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March, 1951

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This is the youngest colliery in the neighbourhood, having commenced operations for the Ashington Coal Co. Ltd. in 1934. The shafts, which are situated comparatively near to the coast, are two in number, and both were sunk to the High Main seam level, which is 486 ft. from the surface. The downcast (No. 1) is 18 ft. in diameter and is used for coal-raising on two shifts per day, and the upcast, which has a diameter of 15 ft., is used for ventilation and emergency manriding only.

The seams being worked are the High Main, the Diamond, the Main, and the Yard. Each of these seams shows practically the same nature of roof and floor as throughout the two neighbouring collieries and the distance between the seams is also comparable. They are, of course, found at slightly greater depths at Lynemouth, the Yard seam, for example, being 660 ft. below the surface near to the shafts, as compared with some 300 ft. at Ellington.

Coalface arrangements

Of the seams mentioned, the Yard has been worked to the greatest extent, although the other three seams have been worked to some extent. For the most part the workings in all seams are laid out on advancing longwall principles. Double units with approximately 84 yards each side are common and face conveyors are of either the B.J-D., Blackett chain, or the Meco 20-in. semi-troughed belt type. A.B.15 coalcutters undercut to a depth of 4 ft. 3 in., and after drilling with Victor high-frequency machines and blasting with Polar Thames explosive, the coal is hand-loaded on to conveyors. Face conveyors discharge on to 26-in, fully troughed Meco gate conveyors. These gate conveyors are limited to a maximum length of 500 yards and in most cases they load direct into pit tubs of 12 cwt. capacity. The tubs are taken to the pit bottom in sets of four attached to endless overtub ropes by Aspinall clips. The haulage roadways are driven in the seam and consequently follow a maximum gradient of 1 in 20 except when approaching the pit bottom, where a length of drift at a gradient of 1 in 8 has to be negotiated.

Where the Main seam is worked under the sea the regulations prevent total extraction and a pillar-and-stall layout is adopted. At present eight places are being driven and the central rectangular pillars are 60 yards long by 42 yards wide. To either side of the central row there are three parallelogram-shaped pillars each 37 yards wide by 60 yards long. The acute angle of the parallelogram is 60 deg. and the flank roads were set off in such a manner to make easier the negotiation of the corners by shuttle cars. The two central roadways will eventually act as main return airways for that part of the colliery.

The working places are driven 16 ft. wide and as the blue shale is of a friable nature three or four inches of coal are left to form a roof, so making a working thickness averaging 7 ft. 9 in. As at Linton colliery, this working thickness normally shows two dirt bands ; one, which averages 6 in. of thickness, appears about 4 ft. from the roof, and the other, which generally runs about 1 ft. from the floor, has a thickness approximating to 4 in. For cutting, two Mayor and Coulson arcshearers are provided, and at each place an 8-ft. deep horizontal cut is made just above the upper dirt band followed by a central vertical shear. Fig. 1 shows a machine making a vertical cut. To bring down the coal twelve shots are used and the necessary holes are drilled with Victor hand-held machines. Four inner holes on the bottom bench of the face are fired simultaneously first ; a second round consists of four outer holes on the bottom bench, and finally four holes above the horizontal cut are fired simultaneously. Sheathed Polar Thames explosive is used and the charges vary from 28 to 10 oz.

After blasting, gathering arm loaders, two of which arc Joy 11 BUs and a third a M. & C. 8BU, are used. They load into Joy 5SC shuttle cars, which deliver to a Meco scraper-chain feeder serving a Meco 30-in, wide fully troughed trunk conveyor. There are five shuttle cars at work in this panel. The trunk conveyor delivers to a loading point less than 500 yards from the pit bottom.

The working places are supported by straight girders, 14 ft. long and of 5 in. by 6 in. section, set upon wooden props. Two horsehead runner girders are slung from the permanent supports at each face and as soon as blasting is finished they are moved forward to provide cover until permanent protection can be given. The jib of the arcshearer is used to lift girders into position ready for securing with props. Ventilation is by Meco 5-h.p. fans and 16-in. dia. Mecotube.

The output from the mechanised pillar-and-stall panel is very satisfactory. When fully staffed there are four men per day on loading (two men on two shifts), twelve men on cutting (two men per machine for two machines on three shifts), four drillers (on two shifts), and eight shuttle-car drivers (working on two shifts). This personnel produces an average output of over 500 tons per day and the face O.M.S. is frequently in the neighbourhood of 25 tons, with a corresponding figure of 10 tons representing the OMS. into the tub.

Machinery maintenance costs do not appear to be heavy and we understand that the shuttle cars are using the same tyres as when the installation started in May, 1948. Breakdowns are very rare.

