An integrated technology for gas control and green mining in deep mines based on ultra-thin seam mining

With the increasing demand for coal resources, coal mining has gradually entered into the deep strata of coal seams. Although the increase in mining depth improves energy security, it is associated with severe hazards, especially coal and gas outburst. Protective seam mining is an efficient method for gas control and has been widely used in major coal-producing countries. However, studies on deep ultra-thin protective seam ( thickness 0.1-1 m, average thickness 0.5 m) mining and its related problems have been rarely reported. Focusing on the challenges resulting from deep mining ( mining depth >1100 m) and the research gap, a coal and gas co-exploitation technique, which combines the gas control technology and green mining ( including coal preparation and backfilling), has been proposed in this work. Significant benefits have been achieved in the twelfth coal mine of the Pingdingshan coalfield ( study area) following the implementation of this technique. The application of the gas control technology markedly improved the gas drainage efficiency, promoted increased gas utilization, and reduced the greenhouse gas emission, providing notable economic and environmental benefits. In addition, implementation of green mining improved the coal quality, relieved the burden of the transport system, and, in particular, effectively prevented surface subsidence, thus protecting the ecological environment of the mining area, which offered significant economic, environmental, and social benefits. The practice in the twelfth coal mine could be used as a valuable example for coal mines with similar geological conditions.