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July, 1948

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This explosion, which resulted in the loss of over 100 lives, originated with the firing of a charge in a shot-hole placed in the roof. An interim report was published in October of last year with the object of directing the immediate attention of managements to the grave risks attending this practice and the present report not only endorses the recommendations and suggestions then made for the avoidance of similar explosions in the future, but also gives them a more precise and extended formulation.

Before giving these conclusions it is sufficient to recall that the explosion originated with the firing of a charge of sheathed permitted explosive in a roof shot-hole which had not been examined for breaks before being fired, this being contrary to the requirements of clause 6 (d) of Part II of the principal Explosives in Coal Mines Order. Other facts established at the enquiry were that

The shot-hole passed through a roof break or breaks and the inner end of the hole either made contact with, or was in very close proximity to, a bed-separation cavity containing inflammable gas which was continuous with an accumulation of explosive gas in the contiguous waste or goaf.

The firing of the shot ignited the gas in the bed-separation cavity.

The gas in the cavity burned for a short interval of time and the flame travelled along the cavity until it reached the explosive mixture in the waste, causing a firedamp explosion.

The flame of the explosion traversed several working faces and nearly 2,000 yards of roadway, including several inbye conveyor roads, about 60 yards of the main return airway and nearly half a mile of the main intake haulage road.

The explosion was marked by few signs of extreme violence.

The initial explosion was almost certainly one of firedamp only. The blast from this initial explosion raised a dust cloud ahead of it and as the explosion travelled on its path the nature of the combustible mixture gradually changed from firedamp-and-air through firedamp-coal-dust-and-air to practically coal-dust-and-air alone, before the flame was finally extinguished by excess of stone dust in the dust cloud.

The excess of coal-dust in the dust cloud was mainly derived from under the roadway conveyor structures and from the recently deposited top layer along the whole length of the inbye conveyor roads, while the stone dust was mainly derived from the main intake haulage road. This stone dust was projected ahead of the coal dust blown from the inbye conveyor roads and did not contribute to the extinction of the explosion until the flame had travelled nearly half a mile outbye along the haulage road.

RECOMMENDATIONS

(a) Shot-Firing. — (1) In all coal mines where inflammable gas is not unknown, the provision of Clause 6 (f) (i) of the principal Explosives in Coal Mines Order, which in effect permits the firing of shots in close proximity to inaccessible cavities or breaks in the gob, goaf or waste, should be strengthened in such manner as to restrict the latitude now allowed.

(2) The firing of that type of shot variously known as "cuckoo," "upper" or "upper-cut," i.e., a shot fired in the roof near the edge of a waste behind a longwall face, should be prohibited in mines where permitted explosives are required because of possible danger from inflammable gas, except with the written authority of the Agent and Manager and that before such authority is granted, the Agent and Manager must satisfy themselves, firstly, that it is not reasonable or practicable to break the roof down otherwise than by shot-firing and, secondly, that the air in the waste does not normally contain more than one per cent. of inflammable gas.

(3) The use of a break detector made to an approved specification, and properly maintained, should be made compulsory.

(4) The maximum number of shots which it is permissible for shot-firers and deputies, respectively, to fire, should be fixed for each district of the mine after a trial made under working conditions, both in respect of the number of shots per statutory shift and per hour during the shift, the trials to have regard, in the case of a deputy, to his primary responsibility to carry out his statutory duties and, in the case of both shot-firers and deputies, to any other duties which may be assigned to them or to any assistance given to them.

(5) A thorough investigation should be made by the management of all collieries where explosives are used into the whole business of storage, records, use and handling of explosives and shotfiring practice in general, including hole-boring, with a view to devising the most efficient system appropriate to the circumstances, and thereafter a superior official of the mine should be given the responsibility of seeing that the approved system is efficiently applied and operated in practice.

(6) Immediate steps should be taken to expedite research work with a view to determining (a) the conditions necessary for ignition when a shot is fired in a hole connecting with a break or parting containing inflammable gas, and (b) the necessary safeguards against such ignition; and that, in the meantime, wherever permitted explosives are used, the very simple practice of pushing a plug of stemming to the back of the hole before it is charged should be generally adopted.

(b) Precautions Against Coal Dust. — (7) In regard to the use of inert dust for neutralizing coal dust on roadways, the principle of "little and often," i.e., the application of small quantities at frequent intervals, should be more generally adopted and should be standard practice for all roadways in which coal conveyors are used.

(8) All practicable steps should be taken to prevent or reduce dust formation at its source and thereafter to suppress, by water infusion, sprays, wet-cutting, wet-drilling or other appropriate means, the inflammable dust that is inevitably made.

(c) Rescue and Recovery Work. — (9) Steps should be taken to standardize the type of self-contained breathing apparatus provided for the use of Rescue Brigades within each geographical Division of the National Coal Board.

(10) The management at each mine should have in readiness a detailed plan which can be operated promptly and effectively in the event of a serious emergency arising at the mine.

(11) In view of the number of lives lost due to carbon monoxide poisoning following recent mine explosions and fires, the question of developing a simple, suitable and easily portable mask for the protection of miners against carbon monoxide — a subject which has received some consideration in past years — is well worthy of reconsideration.

(12) The use of trained dogs to assist in the recovery of missing bodies of victims of mine disasters is well worthy of further consideration and trial.

(d) Appointment of Specialist Mining Engineer and Supervision by Responsible Officials. — (13) A full-time mining engineer, with an intimate knowledge of mine explosion and fire hazards and highly qualified in the science and practice of mine ventilation, should be appointed for the collieries in the Whitehaven district. His duties should comprise the planning and direct supervision of the ventilation system; the development and application of measures to eliminate or safeguard against all explosion and fire risks; and he should have a definite responsibility for these matters along with the managements of the collieries concerned.

(14) In each of the Whitehaven collieries, in addition to the Manager and Under-manager, there should be a responsible official in charge of the mine on shifts when neither the Manager nor the Under-manager is on duty, who should be not less qualified than an under-manager.

In conclusion Mr. Bryan states that action has already been taken to implement certain of the above Recommendations. The Explosives in Coal Mines Order, 1948, which was made on 4th February and came into operation on the 16th February, covers Recommendations (1), (2) and (4) above. In addition, a committee has been set up to inquire into the precautions necessary to secure safety in the use of explosives in coal mines. This Committee will include, among other things, Recommendations (3) and (5) within the scope of its inquiry.

* "Whitehaven William Colliery, Cumberland. Final Report on the causes and circumstances attending the explosion which occurred on Aug. 15, 1947." By A. M. Bryan, J.P., B.Sc., F.R.S.E. Published by H.M. Stationery Office.