川北高台原区废弃煤矿枯水期矿井涌水水化学特征及成因分析

Chemical Characteristics and Cause Analysis of Mine Water Gushing During dry Season of Abandoned Coal Mines in Gaotaiyuan Area,North Sichuan

对废弃煤矿矿井涌水的水化学特征及成因进行分析,可为保护矿区地下水环境提供理论支撑。基于地质背景,通过对比枯水季节川北高台原区废弃煤矿矿井涌水与背景泉点水化学指标,并采用聚类分析方法对矿井涌水中离子指标进行统计,进而对其特征及成因进行了研究。结果表明:地层中黄铁矿中硫元素氧化是矿井涌水水化学特征变化的开端,受研究区矿井涌水补给范围小,地下水短途径流等条件的控制,最终形成了铁质硫酸型水。低pH值的矿井涌水与围岩发生水岩反应,进一步改变其水化学特征,使其富集砷、镉、铜、锰、铅、硒、锌等微量元素。

The analysis of hydrochemical characteristics and causes of water gushing in abandoned coal mines can provide theoretical support for the protection of underground water environment in mining areas.In this study,based on geophysical background,by comparing the chemical indexes of the mine gushing water and the background spring point water of the abandoned coal mine in Gaitaiyuan area of north Sichuan during the dry season,and using the cluster analysis method,the ion indexes of the mine gushing water were counted,and then the characteristics and causes of the mine gushing water were studied.The results showed that the oxidation of sulfur in the pyrite in the stratum is the beginning of the change of the chemical characteristics of the mine gushing water,and the iron-sulfuric acid water is finally formed due to the limitation of small recharge range of mine gushing water and short-distance runofF of groundwater in the study area.Mine water with low pH value reacts with surrounding rock,which further changes its hydrochemical characteristics and enriches trace elements such as arsenic,cadmium,copper,manganese,lead,selenium,and zinc in the mine drainage.