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ACCIDENTS from EXPLOSIONS of FIRE-DAMP or COAL-DUST, classified according
Of the above accidents from explosion of fire-damp or coal dust two occurred in North Staffordshire and four in South Staffordshire.
The particulars are as follow:
Knowle Colliery (South Staffordshire), on 18th January, at 5 p.m., Bar. 29-00, rising. Two injured. A heavy fall of the barometer had taken place during the day, and gas had appeared in several of the headings, necessitating the withdrawal of the men. Two deputies were making an examination for the night shift and were going through a thirling between two heads when the explosion occurred. The men professed ignorance as to the cause of the explosion, and denied that they had with them any light other than locked safety lamps. The lamps used were of the Clanny type, with single gauze and cap, and shielded, and had ordinary screw locks. The lamps were found in the thirling after the explosion, one having its glass broken and more than half of it missing. When produced, the gauze, rings and washers were in proper position and order, and the lamp locked. The ventilation was inadequate, being natural only. Safety lamps were intro
duced and a fan erected.
Cannock Chase Colliery (South Staffordshire), on February 19th, at 12.45 p.m., Bar. 29-38, falling.-One injured. A small accumulation of fire-damp in a cavity between two faults was ignited by a stallman going up into it with a candle to resume bannocking, immediately after snapping.
Mow Cop Colliery (North Staffordshire), on July 5th, Bar. 29.72, falling.-One injured. A dip which had been inundated for some two years was being drained. The water had just cleared the roof at the mouth of a heading, when the owner went down to place the pump suction box in the water. His candle ignited a small quantity of gas, which burned his arms and face. It was stated that gas had not been seen before in the mine.
Coneygre Colliery, No 120 Pit (South Staffordshire), on August 8th, at 2.30 p.m., Bar. 29.5, falling.-One killed. Deceased was lifting the rails and floor to make height at a point where a slip crossed the road, about twenty yards from the working face. He had a candle stuck on the road side pack with a piece of clay. On shifting the candle to the floor, it ignited some fire-damp which burned him severely on the head, face, arms, chest and back. He succumbed six days afterwards. The fireman or "doggie" was in the employment of the charter master, and was paid a small allowance daily by the owner for making the statutory inspections. He admitted at the inquest that on visiting the place shortly before the accident he had heard some" singing" or "hissing"; but as he had examined it with a safety lamp at 6 a.m., and found no gas, he did not think any further examination was necessary. The arrangements for inspection were of a very unsatisfactory nature, and have since been very much improved.
Sandwell Park Colliery (South Staffordshire), on December 5th, at 8.15 a.m., Bar. 29.50, falling. One injured. A slight ignition of fire-damp by a candle in a water lodgeThe fireman stated that he examined the place at 7 a.m. and found no gas. Park Hall Colliery (North Staffordshire), on December 12th, at 10.30 a.m., Bar. 29-2, falling. Ther. (Fah.) 47° after rising 12° on previous day.-Two injured, one of whom died 24 days afterwards. This accident was of a very unusual nature, and its cause is somewhat obscure. It occurred in an underground motor room, 25 feet in length and averaging 10 feet in width, situated at the side of the main return airway, at a point 105 yards from upcast shaft bottom. At this point the intake and return airways are formed by parallel "cruts" or crosscut mines, separated by a pillar 8 yards wide, and the recess for the motor room was formed in this pillar, a brick wall with two doors or openings being built on the side next to the return airway. Protector Marsaut safety
lamps were used throughout the mine, and the nearest working faces were about 1,000 yards inbye. The motor room was at first ventilated exclusively by return air. Eight weeks prior to the accident the manager detected a trace of fire-damp in a cavity in its roof, and forthwith had a loose canvas sheet hung across the return airway to send a greater portion of the air current through the motor room. He also had a small crut driven from the intake air course, and a hole drilled through into the motor room to permit a split of fresh air to flow through it. Since this was done no fire-damp had been seen, although the place was examined daily.
