the face. Metcalfe had no work to perform near where Maddison was working. His body, with his extinguished naked light near him, was found after the explosion at or near a refuge hole, where Maddison was working. The presumption is that Metcalfe, being nearest the explosion of any person in the 2nd East way, bad travelled out after it had taken place, and was overcome by after-damp at the point where his body was found, arriving there before any of the persons working further in ; some of these persons survived, but none of them had seen him alive after the explosion. It is almost certain that Metcalfe was not near the point where his body was found, at the moment of the explosion. He was not burnt, his death having been due to after-damp, and his lamp showed no indications of having been in an explosion.

We come then to Maddison, who carried a safety lamp which was found locked and intact near his body, and proved to be a Donald safety lamp in safe working condition.

A safety lamp of the type and condition of Maddison's lamp could only ignite fire-damp under certain favourable conditions, the first being, of course, the presence of fire-damp. In this case we have not the probable or even, as all the witnesses concurred in saying, the possible presence of fire-damp. The only favourable condition was the speed of the air current, but even this was against the view that the lamp originated the explosion, unless fire-damp was present in great volume. It was soon apparent that the explosion could not be ascribed to fire-damp, and at the inquest no expert or other evidence was given in support of that view, but we think it advisable to put on record reasons for excluding its consideration.

In the course of our examination of the Low Main seam after the explosion we observed no fire-damp, although we tested for it as carefully as the ordinary safety lamp allows at the place where the explosion originated. One of us, when examining as to the limit of the explosion in the Stable way on the 9th November, accompanied by the under-manager and master wasteman, before the ventilation had been fully restored, was unable to proceed on account of stythe or black-damp on the engine plane, and the master wasteman going a little in advance had his light extinguished by it.

The presence of fire-damp in the Low Main seam had not been reported for some years, and the under-manager could not state when it was last seen.

A careful examination showed that Maddison had probably fired some explosive to dislodge some stone which projected into the road.

Maddison had been directed by the master-shifter, to clear away a fall and "plote" or remove any loose hanging stone at a point on the engine plane where Bainbridge, one of the examiners, had reported some work would require to be done before the pit could start next morning. This point was on the main haulage road to the north, near the place where his body was found. He was working alone, as the master-shifter thought there was only sufficient work to occupy one man during the shift. Elliott, a shifter, who was employed at the downcast shaft, had been instructed to bring a pony from the stable and take two empty tubs to Maddison to be filled with the fallen stone, but he had not done so when the explosion occurred.

A plan and section on an enlarged scale is given on Plate V. to illustrate the surroundings, together with a hand sketch. Only the body of Maddison is shown on the plan, as although other bodies were found here they were those of persons who had come out after the explosion and died from after-damp.

So far as is known Maddison was not visited by any person between his starting work, about 10.45 p.m., and the explosion at 11.40 p.m. The examiner, Bainbridge, who had reported the fall, went in-bye with him to the point and would then proceed further in-bye into the 1st East way.

The master-shifter, the only person, except Elliott, likely to have visited him, survived the explosion, and stated that he had not done so, but would have passed him in the ordinary course about 2 a.m., when on his way to the North district.

Maddison worked on day's wage and he had no reason to hurry the work which, however, would require to be completed so that the haulage could start between 6 a.m. and 7 a.m. next morning.

Maddison was a licensed shot-firer for the seam. He and his mate, W. Armstrong, were driving a stone drift in the 2nd East way, but the master-shifter, when examining the workings in that way on the morning of the day of the explosion, found that the rise of some water would prevent their working there at night, and work elsewhere had to be provided for them. Maddison had with him a canister containing 11 cartridges of geloxite, each weighing 4 oz. and one smaller cartridge weighing 2 oz., and two pieces of tape fuse, one 3 feet and the other 5 feet long; this was proved by his marrow, W. Armstrong, who at Maddison's request handed him the shot-box when they parted at the Stable way junction. The canister was found uninjured after the explosion in a refuge hole on the engine plane near where he had been directed to work containing only 10 of the 4 oz. cartridges and the longer length of fuse, and at the same place his coat was found hanging on a projecting stone with a box of detonators in the pocket. It could not be ascertained what was the number of detonators Maddison had with him. The only other men who were using or carried explosives in the Low Main seam at the time of the accident were in the Stable way district.

