Date of the Accident – 4.1.1923
Owner – Bengal Coal Co.
Number of persons killed – 74
Place – Raniganj Coalfield
Parbelia was the deepest coal mine at the time. It had opened up the Dishergarh seam (4.5 m thick and dipping at 1 in 5) through two shafts, about 450 m deep. The mine was in the preliminary stage of development.
In order to secure rapid development, particularly in the dip headings, narrow galleries were driven ahead of the widened galleries. However, this practice was discontinued in May, 1922 owing to the difficulty in ventilating them properly. It was in one of the narrow dip galleries that the explosion had originated. The mine was comparatively dry and inflammable gas had been found in the workings from time to time. On 5th July, 1922 an explosion ascribed to an ignition of firedamp by a defective safety lamp took place in the rise workings and caused the death of 4 miners. Safety lamps had always been used in the mine, but after the July explosion, an improved type of lamp with double gauzes was introduced. In October 1922 an electrically driven coal-cutting machine was first brought into use. From that time Viking Powder No.1, an explosive on the British Home Office ‘Permitted’ list was exclusively used and the management, alive to the possible dangers from inflammable gas and, coal dust, had drawn up and enforced a code of blasting rules considerably in excess of the requirement of the rules made under the Indian Mines Act.
The ventilation of the mine at the time of the explosion was by natural means. Although a fan of large capacity had been installed, it had not been started as the air current produced by natural means was considered to be sufficient.
At the time of the explosion, 80 persons were present belowground of whom only six survived. The survivors were present in such parts of the workings as were not traversed by the explosion. 17 persons had been killed outright and the remaining 57 had severe bum injuries. Although all the injured were brought out of the mine by rescue parties within 5 hours of the explosion, they all succumbed to their injuries within a short time.
Subsequent examination of the mine disclosed that at the time of the explosion a shot had been fired in No.4 dip gallery and that the end of the shot-hole had blown-through into the advance narrow heading. Although the explosive used was a “permitted” one, the blown-through shot must have shattered the coal and projected a stream of burning particles into the air. An explosion must have been caused by the volatile gases in the shattered coal and dust being liberated and ignited by the heat. This initial explosion would raise clouds of fine dust sufficient to feed the flame and carry the explosion to all places where there was a sufficiency of dry coal dust. Whether gas was present on this occasion, it is impossible to say; but in any case, gas did not play an important part in the explosion. The Court of Inquiry concluded that the accident was caused by an explosion of coal dust due to a faultily placed shot which blew-through because of very little burden.
The Court made several recommendations regarding proper treatment of coal dust to render it harmless and suggested precautions to be observed for ensuring safety in blasting operations. Most of these recommendations have since been included in the Coal Mines Regulations.