Study On Hydrogeochemical Of Characteristics And Water Source Discrimination Of Mine With Complex Multi-aquifer

The hydrogeological conditions of coal mines in our country are complex,and frequent water hazard accidents have seriously affected the safe and efficient production of mines.Mine water inrush accidents not only reduce production efficiency,increase drainage costs and cause economic losses,but also seriously affect the life safety of mine production personnel.Quickly and accurately identifying the source of mine water inrush is of great practical significance for mine water prevention and control.The Xinji NO.2 mining area is located in the southern part of the Huainan coal field.The geology of the mining area has both the general characteristics of a North China type coal deposit and the thrust and nappe structural characteristics,making the mine hydrogeological conditions more complicated.This thesis mainly uses Xinji No.2 Mine as the main research object.In this paper,183Cenozoic loose layer water,nappe gneiss water,nappe Cambrian limestone water,Permian Sandstone water,Carboniferous Taiyuan formation limestone water,Ordovician limestone water are collected and used to build a model for single multi-aquifer water samples.Two Cenozoic loose layer water samples,five Permian Sandstone water samples,and six Carboniferous Taiyuan formation limestone water samples in a single aquifer were used to test the application effect of the discriminant model;Sort out 76 and collect 5 mixed water samples from the mine goaf to analyze the mixed source and composition ratio of mixed water.Aiming at the problem of discriminating water sources of single aquifers such as Cenozoic loose layer water,nappe gneiss water,nappe Cambrian limestone water,Permian Sandstone water,Carboniferous Taiyuan formation limestone water,Ordovician limestone water,analysis of its content characteristics,hydrochemical characteristics,analysis of main hydrogeochemical effects,trace elements and isotopes are conducted.On the basis of conventional water chemical analysis,a comprehensive step-by-step discriminant method is proposed.The main research results of the paper are as follows:?1?The water chemistry type of Cambrian limestone water is mainly HCO₃-Ca·Na type,and a few exist HCO₃-Ca type,and it is significantly lower in TDS,Na⁺and Cl^-content than other aquifers.The water chemistry types of Ordovician limestone water are all Cl-Na types,which are significantly higher in TDS,Na⁺and Cl^-content than other aquifers.The anions of nappe gneiss water,nappe Cambrian limestone water,Permian Sandstone water,Carboniferous Taiyuan formation limestone water are mainly Cl^-,HCO₃^-,and cations are mainly Na⁺.The nappe gneiss water,nappe Cambrian limestone water,Permian Sandstone water,Carboniferous Taiyuan formation limestone water cannot be completely distinguished in terms of various index contents.The water chemistry types are mostly Cl·HCO₃-Na type,and a few are Cl-Na,HCO₃·Cl-Na.Generally,in terms of various index contents,nappe gneiss water and nappe Cambrian limestone water are similar,and Permian Sandstone water and Carboniferous Taiyuan formation limestone water are similar.?2?A comprehensive step-by-step discriminant model of water source discrimination for multiple water layers in Xinji No.2 Mine was established by using characteristic ion comparison method and Fisher discriminant method,and different methods were adopted for different aquifers.The paper is simple first and then complex,and gradually identify the type of water source.This model is used to discriminate the water sources of 6 aquifers in Xinji No.2 Mine,and the discriminant effect test is carried out by using the modeling sample back-generation estimation method and the application of new samples.The results show that the established model has a higher overall accuracy,especially Cenozoic loose layer water,nappe gneiss water,nappe Cambrian limestone water and Ordovician limestone water.With regard to Permian Sandstone water and Carboniferous Taiyuan formation limestone water,further discrimination with rare earth elements and isotope indicators will improve the discrimination effect of their.?3?By conserving the chloride ion and its isotope method in the mine goaf water,and calculating the contribution ratio of a single water source in the mine goaf water of Xinji No.2 Mine,it can be obtained that the mine goaf water is generally composed of Permian Sandstone water and Carboniferous Taiyuan formation limestone water.The result of principal component analysis shows that the mixing ratio of Permian Sandstone water,Carboniferous Taiyuan formation limestone water is between 0.63:0.37 to 0.81:0.19.