This method involves removing the overlying rock and soil layers to access the mineral deposits below. The waste rock and soil are then dumped into adjacent valleys, filling them in and creating a flat landscape. The selection of the mining technique is dictated by the physical structure, location, and grade or value of the ore body and by the characteristics of the adjacent geological materials. Although open-pit mining and underground mining are the two most common mining techniques, placer mining and solution mining also have been used for mineral extraction.
It involves the removal of the overlying rock and soil layers in horizontal strips to access the mineral deposits below. The mining xcritical rezension process starts at the edge of the deposit and moves inward in successive strips until the entire deposit is mined. Strip mining, also known as open-pit mining, surface mining, or strip-cut mining, is a method of extracting valuable minerals or other geological materials from the Earth’s surface.
Where is strip mining most common?
- This is far less land than the amount lost to agriculture and urbanization.
- Strip mining involves a series of steps that begin with the removal of overburden, which refers to the layers of soil, rock, and vegetation covering the target resource.
- The consequence of the excavation of open-pits and other mining-related disturbances is that sulfide minerals previously isolated from the atmosphere are exposed to oxygen.
- In this process, crushed Cu ore is continuously leached with sulfuric acid until most of the Cu is solubilized due to both the high acidity and formation of Cu-sulfate complexes.
Strip mining is commonly used to extract thin coal seams and lignite that are very close to the ground surface. Strip mining is a form of surface mining that is employed to strip away a layer or seam of soil, natural vegetation, and rocks (known as overburden) to extract the mineral deposits underneath. Unlike underground mining, it is predominately used to access relatively flat sedimentary mineral reserves that are near the earth’s surface, usually coal and lignite. Surface mine design principles emanate from the operational characteristics of surface mining, which are drilling and blasting, spoil handling, coal removal, and haulage. Except in a few circumstances, overburden in surface mining requires xcritical scam the rock to be fractured by explosives to allow it to be excavated.
Other types of mining methods include mountaintop removal, dredging and highwall mining (an adapted form of auger mining done from the surface). When starting a strip mining operation in Minecraft, you first need to set up the underground base for your mine. This is where you will return to drop your materials and the entrances to each mining strip. When you start off, dig down until you’re standing on a block at y 5 (where Bedrock starts to form) and dig a hole 3 blocks wide by 9 blocks long by four blocks high. Strangely enough, a 1971 Oklahoma law produced effects similar to what the Geological Survey found in Kentucky.
One of the primary environmental impacts of contour strip mining is the alteration of the natural landscape. The removal of the overlying rock and soil layers can result in changes to the topography and drainage patterns of the area. Strip mining process is most suitable for fairly flat shallow single-seam coal, lignite and other bedded deposits. The mineral layer is covered by an even thickness of overburden composed of soft topsoil and weathered rocks in succession.
Wealth Minerals
This means that 30 to 100 tons can be dug in a single “bite” of the shovel. The size of the trucks is matched to that of the shovel, a common rule of thumb being that the truck should be filled in four to six swings of the shovel. Thus, for a shovel of 15-cubic-metre capacity, a truck having a capacity of 120 to 180 tons (four to six swings) should be assigned. The largest trucks have capacities of more than 350 tons (about 12 swings) and are equipped with engines that produce more than 3,500 horsepower; their tire diameters are often more than 3 metres (10 feet). Because of their high mobility, very large-capacity wheel loaders (front-end loaders) are also used in open-pit mines. The following classification, of land disturbance due to coal mining, is adapted from a more general and comprehensive classification of Motorina and Ovchinnikov (1975) and Bauer and Weinitschke (1973).
Economic analysis then determines the area and depth of profitable overburden removal. Finally, contracts must be negotiated with landowners; strip mines commonly end abruptly at property lines. Although open-pit mining is similar to strip mining, during open-pit mining operation, massive, vertical pits are created by using explosives, where the mineral materials are extracted through heavy machinery. Strip mining, however, normally creates horizontal strips or trenches from which mineral extraction or ore deposits are drilled and founded. Spoil handling design is of critical importance, as this function is usually the most expensive cost element in surface mining.
Environmental Geochemistry
An air compressor on the drilling machine forces air down the centre of the drill string so that the cuttings are removed. In smaller pits holes are often drilled by pneumatic or hydraulic percussion machines. Hole diameters are often in the range of 75 to 120 mm (about 3 to 5 inches). As a pit is deepened, more and more waste rock must be stripped away in order to uncover the ore.
Contour mining, on the contrary, progresses in a narrower and custom shaped zone where the overburden is removed, following the contours of outcrops and hilly terrain rather than long strips. A schematic view of the complete operating cycle of mining for shallow-bedded deposits like coal and lignite seams. 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. This results in the obliteration of the land (it can no longer be used for harvesting and cultivation of crops) and soil erosion. 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. Overburden of adjacent cuts is used to fill earlier cuts, just as area-mining.
This overburden is typically moved using heavy machinery, such as bulldozers and excavators. Once the overburden is removed, miners extract the desired mineral or resource, such as coal, oil sands, or minerals like copper and iron ore. Because of their increasing efficiency with larger sizes, the land footprint of a coal power plant can be quite substantial. There typically needs to be sufficient space to unload and store significant amounts of coal feedstock. Coal is often processed at the mine to create uniform-size particles (“comminution”), remove noncombustible minerals, and provide other conditioning to improve performance.
Water Hardness and How is it Measured?
In America, strip mining is also used for mining phosphate fertilizer in areas such as Florida, North Carolina, Idaho, and for obtaining gypsum in western United States. Bowl or cirque-type subsidence caused by the working of medium or thick seams dipping up to 27°. Terraced excavations usually 10–30 m deep with deposit dipped at 8°; some internal storage of overburden (Fig. 2.1C).
Coal extraction follows behind power shovels, leaving a flat, canyon-like cut. Upon completion of a row, the shovel starts back in the opposite direction, placing the new overburden in the now-empty cut. The examples of decimated land in Appalachia have motivated calls for prevention, or at least major efforts at reclamation. Strip mining for xcritical scam coal comprises well over half of the land that is strip-mined, which totaled less that 0.3% of land in the United States between 1930 and 1990. This is far less land than the amount lost to agriculture and urbanization.
When cast blasting is used, the dragline may excavate from the spoil side of the pit, sitting on the leveled, blasted overburden. The more common method is area stripping, which is used on fairly flat terrain, to extract deposits over a large area. As each long strip is excavated, the overburden is placed in the excavation produced by the previous strip.
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