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November, 1959

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One of the most difficult problems faced by the N.C.B. and contractors (The Norwest Construction Co. Ltd.) was that at all times the existing length of railway sidings had to be maintained. The new tracks will eventually pass right through the old installations; this will involve the taking up of over 17,000 yds. of track and laying the new track, totalling approximately 32,000 yds. Fig. 14 shows the stage reached at the time of our visit.

During the erection of the dozen or so buildings involved in this phase of the work about 6,000 yds. of drainage and 5,500 yds. of water mains and other service ducting will be laid. Excavation and fill will be roughly equal, the bulk being in excess of 80,000 cu. yd. Approximately 12,500 cu. yd. of concrete will be involved.

The larger buildings in the scheme are steel frame structures with sheet asbestos cladding. Other buildings are in brick. The architectural treatment both of individual buildings and their grouping has received careful attention with the aim of achieving a functional unity in the completed scheme.

The Architects have carried the principle of "clean and dirty" segregation common in pit-head baths one stage further. It has been applied to the surface layout of the whole colliery. The south side of the main administrative buildings is " clean ", and it is the approach side for men and visitors. No coal will be handled here. There will be a wide grass verge and a belt of trees on the north side of the administrative buildings which will separate them from the railway sidings and coal-handling plant.

The administrative buildings from west to east and are so arranged that a miner entering at the west can leave his bicycle, use the canteen, change into working kit, receive his instructions, collect his lamp and explosives, grease his boots, clock on and go down the shaft without doubling on his tracks. The return journey is in reverse except that he will use the baths and, once a week, collect his pay.

The building contract, as a whole, is said to be running abreast of schedule and this is attributed to careful pre-planning, organisation and the co-operation of all concerned.

Coal preparation

The plant is designed by the Mitchell Engineering Group Limited for a throughput of 4,800 tons per day at the rate of 400 tons per hour, and will consist of a Ridley-Scholes dense-medium washery for treating coal of the 8 in. to in. size range; coal above this size will be hand-picked and provision is also made for the +8 in. coal to be broken, if required. The in. to 0 raw smalls will be extracted for sale without treatment.

The plant has been so designed that at a later date, a Baum wash box could be added if it was decided to wash coal below in.

Arrangements have been made in the plant so that in addition to the coal received at the plant direct from the shafts, wagon borne coal may also be fed to the plant through a 24½ ton capacity side discharge wagon tippler.

The clean coal will be graded into the following :— sizes -1 in.-5/8 in.; 2 in.-1 in.; 3 in.-2 in.; 5 in.-3 in.; 8 in.-5 in.

No. 3 shaft heapstead

The heapstead building will be constructed of a steel frame with reinforced concrete floors, and asbestos wall and roof sheeting.

The main-floor layout is shown diagrammatically in Fig. 17. This is the decking level and the minecar circuit incorporates a single-car elevating traverser and a two-car loading traverser. All the decking equipment was designed by the Rhymney Engineering Co. Ltd., Cardiff.

Full cars from the shaft gravitate to a tippler loading ram which feeds single cars into the tippler. The empty car displaced from the tippler passes on to a pneumatically operated elevating traverser which carries a single car to the empties track. On arrival at the empties track, the traverser deck is tilted and the car allowed to gravitate on to the empties track and pass down to the rams in front of the two-car traverser at the ingoing side of the shaft. Cars on the empties track gravitate alternately to each of the traverser loading rams. When both rams are full, the two-car traverser is loaded and the cars are then transported to the shaft and one is rammed into the cage, displacing the full car. Materials cars are man handled out of the hoist on to the two-car traverser and are then transported to the shaft ready for ramming into the cage.

The middle floor of the heapstead building contains the chutes and plate feeders which transport the coal or stone from the tippler to their respective conveyors, and all the switchgear is also housed at this level.

From the general layout plan it can be seen that the route taken by the coal will be as follows — the 3½ ton minecars will discharge their load on to a 42 in. raw coal conveyor via a plate feeder; the conveyor will discharge into a raw-coal bunker. From the bunker the coal is fed to the preparation plant where it will he cleaned, sized, boom-loaded into endtipping wagons, and transported to the ship-loading bunkers. Inbrought coal will discharge into a track hopper which feeds the raw-coal belt leading to the washery. Cleaned coal may also be conveyed to the landsales building shown in Fig. 6.

