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November, 1943

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An early system of winding was the "balanced tub system" developed by Menzies, who obtained a monopoly for his idea by Act of Parliament in 1750. The first installation was at Chatershaugh Colliery, Durham, in 1753, and consisted of a basket of coal drawn up the shaft by means of a descending bucket of water. At Chatershaugh 6 cwt. of coal were wound from: a depth of 300 ft. in 2 minutes. The disadvantage of this method was the necessity to pump the water back to the surface unless an adit was available for free drainage. In spite of this drawback the balance tub system was extensively used, especially in the South Wales area, until the middle of the nineteenth century — in 1861 there were still some sixty installations at work. These systems were somewhat different from the original in that the cages were equipped with guide rods and a balance rope hung underneath. To the cages were also fitted tanks into which water could be pumped. The tank of water plus the weight of the winding rope at the commencement of the wind was sufficient to wind the cage containing the coal to the surface. This system of water tank and balance rope was often capable of raising 500 tons of coal from a depth of 150 ft. in 12 hours.

Many of the systems already described to counterbalance the load on the winding engine were undoubtedly clumsy, and took up considerable space; they became quite impossible when larger winding installations were necessary to deal with greater outputs at increased depths. A different method of approach was therefore essential, and the problem was dealt with by altering the design of the winding drum.

Curr, a pioneer in winding practice, took out his patent No. 2272 in 1798 for a flat hemp rope. The flat rope consisted of a number of small round ropes stitched together, and was made to lap upon itself during the wind, thereby serving the purpose of a counterbalance. At the commencement of the wind the loaded rope began to coil upon a small diameter, which gradually increased, while the empty rope began to coil off a large diameter, which gradually decreased. It will be seen that as the resistance decreases in the ascending load, the leverage increases, and, as the power increases in the other the leverage diminishes — an arrangement which rendered great assistance to the winding engine.

Such a counterbalancing arrangement was only possible with a special type of drum; this is shown in Fig. 1, and consists of a barrel slightly wider than the rope, which was kept in position as it coiled vertically upon itself by means of a series of arms or jaws. It will be noticed that the variation in the leverage is a constant quantity and is equal to the thickness of the rope.

In 1841 the first flat wire rope was introduced at Pemberton Colliery, but as the round rope became more popular, the flat rope began to fall into disuse until in 1909 its use as a winding rope and as a means of counterbalancing the load on the winding engine practically ceased.

With the greater use of round winding ropes, other means of counterbalancing were devised. The general principle involved was to vary the contour of the winding drum. The first step was the design of the conical drum; it was found that the amount of counterbalancing obtained was negligible, as the slope was limited by the fact that if it was made too great, there was a tendency for the rope to slip off with dangerous consequences. To overcome this difficulty, the spiral drum, which is a combination of the conical and cylindrical drum, was introduced. The cone is generally very steep, and on its side is arranged a continuous spiral groove, usually made of semi-circular troughs rivetted to the barrel. Each groove has to be placed at such a distance from the one immediately above so as to prevent the rope leaving the lower spiral from striking the troughs of the upper spiral; the spiral portion of the drum took up a considerable amount of space, which caused excessive rope angling if the shaft was deep. The size of the drum also tended to be excessive. These difficulties were overcome to some extent by arranging that certain coils took place on the cylindrical part of the drum.

Other objections raised against the spiral drum were —

(1) Counterbalancing was imperfect.

(2) Excessive weight and cost.

(3) The introduction of banking difficulties.

More perfect counterbalancing was obtained by a combination of the conical, spiral and cylindrical drums (Fig. 3). The incoming rope was arranged to coil in shallow grooves on the slightly coned smaller diameter, thereby obviating side friction, and at the end of a certain predetermined number of revolutions, when the winding engine has attained full speed, it rises in about two and a half turns on the spiral portion of the drum; during the remainder of the wind the greater part of the rope was wound on the cylindrical portion of the drum. This drum, while being more complicated and therefore more difficult and expensive to build than the cylindrical type, was much cheaper and lighter than the spiral one. There is more perfect counterbalancing since the drum materially assists the engine at the start and retards it at the end of the wind.

