An example of one of the Otto ropeways is given in Fig. 429, which is a section of the line put up for the Sheba Gold Mining

FIG. 426.

FIG. 428. !

FIG. 427.

Company, Limited, Barberton; it is 23 (4'4 kil.) miles long, and will carry 150 tons per day of 10 hours. The maximum incline is 1 in 16, and the greatest span 1480 feet (451 m.).

A line erected in Southern Spain for carrying iron ore is 9.69 miles (15.6 kil.), long, divided into four independent sections. The greatest span is 918 feet (280 m.), but on an average the sup

porting posts are only 44 yards (40 m.) apart. The hauling rope is made to travel at the rate of 100 yards (90 m.) a minute, and deliver two buckets, each containing 7 cwt. (350 kil.) in that time. This means a carrying capacity of 1200 buckets or 420 tons per day of 10 hours. The line has also been worked with

A A'. Supporting ropes; B B'. Hauling ropes; C C. Grooved pulleys; D D'. Boxes; E E. Hanger; F. Clipping disc; G. Projecting lever for tightening or loosening the clip.

two shifts of 8 hours each, and has transported 900 tons in that time. The total cost of this line, which was surveyed, erected in a very difficult country, and ready to start in ten months, was £26,000; and it has been worked at a cost of 18. 3d. per ton, which includes all that is spent for labour, maintenance and repairs.

At the Menzel colliery in Upper Silesia, 500 to 700 tons of coal are carried in ten hours a distance of 16 miles, for 1d. per

ton per mile, including wages, repairs, interest on capital and depreciation of plant. Fig. 430 shows part of the line at Gottessegen colliery, Upper Silesia.*

A line carrying iron ore in Luxembourg is 3 miles long, and transports 300 tons of iron ore in 10 hours at a cost, again including all expenses-viz., wages, repairs, interest on capital, and depreciation of plant, of 41d. per ton, or 1d. per ton per mile. d and e. Ropeways worked by these systems are rare.

"Otto Patent Ropeway."-The Engineer, vol. lxvii. 1889, p. 115.

CHAPTER VIII.

HOISTING OR WINDING.

Motors, drums, and pulley-frames.-Ropes, chains, and attachments.Kibbles, skips, and cages.-Keps, guides, signals.-Safety appliances, detaching-hooks, safety-catches, automatic stopping gear-Pneumatic hoisting.

In

By hoisting is meant raising the minerals from the underground workings to the surface. In speaking of the subject generally, it is more correct to say hoisting than winding, because this latter term implies the use of the rope, which is not quite universal. As already explained in the last chapter, there is no clear line of demarcation between haulage and winding. the typical case of a vertical shaft and a nearly horizontal level, it is easy to make the distinction; but when the mineral is drawn up through inclines, the name given to the process depends upon local custom. Thus, part of the shaft at a Cornish tin mine is inclined at an angle of only 151° from the horizontal, and nevertheless the work of drawing up the ore is always called winding.

In a few districts carriage on the back still survives; in Sicily, for instance, much of the sulphur rock is brought to the surface by boys on their backs up rough paths, or steps cut in the ground. As lately as ten years ago, I found slate being brought up on the back in the Moselle district. In Mexico and in China, too, the same method is pursued in some silver and other mines. However, this barbarous mode of raising mineral is simply mentioned for the purpose of condemning it.

The regular method of bringing a mineral to the surface is to draw it up a shaft or an incline by means of a rope. The subject is such a wide one that it must be treated under different headings as follows: (1) Motors, drums and pulley-frames; (2) Rope, or chain; attachments of the rope; (3) Receptacle for the mineral or waste rock; (4) Other indispensable appliances, guides, signals, keps; (5) Safety appliances.

1. MOTORS, DRUMS, AND PULLEY-FRAMES.— Motors-As in other departments of mining, the motor employed may be worked by animal power, or by an engine driven by water, steam, compressed air, petroleum or electricity.

(a) Animal Power.-The simplest contrivance for winding is a pulley supported by some suitable frame above the shaft; a bucket is attached to the end of a rope hanging down the shaft, whilst the other end, passing over the pulley, is drawn by men or women: they simply walk away from the shaft and haul up the bucket. Oil wells are sunk in Burmah by this primitive method of hoisting.

The usual method of applying human power is by a windlass. This well-known appliance consists of a wooden cylinder, about eight inches in diameter, provided with two iron handles and supported by two upright posts which are suitably stayed. A sliding bar, which can be drawn out either above or below the cylinder, serves to hold one of the handles, when required.

In this country, the ordinary windlass is used for shallow sinkings of twenty, thirty, or forty yards in depth, such as are made in commencing work at a mine, or in effecting a communication between two levels; but in countries where mining is less advanced, and where labour is cheaper, the windlass may form the sole means for hoisting from depths of a hundred and even two hundred yards. Thus, for instance, at Boryslaw, in Galicia, it is reckoned that six or seven thousand shafts have been sunk during the last thirty years, for the purpose of working ozokerite, to an average depth of one hundred yards, by human labour; four, five, and even six men and women may be seen working the Boryslaw windlass. In the neighbouring country of Roumania, oil wells are sunk in like manner. The windlass is used either with one or two buckets; in the latter case the labour is lightened, for the weight of the empty bucket going down balances the dead weight of the bucket coming up with a load of rock.

As a rule too little attention is paid to the state of the axles and bearings. Windlasses, like other machines, cannot be worked with economy unless means are taken to prevent unnecessary friction, which is sure to arise unless the axles and bearings are kept perfectly true; this fact should be specially borne in mind when the mine-owner is employing expensive human power.

The capstan is an unusual form of winding machine at mines; it differs from the windlass by having its cylinder vertical. As an instance of its use, I may mention the little underground quarries at Swanage in Dorsetshire, where blocks of stone are drawn up inclines by means of capstans turned with bars, after the manner of those used on board ship.

When a horse is employed in the place of men, the bucket, attached to a rope passing over a pulley, is sometimes drawn up by making the animal walk away from the shaft. The framework and pulley constitute what is called a whipsiderry.

Animal power is usually applied by means of a machine called