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Box Cut
A box cut (box pit) is a small open cut built to supply a secure and safe entrance as access to a slope to an underground mine. Generally the box cut is sunk until sufficiently unweathered rock is found to permit the development of the decline. The portal is generally made safe with rock bolts, wire mesh, and shotcrete, which prevents accidental rock falls from closing access to the decline. See also *Underground hard-rock mining Underground hard-rock mining refers to various underground mining techniques used to excavate "hard" minerals, usually those containing metals, such as ore containing gold, silver, iron, copper, zinc, nickel, tin, and lead. It also involves the .... References {{DEFAULTSORT:Box Cut Underground mining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mining
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic viability of investing in the equipment, labor, and energy required to extract, refine and transport the materials found at the mine to manufacturers who can use the material. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock Bolt
A rock bolt is a long anchor bolt, for stabilizing rock excavations, which may be used in tunnels or rock cuts. It transfers load from the unstable exterior to the confined (and much stronger) interior of the rock mass. Rock bolts were first used in mining in the 1890s, with systematic use documented at the St Joseph Lead Mine in the U.S. in the 1920s. Rock bolts were applied to civil tunneling support in the U.S. and in Australia starting in the late 1940s. Rock bolts were used and further developed starting in 1947 by Australian engineers who began experimenting with four-meter-long expanding anchor rock bolts while working on the Snowy Mountains Scheme. As shown in the figure, rock bolts are almost always installed in a pattern, the design of which depends on the rock quality designation and the type of excavation. Rock bolts are an essential component of the New Austrian Tunneling method. As with anchor bolts, there are many proprietary rock bolt designs, with either a mec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shotcrete
Shotcrete, gunite (), or sprayed concrete is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique, first used in 1907 invented by Carl Akeley. It is typically reinforced by conventional steel rods, steel mesh, or fibers. Shotcrete is usually an all-inclusive term for both the wet-mix and dry-mix versions invented by Akeley. In pool construction, however, ''shotcrete'' refers to wet mix and ''gunite'' to dry mix. In this context, these terms are not interchangeable. Shotcrete is placed and compacted/consolidated at the same time, due to the force with which it is ejected from the nozzle. It can be sprayed onto any type or shape of surface, including vertical or overhead areas. Shotcrete has the characteristics of high compressive strength, good durability, water tightness and frost resistance. History Shotcrete, then known as gunite, was invented in 1907 by American taxidermist Carl Akeley to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underground Hard-rock Mining
Underground hard-rock mining refers to various underground mining techniques used to excavate "hard" minerals, usually those containing metals, such as ore containing gold, silver, iron, copper, zinc, nickel, tin, and lead. It also involves the same techniques used to excavate ores of gems, such as diamonds and rubies. Soft-rock mining refers to the excavation of softer minerals, such as salt, coal, and oil sands. Mine access Underground access Accessing underground ore can be achieved via a decline (ramp), inclined vertical shaft or adit. *Declines can be a spiral tunnel which circles either the flank of the deposit or circles around the deposit. The decline begins with a box cut, which is the portal to the surface. Depending on the amount of overburden and quality of bedrock, a galvanized steel culvert may be required for safety purposes. They may also be started into the wall of an open cut mine. *Shafts are vertical excavations sunk adjacent to an ore body. Shafts are sun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
