Most contour miners operate in the steep mountainous regions of Appalachia. In these regions, coal deposits skirt and outcrop from the sides of mountain slopes or hills. Most often, mining companies only utilize strip mining in areas with reasonably flat terrain. The other surface mines not covered by MSHA Part 46, plus underground mines, are covered by MSHA Part 48. The Mining Safety and Health Administration, also known as MSHA, requires that miners who work at surface mines receive specific safety training to reduce the risk of injury, illness, or fatality on the job.
Deforestation and vegetation removal eliminates root structures and promotes soil erosion, further damaging the environment. Once a mining company finishes an operation in an area, the workers take stored overburden and backfill the recently-mined area. Overburden refers to any rock or soil remaining above existing coal beds after topsoil removal. This region spearheads the coal mining effort for most of the country.
Mining companies are nowadays operating mainly in Appalachian Mountains of Kentucky and West Virginia. Some large surface coal mines, such as Wyodak near Gillette in eastern Wyoming have a power plant on-site to utilize the coal at the mine and sell electricity directly into the national grid. The goal of coal pit recovery is to obtain as close to 100% as possible. One method to maximize pit recovery is to minimize drill and blast damage to the top of the coal. Drill and blast damage is reduced by stopping the drill holes from touching the coal seam or by placing nonexplosive material in each drill hole, called stemming. Pit recovery is also maximized by matching the pit width with the characteristics of the machinery used to extract the coal.
Contour mining involves removing the overburden above the mineral seam near an outcrop in hilly terrain, where the mineral outcrop usually follows the contour of the land. Contour stripping is often followed by auger mining into the hillside, to remove more of the mineral. The advantage of contour strip mining is that it can be used to extract minerals from steep hills and mountains without the need for expensive blasting or drilling. The disadvantages are that it can be expensive to set up and it can damage the environment if not done properly. Because valley fills can act like sponges, they can keep streams that might otherxcritical dry up or be reduced to a trickle with a strong flow longer into the year, said Bernhardt, the Duke University professor. While that may sound good, water coming from the mines and through the valley fills is polluted, she said.
Heavier rainfall could also mean more polluted water washing from coal mines, environmental experts say, damaging streams and aquatic life already marred by mining. The process of strip mining can have an adverse effect on the land. The top layer that is dumped in a nearby location can flood surrounding towns, villages and agricultural land during the rainy season. Rain can also push the filth of the mine on the topsoil making it inhabitable for plants and animals. The harmful impact of strip mining can easily be tackled by using reclamation strategies.
In these regions, revegetation and further efforts, such as land reclamation, result from local environmentalist actions. The mining operation sends coal collected from a seam https://scamforex.net/ to treatment plants near the mine site. After removing the topsoil, most mining ventures store it for later use or use it as backfill material in a previously mined area.
Except in a few circumstances, overburden in surface mining requires the rock to be fractured by explosives to allow it to be excavated. The goal of drill and blast design is to optimize rock fracturing, which optimizes digging productivity. Fracturing is optimized by using the correct amount of explosive per cubic yard of overburden employed in the drill hole spacing in plan view.
Like lignite, sub-bituminous coal is mainly used as fuel for generating electricity. In China, coal mining has tarnished the quality of land of an estimated 3.2 million hectares, conferring to a 2004 assessment. The general repair rate of mine wasteland was merely about 10–12 percent. As part of the procedure of clearing the way for a coal mine, trees are chopped down or burnt, plants displaced and pulled out and the topsoil scraped off. The adverse and harmful effects of coal mining cannot be disputed. Contour mining entails making cuts on the slant/angle where the coal seam is traced, to take away the overburden first and then the coal itself.
The findings were published as a doctoral dissertation in 1977 by Clark University. Area mining, Meleen found, produced far more benign impacts than did contour stripping. The worst conditions were encountered where contour mining was adjacent to streams below, especially around the end of ridges.
The profound changes in topography and disturbance of pre-existing ecosystems have made mountaintop removal highly controversial. People are forced to relocate due to all these negative effects, including the deteriorating quality of the air and water they breathe, as well as the increasing exploitation of their own country by coal mines. Trees are felled or burned, vegetation is uprooted and removed, and the topsoil is scraped off as part of the process of making room for a coal mine.