A 100 horse-power motor, with 500 volts direct continuous current, was in course of erection. It was fitted with an oil-immersed controller of tramway type; and had a double-poled quick-break carbon-tipped switch, which, with the fuses and ammeter, was mounted on a slate panel and enclosed in a "gas-tight" wrought iron case 3 feet 3 inches by 1 foot 4 inches by 1 foot 1 inch, having a plate glass front 4 inch thick. Between the poles of the switch a slab of vulcanized fibre, 10 inches in length and inch in thickness, extended outwards, almost or quite to the plate glass front. The motor and controller were earthed, but the switch box was not. The shunt winding being connected across the mains, it had been observed that a considerable flash occurred when the switch was opened, owing to the self-induction of the motor; and to prevent this and protect the insulation of the magnet coils, a "buffer" or non-inductive resistance had been introduced.
One of the motor bearings had been heating and an electrical engineer or fitter, accompanied by a labourer, had gone down to remedy it. The motor room was examined by the fireman at 5.45 a.m. and reported as free from gas and in safe condition. The. fitter and labourer entered it at about 10.20 a.m., both having locked safety lamps, and the accident occurred about ten minutes afterwards. It is not known definitely what they had been doing, further than that the motor had been running empty, the counter shaft. having been slewed out of gear. The labourer was kneeling at the further side of the motor, 6 ft. from the switch box, and was watching the bearing at that end of the motor shaft. The fitter is believed to have been watching the bearing at the other end of the shaft and to have risen up to shut off the current, as the controller was found to have been shut off and the switch pulled out. The labourer heard a muffled sound and a flash or flame passed over him, lasting for "about two minutes." He immediately clapped his hands over his face and fell or threw himself backwards through an opening behind him, and made his way outbye to the shaft bottom. The under-manager, who was on the return airway, about 30 yards inbye, felt no blast, but saw a "flash of light" come from the motor room. On going out, he found the fitter standing in the return airway, close to the motor room. He was in the dark and appeared to have been severely burnt, but could not say what had happened An hour and a half afterwards, after getting the injured men to bank and attended to, the under-manager returned to the motor room; he found no gas or after-damp or any indications of damage, except that two-thirds of the glass front of the switch-box had been blown out, the glass having been scattered right across the motor room. The air-hole from intake was open, as it had been on the previous day. Subsequent investigation showed that none of the broken glass had fallen inside of the switch-box, the paint inside was not scorched or blistered, the poles of the switch had not been fused, blistered, or tarnished more than might have been expected from ordinary The brick wall between the motor room and the main return had not been shaken, and nothing appeared to have been displaced. Some half rotten straw or stable manure adhering to the web of a steel girder supporting the roof, had only been very slightly charred. The feather edges of some bark on the timber poles above the girders were charred in places and some resin had exuded, but whether at the time of the accident or previously is not known. A rope-fall hanging from the girder showed no signs of scorching. The safety-lamps used by the men were found, extinguished, but undamaged and in perfect order.
The surgeon, who attended the fitter until his death took place, stated at the inquest that deceased had been very severely burned about the face, and both hands equally. The burns on the face were such as might have been caused by a flame issuing from a furnace, but those on the hands were quite unlike anything he had previously seen or heard of, and he was unable to classify them. The hands were ivory white, and the palms were as badly burned as the backs, the worst portions being the finger tips; they were not charred or blistered, but were burned to the bone, and, if the man had lived, would have dropped off, as they were completely dead. The skin was at first unbroken, but came off in a piece some days afterwards. He found no signs of glass either on the face or hands. In his opinion, the heat which burnt the hands must have been terrific.
Mr. J. F. Aust, electrical engineer, Shelton, made an exhaustive examination of the installation on instructions from the Coroner. He found that one of the shaft cables had
an earth connection, and that the buffer or non-inductive resistance was out of order and inoperative. These facts, with others herein before stated and the absence of any evidence of an explosion, led him to conclude that the deceased had been burned by a flash blowing out from the tips of the switch, due to the self-induction of the motor. He thought the flash might last for from half a second to a second and a half, and that deceased would have had time to place his hands over his face. He was unable to explain the burning of the labourer at a distance of 6 feet from the switch-box, and attributed the blowing out of the plate glass front of switch-box to the outward pressure of the vulcanite fibre slab, owing possibly to its having absorbed moisture, and swollen.
