Crushing and grinding production
lines
for mines and quarries
Underground mining
A deep coal seam is accessed by an opening to the surface called a portal. The portal opening are called drift, slope, or shaft mines. Drift mines cut down the coal bed from the outcrop, slope mines cut through overburden rock at an angle to get to the coal, and shaft mines access the coal through a vertical shaft. Mining begins with a cutting machine called a continuous miner creating a box work called room and pillar mining. As the rooms are cut, the coal is loaded onto a shuttle car and carried to a conveyor belt that carries it to the surface. As the mining advances, the pillars remain to support the openings. Roof bolts are placed in the ceiling to stabilize the roof. The larger underground mines use a large coal-cutting machine called a longwall miner. This automated machine is 1000 feet long and has moveable three-foot-wide cutting teeth that cut away at the face of the wall of coal. This 36-inch diameter rotating shearer cuts the coal, where it drops onto a conveyor which hauls to the surface. Because this machine cuts a continuous 1000-foot-long swath into the coal seam, there are no pillars left to support the roof. So moveable metallic roof shields are installed all along the 1000 foot zone that will be cut. This keeps the roof from collapsing near the cutting machine. After each 1000-foot-long cut (each three feet deep), the metal shields are moved forward allowing the roof to collapse behind.
Before the coal is ready to go to the market, it has to be processed. According to the products type and the size of coal, choose the suitable coal mining equipments. If you need coal briquette, choose coal washing machine, and coal crushing and screening plant. In this coal crushing process, jaw crusher, impact crusher, cone crusher and other coal crusher, screening machine consist the complete crushing plant. If you need coal powder, a grinding plant is essential. The complete grinding plant includes hammer crusher, ball mill, vertical mill or ultrafine grinding mill and dust catcher.
SBM is a professional manufacturer of crusher and grinding machines in China, provides all kinds of crushing plant for industry, such as coal crushing plant, ore crushing plant, concrete crushing plant and gold mining equipments.
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