The Study Of Groundwater Chemical Environment In GuYuan Salt Mining Area, The South Of NingXia

Guyuan salt mining area has rich mineral reserves with good prospects for development. Development and utilization of the rich mineral resources is of great significance. The presence of mineral resources seriously affects the groundwater quality distribution and chemical characteristics, the development of the mineral resources will impact the groundwater. Therefore, the study of the groundwater chemical environment has a positive effect for the rational development of rock salt and the protection of groundwater.This paper respectively takes Qingshui river plain groundwater, rock salt mining area groundwater and section groundwater of mining area to plain for research examples. First, the author divides Qingshui river plain groundwater into several chemical types, and the same with the salinity distribution. Besides, the author assesses the quality of groundwater along with the conversion relationship between surface water and groundwater. And then, the author focuses on the instruction of the typical ion’s (such as SO42-, Cland F-) distribution characteristics and its influence factors. Second, the author emphasizes the research on rock salt mining area groundwater chemical distribution, in addition of the formation mechanism of the high mineralization springs and the influence of groundwater quality. Finally, the author applies two-dimensional groundwater numerical simulation technique to simulate the groundwater flow in the profile, uses the water cycle theory and hydrogeochemical modeling method to study the groundwater circulation characteristics, analyzes groundwater chemical processes and water-rock interaction forms of different flow paths in the profile. The integrated use of multi-disciplinary theoretical approaches, such as the ancient depositional environment and the rock strata geochemistry, from qualitative analysis to quantitative analysis clarify the effect of the rock strata on the groundwater quality. The study finds that along the direction of groundwater flow in the mining area, the groundwater flow velocity decreases close to the Lijun fault, while the total dissolved solids of groundwater increases. The total dissolved solids of the uplifted springs which lie in the fault contact zone are up to 13.2～40.2g/L. The formation of this highly mineralized spings is closely related to the growth of groundwater residence time near the fault.After the research of water chemical simulation about the three water paths based on the PHREEQC, the study finds that, the main factors controlling the groundwater chemical evolution are the supply of bedrock fissure water from mountains, the dissolution or precipitation of the rock salt, gypsum, silicate, and aluminum silicate, besides the ion exchange of the runoff area, along with the mixing action of the quaternary pore water. Comparison of groundwater flow and groundwater chemistry, we find that the selection of groundwater flow path from the results of numerical simulation of groundwater flow based on the typical section is more accurate and more fully than the directly selection from the water line map. Groundwater of different causes generally has different scale factors on certain ions. In this artile, we do analysis by these scale factors (rNa+/rCl-, rCl-/rCa2+, rCl-/rHCO3-,rSO42-/rHCO3-) combining with the simulation results of hydrogeochemistry, finally respectively confirm the groundwater chemical causes and formation role of Quaternary groundwater, Tertiary groundwater and Cretaceous groundwater.Through analysis of corresponding relationship between regional strata sedimentary environment and groundwater quality, the author finds that the tertiary strata makes a big impact on the tertiary groundwater quality, the cretaceous groundwater from the influence of tertiary groundwater, the influence of tertiary strata on the quaternary groundwater occurs mainly in the contact surface.