Mr. H. W. Wilson, A.M.I.E.E., Liverpool, called by the erectors of the motor, while agreeing that there would be an inductive spark at the switch on the opening of the circuit, was satisfied that such spark could not be sufficiently long to cause the injuries to the men, unless they were actually in contact with the switch.
Experiments with a 60 horse-power motor of same voltage and type, fitted with the same style of switch, and with the buffer non-inductive resistance disconnected, showed a maximum length of spark of 3 inches; and he did not think the spark from the 100 horsepower motor would differ materially from this. The energy to be dissipated in the spark was merely that stored up as a static charge in the field coils of the motor; it might momentarily reach a voltage of 1,500 or 2,000, but would not cause a large or destructive arc, and would only last for a very small fraction of a second, certainly not long enough to have permitted of deceased's raising his hands to his face.
I had, subsequently, an opportunity of examining the burns received by the labourer, and found them to be exactly what I would have expected from an ignition of gas. The palms of his hands were wholly uninjured, the backs were deeply blistered all over, and a small portion of his face. which presumably had been left uncovered by his hands, was slightly blistered. His hair had been burned, but he was otherwise uninjured. From his position in the motor room his head would probably be at a level about three feet lower than that of the fitter.
When electrical experts differ so materially as to the cause of the accident, I find it difficult to come to any definite conclusion. There is no evidence of any explosion of fire-damp having taken place in the motor room. This would presumably have caused greater damage, some portions of the glass front of switch-box would have been blown inwards, and if the fire damp came from a fouled return air current the explosion would have extended inbye. A mere ignition of a small quantity of diluted gas would not account for the intense heat indicated by the deceased's injuries; and, apart from an electric flash, there is no evidence showing how gas could have been ignited.
The sclution is probably to be found in an explosion of gas of some sort inside the switch-box, and the ignition thereby of an accumulation of diluted fire-damp due to an undiscovered blower in the motor room.
Whatever doubt may remain as to the actual cause of the accident, I think there can be none as to the inadvisability of having such machinery or appliances placed in, or ventilated by, the return air in a fiery mine. In this case, the arrangements have been altered so that the motor room is now ventilated exclusively by intake air, and a different type of switch-box has been substituted, in which the switch is enclosed in a much smaller box, made wholly of iron.
Falls of Roof and Side.
The number of accidents from falls of ground reported during the year was 162, causing the deaths of 43 persons and injuries to 128 persons.
The corresponding figures for 1905 were 152 accidents, 36 deaths, and 122 persons injured.
ACCIDENTS from FALLS of ROOF and SIDE, classified according to the PLACE where
Classified according to occupations as designated in the official notification of the accidents, they were as follows:
Dataller, repairer, timberer, dayman, shifter, roadman,
1 killed, 5 injured.
34 killed, 110 injured.
3 killed, 3 injured.
5 killed, 10 injured.
I regret having to report a considerable increase in the number of accidents and deaths from falls of ground. As already stated, this is chiefly attributable to South Staffordshire, and more especially to that portion of it known as the "Black Country " in which 16 deaths occurred. This is largely due to the working of the Thick or Ten Yard Coal, which appears to be attended with special danger, owing to its liability to "bumps caused by sudden and excessive weighting or pressure of the roof.
At Hamstead, on 9th April, a driver was bringing a full tub out from a stall, when one of these bumps took place, reeling out three bars, bringing down 20 to 30 tons of top coal, and killing both driver and horse instantly. The bars had only been set a few hours previously, and the place was thereafter inspected by a fireman or examiner, who considered it to be safe and sufficiently timbered. The overman stated at the inquest that "although this bump would be considered serious at some collieries, it was thought slight at Hamstead, where sometimes as much as 300 tons of rock and coal came down.'
