Underground CMM extracting system
Underground CMM extracting systems are installed in digging areas where the gas release during mining is so enormous that the methane content in the ventilation air can reach more than 1%.
Under the current coal mine regulations in many countries, methane must be controlled during the working places and at other points in the mine. This hd been executed long using a well-designed ventilation system. Due to higher productivity and higher methane content towards deeper coal seams, this task has become more difficult in modern coal mines. Consequently, a CMM extracting system was developed tailored to the local conditions. One of these methods is an underground pipeline grid to suck the gas to the surface by a central degassing station.
The gas is extracted from the surrounding area of the coal layer, while the boreholes are connected to the degassing pipe. This pipe leads the gas through a shaft to the central degassing station on the surface.
For more information visit * http://www.epa.gov/cmop/resources/drain_degas.html
Gas which is released and not collected by the borehole of the extracting system flows into the ventilation air. The methane is transported to the ventilation shaft. The concentration of methane has to be less than 1 % everywhere. In most cases, higher concentration requires have a special permission issued by the coal authority.
