Explosion at Marley Hill Colliery

Extracted from the 1925 Mines Inspectors Annual Report
An explosion of firedamp, which started a local coal dust explosion, occurred in the Brockwell Seam at Marley Hill Colliery, owned by John Bowes and Partners, Ltd., situated at Marley Hill, in the County of Durham, on 14th September, involving the loss of two lives. The occurrence is of great interest because firedamp had not been reported in the district (nor indeed in the seam) during the previous ten years, and also because it was considered that the roof, sides and floor of the roadways were so wet as to be immune from any possibility of a coal dust explosion.

The Brockwell Seam is from 2 ft. 10 in. to 3 ft. in thickness normally, and has a strong post" roof, with a thin bed of ramble intervening in some districts. It is not unusual to find the seam increase in thickness locally up to 8 ft., and an area of this thick coal was being proved, with small faults on the east side of the main winning in the near vicinity of the site of the explosion.

The seam was worked by the bord and pillar system and the explosion originated on the main winning of the Cross Cut Flat, Sandygate District, in whole workings, about one mile from the downcast shaft and at "A" on the accompanying plan (Plate 3.) Safety lamps were introduced into this district ten years prior to this accident, following a slight ignition of firedamp, and the lamp relighting station at the time of the explosion was at "B" on plan; the meeting station appointed under Section 63 of the Coal Mines Act, 1911, being at a junction 792 yds. further outbye.

The mine had not been at work on the day shift on 14th September, and although it had been arranged for the night-shift men to commence at 10 p.m., a stoneman and a shifter named Thompson and Bell, misunderstanding the arrangements, descended the shaft at 8 p.m., travelling along the main winning to "A" and proceeding to "F" on the first west rolleyway bord, where they were to repair the road. They appear to have taken it for granted that the district had been examined by the deputy, although they met no official at the meeting station, nor at the lamp station. The assistant master shifter, Batey, descended later, and began his inspection at the third pillar east, marked "D" on the plan, travelling up the stenton at "A" to the main winning and places adjacent, and later reached Thompson and Bell about 10 p.m. No unusual features were noted by Batey on his inspection and he went outbye to admit the two victims, Watson and Fenwick, who were to work in a drift which was being driven through a fault to the eastward near the face of the main winning. Both men had locked safety lamps, but they were not searched for matches. Later, Bell, who was working at "F" saw a light on the inbye side of the canvas sheet on the first west rolleyway bord, and heard a noise as though a kibble had been turned oft the track on to its side. He did not ascertain who was there, but "felt sure it was Fenwick seeking his gear." A few minutes later the workmen at "F" heard a terrific crash and a cloud of hot air and dust rushed past them up to the face of the bord. They did not observe any flame, and after the blast they tried to travel down the bord to the main winning, but, finding this impossible on account of the hot dust cloud, they returned and eventually reached the main winning two pillar lengths on the outbye side of the first west rolleyway bord. They heard a call for help and went inbye along the main winning without delay, finding Watson at the inbye end of a pool of water, and 45 yds. outbye the first west rolleyway bord. Watson told them that he was following Fenwick in the main winning when they lost their lights just inbye side of the first west rolleyway bord and that he, Watson, was in the act of returning to the relighting station when the explosion occurred. Thompson and Bell then made an attempt to reach Fenwick further inbye, but were unable to do so owing to bad air, after which they took Watson out to the lamp station where the air was fresh. Fenwick was found by the undermanager and master shifter 40 minutes later, very badly mutilated with wounds about the head, arms and hands, and with extensive burns. He expired shortly afterwards. Watson died four days later at the Newcastle Infirmary from burns and shock.

Fenwick's lamp was found severely damaged some 5 ft. away from his body, with the oil vessel detached from the upper portion. All the evidence pointed to the conclusion that the rivet had been cut and the lamp opened, before the explosion occurred. The lamp top screw for the oil vessel was much distorted ; this damage could not have taken place without corresponding. damage to the oil vessel, if the parts had been properly assembled at the time of the explosion, but there was no such corresponding damage. Fenwick's body was found to be extensively burned, but there was a patch of healthy skin under his chin, extending to the top of the breast bone, suggesting that the head was bent forward on to the chest, and it looks as if he was in this attitude relighting his lamp when the gas ignited. His explosive canister had been laid by the side of the road and was found afterwards. underneath a fall of roof. The provisions regarding the use of safety lamps were not required to be observed by law in this district. Lamps had been introduced as a precautionary measure by the management, but from the condition of things disclosed after the accident, it is very evident that the officials and workmen did not take them seriously. Large numbers of spent matches, cigarette packets and candle ends were found at various parts of the district, and at the point where Fenwick was injured ample evidence of open lights and smoking was observed. Fenwick had never worked in fiery mines but had had considerable experience in mines giving off stythe, and he probably thought that both lamps had been extinguished by black damp.

