Assessing the Impact of an Operating Tailings Storage Facility on Catchment Surface and Groundwater Quality in the Ellembele District of the Western Region of Ghana

Abstract

The study assessed the impact of an operating Tailings Storage Facility (TSF) of Adamus Resources Limited (Nzema Gold Mine) in the Ellembele District of the Western of Ghana on catchment surface and groundwater quality. Water samples were collected between June and December 2014 from seventeen (17) sampling sites including the TSF decant water (TSF-DW), three (3) streams, a water storage dam, a pond and eleven (11) groundwater monitoring boreholes within 500 m radius of the mine’s Tailings Storage Facility. Samples were analyzed for pH, true colour, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), biological oxygen demand (BOD), dissolved metals (arsenic, cadmium, copper, mercury) and cyanide (weak acid dissociable cyanide (WAD), free cyanide and total cyanide) using standard procedures. The TSF-DW reported elevated arsenic, free cyanide and TSS concentrations above GHEPA guideline for effluent discharge. Elevated TSS and arsenic concentrations above GHEPA limits were reported in PWSD which is a pond uphill of the TSF and a receptor to effluents from illegal mining sites on the mine’s concession. All other parameters recorded in surface and groundwater bodies studied were within WHO guideline limit for potable water. Results of the study suggest that the quality of surface and groundwater around the TSF has not been adversely affected even though the TSF is contaminated. Study findings suggest that well-engineered tailings dam ofARLwith its effective liner and management systems may have provided a safe structure and prevented contamination of water resources within its catchment.