Open Pit Mining and Quarry
- 2. Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit (the overburden) are removed, in contrast to underground mining, in which the overlying rock is left in place, and the mineral is removed through shafts or tunnels. In most forms of surface mining, heavy equipment, such as earthmovers, first remove the overburden. Next, large machines, such as dragline excavators or bucket-wheel excavators, extract the mineral. Advantages of surface mining include lower cost and greater safety compared to underground mining. Disadvantages include hazards to human health and the environment. Humans face a variety of health risks caused by mining such as different cardiovascular diseases, food, and water contamination. Habitat destruction, alongside air, noise, and water pollution, are all significant negative environmental impacts caused by the side effects of surface mining.
- 10. The Bagger 288 is a bucket-wheel excavator used in strip Strip mining is the practice of mining a seam of mineral, by first removing a long strip of overlying soil and rock as overburden removal. It is most commonly used to mine coal and lignite (brown coal). Strip mining is only practical when the ore body to be excavated is relatively near the surface and/or is mostly horizontal. 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.
- 11. Strip mining at Garzweiler surface mine in Germany. The lignite being extracted is at left, the removed overburden being placed at right. Note that it is a largely flat mine for a horizontal mineral. 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. This method commonly leaves behind terraces in mountainsides.
- 12. Open-pit mining refers to a method of extracting rock or minerals from the earth through their removal from an open pit or borrow. This process is done on the ground surface of the earth. It is best suited for accessing mostly vertical deposits of minerals. Although open-pit mining is sometimes mistakenly referred to as "strip mining", the two methods are different. Open pit mining vs Open cast Mining Open pit mining the deposit shape is mostly parallel to the surface while in open cast mining ,the deposit shape is bedded and tabular. Open cast mining involves the backfilling of waste in the mind out open cast excavations or stopes during the mining process while open pit mining mostly involves the backfilling at the end of the mining life as part of mine reclamation process.
- 13. Mountaintop removal mining (MTR), also known as mountaintop mining (MTM), is a form of surface mining at the summit or summit ridge of a mountain. Coal seams are extracted from a mountain by removing the land, or overburden, above the seams. This process is considered to be safer compared to underground mining because the coal seams are accessed from above instead of underground. In the United States, this method of coal mining is conducted in the Appalachian Mountains in the eastern United States. Explosives are used to remove up to 400 vertical feet (120 m) of mountain to expose underlying coal seams. Excess rock and soil is dumped into nearby valleys, in what are called "holler fills" ("hollow fills") or "valley fills".
- 14. Mountaintop removal mining (MTR), also known as mountaintop mining (MTM) Mountaintop removal mining (MTR), also known as mountaintop mining (MTM)
- 15. Placer mining A gold dredge is a placer mining machine that extracts gold from sand, gravel, and dirt using water and mechanical methods.The original gold dredges were large, multi-story machines built in the first half of the 1900s. Small suction machines are currently marketed as "gold dredges" to individuals seeking gold: just offshore from the beach of Nome, Alaska, for instance.
- 16. Rock blasting at the large open-pit Twin Creeks gold mine in Nevada, United States. Note the size of the excavators for scale (foreground, left), and that the bottom of the mine is not visible.
- 17. Open-pit mines that produce building materials and dimension stone are commonly referred to as “quarries.” Marble quarry in Tuscany, Italy.
- 18. Portland stone quarry, Isle of Portland, Dorset, England Limestone is quarried for aggregate and other uses, Tennessee, U.S. Quarry, place where dimension stone or aggregate (sand, gravel, crushed rock) is mined. The products of dimension stone quarries are prismatic blocks of rock such as marble, granite, limestone, sandstone, and slate. After cutting and polishing, these materials are used in the primary construction of buildings and monuments and also for decorative facing materials applied to the exterior and interior of buildings. Dimension stones are extracted in a highly selective manner, using time-consuming and expensive methods for freeing the blocks from the surrounding rock.