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November, 1924

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The pressing need for economy of production which has characterised all English industrial undertakings since the War has nowhere been more felt than in the coalmining industry, especially in those coalfields not particularly blessed with the thicker seam, and it is only natural that managers and engineers have found it necessary to go fully into the question of their equipment with a view to reconstructing it wherever possible to meet the more stringent economic conditions. Much colliery plant which served its purpose well enough in the days of cheap labour — England's greatest lost asset — cannot nowadays in many cases be made to operate economically, and the management is often confronted with the vexed question as to whether, and to what degree, further capital expenditure on new plant is justifiable. The condition under which recent plant is operating successfully at other collieries is thus a matter of importance to anyone considering reconstruction work of this kind, and we propose here to give some account of a few features which impressed us on a visit to the Allerdale Coal Company's pits.

Naturally adequate particulars of this kind cannot be obtained without the co-operation and assistance of the colliery management, and we have pleasure in acknowledging our indebtedness to Mr. J. F. Foggo, the agent at Allerdale, Mr. J. Bateman, the Commercial Manager and Secretary, and Mr. F. D. Harper, the manager of the coke works, for their courtesy and help.

At present an aggregate of 1,100 tons is raised daily from the William Pit, situated at Allerdale, and the Buckhill Pit, some miles away. Work is at present in progress, however, which will enable the output at Buckhill to be increased from 500 tons (the present output) to 800 tons per day. Here a pumping shaft 11 ft. in diameter, at present utilised solely for pumping purposes and to serve as a second way out, is being fitted with a new headgear and winding equipment capable of dealing with 300 tons of coal in a working shift of 6 hours 40 min. Unfortunately at the time of our visit the work had just begun and it was impossible to take photographs or to get very full data. Double-deck cages will be fitted — two 10-cwt. capacity tubs in each deck — and the shaft will be furnished with rigid conductors, two to each cage. A clearance of 18 in. between the cages assures safety without the use of centre buntons and a third guide. The headgear as a whole is to be supplied by the Norton-Harty Engineering Co. Ltd., of Tipton. The present beam-engine pump, which was installed in 1873, will be replaced by two Lee, Howl horizontal triplex ram pumps, each capable of delivering 375 gallons of water per minute against a head of 550 ft. The rams, which are 9½ in. in diameter by 12 in. stroke, are of gunmetal and work through gunmetal bushed glands and neck rings. The cast-steel connecting rods are fitted with adjustable gunmetal bearings at each end.

These two units will operate in two stages. They are to be electrically driven by 90-h.p. 3,300-volt motors, fitted with ball bearings and a brush shifting device, and manufactured by F. & A. Parkinson Limited, of Manchester. The brush shifting device enable s the speed of the motors to be varied at will, without any considerable loss of efficiency, which is a decided advantage in a pumping installation where the flow to be dealt with is very inconstant.

The Aerial Ropeway.

The ropeway which brings the small coal from the Buckhill Pit to the washery at the William Pit at Allerdale possesses several interesting features, and the arrangement is well worth a brief account. Formerly the slack at Buckhill was fed direct from the screens into railway trucks, but the whole is now taken, without previous screening, to the Campbell-Binnie washery. It is now over eighteen months since the plant, erected by the British Ropeway Engineering Co. Ltd., was first put into operation, and so far it has given the owners every satisfaction, reducing handling costs by no less than 1-3/7d. per ton over the previous system. Only once has it had to be stopped on the score of rough weather, but this was simply due to the amount of coaldust which was blown away by a high wind when other circumstances rendered it necessary to form a tip near the washery, and was in no way due to any operating defect.

The actual length of the ropeway is 3,010 yards, or nearly miles, the capacity being 35 tons per hour. There is a difference in level of 90 ft. between the loading and discharging stations in favour of the full load. A speed of 110 yards per minute is maintained by the buckets, which carry a net load of 8½ cwts. and are spaced at intervals of 80 yards, or, as regards time, at intervals of 44 seconds. There are 80 buckets on the line, and as the number of loads per hour averages 82½, a complete circuit is made in a little under an hour.

In Fig. 3 drawings are given of one of the automatically attaching and detaching carrier trolleys. The mechanism of the arrangement will best be understood with reference to the sectional elevation shown. The load is carried by the hanger flat A, which rests on the portion B encasing the axle C. In the framework D is a slot E, which enables the axle and its sheath B to move freely in a vertical plane. It is obvious that the weight of the bucket is transmitted to the vertical rod F, and thence communicated to the bellcrank lever G, which forms one side of the jaw gripping the travelling rope H. The bell-crank lever gives a mechanical advantage of five to one, so that the rope is gripped with a pressure equal to five times the weight of the load, the bucket and the moving portions of the mechanism to which we have referred.

At the point where it is desired to detach the rope for loading and unloading purposes the trolley is guided between a pair of angle-iron rails, suitably graded, upon which the wheels I mount, thus transferring the entire weight to the rails. As the axle C and its integral portions are raised in the slot, the arm of the bell crank is pulled upwards by the rod F, causing grip on the rope to be released. Reference to Fig. 4, which gives an elevation and a section through the locking and unlocking frame, renders further details of the actual operation. The method of attaching the bucket to the travelling rope is practically a reversal of these operations.

One of the most striking features of the ropeway from a spectacular point of view is the bridge which conducts the ropeway over the L.M. & S. Railway (L.N.W. section). This structure, which stands 82 ft. above the level of the foundation blocks, is shown in the line drawing section, Fig. 2, and the view, Fig. 7. A more detailed drawing is given in Fig. 5.

The main carrying rope, by Glover Bros., is 4 in. in circumference, and, like the empty side rope, which is 3 in. in circumference, is of the locked-coil type. The applied tension on the full side rope is 14 tons, and on the empty 7½ tons. Fig. 9, giving a view of the discharge terminal, shows the tension weights and the manner in which they are applied. The hauling rope is a Lang's lay rope with a hemp core ; it is 2 in. in circumference and has an initial tension of 1 ton. The tension race will be noticed in the foreground of Fig. 8.

Theoretically the energy required to work the ropeway is 18 h.p., but the Robey steam engine which has been installed is designed to develop 25 h.p. to leave a good margin of power.

From Buckhill Pit the coal is discharged on to a rubber belt conveyor which delivers it to the foot of the bucket elevator, whence it is taken to an Avery patent automatic registering weighing-machine situated in a small corrugated-sheeting cabin above the 300-ton coal bunker. A view of this machine, which is of the ½-ton type, is shown in Fig. 10.

Drawings and Photographs accompanying the article