China’s Emission Standard of Coalbed Methane/Coal Mine Gas is the nation’s first regulation that directly regulates methane emission. Although labelled as a “trial”, it has been effective and enforced since 1 July 2008 and will likely be updated as a result of the 14 Five-year Plan (2021-2025). It has set specific technological, equipment, permitting, and monitoring requirements for mine gas and coalbed methane emissions.
The standard obligates coal mines to set up permanent surface gas drainage works or underground mobile pump station drainage works if one of these three conditions listed is met:
- The gas emission rate from one coal face is greater than 5 m3 /min or gas outflow from a tunnel face is greater than 3 m3 /min, when ventilation fails to effectively mitigate the emissions;
- The absolute gas emission rate of the mine meets the thresholds listed in the standard;
- The coal seam has potential coal/rock and gas outburst dangers.
In addition, if the drainage volume of the gas drainage system is over 2 m3/min continuously and is expected to function for over 5 years, a permanent surface gas drainage works is required to be built.
Lastly, the input pipeline of the mine gas drainage pumping station and the output pipeline of the gas storage tank output pipeline should be equipped with sensors to monitor the methane concentration, flow, pressure, temperature, and other parameters. Methane sensors should also be installed in the pumping station to prevent gas leakage.