| Sijiaying iron ore mine is a large sedimentary metamorphic iron ore deposit.The hydrogeological conditions of the mine area are complex,and the long-term drainage of the underground ore body during the mining process has caused the water level of the aquifer in the mine area to decline year by year.The water flow field has changed from a two-dimensional flow field to a three-dimensional flow field,and the bedrock groundwater has changed from a closed equilibrium state to a non-equilibrium state under the action of strong runoff,and the evolutionary course of groundwater has changed.The amount of underground gushing water increases,the risk coefficient of sudden water increases,and there is a possibility of deterioration to surface water resources.It is important to clarify the evolution of groundwater in the mine area for the prevention and control of mine water hazards and the protection of regional water resources.Firstly,we determined the water chemistry characteristics and formation role of groundwater in the mine area,and analyzed the water chemistry characteristics of each aquifer by using Piper trilinear diagram and mathematical and statistical methods,the Quaternary water is dominated by Ca2+and HCO3-ions,and the bedrock water is dominated by Na+,HCO3-and Cl-ions;we drew and analyzed the conventional ion ratio relationship diagram,and concluded that the main formation role of groundwater in the study area is dissolution filtration and cation exchange and adsorption.Secondly,through stable isotope and geochemical simulation,we analyzed the source ratio and seepage process of groundwater in the mine under mining conditions,and derived the mixing ratio of Quaternary water in bedrock influx,the main reaction minerals and the transfer amount of substances in the process of Quaternary water seepage.Finally,according to the chemical thermodynamics and kinetic theory design water-rock interaction experiment,analyze the influence of the dissolution of the main rock-forming minerals in the surrounding rock on the groundwater components.The results show that mica,quartz and feldspar in black mica metamorphic rocks can dissolve and affect groundwater components;at the initial stage of reaction between Quaternary water and surrounding rocks,the first dissolved components Na+and K+dissolve rapidly and Ca2+decreases,and the reaction rate constants of feldspar at room temperature were measured.Combined with the above research results:mining has changed the local water circulation,the dissolution and filtration,mixing and ion exchange and adsorption in the study area are enhanced,which has a greater impact on the chemical characteristics of groundwater,especially bedrock water.In the"skylight"area,the mixing effect is stronger,and the bedrock water evolves in the direction of increasing alkali metals and decreasing strong acid roots;in the deep hydraulic fracture zone,the solubilization and filtration of silicate minerals make the bedrock water evolve in the direction of increasing alkali metals,which provides a theoretical basis for the environmental evaluation of groundwater in the mine area and the rational development and utilization of groundwater.Figure 49;Table 20;Reference 56... |
