Khost Colliery

This coal mine had been the scene of several accidents due to explosions of firedamp. An explosion in 1908 resulted in the death of 20 persons. Since then there had been 3 ignitions one of which caused the death of 2 persons. In 1899, a fire, probably caused by an explosion of gas, had resulted in the loss of 47 lives.

The seam in which the explosion occurred had an average thickness of about 75 cm and an inclination of 53°. It was known to give off firedamp, and safety lamps were exclusively used in the mine.

At the time of the explosion, a short, strike longwall face of about 8 m length was being worked from dip to rise. The mine was ventilated naturally and a hand-operated blowing fan with air-pipes was used to assist the ventilation at the face and in particular to clear out accumulations of gas.

On 9.3.1922 in the day shift 16 persons went to work at the longwall face. During the previous night shift a narrow rise drivage, called pugma, about 2 m wide, was commenced at the inner corner of the face in preparation for a horizontal cut about 1.5 m wide along the face. The pugma was driven about 1 m during the night shift. At the commencement of the day shift, the Charge-man found a small quantity of gas in the pugma. He stopped the work and put up a canvas sheet between the end of the air pipe and the face. This was said to have cleared the gas and coal cutting was resumed until the pugma was driven upto the full distance of about 1.5 m. The cutting of the 1.5 m slice in the level direction was then commenced. During the driving of the pugma, the seam thickness had increased from 0.75 m to 1.20 m. Shortly after mid-day, an explosion of firedamp occurred. The flame of the explosion was projected for 20 to 25 m from the face and severely burnt 16 persons of whom 13 died.

A full inquiry into the accident showed that the ignition was, in all probability, caused by a defective safety lamp which was found hanging on a prop close to the roof. The lamp was examined after the accident and it was found that amongst other defects, the gauge was dirty, the glass was slack and the flame could be extinguished by blowing over the top of the glass, and the lower asbestos ring was old and not air-tight. The accumulation of gas was presumed to have been due to a larger emission of gas than usual from the thickened coal which had just been reached, and to the partial blockage of the air passage by workers and support materials.

It was considered that the use of a blowing fan introduced a danger, as it would tend to produce an explosive mixture at the face instead of withdrawing the gas, as might have been possible if an exhausting fan had been used. The application of an exhausting fan would have been difficult; however, as a longer length of pipeline would have been required and frequent realignment of the pipes would have had to be made. These difficulties probably rendered the arrangement for the fan for exhausting impracticable.

The management was called upon to improve the ventilation of the mine and to provide a sufficient number of serviceable safety lamps.