From April 10 to 12, China Coal Technology & Engineering Group's Xi’an Research Institute showcased its cutting-edge coal mine CBM (gas) coordinated surface-underground extraction technology at the 3rd China (Xi’an) International Mining Equipment and Technology Expo. The innovation offers solid support for mine safety, ensuring comprehensive gas drainage coverage without blind spots.

The coordinated CBM extraction technology system integrates several core techniques, including: horizontal well staged fracturing in coal seams (or roof layers), combined surface-underground directional long-borehole staged fracturing, pneumatic directional drilling with “dual destress” via a single borehole, multi-seam horizontal well co-extraction for deep CBM, surface L-shaped mining-induced horizontal wells, and large-diameter high-level boreholes for underground coal mines.

This advanced system enables efficient gas extraction from both original structure coal and friable soft coal seams. By leveraging pressure relief and permeability enhancement during coal mining, along with extended horizontal bore segments, the method maximizes extraction efficiency. It effectively overcomes extraction challenges caused by constraints of underground conditions and surface geology, and addresses gas control issues in mined-out areas and advance roadways in soft coal seams. It significantly enhances multi-seam deep CBM co-extraction efficiency and overall resource utilization.

Reportedly, this technology has been demonstrated at more than 40 coal mines nationwide, with over 100 wells drilled. It pioneered the successful formation of large-diameter L-shaped mining-induced wells in China and repeatedly set industry records for single-well daily and cumulative gas output in soft coal seam horizontal wells. It has also broken several national records in deep CBM horizontal drilling, generating remarkable economic and social benefits. The technology serves as a benchmark for high-efficiency CBM extraction and regional mine gas management across China.