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August, 1956

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All the coal from the Low Main seam is fed via direct, totally enclosed chutes on to a 36 in. wide Cable Belt conveyor manufactured by Cable Belt Limited of Inverness. This belt runs from the surface down the intake drift, past the Low Main seam level, and its tension end is situated at the inbye end of the drift. A view of this is seen in Fig. 15. The conveyor is supported on its own line stands. The stands are held by pins fixed by concrete in holes drilled in the floor. It is driven by a 350 h.p. motor situated on the surface in line with the top of the drift and runs at a speed of 250 ft. per min. At this speed it is designed to carry 800 tons of run-of-mine coal per hour. The conveyor was installed in February 1954 and is at present 1,500 yards long and has a lift of 600 ft. In the first instance, original-type Cable Belt belting with protruding straps and separate shoes giving a 36 in. carrying width was fitted throughout but this is being replaced as and when necessary by new-type belting which gives a 42 in. carrying width. For joining the belt, either Mastabar belt fasteners or joints designed by Cable Belt Limited are used.

The conveyor is designed so that it can ultimately be extended to 1,815 yards with a lift of 663 ft. At the moment the conveyor is dealing with 1,100 tons of coal in 13 hours, and 120 tons of stone in 6 hours, and the management express themselves as well satisfied from both the performance and maintenance-cost aspects.

A pull-wire signal gear along the whole length of the conveyor is sequenced to all other conveyors delivering on to it, ensuring that when the Cable Belt conveyor stops, all other conveyors automatically stop.

Surface coal handling

Coal brought up the drift on the Cable Belt conveyor is delivered via an enclosed chute on to a short belt conveyor which will eventually tip straight into railway wagons but at the moment is delivering into a temporary screening plant.

A central washery has been built at Weetslade three miles away and it is the intention that all run-of-mine coal from Havannah should go there, In the meantime, temporary screens have been erected at Havannah and coal from them is loaded into railway wagons and despatched direct to power stations, and housecoal, locomotive and steam-coal markets. It is weighed as it passes over the weighbridge at the outgoing end of the sidings. This is shown in Fig. 17 and contains a Mordue Brothers Limited, Newcastle-on-Tyne, weighing machine which will weigh anything from cwt. up to 42 tons.

Coal is graded into the following sizes: 0-1¼ in., 1¼-2½ in., and +2½ in., which last fraction is currently hand cleaned at Havannah.

Stone from the mine is loaded into drop-bottom trucks and taken by rail to the central washery site where it is fed through a track-hopper into aerial ropeway skips for disposal on the dirtheap.

Surface buildings

As can be seen from the plan (Fig. 21) the surface buildings are in two main groups set amid well laid out gardens and lawns.

Away from the main block of buildings but with easy access by road or rail is a group consisting of the stores and workshops, mention of which has already been made earlier in the article. From the outside, the stores and the workshops are almost identical in appearance but inside they differ sufficiently to warrant a more detailed reference. Both buildings are lofty and good use has been made of this height in both buildings by providing overhead cranes for lifting heavy, cumbersome mining equipment.

The stores building is adequately equipped with shelving for dealing with the smallest spares and has plenty of floor space for the heaviest piece of equipment likely to be kept in stock. At one end of the stores, office accommodation for stores clerks has been made available at first-floor level. A five-ton Herbert Morris lifting crane runs along girders set in the side of the building so that heavy equipment can be moved from one part to another.

Adjacent to and running parallel with the stores is the workshops building. This is divided by partitions into bays comprising joiner's shop, electricians', blacksmiths' and fitters' shops.

A ten-ton Herbert Morris lifting crane runs the whole length of this building. Part of the fitting-shop section is used as a garage for a 21 h.p. Hunslet diesel locomotive which is generally used for shunting minecars on the surface.

The second group of buildings may be termed the main group and entrance to them is made through large glass doors into an impressive reception hall off which are the canteen, administrative offices and baths. The inside walls of the reception hall have been left unplastered and the bare brick finish is in keeping with the contemporary motif of all the buildings. The bricks were made by Eden Hall Concrete Products, Penrith, from concrete, and in colour they are tinged with pink instead of the usual red. To complete the contemporary effect, a composition floor is laid in a black and fawn striped pattern.

Light snacks and hot drinks may be purchased from the canteen, a photograph of which appears in Fig. 20.

