underground mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

a hoist or winder is used to raise and lower conveyances within the

mine shaft Shaft mining or shaft sinking is the action of excavating a mine shaft from the top down, where there is initially no access to the bottom. Shallow shafts, typically sunk for civil engineering projects, differ greatly in execution method from ...

. Modern hoists are normally powered using electric motors, historically with

direct current Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can also flow through semiconductors, insulators, or even ...

drives utilizing

Ward Leonard control Ward Leonard control, also known as the Ward Leonard drive system, was a widely used DC motor speed control system introduced by Harry Ward Leonard in 1891. In the early 1900s, the control system of Ward Leonard was adopted by the U.S. Navy and a ...

machines and later solid-state converters (

thyristors A thyristor () is a solid-state semiconductor device with four layers of alternating P- and N-type materials used for high-power applications. It acts exclusively as a bistable switch (or a latch), conducting when the gate receives a current t ...

), however modern large hoists use

alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...

drives that are variable frequency controlled. There are three principal types of hoists used in mining applications:

Drum hoist

Drum hoists are the most common type of hoist used in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. When using a drum hoist the hoisting cable is wound around the drum when the conveyance is lifted. Single-drum hoists can be used in smaller applications, however double-drum hoists easily allow the hoisting of two conveyances in balance (i.e. one skip being lifted while a second skip is being lowered). Drum hoists are mounted on concrete slabs within a hoistroom, the hoisting ropes run from the drum, up to the top of the

headframe A headframe (also known as a gallows frame, winding tower, hoist frame,Ernst, Dr.-Ing. Richard (1989). ''Wörterbuch der Industriellen Technik'' (5th ed.). Wiesbaden: Oscar Brandstetter, 1989. pit frame, shafthead frame, headgear, headstock o ...

, over a

sheave A sheave () or pulley wheel is a grooved wheel often used for holding a belt, wire rope, or rope and incorporated into a pulley. The sheave spins on an axle or bearing inside the frame of the pulley. This allows the wire or rope to move fre ...

wheel and down where they connect to the conveyance (cage or skip).

Advantages

Drum hoists require less routine maintenance than a friction hoist, because the haulage cable is fixed to the drum, and therefore have less

downtime The term downtime is used to refer to periods when a system is unavailable. The unavailability is the proportion of a time-span that a system is unavailable or offline. This is usually a result of the system failing to function because of an un ...

, and the maintenance regime is less sophisticated. Drum hoists can continue to operate if the shaft bottom gets flooded and less shaft depth is required below the loading pocket, unlike friction hoists where such flooding could cover the tail ropes and so on. Because drum hoists do not have tail ropes, the hoisting system is more suited to slinging beneath a conveyance.

Disadvantages

Drum hoists take up more space than a friction hoist for the same service as all of the haulage cable must be accommodated on the drum when the hoist is fully raised. Drum hoists require rapid fluctuations in power demand, which can pose a problem if power is generated on site rather than provided through the main

power grid An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:Kaplan, S. M. (2009). Smart Grid. Electrical Power ...

Friction hoist

Friction (or Koepe) hoists are the most common type of hoist used in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. The friction hoist was invented in 1877 by

Frederick Koepe Frederick may refer to: People * Frederick (given name), the name Nobility Anhalt-Harzgerode * Frederick, Prince of Anhalt-Harzgerode (1613–1670) Austria * Frederick I, Duke of Austria (Babenberg), Duke of Austria from 1195 to 1198 * Frederic ...

. Friction hoists are mounted on the ground above the mine shaft, or at the top of the headframe. Friction hoists utilize tail ropes and

counterweight A counterweight is a weight that, by applying an opposite force, provides balance and stability of a mechanical system. The purpose of a counterweight is to make lifting the load faster and more efficient, which saves energy and causes less wear ...

s and do not have the haulage rope fixed to the wheel, but instead passed around it. The tailropes and weights offset the need for the motor to overcome the weight of the conveyance and hoisting rope, thereby reducing the required

horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the ...

of the hoisting motor by up to 30%, with the overall power consumption remaining the same. Friction hoists, unlike drum hoists, can and normally do use multiple ropes giving them a larger payload capacity, however since they require a larger safety factor, they are impractical for very deep shafts.

Advantages

New friction hoists are less expensive than new drum hoists, and the lead time for delivery may be shorter as there is more competition for manufacturing. Multi-rope friction hoists have a larger lift capacity than a drum hoist. A friction hoist is smaller in diameter than a drum hoist for the same service, making it easier to ship and install than a drum hoist.

Disadvantages

Balanced friction hoists are not suitable for hoisting from multiple

loading pocket Loading may refer to: Biology * Carbohydrate loading, a strategy employed by endurance athletes to maximize the storage of glycogen in the muscles * Creatine loading, a phase of use of creatine supplements * Vocal loading, the stress inflicted on ...

s on different horizons within a shaft, and are generally not suitable for deep shafts. Friction hoists can not operate at normal speeds if the shaft bottom is flooded and water reaches the tail ropes.

Blair multi-rope hoist

The Blair multi-rope hoist is a variation of the double-drum hoist. It is used in extremely deep shafts as the second drums cable are used to balance the primary load.

Examples of hoists

File:Ein-trommelförderung.svg, Single-drum hoist File:Doppel-trommelförderung.svg, Double-drum hoist File:Treibscheiben-Förderung.svg, Friction (Koepe) hoist File:Blair-trommelförderung.svg, Blair-multi rope hoist File:Konische Trommelförderung.svg, Conical drum File:Spiral-trommelförderung.svg, Spiral drum

Footnotes

{{Mining technology Underground mining Vertical transport devices Winches

Drum hoist

Advantages

Disadvantages

Friction hoist

Advantages

Disadvantages

Blair multi-rope hoist

Examples of hoists

See also

Footnotes