Study On Mining With Water Pressure Of Wannian Mine In Fengfeng Coalfield

In China the coal mines suffer serious hazards from the Ordovician limestone high pressure water, only in North China 40 percent of the coal resources can not be normally mined for that. In order to exploit coal resources safely, and protect the karst water resources, carrying out the study on mining with pressure has important theoretical and practical significance.Combining with the hydro-geological conditions of Wannian mine, the paper's primary work is generalized as follow:(1) Use the hydro-geochemical method to analyze the water chemistry composition background value of the main ions in aquifers, according the water chemistry background values to analyze the inrush water origin of the level -240m in North Lane of Wannian mine.(2) Use fracture mechanics and elastic-plastic mechanics to set up mechanical models of motherboard, derive the formulas on the motherboard largest destruction depth and the limit pressure of water inrush on the condition of mining. In Wannian mine, the motherboard largest destruction depth is 2.2-20.2m, the limit pressure of water inrush at normal exploitation is 0.95-53.1MPa, when encountering faults is 0.95- 17.3MPa.(3) Advance one new method-the limit water inrush coefficient method to distinguish water inrush. Actual results show that: normal exploitation of 2#, 4#, 6#, 7# coal seams will not happen Ordovician limestone water inrush, 8#, 9# coal seams will happen Ordovician limestone water inrush; When encountering faults, all 2# coal seam, 4# and 6# shallow coal seam will not happen Ordovician limestone water inrush, 4# and 6# deep coal seam, 7#, 8# and 9# coal seams will happen Ordovician limestone water inrush.(4) On the base of 140 bores data of Wannian mine, respectively use water inrush coefficient method, "below three zones" theory method and limit water inrush coefficient method, to carry out water inrush prediction and division on 2#, 4#, 6#, 9# coal seam, predicted results as follows: southwestern is security zone, center is danger zone, northeastern is high-danger zone. Limit water inrush coefficient method considered more factors, predicted results accord with the fact much more.(5) To the 9# coal seam threatened most seriously by the Ordovician limestone water, use the limit water inrush coefficient to determine the hydraulic pressure value when mining with pressure, according to the water balance principle, if appropriately mining with pressure can effectively protect the groundwater resources about 470.8×10~4m~3-828×10~4 m~3.