Date of the Accident – 18.12.1936
Owner – Bengal Coal Co. Ltd.
Number of persons killed – 209
Place – Raniganj Coalfield
Poidih Colliery was working Disergarh seam, about 4.5 m thick, by two shafts, 225 m and 229 m deep. Coal raising was commenced in 1931 and since then the mine had been worked continuously. Inflammable gas had been found in the workings from time to time. In one place, gas was given off continually in small quantity and it is possible that even smaller quantities were given off elsewhere without having been detected. Magnetically locked safety lamps were used throughout the mine. No explosives were in use in the mine at the time of the accident.
On 18th December, 1936 at about 11 a.m. a violent explosion of firedamp and coal dust occurred and all the persons in the mine to the number of 208 including the manager were killed. Only one person on the surface was killed. The explosion had been of unprecedented violence. The winding gear of both shafts was badly damaged. In the downcast shaft, one cage had been blown to the top of the headgear where it was held. The over-winding bell-boxes with the two heavy girders supporting them had been blown over to the pulley wheels. The cage keps and the heavy girders supporting them had been dislodged and left suspended 1 m above their original position. The wall 1 m in thickness which surrounded the shaft from the ground level to the banking level had been blown down. Empty tubs on the banking level had been smashed and some had been blown off the banking level. At the upcast shaft, the pit-top covering had been blown into the headgear. One cage which was resting on the keps and the other cage which had been at the bottom of the shaft at the time of the accident had been blown up the shaft into the headgear, a distance of over 220 m. The top of the shaft was blocked by a tangled mass of iron work and ropes.
No trained rescue team equipped with the necessary apparatus was available. Two exploring parties descended 12 and 24 hours respectively after the explosion in sinking bucket with safety lamps, electric torches, some light tools and a cage of birds. Considerable damage had been done at the bottom of the downcast shaft. Most of the galleries contained thick white smoke and in the rise galleries, tests showed a large accumulation of inflammable gas. The quantity of gas had increased between the first and second descents. There was no possibility of anyone being alive in the mine and the probability was that all were dead shortly after the explosion. Further exploratory work would have been useless and dangerous. Smell at the top of the upcast shaft indicated the presence of fire in the mine. There was the danger of another explosion if fresh air continued to be circulated. It was, therefore, decided to seal the two shafts.
As the mine could not be examined except for a short distance around the shafts, the actual cause of the disaster could not be ascertained. Wherever the explosion originated and however it was propagated, it seems probable from the great violence that it was not one explosion only, but a series of separate explosions following one another. A gas explosion followed by a coal-dust explosion may have been followed again by another gas explosion.
The main explosion which wrecked the mine probably occurred at some distance from the shafts. No flame was seen coming out of the pit at the time of the explosion, and there was no evidence of flame in or in the vicinity of the shafts after the explosion. In all probability, firedamp accumulated in the goaf of a depillaring district was expelled into the workings by a large roof fall in the goaf.
The cause of the ignition may have been one of the following:
- A defect in, or accidental damage to, a safety lamp.
- Misuse of a safety lamp in the presence of gas.
- Light from a match or other apparatus for producing a light.
- A spark from electrical apparatus.
- A spark from some other accidental cause e.g. a falling stone in a goaf, or a runaway tub.
It is more than likely that the igniting source was one of the first three.
The Court of Enquiry into the causes of this accident made the following recommendations:
- Persons entering a gassy mine should be searched for contrabands.
- Mechanical ventilators should be kept working continuously.
- System of mining should be improved to prevent accumulations of gas in goaf cavities.
- Safety lamps should be examined weekly by the manager or under- manager.
- Electric safety lamps should be used by all work persons as they are less liable to misuse.
- Old workings in gassy mines should be examined once a week by a competent person.
- Regulations and bye-laws relating to coal dust should be examined with a view to their consolidation and possibly more stringent application.
- Stoppings to isolate goaves should be provided with arrangements whereby atmospheric conditions behind the stoppings can be readily ascertained.