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January, 1951

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The Regional Survey Report on the Northumberland and Cumberland Coalfields mentions one region as being among the richest of the coalfield. This region, which is indicated in the accompanying plan, Fig. 1, is roughly triangular in shape and bounded on the south by the Stakeford dyke, to the east by the sea, and to the northeast by the outcrop of the seams. Within these boundaries there is an estimated quantity of over 750 million tons of high-quality steam and house coal, there being more than 10 workable seams above the minus 1,000 ft. ordnance datum level. Although there are a number of well-defined faults, these seams are not dispersed and cut up to any great extent by small faults, and the gradients normally range between 1 in 24 and 1 in 12 except when approaching the Stakeford dyke where grades as steep as 1 in 6 are often encountered.

Before January 1, 1947, most of the collieries in the region under consideration belonged to the Ashington Coal Co. Ltd. This firm has long held an enviable reputation with respect to both their production methods and their workers welfare schemes, it being claimed as long ago as 1937, for example, that as much as 95 per cent, of the output was attained by coalcutting machines and 70 per cent, handled by underground conveyors. In the Ashington district the "Ladder Plan" was forestalled by some 30 years, for in 1920 the colliery company, in conjunction with local education authorities, opened a day continuation school, the object of which was to provide students, selected on merit from among young employees, with a sound non-vocational education. Each boy was paid to attend the school for two days per week throughout a period of three years, after which matriculation standard should have been reached. The success of the scheme may be judged from the large number of Ashington-trained men occupying important positions throughout industry — particularly in coal mining. For employees who were not of a studious nature playing fields extending to an area of 60 acres were provided by the company.

The Ashington Coal Co. Ltd. were always in the forefront with mechanisation of all kinds. They had made more extensive use of machinery both on the surface and below ground than probably any other company in the North of England. Extensive reconstruction plans were drawn up for the future and were progressing at vesting date.

Following Vesting Day the Planning Department had to shape their plans for the area as a whole, the necessities of other Collieries having to be taken into account. Thus, Lynemouth reconstruction plans were revised to include output from the adjoining colliery of Newbiggin, which is scheduled to close.

It was decided by the N.C.B. Area Management that there shall be three main types of colliery. Of these, the smallest will be units producing from 7,000 to 8,000 tons per week from locations near the outcrops. Next in order of size, certain existing collieries are to be enlarged to produce 13,500 to 15,000 tons per week each until their reserves in the upper seams are exhausted; Ellington and Linton are two examples of this type of colliery. The largest units, of which there will be three, are expected to produce a collective output of 80,000 tons per week. These last collieries will work the main resources of the region, a typical example being Lynemouth colliery.

Ellington colliery

This colliery, which before nationalisation was owned by Ashington Coal Co. Ltd., commenced operations in 1910, and the take is now served by two downcast shafts, one upcast shaft and a man-access drift. Of these, the main coal-winding shaft is No. 1, which is downcast, 13 ft. in dia. and 425 ft. deep to the Yard seam level. The other downcast is also 13 ft. in dia. but the upcast (No. 3) has a diameter of 15 ft. No. 2 shaft is sunk to the Five Quarter seam level with its winding inset at the Yard seam level where in addition to being used for manriding it deals with that fraction of the output with which the No. 1 shaft is unable to cope in two shifts’ winding. The No. 3 shaft is 548 ft. deep to the Five Quarter seam and is equipped with a single-deck cage suitable for relief manriding only.

Both the downcast shafts have doubledeck cages which carry two 10½-cwt. tubs on each deck. They are equipped with rail-type rigid guides, and No. 1 pit winding rope has a circumference of 4½ in. which is a quarter of an inch greater than the circumference of No. 2 pit winding rope. Steam winding is practised at both these shafts, the engines, which are of Robey manufacture, having cylinders of 20-in bore and 40-in stroke. Each winder is fitted with Black brakes and has a cylindrical drum 9 ft. dia. by 6 ft. wide.

Ellington has a severe water problem, as much as one million and twenty thousand gallons being pumped out of the pit daily, and we understand that at one time there was at least three tons of water raised for every ton of coal wound. To cope with this amount, ram, centrifugal and Mono pumps are used in bye and at the pit bottom there is the main pumping station depicted in Fig. 2. Each of the three pumps shown is of Drysdale manufacture and has a rating of 1,000 gallons per minute ; the necessary driving power is provided by English Electric 200-h.p. slipring induction motors working at 3,000 V.

