20^th September 1952

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Cause Of Mine Disaster

Firedamp Ignition

Inspector On "Bad Practices"

The Chief Inspector of Mines, Mr. H. C. W. Roberts, in a report issued yesterday on the explosion in which 83 men lost their lives at Easington colliery, Durham, in May last year, states that the cause was the ignition of firedamp through the friction of coal cutter picks on pyrites.

Mr. Roberts reports that the inquiry brought to light a number of "bad practices" and even direct contraventions of statutory provisions and regulations not casually connected with the explosion but which had to be considered in forming an opinion of the way in which the colliery was managed.

It was admitted, he says, that the provisions of the Explosives in Coal Mines Order was not complied with in that some at least of the deputies had not been instructed about the maximum number of shots they were permitted to fire in any one hour or any one shift ; no tests had been made since 1948 to determine the time required to fire a shot. The same order was contravened, in spirit at least, by the practice of allowing the deputies to take into the mine more detonators than they required for use in their own districts, so that they could fire shots in other districts.

Shots In Roof

Evidence was given by two deputies that they had neither been given a copy of the Explosives in Coal Mines Order, 1948, nor had they been informed of the prohibition of the firing of shots in the roof at a longwall face other than with the provision in writing of the agent and manager. There was evidence that on several occasions shots had been fired in the roof for the purpose of releasing very tight chocks. The agent and manager denied any knowledge of the practice ; the fact that this method of releasing tight chocks remained undetected was a reflection on the value of the supervision exercised.

There was evidence that auxiliary fans had been started by unauthorized persons contrary to the requirements of the Coal Mines (Ventilation) General Regulations, 1947 ; the stoppings between the main intake and return airways in the Duckbill district (where the explosion took place) did not conform with the requirements of general regulation 91 ; a man in charge of an electric drilling machine had not been provided with a firedamp detector as required by regulations ; and on one occasion electrical apparatus which had been removed and re-erected in a new position had not been tested.

Although singly, some of these matters might not be of great moment, the report continues, collectively and taken in conjunction with unsatisfactory features discussed in other parts of the report, they indicated a disquieting lack of control and direction.

"The officials who gave evidence," Mr. Roberts comments, "impressed me as being hard working and conscientious men, but they seemed to lack that ability to anticipate events and that comprehensive knowledge of what was happening at the colliery which is characteristic of good management. The manager appeared to be so fully occupied in day-to-day details of administration that he was unable to exercise effective supervision and direction of the mine as a whole. Still less had he time to think out all the possible consequences of a major change of policy such as the decision to adopt longwall retreating with full caving in a district originally planned to be worked by other methods. Because of their duties in connexion with two other large mines in the group under their charge, the activities of the agent and his assistant were too widely dispersed to permit of their giving any effective help and guidance to the manager. . . . In short, nobody seemed to be in a position either to see the situation as a whole or to think it out if he did."

Specialist Consultations

Mr. Roberts agrees that there was evidence that full use was made of specialist consultant services up to divisional level when the decision was taken in 1947 to plan the area where the explosion took place as a duckbill district, but he comments : "I am left in some doubt about the value of consultations which did not make provision for the particular difficulties in roof control likely to be encountered when opening out on the caving system from a narrow heading in a virgin area, and which overlooked the ventilation problem resulting from a change."

The inspector states that it has been known for many years that firedamp could be ignited by the action of coal-cutter picks on pyrites and on certain types of rock or inclusions containing quartz. It would seem that ignition was not caused by sparks so much as by finely powdered pyrites dust, which was heated by friction until it burst into flame. This was an important distinction because it accounted for the fact that blunt picks were more likely to cause ignition than sharp ones. After a recommendation by the Safety in Mines Research (Advisory) Board a working party had been formed to investigate the hazards of firedamp ignitions by frictional sparking or frictional heating. Mr. Roberts lists a number of precautions that should be taken pending the findings of the working party, these including the recommendation that every effort should be made to use only sharp picks.

After giving the initial cause of the explosion as ignition of firedamp, Mr. Roberts states that the main issue of firedamp was from an accumulation in large cavities in the waste behind the longwall face and that it was forced out during a roof weight. Due consideration was not given to the risk of firedamp accumulation and of roof weight when deciding on the method of work, he adds. The explosion was afterwards continued by coal dust derived mainly from the conveyor belt and structures, from the vicinity of the transfer points, and from the stentons. There were defects in the system of dust sampling and in the measures taken to prevent, suppress, and treat coal dust ; and insufficient consideration had been given to the system of ventilation, particularly the use of auxiliary fans.

Tightening Control

All the recommendations of the report are aimed at tightening up control and investigation of the points mentioned above, including a review of all existing systems of ventilation with multiple fans ; an investigation of the emission and means of draining firedamp from wastes of retreating faces ; an investigation of roadway conveyors to determine the limits within which they may be safely and usefully employed ; and the acceleration of dust control, suppression, and sampling. The report states that action has already been initiated on recommendations on which prompt steps can be taken.

Mr. Roberts pays tribute to the rescue teams and colliery workers who assisted in the recovery operations at the time of the explosion ; two members of rescue teams lost their lives, one collapsing during exploration. The report includes a recommendation that the requirements of the medical examination of rescue workers should be reviewed.

The report is published by the Stationary Office.