Effect Of Water Mine Drainage On Surface Runoff In Hilly Area Of South Lujiang County

It is the place southern Lujiang that is an ore-centralization area main of iron ore and the mining depth is usually -300～-1000m in Anhui province, which in the subtropical humid monsoon climate zone, the average rainfall of previous years is 1157.6mm. The landscape belongs to the low hilly land and the river system is well-drained. Cenozoic loose bed thickness is about 5m which develop long the gully and valley, and the bedrock weathering crust development is deep which generally less than 10 m.As the development and utilization of mineral resources in support of economic and social development, a lot of influence on the formation of water resources and water environment. The underground mining engineering construction and operation process would inevitably produce a large number of mine water and the source of water-full is bedrock fissure water in the ore body of surrounding rock from cenozoic loose bed and bedrock weathering crust. The influence of surface water resources on mining is mainly characterized by a wide range and multiple projects that changed horizontal flow to vertical flow because of mining for a long time. Large amounts of groundwater are discharged during underground mining operations, which result in the drawdown of groundwater, known as aquifer dewatering in mining areas. The aquifers storage capacity is reduced above the deposit and the surface water will recharge phreatic aquifer while the mine is draining.Taking an example of two contiguous large iron ore, establish of hydrogeology conceptual model of mines according to the exploration of the existing achievements. Using the numerical simulation method, the above mentioned problems are given detailed analysis in the case study of a mine lied in Lujiang county of Anhui province. According to the mine development and utilization scheme, the mine water yield calculated using the numerical simulation software named MODFLOW established numerical simulation model and the mine inflow of water is 12240 m3/d to 4400m3/d during the twenty-four years of mining. The area having obvious groundwater level drawdown caused by the mine drainage is about 68.90km2. Besides, the coefficients of rainfall infiltration increased 14.4% and the surface runoff reduction is 186.6×104 m3/a.It not only has a certain theoretical significance but also has a direct application value on protecting mine environmental and constructing a harmonious society based on impact prediction, evaluation and remedial action scheme.