Prediction Study Of Hydro Geological Condition And Mine Water Inflow In Radish Mountain’s Lead-zinc Mining Area Which Located In Pu-er City,Yunnan Province

With an exploitation history of 40-old years, lead-zinc mine of Radish Mountain has been mined to the lowest erosion basis of river. However, a professional hydrogeological survey has not been carried out yet. It’s a typical karstic water-filing mine characterized with corroded fissure. As we are uncertain of the development law of karst and the burial condition of water-filing fissure, the hydrogeological condition of deep mining area has been changed greatly after many years’exploitation. Deep mining will change hydrogeological condition and ground-water seepage field. As mining goes deeper, water inflow will be on the rise, especially at the faults and joints that connect to surface water. In future, the middle section of deep mining area is located below erosion basis, so water inflow of mine will become a primary factor that gets in the way of deep mining. It’s significant to conduct a study on hydrogeololgical condition and water inflow of mine in a bid to ensure the safety of deep mining at the middle section.By analyzing the existing data on the hydrogeololgcial condition of the mining area as well as carrying out an in-depth survey on the mining area on both dry season and wet season, find out the hydrogeololgical condition and groundwater motion characteristics of the mining area, carve out hydrogeololgical unit reasonably, and use GMS (Groundwater Modeling System) to simulate the change characteristics of groundwater seepage field and the change of waterline. Meanwhile, under current and future mining conditions, use the modflow whose parameter has been adjusted to simulate the water inflow of the middle section at different depths as well as seepage field change in different periods. The study obtains the following conclusions:1 Main water resisting layer of the lead-zinc of Radish Hill is J2h, P21,which formed the water partition boundary of the two sides of the East and west sides of the mining area mainly containing water Pi1 and pi2. The Pi’for ore bearing strata constitute deposit water filling, corroded fissure karst deposit area filling with water.Two aquifers are stable, and there is no aquifer between them, which will directly form the roof and bottom plate of the deposit.2 Rainfall intensity, surface water distribution, karst fissure development, filling materials of tectono-fracture zone, stratum attitude, and topographic condition produce primary impacts on deposit water filling. Due to high altitude, steep slope, surface gully, and small catchment area, the mining area is only fed by limited rainfall and surface runoffs. Though seasonal surface runoffs will seep into the ground along valley, most runoffs discharge to Puer River and Simao River; surface water below corrosion basis produces some influences on deposit water filling; tectono-fracture zone and karsst fissure, the main channels of groundwater seepage, control the change of groundwater seepage field.3 Above the elevation of 1000m of lead-zinc mine of radish mountain is elevation only accept the recharge of atmospheric and mine inflow of water can be discharged naturally, a simple hydrogeological conditions of ore deposit, under the 1000m elevation of lead-zinc deposit is elevation which does not accept the rainfall recharge, receive surface water supplya and a medium complex ore deposit which belongs to the hydrogeological condition.4 To the area for a period of one year dynamic observation of groundwater, the observation results show that, above 1000m elevation mine poured water sources in atmospheric rainfall and aquifer static reserve,1000m elevation below mine poured water sources in atmospheric precipitation, surface water and aquifer static reserves. But the main or to consume the aquifer static reserves is the main, by the seasonal effect is more obvious, wet season water inflow increased significantly.5 Under current and future mining conditions, study water inflow as well as the change of groundwater seepage field in different periods through applying the modflow whose measured borehole water level is checked. The results show that groundwater seepage field, with drainage time being prolonged, forms a deeper depression cone at the middle section of deep mining area to cause that water inflow in some pits drains away as a result of limited water supply.