Compressors and air-receivers are housed at ground-floor level in the heapstead building and the switchgear on the first floor. At the ground floor level also, materials are brought in for transportation underground. Decking rams will be provided for loading mine-cars directly into the cages, otherwise materials will be raised in hoists up to the main decking level. At present there is no kep gear at No.3 shaft, exemption being granted until completion.

Dirt disposal

The dirt disposal arrangement can be followed from the general layout drawing, Fig. 6.

Pit dirt will leave the heapstead, via tippler and plate feeder, on a 42 in. dirt conveyor. This conveyor will pass across the pit yard, pick up all the dirt from the new preparation plant, and will discharge into end-tipping wagons. The wagons are shunted alongside the river where they discharge into a 20-ton hopper. A plate belt feeds the dirt on to a 42 in. belt, 605 ft. long, which in turn loads a dirt barge at a special jetty which has been built.

The dirt disposal plant is already in operation handling dirt from the drivages and at present about 1,500 tons are being dumped daily beyond the three mile limit.

Originally, the barges were towed out by a tug but this proved unsuccessful, especially in rough weather, so a powered barge (Fig. 18) is now hired for the job. The barge normally makes three trips per day carrying about 500 tons each trip.

Channels must be regularly dredged at the jetty at N.C.B. expense.

Pit-bottom layout

Fig. 19 shows diagrammatically the pit-bottom layout at the Beaumont level. This layout is suitable until the shaft is deepened and the second winder brought into operation. Then an alternative route for the empty minecars will be available as indicated on the layout drawing.

The main locomotive haulage roadway was driven by the Cementation Co. Ltd., under contract to the N.C.B., and the decking equipment was designed and installed by the Rhymney Engineering Co. Ltd. At the time of writing, the new pit-bottom was handling dirt only. When the plant is in full operation, only three men will be required in the pit-bottom, including the weighman.

Trains of 30 full minecars are hauled by locomotive to marshalling creepers where the locomotive is uncoupled and the train of cars is then fed to an uncoupling point. Cars are fed singly from the uncoupling point to a weighbridge loading ram, which positions them on the weighbridge. After weighing, the car is pushed off by the following car and gravitates to the decking ram. Cars are fed automatically to one or other of the decking rams.

The full car is rammed into the cage displacing an empty car, which is delivered on to an electrically driven traverser, the car being stopped on the traverser by means of an hydraulic stop mounted on an independent structure.

The traverser is set in motion by the onsetter and carries the car to a rail track running to the foot of an elevating creeper. The traverser is automatically stopped in line with this track and the car pushed off by a boxer ram. When clear of the traverser, the car operates a track pedal which returns the traverser to the alternate decking position to receive the next car.

After passing up the elevating creeper the car gravitates to a marshalling creeper at the coupling point, where a train of 30 empty cars is made up to be hauled inbye by locomotive.

There is standage room for 115 minecars, i.e. 400 tons of coal in the bit-bottom.

Power for the decking equipment is supplied by a 60 h.p. Holman compressor situated on the surface, and the pit-bottom is illuminated by MetropolitanVickers 80 watt fluorescent tubes set at 5ft. intervals.

Underground

At the time of writing, ten longwall faces were being worked, five in each seam, The faces vary in length from 100-200 yds. and the majority are single units. In the Beaumont seam three faces are flight-loaded (A.B. Duplex flight loader running on Armadillo chain conveyor, and two A.B. cutters with Lambton flights filling on to Huwood bottom belts), and an A.B. Trepanner is in operation in the Plessey seam filling on to a 120 h.p. Sutcliffe chain conveyor.

On the power-loading faces strip packing is practised while total caving is common to hand filling. Some solid stowing was being carried out in the Beaumont seam with a 15 h.p. Austin Hopkinson slushers in the tailgates.

In the future it is proposed that all faces should be power loaded.

