尾矿库堆积过程污染物运移模拟分析

Simulation of Contaminant Transport in Tailings Accumulation Process

以攀西地区安宁河流域某尾矿库为例,在分析库区水文地质条件基础上,利用Stiff图进行了库区地下、地表水水化学组分对比分析,结果表明安宁河旁井水水质受尾矿库影响较大。进一步选取典型剖面,利用Visual MODFLOW软件建立了二维地下水流模型和污染物运移模型,取得了典型剖面的地下水动力场,对现状尾矿库进行时空离散化,将其20a的尾矿堆积过程概化为动态变化的污染源边界,基于水化学分析结果选取氟化物作为模拟因子。根据尾矿库下游井点氟化物浓度的观测数据反演了污染源的污染强度,模拟结果也证明该尾矿库防渗措施不够严密,导致了库下游地下水的污染。

A tailings pond,located in Anning River basin of Panzhihua-Xichuang region,was taken as an example. Based on the hydrogeological conditions analysis,the chemical components of groundwater and surface water were studied by using Stiff diagram. The results showed that the upstream tailings pond greatly affected the water quality of riverside wells. A two-dimensional groundwater flow model and contaminant transport model were built by using Visual MODFLOW. The groundwater flow field of the typical profile was obtained. In addition,the tailings pond was conceptualized as a changing pollution source boundary,both temporal and spatial discretization were carried out to represent the 20-year accumulation process of the tailings pond. Fluoride was chosen as the transport variant for the MT3 DMS model. The concentration of the pollution sources was calibrated,according to the observations of fluoride in the downstream wells. This simulation work also demonstrated that inadequate water-proofing construction resulted in the groundwater contamination.