Maddison's body was found 25 yards out-bye from where he had been directed to work. He was lying between the rails on his face with his head out-bye. He was in his shirt sleeves. Eleven yards nearer his place of work was the refuge hole in which his coat hung, and he had probably either stood here at the moment of the explosion or in the end of an old way, known as the Greaser way, 6 yards further out-bye.

Near his place of work some spent or used fuse was found, and also some coal dust and roller grease, made into a kind of paste, which it was suggested he had used to confine a charge. Careful examination showed that some explosive had been fired in a crack or cavity above a projecting stone, and a piece of which, about 18 inches cube, lay on the floor and had apparently been blown down, and fitted into a space in the stone in situ above.

Maddison's mate, W. Armstrong, stated at the inquest that when he handed the shot box to Maddison it contained two more cartridges and one more piece of fuse than were found in it after the explosion, and the presumption is that Maddison had used these in blowing down the piece of stone. The explosive used would be one 4 oz. cartridge, and one 2 oz., or 6 oz. in all.

There was no shot hole and he bad no drilling gear with him. The stone he blew down had existed as he found it for 25 years, but was of the nature of an inconvenient excrescence to any person travelling on the road, and probably he thought, that while waiting for the tubs, he could usefully employ himself in removing it. The under-manager could not state when the last shot had been fired on an engine plane in the Low Main seam, it was so long ago.

Maddison bore a good character, and at the inquest no strong terms with regard to his unfortunate act were made use of. There is one circumstance which occurred prior to the explosion, which we think it necessary to place on record. On the 2nd June last, Maddison and his marrow, W. Armstrong, were shooting down top stone in a place in the Low Main seam, ventilated by a scale of air coming through a broached brick stopping and returning through an air box 11 inches square. They had drilled a hole about the centre of the place, and owing to the long drill being worn were unable to place the 24 oz. of colliery cheddite they used as the explosive right to the back of the hole, but left an air space about 12 inches long. The charge was stemmed with clay and fired by a fuse and a No. 7 detonator. Owing to the air space behind the charge there may have been incomplete detonation, and when they returned after waiting 10 or 1 5 minutes were both affected by the fumes and decided to leave the face ; while doing so Maddison fell and became unconscious. Armstrong did not feel able to carry him further out but went for assistance, and on a rescue party reaching the place in 30 minutes he was found still insensible. He was removed further out and recovered consciousness, but was off work for eight days and was apparently none the worse.

That the flame of the explosive started the explosion was not disputed.

A pack wall, 3 feet deep and 4 feet high, built of rough stones on the left side of the road and immediately under the shot, carried a good deal of coal dust. There were a few single props and headtrees on the same side, and some crowns across the road resting on a prop on the left side, and let into holes cut in the stone side on the other. It will be noticed that the roadway here was formed in the roof stone of the coal seam, so that the sides as well as the roof were of stone, which carries more coal dust than coal sides because the surfaces are rougher and there are more ledges and cavities to hold coal dust.

The explosion of the geloxite would shake a cloud of coal dust into the air current, and the flame would ignite it; expansion, due to the heat, would follow, and more dust would be disturbed on each side, and the burning continued quietly over the length of undisturbed ground when the two diaphragms of flame, fully established, extended with violence in opposite directions as far as the supply of coal dust continued.

In-bye the supply of coal dust ceased near the curve to the east; there was not sufficient dust to carry flame far up the 1st East way.

The flame, in passing the Stable way junction, going out-bye, divided, and came back at an acute angle and extended so far along that way.

The main body of the flame continued on to the shafts, making a side excursion to, and perhaps up, the drop staple. Arrived at the shafts, which were wet and free from coal dust, combustion perforce ceased.

In its passage to the shaft the explosion passed over two portions of road, one 40 yards long, where, at any rate after the explosion, the bottom of the road was wet, and where a sump to collect the water was cut by the road side ; the sides and roof of these wet portions were dry, and appear to have been coated with sufficient fine coal dust to carry forward the flame.

The area affected by the explosion was practically coincident with the area over which coal dust was present in sufficient quantity, or, to borrow an expressive phrase from the Home Office Report on the Courrieres explosion,* "the "flame had been almost co-extensive with the dynamic effects of the explosion."

* Report to His Majesty's Secretary of State for the Home Department on the disaster which occurred at Courrieres Mine, Pas de Calais, France, on March 10th, 1906, by H. Cunynghame, C.B., Assistant Under-Secretary of State, Home Department, and W. N. Atkinson, one of H.M. Inspectors of Mines.