Cage guides

When the mined coal and underground workers travelled in the shaft by means of the "clatch iron" or by wicker baskets, the load on the rope or 'chain swung freely, which often resulted in collisions with the sides of the shaft, the partitions, or with the other basket. The velocity at which the basket could travel w a s therefore limited and was a limiting factor on the output of mines using such winding arrangements. The introduction of small rectangular wooden tubs further complicated matters, as it is apparent that, being rectangular, there was a greater possibility of collision than with circular baskets.

The difficulty was overcome by the introduction of guides by Curr in 1788, who took out patent No. 1660 for methods of "raising coals, lead and other minerals, out of mines, so as to prevent the corves running foul of each other; platform for landing and delivering." The conductors in the words of the designer were "nothing more than two or three upright rods of deal, 4 by 3 in., brazed upon opposite sides of the pit, forming mortices or channels, by which the corves are conducted, being suspended upon cross bars with rollers at their ends, Which run within the mortices." Upon arrival at the pit top, the carriage or tub was raised above ground level, when a wooden platform was placed beneath it and upon which it was lowered. It was then detached from the rope and run off, an empty carriage taking its place; this was then raised so as to enable the operatives to remove the platform, after which the carriage was lowered to the shaft bottom. Curr claimed that with this arrangement it was possible to attain a shaft speed of 420 ft. per minute.

The introduction of this system of guides was a milestone in the history of winding, as it marked the first possibility of high-speed winding, with beneficial effect on output and safety. Although Curr's arrangement was a considerable improvement, its use did not become universal and was restricted to the shallow shafts in the Yorkshire and Southern areas; it was not suitable for the deeper pits in the Northumberland and Durham coalfield.

Curr's arrangement of guides was not improved upon until Hall, at South Hetton Colliery, in 1833, attempted to employ circular iron tubs for carrying coal in the shaft. In order that these circular tubs could be raised steadily, and to prevent damage to the shaft by excessive oscillation, Hall lined it with timber, forming a smooth lined passage way only slightly larger in diameter than the tub itself. His arrangement, after due trial, was not entirely satisfactory, for obvious reasons. In 1843 he decided to use small tubs, taking these to the surface two at a time in a two-decked iron cage or chair, the cage being guided and oscillation prevented by the timber lining of the shaft.

In 1835 Hall took over the management of the Glebe Pit, near Ryton, and being convinced of the possibilities of his system of winding, introduced it there but with the addition of guide rods; three guides to each cage were applied, the cages having shoes attached fitting closely round the guides, thereby permitting the cages to ride in the shaft with increased rapidity, smoothness and safety. Although wicker corves were in use as late as 1871, Hall's system, with its many advantages, rapidly spread throughout the mining areas. Its popularity is indicated by the 1849 Report, which indicates in that year only two collieries in the North of England were without it. With slight modifications, wooden guides have remained popular to the present day, especially in certain areas such as Scotland where the shafts are often rectangular and not circular in shape. The shoes on the cage were of channel section, similar to the type used today. In the Midland area, rollers were sometimes used in the place of shoes, but these never became popular.

With the introduction of wire ropes and the greater use of iron and steel, iron rods were used as guides in 1850, and became especially popular in the Yorkshire and Lancashire Coalfields; at the same time South Staffordshire and South Wales used chains for this purpose. With the acceleration in the use of wire ropes after their application to mining in 1842, round ropes began to take the place of wooden guides in many areas. It was not until the early part of this century that locked coil ropes were used for this purpose.

In 1862 flat footed rails were used as guides. These were arranged on one side of the cage only, and were secured to cross sleepers 6 ft. apart through the entire length of the shaft. With this type of guide crescent shaped slippers were used.

The necessity for guides from the safety point of view was officially recognised in 1872, when the Coal Mines Regulation was passed, which made it compulsory that guides should be adopted in all shafts over 50 yards deep.

(To be continued.)

Drawings and Photographs accompanying the article