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Room and pillar or pillar and stall is a variant of breast stoping. It is a mining system in which the mined material is extracted across a horizontal plane, creating horizontal arrays of rooms and pillars.
General layout of a room-and-pillar mine. Retreat mining is the removal of pillars in the underground mining technique known as room and pillar mining.. In the first phase of room and pillar mining, tunnels are advanced into the coal or ore body in a rectangular pattern resembling city streets.
Once room and pillar mines have been developed to a stopping point limited by geology, ventilation, or economics, a supplementary version of room and pillar mining, termed second mining or retreat mining, is commonly started. Miners remove the coal in the pillars, thereby recovering as much coal from the coal seam as possible.
Pillar. A pillar is a section of unworked coal supporting the roof. Unworked pillars of coal are left to prevent subsidence to surface features. The shaft pillar is left to prevent damage to the shafts from the workings. [1] Pit. Strictly refers to a shaft, though also used to refer to a colliery more generally. Pit brow lasses
Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically 0.6–6.0 m (2 ft 0 in – 19 ft 8 in) thick). The section of rock that is being mined, known as the longwall panel, is typically 3–4 km (1.9–2.5 mi) long, but can be up to 7.5 km (4.7 mi) long and 250–400 m (820–1,310 ft) wide.
A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member .
Timber framing is a general term for building with wooden posts and beams. The term post is the namesake of other general names for timber framing such as post-and-beam, post-and-girt construction and more specific types of timber framing such as Post and lintel, post-frame, post in ground, and ridge-post construction.
The systematic layout planning (SLP) - also referred to as site layout planning [1] - is a tool used to arrange a workplace in a plant by locating areas with high frequency and logical relationships close to each other. [2] The process permits the quickest material flow in processing the product at the lowest cost and least amount of handling ...