coal mining method

In the process of coal mine construction and production, various types of source water will enter the roadway and working face through different ways. In order to ensure the safety of coal mine and prevent water disaster, it is necessary to drain the mine water inrush. According to incomplete statistics, in the process of coal mining, in 2004, there were about 3 billion m & sup3 tons of coal with an average water inflow of about 2 m&; sup3。 The utilization rate of resources only accounts for about 22%.

Gas drainage and mine ventilation

Gas drainage before and during coal mining is an important measure to ensure coal mine safety. However, the emission of gas into the atmosphere will have a strong greenhouse effect, and the greenhouse effect of methane contained in gas is 20 times greater than that of carbon dioxide. In addition, in the process of coal mine production, underground tunnels need hundreds of thousands or even millions of cubic meters of air per second, mainly by mine ventilation, which also contains gas and a lot of dust. According to the evaluation and estimation in recent years, the coalbed methane resource in China is 3× 106. In 2002, the output of coalbed methane in national key coal mines was 9773.37, of which the gas utilization was 5 17.49, and the utilization rate was about 5%.

Ecological damage caused by mining

Traditional coal mining ignores the mining, processing and utilization of other biological sources and associated minerals, resulting in a waste of resources. There are more than 20 kinds of minerals associated with coal measures in China, most of which are not used. In addition, the random storage and discarding of minerals will also cause environmental pollution and destroy the ecological environment.

Coal mining destroyed the original mechanical equilibrium of the earth's crust. Lead to surface subsidence, the original ecosystem was destroyed. This kind of destruction reduces or loses the original land income, and also causes the destruction of surface water conservancy facilities and the deterioration of ecological environment. The surface subsidence area caused by mining reaches 400,000 hm2 every year, with an average annual growth rate of 6.5438+500,000 hm2.