At Saltwell, No. 37, on 24th May, a fall of roof took place, resulting in the loss of four lives. The accident occurred in an "opening" or chamber, 35 feet long by 21 feet wide, formed in the lower portion of the Thick Coal. The opening was not in solid coal, being bounded on two sides by gob and thin ribs of coal; and it was in a district where the seam was full of slips and liable to bumps. At one end, the opening had fallen up the "White Coal," a bed about 13 feet from the floor; and at the other, where the accident occurred, the roof was formed by the "Brazils,"-a stratum of coal 2 feet 2 inches thick with a well defined parting above it,--and in this part the opening was 7 feet high. The Brazils formed the roof over an area 19 feet by 20 feet, and in this area of 380 superficial feet, there were only three props for support. The miners had been engaged under the Brazil roof in filling coal brought down by the removal, on the previous afternoon, of eleven posts. At the time of the accident they were about to set a fourth post under the Brazils, but before this was done a bump occurred, and a large portion of the Brazil roof fell upon the men, killing three of them, and so injuring a fourth that he died five days. afterwards. Mr. Atkinson happened to be in the locality and inspected the place a few hours after the accident, and Mr. Makepeace examined and measured it on the following day. They were both of opinion that more timber could and should have been set before the fall occurred; although it was contended by the management that this was impracticable, on account of the fallen coal which the men had been engaged in filling into tubs. The pit was worked by a charter-master or contractor who employed the miners and supplied the timber; and the fireman or "competent person," whose duty it was to see the timber set, and who at the time was working as a miner where the accident occurred, was also employed by the charter-master, although paid sixpence per day by the owner for making the examination of the workings required by General Rule 4. Such conditions, it may be presumed, are liable to lead to more attention being paid to the filling of coal than to the safety of the workmen. At the inquest the jury exonerated all parties from blame.
A very similar accident occurred at Himley No. 4 Pit on October 27th, but fortunately only one man was killed, although another had a singularly narrow escape. Some details are given in Appendix I.
From the above and similar cases it appears to be clear that the working of this Thick Coal requires very special care and supervision, and that matters should be so arranged that the pecuniary interests of all the parties exercising such care and supervision should not be permitted to interfere with the proper performance of their statutory duties.
Seven shaft accidents were reported during the year, resulting in two deaths and injury to five persons.
Details of the former will be found in Appendix I. One of the non-fatal accidents, at Whitfield, on September 24th, was directly due to a contravention of Special Rule 72; the injured person, having attempted to run across the shaft bottom while the cages were in motion, was caught and knocked down by the descending cage.
Miscellaneous Underground Accidents.
Twenty-seven fatal and 111 non-fatal accidents were reported, resulting in 28 deaths and injuries to 118 persons.
The corresponding figures for 1905 were 18 fatal accidents causing 22 deaths, and 105 non-fatal accidents causing injury to 109 persons. The increase is due to accidents by explosives, and by being run over or crushed by trams and tubs.
ACCIDENTS with EXPLOSIVES, classified according to the NATURE of the EXPLOSIVE.
ACCIDENTS With EXPLOSIVES, classified according to their CHARACTER OF CAUSE.
* Not including accidents which come under the head of "While charging or stemming holes."
The following are details in brief of some of the more interesting cases :
At Coneygre Colliery, Worcestershire, on January 3rd, two men charged two shots 9 feet apart, intending to fire them together. One of them lighted his fuse and called to the other to come away. Both men retired, and on hearing a shot explode, one of them at once returned to light his shot, apparently believing that he had formerly failed to do The shot went off as he approached, and killed him. This is a comparatively frequent source of accident, and is not sufficiently covered by the existing Special Rules. Where anyone has lighted or attempted to light a shot or shots, no one should be permitted to return to or enter the place until after the explosion of the shot or shots, or until a stipulated time has elapsed.
At Silverdale, North Staffordshire, on February 21st, a charge of gunpowder had missed fire. A second charge was placed in the hole over it, there having been very little stemming, and the fuses of it and another shot were lighted together. Two reports were heard, and the fireman returned with the miner to recover the unexploded first charge. It exploded as they approached it, and a stone projected by it seriously injured the miner. In this case the result might have been expected. The fireman was subsequently charged with a contravention of Special Rule, was convicted, and fined in the maximum penalty of two pounds, with fifteen shillings and sixpence of expenses.
At Whitfield, North Staffordshire, on February 16th, a fireman was injured by a stone projected by a shot of Negro Powder. He fired the shot from a manhole on the