Investigation showed coked dust in considerable quantities in the area shown cross-hatched on the plan. The course of the flame followed the air current on the west side of the main winning and no signs of coking could be found on the east side with the exception of one length of 30 yds. down the driving road to the third pillar east. There was evidence of considerable violence for a distance of 50 yds. from the face of the main winning, in shattered coal tubs, rails and turns torn up and thrown outwards (in one case for a distance of 7 ft.), and in displaced roof supports which were carried outwards for considerable distances. There was only one fall of roof of any magnitude and this was on the main winning near the point of origin of the explosion at "A." Brattice sheeting (see "E" on plan), with its supporting timber between the second and third west bords, was carried outbye, and only occasional bits of charred brattice could be found on this length of roadway. All the evidence of violence was on the inbye side of the seat of the explosion and all indications of the direction of the blast were outwards.

There were no wooden doors controlling the ventilation of the district and the brattice sheets must have allowed a considerable volume of air to scale into the return without doing useful work. Air measurements taken showed that a very much reduced volume of air was coursing through the district after the explosion, but even under these altered conditions and with the brattice at "E" blown away, firedamp did not accumulate in the main winning. The day following the accident an accumulation of firedamp was found in the south heading off the third east pillar at "D" on the plan, which was bratticed prior to the explosion but this gas practically disappeared in the following two days without any effort being made to clear it. This heading was in direct communication with the site of the explosion, but there was no evidence of flame along this road, so that it must be assumed there was no connecting explosive atmosphere between "D" and "A" at the time of the accident.

No satisfactory explanation can be given for the sudden appearance of firedamp at "A," but the thickening of the seam, with the consequent local faulting possibly had some bearing. The most important point to emphasise is that an explosion of firedamp originated a local coal dust explosion of some violence although the roof, sides and floor were damp, and pools of water were standing on the floor in places. After the explosion the roof and sides were very dry and dusty and four or five days elapsed before the original damp conditions prevailed again.

Stone dust had been applied to some of the main roads, including the main winning to the first west rolley bord and on the return to a point five pillar lengths back from the face and this, together with the generally wet state of the district, no doubt checked the propagation of the explosion. Stone dusting had not been carried on up to within 10 yds. of the face as required. Prior to the explosion no samples of road dust had been taken by the management in the district where the explosion took place.

I think it was fortunate that the outbye part of this district, in spite of its damp condition, had been treated with inert dust, as this undoubtedly checked the spread of the explosion, the force from which had been extremely violent in the untreated areas.

The lessons of this accident clearly indicate the importance of coursing the air by means of properly arranged wooden ventilating doors and rigidly carrying out the Coal Dust Regulations in relatively wet mines, and I would call the attention of colliery officials to the report* by the Chief Inspector of Mines, on the causes and circumstances attending an explosion which occurred at the Haig Pit, Whitehaven Collieries, Cumberland, on 5th September, 1922.

The following contraventions of the Coal Mines Act, 1911, and General Regulations, were disclosed as a result of the accident :

Section 63 was violated inasmuch as the two workmen, Thompson and Bell, went beyond the station before the district had been examined and reported to be safe.

Section 64 was contravened in that the whole of the district beyond the station was not inspected by a deputy before the commencement of work in a shift.

The General Regulations as to the precautions against coal dust had not been fulfilled as the floor, roof and sides of roadways had not been treated with incombustible dust or water to within 10 yds. of the face.

Attention should also be called to the requirement of the General Regulations regarding representative samples of dust to be taken by the management monthly.

During the year 1925, and up to the date of the explosion, only nine samples of road dust had been taken and analysed by the management. These had been collected, one each month, over approximately 50 yard lengths on each occasion.

The main intake haulage roads alone in this seam (disregarding returns and other putting roads) measure several miles, and of the whole of this distance only 50 yds. of roadway were tested monthly. None of the samples had been taken in any particular district and all within a radius of a mile of the shaft. Miles of roadway had not been sampled during the year.

Surely, if the word "representative" means anything at all, it must require samples to be taken at intervals throughout the whole of the mine.

By your direction, proceedings were instituted against the Under-manager (who deputised for the Manager during the latter's illness, prior to, and at the time of, the explosion), alleging breaches of the General Regulations regarding precautions to be taken against coal dust, and for not taking representative samples of mine dust. He pleaded guilty to both charges and was fined £10 in each case and ordered to pay £5 5s. in costs. For statistical purposes — the case having been heard during 1926 — details of the informations laid and of the verdict will be given in Section IV of my next report.