Classification of Coal Resource Mining Methods

Based on the coal resource endowment, traditional coal mining methods are categorized into open pit mining and shaft mining (underground mining). [2] The surface cover of coal seams in open-pit coal mines is shallow, and coal can be mined by digging up the surface layer, with a low risk factor. The coal seams in shaft coal mines are deeper, and must be dug into the strata for coal mining, underground work, with a high risk factor.

Although from the policy point of view, China from the first five-year plan, has always attached great importance to prioritize the development of open-pit coal mining, and as a national technology policy, but China's coal mining is still mainly mine mining, open-pit coal mining development is slow. Since the founding of the country, the proportion of the output of open-pit coal mining has been below 10%, with most years below 5%. And the world's mining conditions in good countries, the proportion of open-pit mining has reached more than 50%.

The limit depth of surface mining, in theory, commonly used in the realm of stripping ratio is greater than the principle of economic reasonable stripping ratio to determine. But the economic reasonable stripping ratio is a factor with the change of mineral prices. Modern scientific research design and production generally use floating cone method, according to the market price of minerals to determine the limit depth of open pit mining, and modify at any time. Open pit to underground mining mines, open pit mining limit depth can not be calculated and determined by the original single use of open pit mining, should be based on open pit mining and underground mining per ton of ore, the principle of equal production costs to determine more reasonable, at this time, the limit of the open pit mining depth with a single use of the open pit mining mines are different. In addition, modern society on land, environmental protection, safety and production requirements have become an important factor in the choice of mining methods, to determine the depth of open pit to underground mining open pit.