System for Prevention and Control of Old Goaf Water during Coal Mine Re-mining
Abstract One integrated mine was currently threatened with an old goaf water disaster, therefore, the development of an advanced detection-guarantee system for roadway excavation with no blind area was imperative. Further, multiple geophysical exploration in combination with two types of boreholes were used to explore and drain water technology, with the anomalous geophysical area as the target area, The conventional borehole with the largest water outflow was taken as the target spot, at a low elevation of the mining area, and a remote directional borehole was used to drill into the old goaf along the stable rock strata below the coal seam floor to intercept the dynamic recharge water, which increased the efficiency of roadway excavation 4–9 times. The ‘isolated island’ old goaf water in the mining face was controlled through multiple geophysical exploration combined with the full-coverage exploration technology by conventional boreholes, and the water-rich anomalous area and geological anomalous area were determined, thus ensuring the safety of the mining face in terms of old goaf water. The technology for advanced short-distance exploration, advanced estimate, roadway exploration, and dynamic old goaf water with drainage was used to comprehensively guarantee real-time, safe mining. This system for the prevention and control of old goaf water was applied to a control project for the old goaf water disaster in the 101 mining face. At present, 1.37 Mt of coal has been safely mined from this mining face. The technical system has improved The Detailed Rules for Water Disaster Prevention and Control of Coal Mine (NCMSA 2018), and improved the technology for the prevention and control of old goaf water under conditions where the upper portion in the same coal seam was destroyed by a small-scale coal mine and re-mining.