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It was generally agreed the locus of the explosion was the Back Drift, and that it had been brought about by shotfiring at the coal face of this place. When Smith left this face a few minutes before the explosion occurred the face was cut and the cutter gummings cleared ready for shotfiring; the cutting of the face and the boring of six shot holes having been carried out during the previous shift. Smith had reached the landing and after a short conversation with the landing lad Abbott, who was some 50 yards outbye on the landing, was sitting down when he heard a thud and then felt a rush of wind from inbye followed by smoke and dust which, until he heard the boy Abbott crying out for help, he thought was due to a burst compressed air joint.

When it was possible to examine the Back Drift at about 12 midnight, the body of deputy Worth was found 12 yards from the face, and on the left side and opposite him was a multi-shot exploder with the firing cable leads still attached. The coal face had been shot down and pieces of detonator wire lying about confirmed a first impression that shots had been fired simultaneously by this deputy from the position in which he was found.

There was at this time two per cent, of firedamp in the general body of the air at the point where the deputy lay, which rapidly increased to explosive point at the face. The side brattice had been completely burnt away and the place was consequently not being ventilated but some 36 hours or so afterwards it was only possible to proceed seven yards up the drift owing to the presence of firedamp.

Deputy J. Dent, who owing to the absence of the First Shift deputy had been in charge of the First and Second shifts, had had trouble with firedamp in this drift during the Second Shift, although he had allowed the coal fillers to work there for a time and the arc-wall cuttermen had afterwards cut and bored the face. Towards the end of the Second Shift he had again found the place foul and had applied the "hogger" (compressed-air flexible pipe for the arc-wall machine) to remove the gas, but the place quickly fouled again and at about 4 p.m. he fenced the place off, when he says there was two per cent. of firedamp present, and handed it over to the Third Shift deputy J. Worth, admonishing him to be careful of this place.

It is difficult to accept Deputy Dent's evidence that there was only two per cent. of firedamp at the face of the Back Drift at 4 p.m., and I consider it more likely that at that time an accumulation of firedamp at explosive point was there. It was evident after the explosion that the side brattice had not been extended and it is reasonable to assume firedamp was present at the face during the Third Shift. Deputy Worth's gas detector safety lamp was afterwards found under a fall of root in No. 1 Stenton and I can only conclude that he decided to fire all the six shots together with the multi-shot exploder (obtained from the stone drift) without having first examined for gas.

The inquest, held by Mr. T. V. Devey, H.M. Coroner for the area, sitting with a jury of seven men, occupied two days and every facility was given to call and examine the necessary witnesses. The jury decided that the deaths were due to "an explosion of firedamp, and the firedamp exploded because of the simultaneous firing of six shots by the deputy."

History of Gas in the District. - Firedamp had been reported in the Middle Drift face for three shifts during early June, 1942, but in the Back Drift does not appear to have been met with since March of this year until the Second Shift of 25th June, the day prior to the explosion, when the shift deputy reported it as "foul 3 per cent." It was reported clear the following shift and until the Second Shift of the 26th immediately prior to that on which the explosion occurred, when Dent again reported gas in the same terms.

Igniting Cause. - No electrical apparatus for power or fixed lighting was installed in the Flat, and the intrinsically safe signalling system was too remote from the source of ignition to be even suspect. No contraband was found in any of the clothing or in the affected area, or any likely defect in any of the safety lamps in use there at the time; and deputy Worth's cap lamp was found on his body still alight and undamaged.

The state of the face in the Back Drift indicated that the shots had been overcharged, and the centre top shot appeared to have been slightly blown out as there was a socket 7 ins, long left in the back of this hole, which also contained some remains of explosive wrapping and sheathing material.

The multi-shot exploder was of the continuous rotation type, not approved for firing shots where inflammable gas is a hazard, and tests of the apparatus at the Testing Station at Sheffield confirmed that it was capable by the adventitious contact and separation of the firing leads of producing a spark which very readily ignited the most easily ignitible mixture (8.5 per cent.) of firedamp and air.

The outer end of the shotfiring cable was found after the explosion still attached to the exploder: one end having been properly clamped to its terminal but the other loosely wrapped around the spindle of the other terminal of the exploder, due to the clamping screw being out of order. I consider this to be significant.

Precautions against Coal Dust. - The natural conditions in the Back-over Flat are dry but not very dusty, although it is likely a heavy cloud of coal dust was created at the face of the Back Drift by the over-charged shots. The stone dust in general use at this colliery consists of shale sent out from underground and ground at bank; it contains 88-90 per cent. incombustible matter and averages 70 per cent. by weight passing a 200-mesh sieve, and it is spread by hand.

