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 current coal mine regulations in many countries, methane must be controlled at the working faces and at other points in the mine. A well-designed ventilation system performed it long time. Because of higher productivity and higher methane content towards deeper coal seams this task became more difficult in modern coal mines. So a CMM extracting system was developed the depending on 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. 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. Mostly higher concentration must have a special permission by the coal authority.
