Case Studies of Comprehensive Gas Control Method during Fully Mechanized Caving of Low-Permeability Ultrathick Coal Seams

Slicing fully mechanized caving mining is a standard high-efficiency method for ultrathick coal seams. However, the effectiveness of gas control has accentuated difficulty in top low-permeability This study focused on No. 9-15 Liuhuanggou Coal Mine, Xinjiang Province, China. To this aim, results theoretical analyses and field tests were combined to explore comprehensive The (9-15)06 panel was top-slicing with height 9 m. Gas analysis revealed that emissions are mainly sourced from wall, coal, goaf, neighboring Based source separation, proposed. proposed based combination predrainage alongside seam, high-position drilling top, preburial pipes pressure-balancing ventilation. permeability enhanced by hydraulic fracturing According characterizations seam crustal stress distribution, arrangement boreholes backward-segmented technology designed. From results, presented remarkable prefracturing under fracturing. Besides, mean four times compared prehydraulic state. Finally, using sources, performed panel. measured demonstrated concentration return airflow fluctuated within range 0.05% 0.35%. can provide an insightful reference other similar projects.