Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or (coal) seam. The nature of mining processes creates a potential negative impact on the environment both during the mining operations and for years after the mine is closed.
The world of mining has more than seven thousand producing mines around the globe and every year we can find that there are more quickly progressing and being developed. These mines give us the raw materials needed for the construction, manufacturing and industries of chemicals and the majority of the minerals of energy upon which our everyday life is so needed of.
The process of mining from discovery of an ore body through extraction of minerals and finally to returning the land to its natural state consists of several distinct steps. The first is discovery of the ore body, which is carried out through prospecting or exploration to find and then define the extent, location and value of the ore body.
There is a wide variety of methods of extraction which one can choose from as the ore bodies have shapes and sizes. The orientation and shape of an ore body, the strength of the ore and the surrounding rock and the form. in which the valuable materials are distributed are different for each ore area. These factors among others are what will influence the selection of a mining method and the overall plan for developing the ore body.As the professional manufacturer of complete sets of mining machinery, such as sand maker, Henan Hongxing is always doing the best in products and service.
Mining techniques can be divided into two common excavation types: surface mining and sub-surface (underground) mining. Surface mining is much more common, and produces, for example, 85% of minerals (excluding petroleum and natural gas) in the United States, including 98% of metallic ores. Targets are divided into two general categories of materials: placer deposits, consisting of valuable minerals contained within river gravels, beach sands, and other unconsolidated materials; and lode deposits, where valuable minerals are found in veins, in layers, or in mineral grains generally distributed throughout a mass of actual rock. Both types of ore deposit, placer or lode, are mined by both surface and underground methods.
Surface-mining methods include area, contour, mountaintop removal, and auger mining. Area mines are surface mines that remove shallow coal over a broad area where the land is fairly flat. Huge dragline shovels commonly remove rocks overlying the coal (called overburden). After the coal has been removed, the rock is placed back into the pit. Contour mines are surface mines that mine coal in steep, hilly, or mountainous terrain.
Underground modes of access include drift, slope, and shaft mining, and actual mining methods include long wall and room and pillar mining. Drift mines enter horizontally into
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