⛏️ Comparing Different Types of Surface Mining
If the firm fails to do so, it leaves behind an area that is full of uneven strips of soil, rock, and waste. The next step after evening out is to cover it with topsoil so that trees and plants can be planted xcritical cheating on it. Mining operations, meanwhile, have stripped the near-surface environment of ores and fossil fuels, leaving large open pits, tunnel complexes, and, in the case of strip mining, sheared off mountaintops.
Strip mining is used for mining phosphate fertilizer in Florida, North Carolina, and Idaho, and for obtaining gypsum in western states. Across the nation, a schism that separates pro-coal and pro-environment movements over mountaintop removal, a destructive yet highly effective form of strip mining, is deepening. The size of coal deposits found in pit mines often results in insufficient remaining overburden and topsoil replacement.
If a mountain is blocking a coal seam inside, it will successfully burst or be destroyed, leaving a ruined landscape as well as disturbing ecosystems and wildlife habitats. It is indisputable that strip mining has negative and detrimental repercussions. The most noteworthy effects of strip mining xcritical on the environment are listed below. Even though the majority of surface coal mining occurs in North America, it started in the middle of the 16th century and is being used today all over the world. Large stripping shovels or draglines are used in large open pit mines to remove the overburden.
Environmental Impacts of Strip Mining
Overburden of adjacent cuts is used to fill earlier cuts, just as area-mining. A schematic view of the complete operating cycle of mining for shallow-bedded deposits like coal and lignite seams. Blasting at a mountaintop removal mine expels dust and fly-rock into the air, which can then disturb or settle onto private property nearby. This dust may contain sulfur compounds, which some claim corrode structures and tombstones and is a health hazard.
- Contour stripping is often followed by auger mining into the hillside, to remove more of the mineral.
- Sure, the EPA blocked the largest mountaintop removal permit in West Virginia last week—70-odd permits still remain in limbo, as 3 millions pounds of ANFO explode daily in WV and KY.
- This will significantly affect water quality for people living nearby.
- Many people confuse strip mining with other types of surface mining.
Dump trucks used at strip mines often weigh more than 300 tons and have more than 3,000 horsepower. ] contend that mountaintop removal is a disastrous practice that benefits a small number of corporations at the expense of local communities and the environment. A U.S. Environmental Protection Agency environmental impact statement finds that streams near valley fills sometimes may contain higher levels of minerals in the water and decreased aquatic biodiversity. The statement also estimates that 724 miles of Appalachian streams were buried by valley fills from 1985 to 2001.
The operator removes the box cut spoil from the area where mining will proceed by placing it on one side. Then, holes are dug to deposit explosives that will loosen the overburden so that earth-moving machinery may remove it with ease. Machines like stripping scoops, basin wheel excavators, or draglines are used in the process to remove the stone and expose the valuable metal that is being mined.
Enzymology of Disturbed Soils
Strip mining is the practice of mining a seam of mineral, by first removing a long strip of overlying soil and rock ; this activity is also referred to as overburden removal. Strip mining is only practical when the ore body to be excavated is relatively near the surface and/or is mostly horizontal. This type of mining uses some of the largest machines on earth, including bucket-wheel excavators which can move as much as 12,000 cubic metres (16,000 cu. yd.) of earth per hour. In Oklahoma, a study conducted by Nathan Meleen dealt with a mix of both flat and hilly terrain.
Upon completion of a row, the shovel starts back in the opposite direction, placing the new overburden in the now-empty cut. After a strip mine is closed, the mining company should fix the region. After the final strip is filled back in, the entire area should be bulldozed to create level land.
The overburden is removed by opening successive and progressive benches in the case of deep-seated bedded deposit within a permissible stripping ratio. Multiple seam mining is done by operating a first pair of overburden and coal beds, followed by second and third pairs in sequence. Finally, the total overburden rocks, stockpiled around the mine opening, is backfilled to reclaim the abandoned excavation.