Modern Practice in Mining by Richard Augustine Studdert Redmayne

Author:Richard Augustine Studdert Redmayne
Language: eng
Format: epub, pdf

Fig. 87.—Double Stall Working, showing Method of Removing the Bibs.

in the headways course, which is also the haulage road, where the heavy traffic tends to interfere with the regular flow of the current. In order to obviate this, holings were made through the ribs from stall to stall, the doors being placed in the stalls, where the traffic is less than on the headways course. The distance which the air current has to travel is also lessened by this means.

The other case in which the double stall was adopted instead of the ordinary bord and pillar method of working was at a neighbouring colliery where the seam lay at a depth of 240 yards from the surface, and the section of the seam was as follows :

Ft. In.

Good coal 3 6 Very hard.

Splint coal . .04 Thrown back.

Height of seam . . . 3 10

The seam was nearly flat. The roof of the seam was a good one, being composed of sandstone rock and a hard floor of shale.

The mode of working was practically the same as that described in the last example. The stalls, however, were driven for a greater distance, in one instance for a length of 130 yards, before the working off" of the ribs was commenced. On account of the strength of the roof allowing of it, the ribs were worked back towards the headways course.

As regards the double stall method in the South Wales Coal-field, the late Mr. T. F. Brown, writing in 1874,' stated that " in South Wales there are three principal systems of getting the coal, namely: first, single road stall; second, double road stall; and third, long-wall. . . . The seams of the upper and lower Pennant series, and the

* " The South Wales Coal-field," by Thomas Forster Brown. Transactions of North of England In^stitute of Mining and Mechanical Engineers, vol. xziii. p. 220.

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9-feet seam of the White Ash series, are generally worked by the first or second systems, or a modification, and the seams of the White Ash series are chiefly worked upon the long-wall system;" and he adds, **the last-named system was generally substituted a few years ago for No. 1 system in working the steam coals of the Ehondda and Aberdare Valleys, and the result has been to increase the produce of large coal, simplify the ventilation, and reduce the labour of the workmen." However, as has been previously remarked, there are conditions, and in South Wales too, which are more favourable to the adoption of the stall system of working than even long-wall, more particularly, perhaps, in the anthracite region, where the veins, as the seams are called, frequently highly inclined, are variable in dip.

The double stall system used to be practised in the Black Vein of the Celynen Colliery, but the long-wall system has of late years been adopted in preference. The seam varies from 5 feet 6 inches to 9 feet in thickness, the average thickness being about 6 feet, and it is of slight inclination.

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