Seam conditions

The seams at present being worked are the High Main, the Diamond, and the Yard. The High Main seam is found at depths of from 80 to 300 ft. throughout the Ellington take and varies in thickness from 2 ft. 6 in. to 5 ft. ; the immediate roof is a strong blue shale and the floor is fireclay. The Diamond seam is about 30 ft. below the High Main and has an average thickness of 3 ft. 4 in. ; the roof varies from an excellent blue bind where the intervening strata is thick, to a soft bind with coal "pipings" where the distance between seams lessens. A further seam, the Main, which is about 4 ft. thick and normally some 45 ft. below the Diamond, has not been developed so far, but in one locality (to the east and under the sea) these seams combine to give a worked thickness of about 8 ft. The Yard seam, which lies about 120 ft. below the Diamond seam, is approximately 3 ft. 6 in. thick and has a blue shale roof and a hard fireclay floor.

To date, most of the output has been obtained from the High Main and Yard seams — the former being now practically exhausted, its output being replaced by workings in the Diamond seam.

In all seams where complete extraction is permitted single-unit longwall faces are laid out either advancing or retreating according to the gradient, and varying in length from 60 to 100 yards depending upon the known floor-and-roof conditions. Winning out is done by means of single-unit 40-yard faces set out to leave a rib of coal 30 yards wide on either side.

By following this system it is possible to survey the whole area to be exploited and thus ascertain the nature of the strata, and at the same time all stones from the rippings are stowed on the face resulting in better roof control at the face and obviating the need for back ripping on the gateroads. It is the intention to extract these ribs later on the retreat. Huwood bottom-belt conveyors are employed on the longer faces, and where the gradient is in favour on the shorter faces Meco electrically-driven shaker conveyors are installed.

On the faces the coal is undercut to a depth of 4 ft. 3 in. by either A.B. or B.J.-D. machines, blasted, and handloaded onto conveyors. The face conveyors discharge on to 26-in. Meco gate belts, and the main-winning headings are spaced so as to limit the maximum length of gate conveyor to 400 yards. Single-unit retreating faces up to 100 yards in length have been successfully used in suitable conditions and have generally been equipped with Huwood conveyors.

Formerly, tubs were loaded directly from the gate conveyors and transported by rope haulage to the pit bottom. As the advantages of trunk conveying became apparent, however, there was a tendency to concentrate on fewer loading points and Figs. 3, 4 and 5 refer to a trunk conveying system which commenced operation in May, 1946. The main conveyor of this system is a 30-in. Meco unit and the loading point, which has successfully handled an average output of more than 700 tons per working day for more than four years, is fitted with a slow-speed double-chain tub feeder.

Where the workings are undersea and the cover is such that total extraction is not permitted bord-and-pillar methods are practised. The stalls are taken either 15 ft. or 18 ft. wide ; in the former case they are spaced at 24-yard centres and in the latter at 27-yard centres, so as to limit extraction to 40 per cent. The places are undercut by rail-mounted A. B. arcwall machines and after blasting, the coal is handloaded direct into tubs.

The secondary haulage systems from all faces are of the endless-overtub type. The tubs are attached in sets of four by Aspinall clips, and the track is of 28-lb. section rails to a gauge of 2 ft. upon wooden sleepers. Through the medium of a number of subsidiary faults and various short drifts all the haulage roads converge on to one of two main arterial roads, one going practically due north from the shafts and the second going towards the east (Fig. 6). Formerly both these main haulage planes were worked with overtub endless ropes, but a considerable length of the north arterial, having now been widened, graded and equipped with new track, has had diesel-locomotive haulage since July, 1949. The gradient along this stretch of road varies from 1 in 100 to 1 in 150 in favour of the load, and the support throughout the length near the pit bottom consists of 6 by 8 in. section straight girders, 14 ft. long, set upon brick walls 2 ft. in thickness, as shown in Fig. 7. Further inbye the locomotive road is supported by 14 ft. by 10 ft. 6 in. steel arches which are brick panelled to the springing and lagged with steel sheets around the semi-circular section. At intervals of approximately 20 yards Victor filament-type mains lighting fittings are installed. The track is of 60 lb. section rails fastened by means of coach screws and mild-steel plates to wooden sleepers 5 ft. long and of 4 by 5 in. section. This length of sleeper has been adopted because it is planned to replace the pit tubs with 2¼-ton mine cars running on a 3 ft.-gauge at a later date, and existing tracks have so been laid that the changeover will merely entail the re-siting of one rail. With the exception of a shunt road near to the shaft, there is no curve with a radius less than 75 ft.

The locomotives used are of the Ruston 48 DLZ type, and as this class of locomotive has been described in some detail in an earlier issue of this journal there is no point in repetition here. It will be remembered* that this locomotive has a rated capacity of 48 b.h.p. and powered by a Ruston four-cylinder engine. A tensioned chain drive is used and a Ruston three-speed constant-mesh gearbox is fitted the machine is, of course, fully flameproofed. The wheel-and-axle mountings exhibit a very useful feature, for by a mere interchange of wheels and axles it is possible to fit the locomotives for service on track of a different gauge. This factor was probably the most decisive one influencing the choice of locomotive at Ellington because, as has already been inferred, it is planned to increase the gauge to 3 ft. eventually.

