Hoist (mining)

In the drum winder, a specific drum is used as a cable support, to which the transport cable is wound or unwound. Drum carriers are well suited for very small and for very large depths.

History

In the early days of mining they used a generator driven by a crank round tree, on the one wrapped or transacted the Rope. A further development was the gin. Here developed cable drums have been used. When hoisting of the skip the Rope wrapped in clean turns on the cable drum. The rope was passed through helically extending grooves which were in the wood covering of the cable drum. From this construction, then one also developed two basket funding with two hoisting ropes and two drums, a fixed barrel and a loose drum. While you came mid-19th century to the limits of performance of drum machines, it is now possible to promote with modern drum carriers payloads of 31 tons at a speed of 18 m / s from depths of up to 3000 m.

Function

A carrier drum works on the principle of a cable, which is wound on a drum. The running cable, the cable is unwound from the drum, the run- rope being wound onto the drum. To ensure the friction, must remain on the drum at the lowest position basket, two full turns. For security reasons, additional cable lengths are taken into account when dimensioning the cable length is usually for the so-called blow-off. In order for the winding ropes do not come loose from the drum attachment, they must be secured with at least two cable clamps on the cable carrier. For secure cable guide on the drum, the introductions are made as light as possible. A twin-drum winder is in principle a double reel, wherein on each of a drum a rope on and the other one is unwound.

Counterbalance

In promoting the low continuous cable is getting longer and thus heavier. In two- drum promotions then the rising rope is shorter and therefore easier. In the middle of the shaft both ropes are of equal length and the cable weight balanced. These different loads lead to an unsteady and non-uniform response of the carrier. This has a disturbing effect on the operation. , The weight balance is achieved by two ways, either by the use of conical cable drums or by the use of counterweights. At the conical cable drums, the hoist rope is wound, starting with the smallest diameter drum when raising the load on the helical drum. For double drum machines simultaneously the rope down the continuous load is handled starting with the largest drum diameter. Characterized in that the now engages the unwound wire at the small and the wound cable on the large radius, an approximate equality of the static moments is achieved. These drums reach due to their size and correspondingly large weights were rarely used in Germany. In the United States of America and in England they were very often used. In England, the drum machines were often provided with counterweights. For this purpose, a second, smaller wire basket was attached to the rope basket shaft on the counterbalance was wound in the form of a chain. This chain was usually performed in a second small bay that lay beside the conveyor shaft. By the opposite direction to the direction of winding and unwinding of the chain, the weight balance was achieved. The weight and thus the length of the chain had to be calculated according to the payload.

Designs

Drum carriers are mainly built as a material handling machines, due to the strong rope deflection tower carriers are very rare. A distinction ( two-drum drive units ) between single drum machines and double drum machines. Single drum machines have a drive motor which drives the drum via a gearbox or directly. As brake drum or disc brakes are used. Double drum machines are available with both a hard drum and a lottery wheel, as well as with two lottery-wheels. The Lost drums are connected as a cable carrier on a hiding device with the drive shaft. The actuation is accomplished by one or two motors. The motors can be directly connected or connected through gears with the drum. When brakes also drum or disc brakes are used. For two drum machines, it is possible to equip this with a so-called hiding device. In these machines, it is imperative that to hide a separate brake is available for the lottery wheel.

Drum Carrier of the Soudan Mine

Side view of the carrier

Promotion drum having a cylindrical drum

Drum Carrier in open terrain

Two basket operation

In some mines, such as ore mining, it is often required that needs to be promoted during a shift of several different soles. In drum conveyor machines with double drum a two- tray operation of each sole is possible. To this end, the drums must be equipped with lottery-wheels. This lottery-wheels can be coupled in any position of the hard drum. To make the two- tray operation of a midsole, first a pit cage at the corresponding midsole needs to be positioned. Then the lottery wheel of the respective page is blocked with a parking brake and uncoupled. As a result, the drum does not rotate during positioning of the second conveyor basket with. After the second basket at the corresponding point is positioned, the lottery wheel of the first page is again coupled with the hard drum and release the parking brake.

Large depths

At great depths encounter normal drum carriers to their limits. This will reflect the great weight of rope, which also has to carry the weight in addition to the weight of the payload and the weight of the conveyor. In 1957, the engineer Robert Blair presented a drum carrier, wherein the line carrier was designed for two hoist ropes. This system is ( > 2300 meters ) suitable due to the special construction for very large depths. In 1958, the first Blair Carrier was installed. The cable drum has two winding areas in this machine. The conveying cable is a continuous cable which is mounted on two drums. On the bucket conveyor cable is not attached to an intermediate dishes, but is passed around a bucket attached to the deflection pulley. Load balancing is achieved by a second identically constructed system. The two systems are coupled either electrically or mechanically. If the two systems electrically coupled, the system as two separate machines responding. In the mechanical coupling, the two systems are connected to each other via a universal joint. Thus, the compensating force of the other strand is used, the required torque in the loaded system is thereby reduced. Blair carriers are predominantly used in South Africa.

Examples of drum carriers

On the Ibbenbüren mine Blair a single drum conveyor machine is operated. The machine supports from a depth of 1500 meters, a maximum payload of 15 tons. The machine has a direct drive with a drive power of 1,500 kilowatts. On the Kidd Creek mine is a double drum winder with a drive power of 4,000 kilowatts. The machine is provided with hiding devices and can move from a depth of 1818 meters, a payload of 16.8 tonnes with a conveyor speed of 16 meters per second. The drum diameter of the cable carrier is 5.5 meters. On the former ore mine Ramsbeck located underground is the largest drum carrier ever built in Europe underground. The machine was used as a drive for a blind shaft and had a drive power of about 1,250 kilowatts. On the Neves Corvo mine a double drum winder is operated, the drive has a capacity of 2,450 kilowatts. The machine is equipped with a hidden device and can carry a payload of 12.5 tons from a depth of 585 meters lift with a conveyor speed of 12.5 meters. The diameter of the cable carrier is 6.1 meters.