Co-extraction of coal-methane

Co-extraction of coal and methane is a new approach to coal exploitation. The new system integrates the two previously separated operations of coal extraction and gas drainage. Different from gas drainage, the system requires methane drainage to maintain consistently high flow and methane purity which is fit for utilisation. This system not only enhance methane extraction and utilisation as a resource, but also improves coal production and reduces fugitive gas emissions.

In collaboration with Huainan Mining Industry (Group) of China, our research has led to significant findings which effectively support the design and implementation of the co-extraction system. A three-dimensional annular overlying zone (AOZ) about a longwall goaf, figure below, was identified as the “sweet spot” for longwall methane drainage to meet the requirements of consistently high flow rate with high methane purity.

A further project of the Asia-Pacific Partnership has successfully demonstrated the AOZ as a practical approach for planning and designing the coal-methane co-extraction system at Huainan Pansan mine. The application has led to increased methane capture and use, reduced coal and gas outburst risks, and reduced fugitive methane emissions.

The annular overlying methane drainage zone for the co-extraction system