Room and pillar is a mining system in which the mined material is extracted across a horizontal plane while leaving "pillars" of untouched material to support the overburden leaving open areas or "rooms" underground. Mining is the extraction of valuable Minerals or other geological materials from the earth usually (but not always from an Ore body Overburden is the term used in Mining to describe material that lies above the area of economic interest e It is usually used for relatively flat-lying deposits, such as those that follow a particular stratum. In Geology and related fields a stratum (plural strata) is a layer of rock or Soil with internally consistent characteristics that distinguishes
The room and pillar system is used in mining coal, iron and copper ores particularly when found as manto or blanket deposits, stone and aggregates, talc, soda ash and potash. Iron ores are rocks and Minerals from which Metallic Iron can be economically extracted Manto orebodies are stratabound irregular to rod shaped Ore occurrences usually horizontal or near horizontal in attitude In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere Construction aggregate, or simply " aggregate " is a broad category of coarse particulate Material used in Construction, including Talc (derived from the Persian via Arabic talq) is a Mineral composed of Hydrated Magnesium Silicate with Sodium carbonate (also known as washing soda or soda ash), is a Sodium Salt of Carbonic acid. Potash (or carbonate of potash) is an impure form of Potassium carbonate ( K 2 CO3) [1]
The key to the succesful room and pillar mining is selecting the optimum pillar size. If the pillars are too small the mine will collapse. If the pillars are too large then significant quantities of valuable material will be left behind reducing the profitability of the mine. [1] The percentage of material mined varies; stone and aggregates 75%, Coal 60% and Potash 50%[1]
Extensive statical calculations are used to determine the efficiency of room-and-pillar layouts. Statics is the branch of Mechanics concerned with the analysis of loads ( Force, torque/moment) on Physical systems in Static equilibrium The pillars are sometimes mined at a later date, when the roof has been shored up.
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Retreat mining is a term used to reference the final phase of an underground Mining technique known as Room and pillar mining Longwall mining is a form of underground Coal mining where a long wall (typically about 250-400 m long of coal is mined in a single slice (typically 1-2 m thickDapyx Software network: MP3 Explorer | Ebook Manager | Zenithic