Study On The Forecast And Prevention Of Water-Inrush From The Lower-Group Coal Floor In Zhaoguan Coal Mine

The paper analyzed detailedly the water abundance and the water. inrush danger of the Xujiazhuang Limestone and Ordovician Limestone aquifers in the Mining Field aiming at the safe mining of the lower coal seam in Zhaoguan coal mine. The paper made researches on other borehole units-inflow adopting the induction and analysis of the relationship of the units-inflow and the depth by collecting the existing exploration data and geological and hydro geological data of the section; quantized the structure indexes of the mining field using fractal dimension value of the faults, and rationally evaluated the complexity degree of the structure in the section. Synthetically considering all kinds of factors, such as units-inflow, depth, the complexity degree of the structure, leaking drill hole distribution and existing geophysical exploration data, the multivariate and information science compound model was structured and the the water abundance of the Xujiazhuang Limestone and Ordovician Limestone aquifers was forecasted. By analyzing the influencing factors of limestone aquifers'water bursting, the paper generalized the "four factor theory" which affect water-inrush from coal bed floor, they were hydraulic pressure and geological structure, aquifuge thickness and water abundance of aquifer. Based on the water-resisting layer' thickness, lithological association, structure, hydraulic pressure and mining activity, combining the sedimentary characteristics, the watertightness of aquifuge was evaluated. Taking 11 coal seam of Zhaoguan coal mine for example, the paper had quantitative evaluation of factors affecting water inrush from floor by principal component analysis and expert experiences, at the same time, determined the weight of influence factors. They were: geological structure(0.1), hydraulic pressure(0.15), aquifuge thickness (0.25), water abundance(0.5). This paper integrated quantitative and qualitative methods to determine the linear relations of the water-burst from coal floor and the influence factors and forecasted the water inrush danger from the Xujiazhuang Limestone on the exploitation of 11 coal seam. Compares the predicted results of principal component analysis and water irruption coefficient, the former was more suitable to the circumstances. The methods was applied to forecast the water inrush danger of the Xujiazhuang Limestone and Ordovician Limestone aquifers on the exploitation of other lower group coal seam.The evaluation results provided the strong evidence for preventing and controlling the water inrush from coal floor in lower group of coal seams mining and had important theoretical guiding significance to achieve the safety of mining.