Lead And Zinc Mines Of Water Inflow In Mengxing Numerical Simulation

Since been building in 1958, MENGXING lead-zinc mine has gradually expand after several technical innovation. So far, a total of four Tunnels:1020,860,860-Ⅱand 795 have been opened up, some transportation roadway and inclined have been dug to carry out large-scale mining exploration work. Now they are mining in the 580 center-sections, and excavating direct towords 550 center-sections, water inflow in most of the center-sections at different mining elevation of the current production tunnel, especially in 795 center-sections located on north of the 88 line, it's water inflow reaches at 4294m3/d, and the water yield increased as the depth of mining. According to the latest exploration results, there are mineralized bodys (ore) with seam-bit extension below to 200 meters deep. Therefore, in the future the mining depth of deposit will be lower than 200 meters elevation and more than 800m to the vertical height difference between the surface elevation,so water inflow will be the the main factors constrained deep mining.To ensure the security of future mining activities in the deep deposits, it is great significance to do a detailed hydrogeological investigation and research, as well as numerical simulation of the deep mine water inflow forecasting.This study is to investigate the hydrogeological of the mine area by wet and dry seasons, we obtained a large number of hydrogeological information and observational data, analysed the mining hydrogeological features in-depth based on the previous research, understood the hydrogeological conditions of the mining area comprehensively, in addition, the aquifer group and hydrogeological unit have been divided reasonably, the hydrogeological type of deposits and the main source of water filling have been further confirmed. Besides this, we analysis the groundwater chemical composition of mining area systematically, identified the recharge, runoff and discharge conditions of groundwater in the mining area. Based on systematic analysis the hydrogeological conditions of hydrogeological unit in the mining area, we generalized the hydrogeological conceptual model of groundwater in the mining area and established a mathematical model for the simulation area. Finally, we built the three-dimensional finite difference mesh model of groundwater in mining area with GMS, using the Modflow Module computing and simulation seepage field features variation of groundwater under different mining conditions in the area, and analyzes the sensitivity of various hydrogeological parameters to the simulation models. The study obtained the following understanding:1. Permeability coefficient, water storage coefficient, tailings leakage is the important factor of water inflow at deep mining condition in the future.2. The mainly factors that affect the deposits water-filled are atmosphere precipitation intensity, degree of crack development, stratigraphic occurrence, Tailings Reservoir, and terrain conditions. Terrain height and the steep of terrain slope determines the size of surface water recharge on the deposits water filling; atmospheric precipitation is the main recharge source for sap groundwater; structural cracks and fissures between layers is the main Channels of groundwater flow, and it controls the variation of groundwater seepage field; while deposit mine dewatering pumping is a major drainage way in deep groundwater discharge.3. The results show that consuming groundwater static reserves is the main way in mine deep mining in the future, but with the depth of exploitation deeper, the lever of groundwater head become higher, hydrostatic pressure is also growing, moreover, which might cause short-term water flush and water inrush phenomenon in the exposing rich water segment that the deep structure is complicated, the distribution of rich water segment of the fractured aquifer is extremely uneven.4. Appling the corrected Modflow numerical simulation model to simulation seepage field features variation of groundwater under different mining water inflow conditions of the area, The results showed that:with the pumping and drainage of exploitation time prolonged, the seepage field of deep exploitation center-sections which have expose the aquifers will formation a deep landing funnel.For the less water abundance aquifer, the water inflow of some part of the tunnel will gradually have been dewatering due to limited sources of supply.