Shaft widening and deepening

As mentioned earlier, all the coal-raising is concentrated at No. 1 shaft and No. 2 is used solely for ventilation. Since May, 1949, however, the Cementation Co. Ltd. have been engaged increasing the diameter of No. 2 shaft to 18 ft. At the time of our visit approximately 450 ft. of the shaft had been widened and the work was proceeding as programmed. As the widening is completed, a concrete lining to the shaft is being provided. Reinforcing is encased in the concrete at the shaft collar, for the first 60 ft., and at all insets. The normal thickness of the concrete lining is 9 in. but the figure is increased to 21 in. at the shaft collar, to 18 in. through some gravel ground near the surface, and to 15 in. through water-bearing strata. The shaft work is carried out from a scaffold which is slung from the headgear and which provides an adequate safety fence at the widening point. To allow ventilating air to pass the scaffold has grilled inserts. Removal of the old lining and blasting of the rock inevitably causes material to fall down the shaft, and to avoid double handling an inverted conical seal has been built at the shaft bottom. In this seal there is a sluice gate and a chute enabling the debris to be run off at will into tubs. This debris is then taken inbye and stowed.

As the handling of this debris places a strain on the underground haulage system however, the management prefer most of the sinking dirt to be sent to the surface. Dirt going upwards is hand-filled into hoppits, hoisted to the surface and then tipped inside the air lock on to a chute. The chute discharges as is shown in Fig. 2, through hinged doors, on to a Meco 26-in, conveyor belt. From the conveyor belt the debris is taken in wagons to the beach, where it is dumped into the sea.

Concrete for the walling is mixed on the surface in the two Liner mixers shown in Fig. 4 and loaded into the drop-bottom hoppits also visible in Fig. 4. As filled, each hoppit is transported on a low trolley to the shaft mouth, from where it is lowered to deposit, through the drop mechanism, the concrete behind the shuttering. The average rate of progress in shaft widening to the present works out at about 60 ft. per month.

To provide a second means of egress from the colliery while work on No. 2 shaft is in progress, an underground connection has been made with the workings of Woodhorn colliery.

When the widening is completed the Cementation Co. Ltd. are to deepen the No. 2 shaft 233 ft. At this horizon a new pit bottom will be formed in accordance with the plans shown in Fig. 5. The new bottom is designed for the handling of 5-ton mine cars and each shaft will be used to wind coal to a capacity of 350 tons per hour. The loaded cars will be weighed underground and throughout all the pit-bottom area their movements will be controlled by Lofco oil-hydraulic feeders and rams, so keeping labour requirements to a minimum.

Loaded tubs will be brought to the pit bottom along a main arterial road and it is hoped that electric-trolley locomotives will be used for hauling. It is intended to drive the main arterial road due north on a gradient of 1 in 400 in favour of the load for a distance of 860 yards. At that point a junction will be formed with other arterial roads radiating to the north, to the east and to the north-west respectively. The north-west arterial road is scheduled to have a gradient of 1 in 400 in favour of the load and to intersect the Yard seam at a point approximately 500 yards from the junction. Beyond this point subsidiary faulting will also enable the working of the Five Quarter and Plessey seams. This arterial road will thus deal with the output from the western areas of Lynemouth colliery and those deeper seams at Ellington colliery which, as explained earlier, are not to be worked at that colliery.

From the main junction the northing arterial road will continue level to intersect at a distance of 1,250 yards the Plessey seam, after which it will continue in the seam. Subsidiary faulting allows the road to progress below the Yard, Five Quarter and Plessey seams in this locality.

The road to the east will be driven at a gradient of 1 in 400 in favour of the load until it intersects the Yard seam some 2,030 yards from the junction, after which it will continue at this gradient in the seam as far as geological conditions will permit. By means of staple pits and back drifts access will be obtained to the High Main, Diamond, Main and Yard seams in this area.

From a point about 2,000 yards along the east arterial road a subsidiary arterial road will be driven south on a level gradient for a distance of 1,570 yards. At that point a division will be made, one fork going to the south-east, to carry output from the Five Quarter, Low Main and Plessey seams in the present Newbiggin colliery take, and the second in a south-westerly direction to pick up the Five Quarter seam in the Woodhorn colliery area.

It is proposed to support the arterial roads by flattened arches 16 ft. wide by 13 ft. high. The arches will be of 5 in. by 6 in. section and encased in concrete. The track will be of 60-lb. rails to a 3-ft. gauge. Wolmanite-treated wooden sleepers will be used and the fastening between rail and sleeper will consist of a mild-steel pad-and-coach-screw assembly.

Cars will be loaded in the arterial roads, and spiral chutes will be used to lower the coal from the upper seams. Trunk conveyors in the seams will deliver to the staple pit and each spiral chute will be arranged to receive from three seams. Rise drifts on a gradient of 1 in 3 will be used to take supplies inbye from the arterial road to the seams. Details of the proposed standard loading station are given in Fig. 7.

Drawings and Photographs accompanying the article