Coal from both seams is carried by gate and trunk conveyor to the locomotive haulage road in the Beaumont seam where it is loaded into Distington 3½-ton minecars and hauled outbye by 100 h.p. HuwoodHudswell diesel locomotive. Three locomotives are in service underground with one in reserve.

As the No. 3 shaft heapstead is not yet completed, the minecars are tipped underground and reloaded into tubs. The minecars are tipped into a Rhymney hopper and the coal is fed to a 60 h.p. B.J.-D. belt conveyor via plate belt, at the rate of 3½ tons per min. The belt conveyor discharges to a surge bunker with dual outlet which, in turn, feeds the 14 cwt. tubs on abjacent tracks. The tubs are wound up Bates shaft, four tubs per wind in double-deck cages which are simultaneously decked with the use of .drop cages.

As shown in the layout drawing of the workings, the first phase of the underground development consists of driving the main locomotive roads further inbye and making connections to the Plessey seam at strategic points by short drifts. This will considerably reduce the amount of belt transport required in the Plessey seam.

At the same time the main roadways in the Plessey seam are being enlarged to form a system of return airways; about five miles of roadway enlargement is to be carried out altogether.

The locomotive haulage road is at present advancing at the rate of 28 yards per week. Three shifts per day are worked on this main drivage, with four men per shift. An average of 50 shotholes are drilled with three Atlas-Copco compressed-air drills to form a wedge-cut drilling pattern. The round is fired by a Schaffler exploder and the debris loaded into minecars by two Eimco Rockershovels. The normal arrangement of double track and Californian crossing is in use at the face of the drivage.

The heading is ventilated by a 15 h.p. Sirocco booster fan delivering 7,000 cu. ft. of air per mm. and is supported by 16 by 12 ft. arch girders set at 3 ft. intervals and timber lagged.

Shunting of the full cars is carried out by two 20 h.p. Greenbat battery locomotives on to the main diesel haulage road.

The general gradient of the drivage is 1 in 400 in favour of the load.

At the present time the colliery is ventilated by a 100 h.p. Sirocco fan running at 210 r.p.m. and delivering 76,500 cu. ft. of air per min. at 2.9 in. w . g. Before long it will be necessary to increase the ventilation and so a new fan and duplicate standbye are to be installed at Bates shaft, the present downcast shaft. They are planned to be 150 h.p. axialflow types delivering 120,000 cu. ft. per min. at 4.9 in. w.g. The new fan will not be put into operation until the Plessey roadways have been enlarged, which will allow time for the fan house and drift to be completed, which has been made unusually complicated by the fact that Bates headgear is set on solid concrete walls instead of piers.

Man-riding sets of empty minecars together with trains are run at the beginning and end of each main shift, while each set during the shift has one manriding car attached at the rear. Rope haulage is now only used at the colliery to take supplies from the minecars further inbye.

General

All the surface reconstruction work should be completed by the end of 1960 and the increase in output built up until 1962. The scheme is expected to increase the raised and weighed output of the colliery from 2,000 to 3,600 tons per day and to increase the overall O.M.S. from 27 to 36 cwt. The extra men needed to achieve this will be about 400 face men, 270 others underground chiefly on development work, and a reduction of 32 surface men.

When reserves in the Plessey and Beaumont seams are nearing exhaustion, further development will take place at a lower level where an estimated 30 million tons is available in the Denton Low Main, Upper Busty, Threequarter and Brockwell seams.

Most of the coal from the colliery is shipped to the South Coast, the smalls to power stations and the bulk of the remainder for household purposes. Some coal is still exported, mainly to Denmark.

Acknowledgments

For permission to publish this article we are indebted to Mr. W. J. Charlton, Area General Manager, No. 2 (Mid-Northumberland) Area, N.C.B. Northern (N. & C.) Division and we should very much like to express our thanks to Mr. R. H. Charlton, Area Deputy Production Manager (Planning), Mr. J. Moss, Area Planning Engineer, and Mr. P. Coen, Manager of Bates Colliery for their assistance in the preparation of the article.

Drawings and Photographs accompanying the article