Bath accommodation comprises 828 lockers and 84 showers. The clean entrance leads off the reception hall and the dirty entrance is by way of the lamproom and time office. A gay colour scheme is again adopted throughout the baths, grey for the lower part of the locker-room walls, bright yellow for the upper part, white tiles of course for the shower-bath walls and the doors are painted a bright red. Adjoining the dirty locker room is a fully equipped first-aid room, a photograph of which can be seen in Fig. 22. Also attached to the baths building are the usual rooms for boot brushing, boot greasing, clothes dusting, and for drying wet clothes, in addition to the boiler house. As well as providing hot water for the showers, the boiler plant also supplies hot water for the central-heating pipes and radiators throughout the whole block of buildings.

Leaving the dirty end of the baths, workmen pass through the time office. Each workman, whether surface or underground, has a clock-card and his time of "going-on" shift and "coming-off" shift are recorded, by means of a Time Recorders (Leeds). Limited time clock, on the card, from which entries time-office clerks calculate the payment due.

The last building workmen enter before going down the mine is the lamproom which in keeping with the other buildings is well lighted and pleasing in appearance. Concrete bricks are again used for the internal finish of the walls, the floor is composed of a black bitumen compound and the ceiling is of white plaster board. Lighting is by 20 G.E.C. single fluorescent tubes hanging from the ceiling. The layout of the lamproom is shown in Fig. 24.

The caplamps in use at Havannah are the Edison type manufactured by Mine Safety Appliances Co. Ltd. of Glasgow. With this type of installation only a short charging cycle is required. Consequently, a charging-rack capacity that is sufficient to cover the requirements of the largest shift is ample, although of course, there must be storage-rack space for all the lamps. A workman coming out of the pit places his lamp in the storage-racks according to lamp number on the "dirty" side of the lamproom. The lamps are later removed from these racks by an attendant who places them on the charging-racks irrespective of lamp numbers. After charging, the lamps are placed on the appropriate storage-racks according to lamp number on the "clean" side of the lamp room where they await the oncoming shift, and thus leave the charging-racks empty once again for the lamps of the workmen of the shift coming off duty.

Both charging and storage racks have a capacity of 60 lamps each and the general overall dimensions of each rack are 4 ft. 4 3/8 in. long by 6 ft. 1¾ in. high by 2 ft. 6 in. wide. On the charging racks the shelves are staggered so that interference of the headpieces is avoided when batteries are inserted with headpieces hanging downwards. The shelves of the charging racks are grooved to permit charging clips to be slipped out of the way for easy placement of the batteries. A bench on which unlocking magnets can be mounted is incorporated in the lower part of each storage rack.

For charging purposes, four 550 V a.c., 250 V d.c. Westinghouse rectifier transformer units supply the charging racks; that is one rectifier unit to each pair of racks so that each pair is independently supplied.

The battery of the Edison caplamp, model K1-PMX is enclosed in a steel outer container which is magnetically locked in the lamproom to prevent tampering by workmen in the pit. Each of three inner cells which is equipped with a plunger-type valve is protected by an insulating rubber sac and contains a nickel-filled positive plate and an iron-filled negative plate with surrounding alkaline electrolyte. The lightweight bakelite headpiece of the lamp features a single-filament bulb and an aluminium reflector coated with a film of transparent aluminium oxide to maintain reflector performance. A lead riveted, aluminium bezel ring holds an armour plate glass lens securely in position.

A feature of this lamp is the absence of any switch. The lamp switches on when it is magnetically locked in the lamproom and remains on until it is returned and the lamp is broken for charging purposes. Nominal voltage is 375 for 10 amp-hour and the weight of the battery with electrolyte is only 44 lb. Any krypton-filled bulb rated at 3.6 V. 1 A, with clear 18 m.m. round glass and spiral-bow filament is stated to be suitable for this type of lamp.

The ease of running such a lamproom as this is borne out by the fact that only one attendant on each shift plus a head lampman, who is usually on the day shift, are sufficient to keep the system working smoothly. As well as recharging and maintaining 480 caplamps, the attendants have to clean and prepare 130 oil lamps and 44 relighting safety lamps. In addition to this, photometer tests of each lamp are carried out once a month and an alkaline gravity test once every 12 months.

Drawings and Photographs accompanying the article