BLAENHIRWAUN. Cross Hands, Carmarthenshire. 6th. September, 1955.
The Blaenhirwaun Colliery was situated near the village of Cross Hands about 16 miles north-west of Swansea and was near the extremity of the coalfield. It had been working since 193 producing high grade anthracite with an output of about 350 tons per day. 360 people were employed below ground and 80 on the surface. It was served by two vertical shafts sunk to the Green Vein. The No.1 shaft was 10 feet in diameter and 155 yards deep and as the upcast. It was equipped with a Walker Paddle fan which produced about 55,000 cubic feet of air per minute at a water gauge of 3.125 inches. The No. 2 shaft was 13 feet in diameter and 212 yards deep and was the downcast and winding shaft for men and materials.
The mine was in the No.1 Area of the South Western Division of the National Coal Board and the principal officers were, Mr. J.G. Tait, B.Sc., Area General Manager, Mr. J.D.H. Davies, Area Production Manager, Mr. D.J. King, Deputy Area Production Manager (Operations), Mr. I.R. Jeffreys, manager and Mr. J.H. Morgan, undermanger.
The seams that were worked at the colliery in descending order were the Big Vein, the Stanllyd and the Lower Pumpquart. Safety lamps had always been required throughout the mine and automatic firedamp detectors were required by the Coal Mines (Ventilation) General Regulations, 1947 had to be provided on the longwall faces where electric power was used. The lamps throughout the mine were Nife N.C. 113C electric cap lamps with E. Thomas and Williams Cambriam No.1 flame safety lamps and Naylor Spiralarms Type M, for the use of workmen as firedamp detectors. Prestwick Patent Protector Type 6 flame safety lamps were used by the officials for their official inspections.
The Lower Pumpquart seam had an average thickness of about three feet with a roof of clift and a fireclay floor. The volatile content of the coal was 5.5 per cent and it had been reached by driving cross measure drifts from the Green Vein about 26 yards before. Since then it had been extensively worked by the longwall method and the whole of the working area was generally disturbed with numerous faults, patches of barren ground and steep and variable gradients. At the time of the explosion the workings in the seam consisted of two longwall, single-unit faces, known as “P” and “Q”. These faces were ventilated in series, the air current first entering the “P” face.
The “Q” face was advancing north in a virgin area. It was about 80 yards long with the intake loading gate at the right and the return supply gate at the left. The gates were advancing to the rise at gradients of 1 in 2.5 i the loading gate and 1 in 2.1 in the supply gate. On the face there was rise form right to left at a gradient of 1 in 3.5. The face started production in January 1955 and had advanced about 90 yards. It was the intention to advance it a further 20 yards and then to replace it by a face formed by the ribside of the loading gate, to advance to the east.
The coal was hand got by pneumatic picks and shots fired in the flanking holes drilled into the solid coal. It was filled onto a retarder conveyor on the face and taken to a tub-loading pint by means of two belt conveyors in tandem in the loading gate. The face conveyor was driven by compressed air and the belt conveyors by electricity. Top rippings were taken in both gates with an additional floor ripping in the supply gate. Shots were fired in all the rippings. Both gates were supported by steel arch girders.
Dust was suppressed by the pneumatic picks being water fed, hand sprays were used on the face and fixed sprays at the transfer and loading points. Water infusion of the face had been tried but had proved of little use due to the fact that the face was advancing on the ends of well-defined cleats in the coal.
The face was worked on a 48-hour cycle and the operation usually performed by each shift was as follows. The morning shift, 7.30 a.m to 2.30 p.m. were employed in coal getting and filling, ripping and packing in the supply gate. The afternoon shift, 3.0 p.m. to 10.30 p.m., ripped and packed in both gates. The withdrawal of supports and the advancing oft he strip packs on the face and the moving forward of the conveyor on alternate days. The night shift, 11.0 p.m. to 6. 30 a.m., drilled shot holes and fired shots in the coal. The face formed a deputy’s district on each shift, except at weekends when each deputy made the per-shift inspection for the succeeding shift. The “P” and “Q” faces together formed an overman’s district on each of the three shifts.
The roof at the face was supported by wooden bars set at right angles to the face on wooden props. Each of the gates had solid coal on one side and a pack on the other, about 10 yards wide, built from stone from the rippings. Along the face, strip packs about 6 yards wide were built from stone from the intervening wastes and were about 9 yards wide. Two hardwood chocks were maintained at the edge of each waste, the roof control had always been satisfactory on this face and there was no history of roof weighting or falls of ground.