At present a daily output of just over 1,000 tons is being handled by one locomotive, with a second as standbye and the installation is giving every satisfaction. To date, the conversion has allowed a 30 per cent. reduction in personnel along the plane.

In the main, underground modernisation at Ellington is concerned with the substitution of rope haulage by locomotives and trunk conveyors. Now that the conversion has been effected satisfactorily along the north arterial road, this haulage plane is being extended by a cross-measure drivage continuing along the same bearing. This locomotive road will have a gradient of approximately 1 in 100 in favour of the load, and although subsidiary faults and local geological disturbances cause certain variations, it will for the most part be just below the Yard seam. A similar locomotive road will also be driven in a north-easterly direction to tap the undersea reserves.

Coal from the upper seams will be lowered by spiral chutes to the level of the locomotive roads. Supplies will be taken from the locomotive roads to the upper seams by short backdrifts fitted with direct rope haulage.

Fig. 10 shows the rock face of the extension to the locomotive road. For drilling the face a pair of Joy hydro-drill jibs mounted on a T2 caterpillar truck is provided ; mucking is done with a Joy-Sullivan slusher. Work is carried out on three shifts per day and on each shift there are two drifters who are responsible for drilling, loading and support erection. Tubs are supplied to the slusher loading point by a separate gang of workmen who are also responsible for the delivery of supplies. Supports along the new length of locomotive road are similar to those on the present diesel run ; that is, 14 ft. by 10 ft. 6 in. steel arches. With the personnel mentioned a weekly progress of 12 yards is usual.

The existing pit-bottom tub circuit is to be replaced by a new mine-car circuit, details of which are given in Fig. 11. The control gear in the new pit-bottom circuit and the cageloading rams are to be all electrically operated equipment as supplied by Tudor Auto Services Limited and it is expected that a considerable saving in manpower over the existing method will result. The bulk of the output will continue to be wound at No. 1 shaft, and the other downcast, although fully equipped for coal winding, will be used primarily for manriding, dirt and supplies.

To accomplish the pit-bottom reorganisation certain existing roads will have to be stowed and new ones driven. The driving is now being actively pursued and Fig. 12 shows the face of one of the headings. It is being driven to to a finished width of 12 ft. and a height of 10 ft., and is supported by straight girders carried on brick walls. Drilling is performed by hand-held electrically-driven rotary machines and for mucking a Sullivan slusher is provided. At the face of the head there are two stonemen who are responsible for drilling, loading out stone and erecting the roof girders upon temporary legs. At a convenient distance back, a gang of bricklayers follow with the permanent walling. Normally there are stonemen at work for three shifts each day and the rate of advance averages 10 yards per week.

Fig. 11 also indicates that provision has been made to ride the men inbye by locomotive, but it must not be supposed that Ellington is without previous experience of manriding. In fact, a manriding haulage has been operating in the Yard seam for the last twenty years or so. At present this set travels about 4,000 yards and it is drawn by a reversible endless under rope moving at a maximum speed of 8 m.p.h. Rigid clamp-type clips attach the cars to the rope.

Surface modifications

The underground developments mentioned so far have been confined to the Yard seam and those above it. Seams deeper than that will be worked by Lynemouth colliery. There is believed to be a life of approximately 40 years in the upper seams, and consequently capital expenditure on surface plant has been limited to those items likely to offer reimbursement during that period.

The proposed introduction of 2¼-ton mine cars necessitates the laying of new heapstead tracks, however, and advantage has been taken of this opportunity to remodel the mine-car circuit at the surface. Fig. 13 shows the proposed layout, the details of which have been worked out with great precision. Work on the conversion is now in hand and progressing to schedule.

Most of Ellington coal is transported by steam locomotives, over an internal railway system, for washing at either the Ashington or Lynemouth plants. Coals above 4 in. are sorted by hand at Ellington, however, and those between 4 in. and 1 in. treated in a spiral dry-cleaning plant. For the future it is proposed to load run-of-mine output at the colliery and transport by internal railway to a 800-ton per hour washery to be erected as part of Lynemouth colliery main reorganisation scheme.

The existing steam winding engines are to be replaced by Metrovick automatic a.c. winders which have already proved most successful at Lynemouth colliery.

At present the colliery is producing nearly 11,000 tons per week with an underground personnel of 1,170 and a surface staff of 240. When the reorganisation is complete a weekly output of 15,000 tons is expected with an overall O.M.S. approaching 43 cwt. Ellington has enjoyed a profitable past and it seems that the future is well assured.

* COLLIERY ENGINEERING, page 271, October, 1946.

Drawings and Photographs accompanying the article