Explain any 5 methods used for extraction of minerals (you need to explain them)
Answers
Surface mining.
Surface mining is done by removing (stripping) surface vegetation, dirt, and, if necessary, layers of bedrock in order to reach buried ore deposits. Techniques of surface mining include: open-pit mining, which is the recovery of materials from an open pit in the ground, quarrying, identical to open-pit mining except that it refers to sand, stone and clay;[35] Strip mining. which consists of stripping surface layers off to reveal ore/seams underneath; and mountaintop removal, commonly associated with coal mining, which involves taking the top of a mountain off to reach ore deposits at depth. Most (but not all) placer deposits, because of their shallowly buried nature, are mined by surface methods. Finally, landfill mining involves sites where landfills are excavated and processed.[36] Landfill mining has been thought of as a solution to dealing with long-term methane emissions and local pollution[37]
High-Wall Mining
High wall mining is another form of surface mining that evolved from auger mining. In high wall mining, the coal seam is penetrated by a continuous miner propelled by a hydraulic Push-beam Transfer Mechanism (PTM). A typical cycle includes sumping (launch-pushing forward) and shearing (raising and lowering the cutter-head boom to cut the entire height of the coal seam). As the coal recovery cycle continues, the cutter-head is progressively launched into the coal seam for 19.72 feet (6.01 m). Then, the Push-beam Transfer Mechanism (PTM) automatically inserts a 19.72-foot (6.01 m) long rectangular Push-beam (Screw-Conveyor Segment) into the center section of the machine between the Powerhead and the cutter-head. The Push-beam system can penetrate nearly 1,000 feet (300 m) into the coal seam. One patented high wall mining system uses augers enclosed inside the Push-beam that prevent the mined coal from being contaminated by rock debris during the conveyance process. Using a video imaging and/or a gamma ray sensor and/or other Geo-Radar systems like a coal-rock interface detection sensor (CID), the operator can see ahead projection of the seam-rock interface and guide the continuous miner's progress. High wall mining can produce thousands of tons of coal in contour-strip operations with narrow benches, previously mined areas, trench mine applications and steep-dip seams with controlled water-inflow pump system and/or a gas (inert) venting system.
Underground mining
Mantrip used for transporting miners within an underground mine
Sub-surface mining consists of digging tunnels or shafts into the earth to reach buried ore deposits. Ore, for processing, and waste rock, for disposal, are brought to the surface through the tunnels and shafts. Sub-surface mining can be classified by the type of access shafts used, the extraction method or the technique used to reach the mineral deposit. Drift mining utilizes horizontal access tunnels, slope mining uses diagonally sloping access shafts, and shaft mining utilizes vertical access shafts. Mining in hard and soft rock formations require different techniques.
Other methods include shrinkage stope mining, which is mining upward, creating a sloping underground room, long wall mining, which is grinding a long ore surface underground, and room and pillar mining, which is removing ore from rooms while leaving pillars in place to support the roof of the room. Room and pillar mining often leads to retreat mining, in which supporting pillars are removed as miners retreat, allowing the room to cave in, thereby loosening more ore. Additional sub-surface mining methods include hard rock mining, which is mining of hard rock (igneous, metamorphic or sedimentary) materials, bore hole mining, drift and fill mining, long hole slope mining, sub level caving, and block caving.