The “Q” face was ventilated by an air current of about 8,000 cubic feet of air per minute which had already ventilated the “P” face and according to all the evidence the ventilation had always been adequate. On two occasions only had gas been detected and reported by the deputies. These were on the 5th. May and the 27th. June 1955. On each occasion a trace of gas was reported at the ripping face of the supply gate. After the first report on the 5th. May, the manager gave instructions for a hurdle sheet to be erected and maintained across the roadhead of the supply gate so as to divert a flow of air into the ripping face. The deputies foresaw difficulties in maintaining a hurdle sheet on this steep gradient and suggested a small fan to be installed so as to blow air on to the ripping face. The manager accepted this ides and a 12-inch diameter Meco, compressed air turbine fan was installed. This fan, with a 6-feet length of steel ducting attached on each side, was suspended by means of a wire from the steel supports so that the ducting was approximately at the same gradient as the roadway and with the outlet ducting pointing to the ripping face. The fan with the ducting was moved forward as the ripping face advanced made this method of ventilating the ripping lip was still in operation when the explosion occurred. Samples of the air taken in accordance with the Regulations showed a percentage of methane in excess on 0.4 per cent on only three occasions. There were 0.55 on 28th. May, 1.10 on 27th. June and 0.70 on the 19th.August.
The morning shift of the 6th. September, stated at the normal time, the per-shift inspection had been made by the deputy on the night shift and everything was found to be in order. The face conveyor had been moved forward in the afternoon shift of the previous day and the strip packs and waste edge chocks had been advanced. The roadside pack of the loading gate had also been advanced, but the roadside pack of the supply gate was about yards back from the coal face. Over a length of a few yards at the return end of the face, the seam had thickened from it’s normal 3 feet to about 7 feet and the slip of what appeared to be a downthrow fault had been exposed, running roughly in line with the ribside of the supply gate.
There were 13 colliers engaged in getting coal and two advancing the top rippings in the supply gate. Also at the face were two conveyor attendants, one at the drive of the retarder conveyor at the return end of the face and one at the transfer point at the intake end. There were two men getting supplies of timber to the face in the supply gate and seven men outbye of the face on the loading gate and haulage road. These men, with the deputy and the shotfirer, brought the total in the district to 28.
The deputy commenced his first inspection from the face about 8 a.m. and he was accompanied by the overman. Between 9 and 11.30 a.m., the deputy made another inspection of the face during which time four shots were fired in the coal. He was making his third inspection when the explosion occurred at about 1. p.m. The deputy said that through all the tests he had done he found no gas and this was confirmed by the overman who was with him.
The shotfirer employed on the face fired about 22 shots between 7.45 a.m and 12. 20 p.m. He fired 20 of these shots in the coal on the face and two in the supply gate top rippings shortly before noon. The last coal shots to be fired were at the intake end of the face at about 12.20 p.m. All the shots were fired singly. The shotfirer said that he tested for gas and found none for any of the shots.
At about 1. p.m. the deputy was making his third inspection and travelling with the air current, he reached the return end of the face and had found work proceeding normally and everything apparently in good order. He was one of a group of nine persons in or about the supply gate roadhead who were suddenly enveloped in flame and blow off their feet by the explosion. They all sustained severe injuries, from which two of them subsequently died but they were not inured by the blast. Two colliers working together about 25 yards down the face from the supply gate were buried under a large fall of roof which occurred as a result of the roof supports being displaced and blown downhill by the blast. When they were recovered from beneath the fall both bodies showed evidence of burns caused by the passage of the flame before the roof fell. The men working further down the face were badly burned and must have died instantly from the multiple injuries caused by the blast. Those men working further down the face at the roadhead of the loading gate were blown downhill and three of them sustained burn injuries but in no case were they of serious nature. The only person in the supply gate outbye of the roadhead was one of the two men engaged in getting timber to the face and his body was found burned and severely injured by the blast. He was found about 90 yards outbye from the face.
The alarm was immediately raised by those who were uninjured in the loading gate and help with additional first aid equipment and stretchers quickly arrived on the scene. The emergency organisations of rescue and ambulance services was quickly put into operation. Despite the difficulties created by the fall which blocked the face, all the injured were soon brought out, given efficient first aid at an emergency dressing station in the district and sent to the surface and the to hospital. It took until the following day to clear sufficient of the fall for the recovery of the bodies on the men beneath and both must have been killed instantly.
