Method of extracting gas in coal mining and extraction pipe for carrying out the method

摘要

According to a method of extracting gas in coal mining by means of an extraction pipe strung together from several pipe sections, plastic deposits are formed in some of the pipe sections. The plastic deposits can be activated by remote control for foaming the annular space between the extraction pipe and the borehole wall. Selective foaming operations along the extraction pipe are thus possible as required or else full foaming over a hitherto unattainable length. The plastic deposit is accommodated as a cartridge filled with plastic and propellant gas in the interior of the extraction pipe. The cartridge filling discharges into the annular space via a line after the opening of a valve by means of a cable led out of the bottom end of the extraction pipe or after the opening of a valve remote controlled by means of compressed air. If need be, the cartridges including the associated valves and partly the lines can be removed from the interior of the extraction pipe after the foaming. IMAGE