EXPLOSION AT MURTON COLLIERY,

DURHAM

I. — GENERAL

This is a large and extensive colliery where coal has been mined for the past 100 years in the heart of the Durham coalfield, seven miles to the northeast of Durham city and six miles south of Sunderland. It has three coal winding shafts (East, Middle and West) and is owned by the South Hetton Coal Co., Ltd. The Agent is Mr. G. Raw and the Manager Mr. W. O. Blenkinsopp, and Mr. J. Grogan is the Undermanager in charge of the Main Coal Landing from which the Main Coal and Five Quarter seams and the Polka area of the Low Main seam are wound, with two undermanagers in charge of the upper and lower landings.

Nearly 2,000 persons are employed underground and 452 were at work (270 in the Main Coal Landing) at the time of the explosion. The mine is worked by safety lamps throughout.

The explosion occurred in the Back-over Flat or District of the Five Quarter seam, which is reached by a stone drift driven through a large drop fault from the Main Coal, lying 26 fathoms below and 204 fathoms deep at the shafts.

The seam is 4 ft. 9 ins, thick in this Flat, interposed by two thin bands of dirt, with a thick laminated sandstone roof containing thin shale beds. It is a fairly hard steam coal, with a volatile matter content averaging 35 per cent., and has to be shot down systematically by explosives.

The Back-over Flat is a whole working being driven back-over towards the shafts from the 1st East Main Plane for the purpose of providing (1) a return airway for a new development in the seam to the South, and (2) a new return airway to cut out a long and tortuous return now serving the Five Quarter seam; and, incidentally, to provide a travelling way for the men and so obviate travelling a main engine plane where high speed main and tail haulage operates.

It will be seen from the accompanying plan that the final phase of this scheme had been reached at the time of the explosion; the companion stone drift rising 1 in 6 southwards being in progress, and the winnings, F ore, Middle and Back Drifts, rising on the full gradient of the seam 1 in 23, having reached the point where the drivage to the shafts would be made.

The Flat was on its own ventilating split, and being a nearby and small district the ventilation was heavily regulated (the most remote working in the seam is about 3½ miles from the shafts), and the last measured quantity of air at a point 100 yards from the first working place was 5,670 cubic feet per minute. The seam in this Flat was cut by arc-wall machines operated by compressed air, the length of jib being 6 ft. The working places were normally about 16 ft. wide and the "cut" was made in the coal 21 ins. from floor level. Shot-holes bored by compressed air machines were ordinarily 5 ft. deep, three being placed systematically in the top coal and three in the bottom coal; and the usual charge was 7 ozs. of explosive in the centre and 6 ozs. in the side holes, sheathed Minex explosive being used. An approved type H.T. single-shot exploder was provided for coal shots and a multi-shot exploder for tiring volleys of shots in the stone drift. Sand-and-clay mixture was provided for stemming and home-ground shale dust for use on the roadways and for shotfiring.

Gray-Sussman electric hand lamps, with a due proportion of Patterson schedule B oil lamps as gas detectors, were in use in this flat or district, and the deputies were provided with Edison Model J cap lamps and Wolf re-lighter oil lamps.

In common with County Durham practice, four coal shifts are worked daily with a deputy in charge of each shift in each flat. In the Back-over Flat the deputies fired all the shots in the flat, including the stone drift, and they had ample time to do this work and at the same time attend to any necessary bratticing and generally carry out their statutory duties in a proper manner.