Longwall mining

longwalllongwall minelong walllong wall miningLong-wall mininglong wall ploughLongwall facelongwall methodlongwall shearerlongwall shearers
Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically thick).wikipedia
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Coal mining

coal minecollierycoal miner
Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically thick).
Coal mining has had many developments over the recent years, from the early days of men tunneling, digging, and manually extracting the coal on carts to large open cut and long wall mines.

Mining

mineminescopper mine
By 1940, some referred to longwall mining as "the conveyor method" of mining, after the most prominent piece of machinery involved.
Other methods include shrinkage stope mining, which is mining upward, creating a sloping underground room, long wall mining, which is grinding a long ore surface underground, and room and pillar mining, which is removing ore from rooms while leaving pillars in place to support the roof of the room.

Room and pillar mining

room and pillarbord and pillarpillar and stall
Longwall mining has been extensively used as the final stage in mining old room and pillar mines. Longwall has better resource recovery (about 80% compared with about 60% for room and pillar method), fewer roof support consumables are needed, higher volume coal clearance systems, minimal manual handling and safety of the miners is enhanced by the fact that they are always under the hydraulic roof supports when they are extracting coal.
Due to a recovery rate as low as 40% in some cases, room and pillar mining cannot compete in terms of profitability with many modern, more mechanized types of mining such as longwall or surface mining.

Retreat mining

retreating
In this context, longwall mining can be classified as a form of retreat mining.
*Longwall mining

HD Mining International

HD Mining
A mine opened by HD Mining in 2015 in British Columbia, causing disputes regarding the hiring of foreign workers instead of Canadians, and its potential impacts to the environment.
It is involved in the Murray River Project, a longwall coal mine in Peace River Country near Tumbler Ridge, British Columbia.

England

🏴󠁧󠁢󠁥󠁮󠁧󠁿󠁧󠁢󠁥󠁮󠁧󠁿EnglishENG
The basic idea of longwall mining was developed in England in the late 17th century.

Shropshire

SalopCounty of ShropshireShropshire, England
This was known as the Shropshire method of mining.

Coal

coal seamcoal industrycoal-fired
While the technology has changed considerably, the basic idea remains the same, to remove essentially all of the coal from a broad coal face and allow the roof and overlying rock to collapse into the void behind, while maintaining a safe working space along the face for the miners.

Conveyor belt

conveyor beltsconveyorsconveyor
Unlike earlier longwall mining, the use of a conveyor belt parallel to the coal face forced the face to be developed along a straight line.

Electricity

electricalelectricelectrically
The only other machinery used was an electric cutter to undercut the coal face and electric drills for blasting to drop the face.

Drill

drill pressdrillspower drill
The only other machinery used was an electric cutter to undercut the coal face and electric drills for blasting to drop the face.

Centerville, Iowa

CentervilleCenterville, IA
The best known example was the New Gladstone Mine near Centerville, Iowa, "one of the last advancing longwall mines in the United States".

Slope mining

slopeslope mineslope mines
This longwall mine did not use a conveyor belt, instead relying on ponies to haul coal tubs from the face to the slope where a hoist hauled the tubs to the surface.

Rock (geology)

stonerockrocks
While the technology has changed considerably, the basic idea remains the same, to remove essentially all of the coal from a broad coal face and allow the roof and overlying rock to collapse into the void behind, while maintaining a safe working space along the face for the miners.

Coal dust

pulverized coalcoalcoal dust explosion
Once past the face the air is no longer fresh air, but return air carrying away coal dust and mine gases such as methane, carbon dioxide, depending on the geology of the coal.

Methane

methane gasCH 4 liquid methane
Once past the face the air is no longer fresh air, but return air carrying away coal dust and mine gases such as methane, carbon dioxide, depending on the geology of the coal.

Carbon dioxide

CO 2 CO2carbon dioxide (CO 2 )
Once past the face the air is no longer fresh air, but return air carrying away coal dust and mine gases such as methane, carbon dioxide, depending on the geology of the coal.

Geology

geologicalgeologistgeologic
Once past the face the air is no longer fresh air, but return air carrying away coal dust and mine gases such as methane, carbon dioxide, depending on the geology of the coal.

Fan (machine)

fanfanselectric fan
Return air is extracted by ventilation fans mounted on the surface.

Combustion

burningignitionincomplete combustion
To avoid spontaneous combustion of coal in the goaf area, gases may be allowed to build up behind seals so as to exclude oxygen from the sealed goaf area.

Jack (device)

jackhydraulic jackjacks
A number of hydraulic jacks, called powered roof supports, chocks or shields, which are typically wide and placed in a long line, side by side for up to in length in order to support the roof of the coalface.

Rack and pinion

rack-and-pinionrack and pinion steeringrack
The shearer is carried along the length of the face on the armoured face conveyor (AFC); using a chain-less haulage system, which resembles a ruggedised rack and pinion system specially developed for mining.

Conveyor chain

scraper chain conveyorscrapers
The coal is removed from the coal face by a scraper chain conveyor to the main gate.

Resource recovery

recoveryrecover chemicals and nutrients for recyclingrecovers resources
Longwall has better resource recovery (about 80% compared with about 60% for room and pillar method), fewer roof support consumables are needed, higher volume coal clearance systems, minimal manual handling and safety of the miners is enhanced by the fact that they are always under the hydraulic roof supports when they are extracting coal.