Arrangements were made for additional first aid men and equipment to be sent to the “Q” face where the emergency dressing station was situated. Within half an hour Dr. Ivor Evans who was in practice in Penygroes and Dr. Sheeman at Cross Hands arrived at the colliery. They immediately went down to the “Q” district where they gave their services at the dressing station. As the injured were brought to the surface they were seen by Dr. R. Thomas of Penygroes assisted by Dr. Schofield who was in charge of the first aid room and nursing sisters from neighbouring collieries before they were taken by ambulance to the Morriston General Hospital. The last of the ambulances left the colliery at about 5 p,m,. During the night the nine most serious cases were transferred to the Plastic Surgery Unit at St. Lawrence Hospital, Chepstow.
The victims of the disaster were:
- J. Davies
- N. Howells
- R. Morris
- W.H. Richards.
Those fatally injured:
- D. Pennington
- A.C. Phillips.
- B.R. Burton
- W. Cooper
- C. Davies
- H. Davies
- S. Davies
- S. Evans
- V. James
- M. Jones
- D. Phillips
- D.H. Rees
- W.J. Wilson.
Four were killed in the explosion and 13 others injured. One of the injured died in hospital on the 18th. and another on the 30th. September 1955 which brought the final death toll to six.
The report on the causes of and the circumstances attending the explosion which occurred at Blaenhirwaun Colliery, Carmarthenshire on 6th. September 1955, was conducted by Mr. T.A. Jones, O.B.E., H.M. Divisional Inspector of Mines and reported to The Right Honourable Lord Mills, K.B.E., Minister of Power in October, 1957.
The inquest was held on 23rd. November 1955 by Mr. W. Locke Smith, H.M. Coroner for the Three Commontts District of the County of Carmarthen who sat with a jury, who recorded a verdict to the effect that the six men had died from injuries accidentally received in a coal gas explosion, the cause of which had yet to be ascertained.
The inquiry looked into all the factors relating to the explosion and all interested parties were represented. The nature of the explosion, the source of the gas and the means of ignition were all closely looked at. The explosion occurred in the top corner of the face near the supply gate roadhead and the only gas was present after the disaster was from a blower in the roof about 20 yards down the face from the supply gate which was so great that it had to be piped into the return airway and it was estimated that 400 cubic feet per minute were issuing forth. It was concluded that gas came from this blower and it had commenced to come out only a minute or so before the explosions.
As to the source of ignition, all the safety lamps were tested and found that none could ignite the gas and there was no electricity in the face. Contraband was discovered in a jacket after the disaster but it was thought that no men had been smoking. Frictional heat was ruled out as the only fall was on the face after the explosion and there was nothing to support the theory that shot firing had been the source of ignition, Even though there were two patched leaks on the compressed air hoses, they were tested at the Mines Research Establishment and this was ruled out as a source and attention focused on the Meco, Type CF3 compressed air driven fan. When this was examined it was found that the four blades showed signs of damage by rubbing on the trailing edge. In experiments at the Mines Research Establishment, it was found that at speeds less than those which would be the running speed of the fan sparks were produced that could ignite the gas.
The inquiry came to the following conclusions-:
At a time when work was proceeding normally with the ventilation taking it’s normal course, a blower of firedamp of considerable magnitude suddenly issued from the roof some 20 yards down the face from the supply gate. The rate of emission was such that within a minute or so the methane content of the air current on the return side of the point of issue was raised above the lower explosive limit. Simultaneously, migration of the firedamp caused a richer and more highly explosive mixture to accumulate in the top corner of the face. As soon as the mixture drawn through the fan became inflammable, it was ignited by sparks produced by friction between the trailing edges of the fan blades and pieces of stone which had been projected by the ripping shots into the outlet ducting and were now fouling the path of the blades. Flame instantly spread throughout the inflammable atmosphere and reached the highly explosive accumulation at the top corner of the face, whereupon flame and blast were projected down the face and outbye along the supply gate. The men at the top end of the face were enveloped in flame but were too near the seat of the explosion to be affected by blast.
It may be asked why, with the fan continuing to run after the explosion, this sequence of events was not repeated. The answer seems to be that before the ventilation current could resume it’s normal course after being interrupted by the blast down the face, the fall of roof occurred. This obstruction caused by this fall so reduced the quantity of air flowing that, with the issue of firedamp continuing undiminished, the methane content of the atmosphere throughout the area on the return side of the point where the issue was above the upper explosive limit. This state of affairs continued until the fan was stopped before steps had been taken to restore the ventilation.
The report of the causes and the circumstances attending the explosion which recurred at the Blaenhirwaun Colliery, Carmarthenshire on the 6th. September 1955 by T.A. Jones, O.B.E., H.M. Divisional Inspector of Mines.
Information supplied by Ian Winstanley and the Coal Mining History Resource Centre.Return to previous page