Groundwater Flow Modeling in the Vicinity of a Metallurgical rocessing Plant in the D.R.Congo

摘要

This paper presents the methodological approach used and the results obtained in an attempt to estimate the steady state conditions for groundwater flow in the vicinity of a metallurgical plant where waste dumps/ore heaps are seen,in the Katanga province,Democratic Republic Kongo.Modelling was performed using the finite difference code of Visual Modflow and the modeled area,which included 4 layers,was 7km×7km on a 100m×100m grid.Data were mainly derived from available topographic and geological maps,as well as borehole sections. Permeability data were extracted from pumping tests and/or the literature. Furthermore,the permeability values applied for all units were higher by one order of magnitude than the ones calculated in order to investigate the worst possible scenario.In the unconfined or partially unconfined aquifers(as in this case),the specific yield is considered almost equal to the effective porosity of the formation. Annual precipitation data were used in conjunction with monthly variations to extract monthly precipitation data. The paper focuses on the solutions regarding the steady state model,which was solved for a period of 10 years.Boundary conditions included two major watering wells on the Kimilolo River providing water for the city of Lubumbashi.Results are presented as groundwater flow lines and contours atvirtual observation points at the aquifer starting from the plant area.