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Colliery Engineering

May, 1931

Pumping Equipment.

The shallowness of the seams and the proximity of the Hauxley Fault have naturally caused the workings to make a good deal of water, and the pumping duty is consequently very heavy. The main pumping plant is situated at Newburgh, and consists primarily of a 4-stage 700 g.p.m. Mackley unit, driven by a 160-H.P. motor, this delivering direct to the surface against a 480-ft. head. A Boving sinking pump, having a capacity of 500 g.p.m., has been installed on permanent foundations as a standby, and in addition there is an old steam-driven quadrant pump capable of dealing with 400 g.p.m. At Broomhill a further pump, supplied by Edward N. Mackley & Co., is in service, and has a capacity of 1,400 g.p.h. These pumps are provided with duplicate motors of 160 H.P. each. Numerous small pumping sets are, of course, installed inbye to concentrate the water on the two main stations, these auxiliaries being for the most part of the electrically-driven ram type, in units of 25, 50 and 100 g.p.m. capacity.

In the winter months the average quantity of water raised at Broomhill is 1,000 g.p.m., and at Newburgh 800 g.p.m., so that the total quantity dealt with approaches 500 tons per hour

Surface Plant.

There is no power plant at Hauxley Colliery, electrical energy being generated at Newburgh power station and transmitted at 3,000 volts 50 cycles by an overhead line of 1,000 kVA. capacity. Duplicate supply is provided by a similar line from the Newcastle Electric Supply Co., and is converted from 40 to 50 periods in a frequency changer. The current is stepped down to 500 volts, in transformers of Parsons manufacture, at which pressure it is consumed by the various screen motors. The winder, which was supplied by M. B. Wild & Co. Ltd., is driven through gearing by a 216-H.P., 3,000-volt, 40-period Metrovick motor. It is provided with a 10-ft. diameter parallel drum, and is capable of making 70 winds per hour, the winding time being 37 sec. and the changing time 20 sec. The current consumption is 1.64 kW. per trip. The braking gear is operated by compressed air, an electrically driven compressor in the basement providing the necessary air supply. A view of this equipment is given in Fig. 14.

The headgear, heapstead and screening plant were supplied as a whole by M. Coulson & Co. Ltd., of Spennymoor. The headgear is 80 ft. high from ground level to the centre of the sheaves, which are 12 ft. in diameter, and is constructed of rolled-steel joists, with mild steel bracing. Steel chequer-plate platforms are arranged around the pulleys and detaching hooks, the latter being of the Ormerod pattern. Fig. 15 shows the shaft top, one of the cages and two of the 25-cwt. capacity tubs. It will be noticed that the cages are of the double-track variety, and contain two of the larger tubs or four of the smaller ones. They have inclined bottoms and are fitted with Simplex tub stops. Beien-type keps are incorporated, so that it is not necessary to lift the cages before commencing the wind.

The heapstead has a steel framework construction, with concrete floors, galvanised-sheeting walls, and a sheet asbestos roof fitted with continuous skylights and ventilators.

The screening plant consists of two units, each comprising a tippler, jigging screen, picking belt and small coal conveyor, but the structure has been made sufficiently large to accommodate a third unit when required. The tipplers are fitted with automatic releasing and stopping gear, and the empty tubs are arranged to gravitate to a point from which they are raised by a double-chain creeper and allowed to run back to the shaft.

The screens are arranged to make two sizes of coal, and, to reduce vibration as much as possible, are made in two balanced parts. Large coal passes to the 4 ft. 6 in. wide picking belts, provided at the delivery ends with lowering jibs to reduce breakage. An 18-in, band conveyor handles the small, which is delivered direct into trucks. Each screening unit is driven by a 20-H.P. motor, all the motors being housed in a separate compartment situated behind the jigs. Any refuse picked off the belt is dealt with by means of openings in the floor, which are fitted with slides and operating gear, worked from rail level, to regulate the delivery into the wagons. All the truck roads are spaced at 14-ft. centres to allow ample space between the sides of the wagons and the heapstead stanchions.

Method of Working at Broomhill.

At Broomhill Colliery the seams are moderately level, and whereas a number of conveyor faces are laid out on similar lines to those at Hauxley, the chief item of interest here is the improved method of bord and pillar working that has been introduced. This is a panel system, the object being to cut up the coal in blocks of limited area and to extract them soon after their formation. As nearly as possible 50 per cent. of the coal is got in the first working and 50 per cent. in the second, the balance thus struck between the "whole" and "broken" coal enabling the formation of the blocks to keep pace with their extraction.

Reference to the plan in Fig. 19 will make the method clear. The first working is restricted to a definite area, that is, to a block beyond the small landings shown to the left and right of the main place or mothergate. As soon as this limit is reached, the second workings are commenced, and as the blocks already formed are being extracted a second panel is cut out. Arcwall cutters are used for both operations, the machines used being electrically driven and of Anderson Boyes manufacture.

Tub roads are laid up each place parallel with the mothergate, the rails and roof supports remaining in position for the extraction of the blocks. In this way, as the second working follows closely upon the first, the risk of falls and the amount of shift work common to many systems of bord and pillar working are substantially reduced. The cross places or cut-throughs are for ventilation only, and as soon as they are holed the rails are pulled out and the props withdrawn. One place however, is retained next to the working place for ventilation purposes.

The size of the blocks is kept small in order to conform as nearly as possible to the 50 50 requirement, and the panels are arranged to keep the putting distances within reasonable limits, the mechanical haulage being kept well advanced so that a quick supply of tubs is ensured at the working places. The small landings serve both the advancing places and the broken workings.

Detailed care is given to the laying and position of the tub roads. These are built up with 25-lb. B.E.S.A. rails, 16 ft. in length, laid on steel sleepers of the clip and bolt type, the bolts being "clinked" over before being sent underground in order to avoid the loss of nuts. All the road measurements are multiples of 16 ft., so that no rail-cutting is necessary ; moreover, a special type of reversible turnout is in use which has an overall length in each direction of 16 ft. A disused turn can thus be pulled up and replaced by a 16-ft. rail without any further adjustments to the track being necessary. A drawing of the turnout is given in Fig. 18. It is marketed by Hugh Wood & Co. Ltd. and is built up in sections, each of which can easily be taken by an ordinary-sized timber bogie. The sections are rigid and are assembled very simply by means of bolted joints, forming a properly gauged turn which is perfectly accurate both as regards length and lead-off. No sleepers are required unless the floor is very soft. Four sections complete the layout, which is foolproof to lay, and as the whole structure is quite rigid when bolted together it can be made into either a right or left hand by simply taking it up and turning it over. The manner in which it is braced effectively prevents any distortion, and as the separate sections are rigid no skill is required to assemble them, the time taken being stated to be less than one quarter of that necessary for an ordinary turnout. Fig. 17 illustrates a modification of the turnout, the design being smaller for use with ordinary putting. This view shows the check rails to better advantage these are provided with slotted holes so that when the turnout is reversed for an opposite hand turn they project above the running rail the correct amount. The cross members consist of bolts fitted inside hydraulic tubing.

This system of working not only enables large outputs to be obtained from a restricted area, but also, owing to the close proximity of the "whole" and "broken" workings, enables the machine power to be conserved, as one cutter can deal with both classes of place. Actually, double the number of working places are available compared with the usual bord and pillar system, and the improved method enables all the advantages of intensive production to be attained.

In conclusion we have pleasure in expressing our thanks to Major A. M. Morison, the manager, for affording us facilities to visit the collieries and for various other kind offices he undertook in helping us to prepare our article.

Drawings and Photographs accompanying the article