Methane drainage and utilization in coal mines with strong coal and gas outburst dangers: A case study in Luling mine, China

• Methods and effects of gas drainage and use are examined.
• Improvements on gas drainage and use are proposed.
• Projections for methane drainage and use are made.
• Gas drainage rate is projected to be greater than 75% and 80% of it is to be used by 2018.

Outbursts are sudden and violent release of coal and gas from a coal face, which can result in damage to excavations and equipment, loss of life. The Luling coal mine exploits the Nos. 8 and 9 seams, both of which are highly outburst-prone. The maximum gas pressure and gas content measured in these seams are 5.5 MPa and 25.0 m3/t, respectively, and several large-scale gas outburst accidents have occurred there. In this study, methane drainage and utilization at the mine is examined. Based on our analysis, several improvements, such as protective seam mining, drainage system upgrades and the use of medium-quality methane by local industry, are directed. In the coming years, the volumes of drained methane and utilization methane are projected to reach 70 and 58 million m3 per year, respectively, thus accounting for more than 75% and 60% of the mine's methane emissions, respectively. Important lessons learned at the Luling mine could be applied to other outburst-prone coal mines in China and elsewhere.