In order to form some idea of the state of the inbye roadways in respect of dust, samples were collected by H.M. Inspectors of Mines about 36 hours after the explosion along three zones immediately outbye points where it was evident the explosion flame had died out (see Plan). These samples were found on analysis to contain the following percentages of incombustible matter :-

	Floor	Roof	Sides
Back Drift (A)	76.0	86.2	86.6
Middle Drift (B)	84.2	85.3
Fore Drift (C)	82.2	79.9	73.7

The stone dusting on the roadways was effective in limiting to the face area an explosion which had received a flying start in the Back Drift and had been fed by coal dust lying in the old walls and stentons on either side of this airway. That is an important and reassuring fact which, in my judgment, is established beyond doubt or question in this case.

There was no evidence to show whether or not stone dust had been spread at the face prior to firing the six shots or, if- it had, whether the area was thoroughly treated as required by clause 6 (f) (ii) of the Explosives in Coal Mines Order of 1st January, 1934. There was a convenient dump of stone dust in the Back Drift as well as at other salient points in the Flat.

Conclusions. - Despite the fact that the shots in the face of the Back Drift were overcharged, especially the centre shot in the top coal, there was nothing to indicate they had behaved in any untoward manner, nor do I consider that the firing of six shots simultaneously, which was a contravention of clause 6 (g) (i) of the Explosives in Coal Mines Order of 1st January, 1934, had any bearing on the explosion beyond the fact that these shots had been fired by an exploder which was not an apparatus approved for coal shots, as required by clause 6 (h) (i) of that Order.

It seems clear that the igniting cause was an incendive spark created by the exploder while the shots were actually being fired by Deputy Worth in an atmosphere containing an inflammable mixture of firedamp and air. The burning of timber some distance from the face of the Back Drift suggests that a rich mixture was ignited in the neighbourhood of the exploder, rather than at the face itself; and the faulty connection of one of the cable leads with one of the terminals of the exploder would be sufficient to bring about at the exploder a spark of sufficient incendivity, apart from any sparking inside the exploder.

I am satisfied that if proper steps had been taken by either of the deputies concerned to extend the side brattice nearer to the face the amount of air entering the Flat was sufficient to have rendered harmless the firedamp being given off at the face of the Back Drift. It was stated there was a shortage of spare brattice cloth in the Flat during the Second Shift, although a spare roll was afterwards found at the kist, and it is unfortunate that prompt steps were not taken either by the deputy or the fore-overman, who were aware there was firedamp present, to procure a further supply instead of the deputy adopting the handy but quite unsatisfactory expedient of using the hogger

Recommendations:- I have already stated that, in my view, all the facts point to the use of the multi-shot exploder for firing shots at the face of the Back Drift having caused the explosion, and I recommend that the work of developing a safe multi-shot exploder should be pressed on as a matter of urgency so that the taking for use into any mine or any part of a mine where safety lamps are required to be used of any unapproved exploder for any purpose can be totally prohibited at the earliest possible date.

The danger attendant upon coal dust deposited by the ventilating current and by disintegration of the coal sides in disused roadways, abandoned but still remaining open, also arises in connection with this explosion. In this instance, there was every indication that the explosion was fed by coal dust lying in the old walls and stentons opening off the inbye length of the return airway. These old roads had been drawn off, in view of the need for economy in the use of timber at this time, and they were for the most part still standing intact but inaccessible owing to the roof being unsupported.

Dr. F. V. Tideswell, of the Safety in Mines Research Board, made an examination of the affected area and an extract in his report deals with this aspect as follows :-

It seems evident, therefore, that steps should be taken to deal with this danger from coal dust in such disused roadways, which abound in bord and pillar mining, and I recommend that in all dry and dusty mines these roadways, unless maintained in a safe and accessible condition and regarded as "roads" for the purpose of the Coal Mines General Regulations (Precautions against Coal Dust), 1939, or, alternatively, sealed off with a substantial stopping at every entrance, should be heavily stone dusted immediately before being drawn off or abandoned, and either a light stopping sufficient to prevent the deposition of fresh air-borne dust erected at each mouth, or two or more simple multiple shelf barriers installed and loaded with a highly dispersable stone dust, renewed at such intervals as may be necessary to maintain the dust in effective condition.