The term winding refers to the operation associated with hoisting the mined mineral to the surface. In modern mines winding is automated i.e. controlled by electrical contacts in conjunction with acoustic and visual signaling and various devices to ensure safety when men are being raised or lowered. All winding systems embody the counterweight principle, with two cages (or skips) moving in opposite directions one ascending while the other descends.

The basic characteristic of the winding gear are the winding engine or motor, the headframe usually a lattice steel structure, up to 200 ft. high, over the shaft, the winding rope and drum, the cages or the skips, the intermediate gear whereby the latter are connected to the rope, and cage guides in the shaft.

Large-diameter shafts of circular section up to 7 m (23 ft.) diameter –are normally equipped with two sets of winding gear; there are thus four hoistways (Fig.1), in each of which a cage moves up and down. Steam-powered winding engines or electric winders are employed, the latter usually being driven by direct-current electric motors with Ward-Leonard control. Such motors may have power ratings of as high as 12,000 KW and hoist coal or other minerals at a rate of 10,000 tons per day from shafts 800 m (2600 ft) in depth. The hoisting speed in deep shafts is about 22m/sec. (70-75 ft/sec.) with a 30-ton payload.

The winding operations are controlled by a device known as winding-speed regulator. It calculates the hoisting speed in relation to the distance traveled and more particularly limits the acceleration of ascent and descent. In addition, every winding system includes a depth indicator, which consists essentially of a screw spindle along which a nut travels; the position of the nut on the spindle indicates the position of the cage in the shaft.

This device is linked to an overwind-prevention device, which actuates a second brake (drop-weight brake) if the cage ascends too high and the counter-balancing cage consequently descends too low. In the event of overwinding, the cage is slowed down and braked by such means as thickening the cage-guide rods in the top part of the headframe.

Winding ropes are composed of several strands which in turn consist of cold-drawn steel wires of 2.5mm (0.1 in.) diameter, with a tensile strength of 200 kg/mm2 (127 tons/in2)(Fig.4). Such ropes may be as much as 100mm (4 in) thick and have breaking loads of around 700 tons.

In Britain, cage winding is still predominant in coal mining. However, skip winding is progressively being introduced; it is already extensively used in the United States and in various continental countries. A skip is a guided steel or aluminum-alloy box (Fig.5) which is automatically filled at the bottom of the shaft and automatically discharged when it has been hoisted aboveground.

The advantage of skip winding is that a skip can carry a relatively larger payload than a cage with tubs or cars; the proportion of payload to total load can be raised by nearly 40% by substituting skip for cage winding, and loading and unloading are faster. In the main, there are two systems of winding gear: drum winding and Koepe winding.

Of these, drum winding is the more widely applied. The drum may be variously shaped: cylindrical, conical, cylindroconical. The object of the conical shape (Fig.3) is to equalize the driving torque by using a smaller diameter of drum when exerting maximum rope pull to lift and accelerate the cage (or skip). In Germany and Holland the Koepe system (Fig.2) is generally preferred. In this system the massive drum is replaced by a wheel with one peripheral groove.

A single winding rope lies in this groove, and all controlling forces transmitted through the rope depend on the friction of the rope in the groove. The cages (or skips) are suspended one on each end of the rope, which passes over the Koepe wheel. The system offers certain advantages and is more particularly suitable for winding heavy loads from deep levels.