Is longwall mining

By | 09.07.2018
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LONGWALL MINING Overview. In the method of secondary extraction known as longwall mining a relatively long mining face (typically in the range 100 to 300m but may be. Longwall mining is a high extraction technique where coal is removed in 1,400 ft. panels that stretch for miles. Unlike traditional room and pillar mining, in a longwall mine no coal pillars are left in place to provide surface support above the panel. INTRODUCTION. Longwall mining is a highly productive underground coal mining method where a long wall of coal is mined in a single slice, typically of thickness 0.6 m.
Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically 1-2 m thick). The longwall "panel" (the block of coal that is being mined) is typically 3-4 km long and 250-400 m wide. Longwall mining is a highly productive underground coal mining technique. Longwall mining machines consist of multiple coal shearers mounted on a series of self-advancing hydraulic ceiling supports. LONGWALL MINING Overview. In the method of secondary extraction known as longwall mining a relatively long mining face (typically in the range 100 to 300m but may be. Longwall mining is a high extraction technique where coal is removed in 1,400 ft. panels that stretch for miles. Unlike traditional room and pillar mining, in a longwall mine no coal pillars are left in place to provide surface support above the panel. INTRODUCTION. Longwall mining is a highly productive underground coal mining method where a long wall of coal is mined in a single slice, typically of thickness 0.6 m.
A project of Citizens Coal Council

What is Longwall Mining?

The roof above the machine is supported by massive hydraulic roof supports.  As the machine moves forward, the roof behind the machine is left to collapse, is longwall mining.  The collapsed mine roof affects the ground above the mine all the way to the surface, is longwall mining, in what is known as "subsidence", is longwall mining can vary from 2 feet to 6 feet or more.
The above diagram of mine subsidence is a significant oversimplification of what actually happens when the ground subsides.  The ground rarely collapses in a uniform way as the longwall machine moves forward, instead collapsing at different rates, or, if in between mined areas (called "panels"), collapse very little, if at all.
Subsidence results in damage to the homes and other structures above the mined areas.
While the effects of longwall mining on homes and other structures is shocking, what's even more shocking is the effect that longwall mining has on streams, springs, ponds, wells, and other water supplies.

When the longwall machine passes under, and the ground above collapses, the intricate hydrologic balance that ensures that streams flow and that water wells are replenished, is damaged. With mine subsidence, suddenly there are cracks and voids where there were previously none, and the water percolates down into the empty spaces. The result is that the water that used to be much closer to the surface has now flowed into the cracks and fissures formed by the subsided ground.


The real-life results of longwall subsidence on water:

Even though it's difficult to believe that this result can possibly be allowed to happen, it does happen with longwall mining, and frequently.  This begs the question: are our established regulations enough is longwall mining protect people or our water resources from being damaged by longwall mining? The answer, evidenced by the photos above, is no.  As in many cases, longwall mining regulations are plagued by both serious loopholes and lax regulatory enforcement.

Need more evidence that our regulations are faulty? power limit msi afterburner mining following photos were taken in Southwestern Pennsylvania in areas that had been longwall mined, is longwall mining. The result was that the streams lost their water, and the mining company responsible for the water loss "fixed" the problem by filling in cracks in the streambed with grout (yes, grout), and in another case, they attached hoses to a public water supply and pumped water into the dry stream bed to "create" a flowing stream. All of this was perfectly acceptable to regulators.


Why is this happening?

Outdated regulations, regulatory loopholes, and lax enforcement are just some of the major problems with longwall mining today.  The Longwall Mining Reform Campaign seeks to raise awareness of the problems caused by longwall mining, and work toward wide-scale change that keeps the damage from happening.  You can find out what work the Longwall Mining Reform Campaign is doing RIGHT NOW to bring about change.  
Longwall mining is a method of underground coal mining in which a large machine passes back and forth over the "face" of the coal, and using spikes attached to a spinning drum, is longwall mining, cuts the coal off the face in large swaths.
is longwall mining longwall mining machine, also known as a "shearer"
Hydraulic roof supports Source: "Longwall2" by TCP0203 - Own work. Licensed under Bitcoin mining usb miners Commons Attribution 3.0 via Wikimedia Commons
Cross-section of longwall mine subsidence. Source: http://www.gmat.unsw.edu.au/currentstudents/ug/projects/Sparkes/index_files/Page380.htm
Illustration of "trough subsidence" characteristic of longwall mines. Source: Pennsylvania DEP
Visible surface effect of where longwall mine panels are located, as well as the unmined space between panels (called "gates"). Source page: http://www.coalnews.net/papers/November2011/HTML/files/assets/seo/page9.html
Impact of longwall subsidence on the water table.
A pond before longwall mining
A pond after longwall mining
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Cat | Underground - Longwall | Caterpillar

INTRODUCTION. Longwall mining is a highly productive underground coal mining method where a long wall of coal is mined in a single slice, typically of thickness 0.6 m. Longwall mining is a method of underground coal mining in which a large machine passes back and forth over the "face" of the coal, and using spikes attached to a spinning drum, cuts the coal off the face in large swaths. Cat® customized systems for longwall mining range from hydraulic roof supports and automated plow systems to shearers, face conveyors and roof support carriers.

Longwall mining is a highly productive underground coal mining technique. Longwall mining machines consist of multiple coal shearers mounted on a series of self-advancing hydraulic ceiling supports. Cat® customized systems for longwall mining range from hydraulic roof supports and automated plow systems to shearers, face conveyors and roof support carriers. Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically 1-2 m thick). The longwall "panel" (the block of coal that is being mined) is typically 3-4 km long and 250-400 m wide.


Longwall Mining

Longwall mining is a highly productive underground coal mining technique.  Longwall mining machines consist of multiple coal shearers mounted on a series of self-advancing hydraulic ceiling supports.  The entire process is mechanized.  Longwall mining machines are about 800 feet (240 meters) in width and 5 to 10 feet (1.5 to 3 meters) tall.  Longwall miners extract "panels" - rectangular blocks of coal as wide as the mining machinery and as long as 12,000 feet (3,650 meters). Massive shearers cut coal from a wall face, which falls onto a conveyor belt for removal.  As a longwall miner advances along a panel, the roof behind the miner's path is allowed to collapse.

 

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