Assessing the Impact of an Operating Tailings Storage Facility on Catchment Surface and Groundwater Quality: A Case Study of Adamus Resources Limited (Nzema Gold Mine) 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, Western 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 500m 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. Structured questionnaires were also administered to one hundred and twenty inhabitants living close to the TSF to solicit their opinion regarding the impact of the facility (TSF) on water quality in the communities out of which one hundred people responded. Results obtained from the analysis of water samples from the TSF-DW indicated that pH values range from 7.4 – 8.9 (mean 8.2), EC 1340 – 1630 μS/cm ( mean 1507.1 μS/cm), TSS 19 – 105 mg/l (mean 55.3 mg/l), arsenic 0.17 - 5 mg/l (mean 1.26 mg/l), cadmium 0.0001- 0.0004 mg/l (mean 0.0002 mg/l), copper 0.058 - 0.35 mg/l (mean 0.15 mg/l), mercury <0.0001 - 0.0002 mg/l ( mean 0.002 mg/l), Weak Acid Dissociable (WAD) cyanide <0.005 - 1.04 mg/l (mean 1.04 mg/l), total cyanide <0.0005 - 1.55 mg/l (mean 0.59 mg/l) and free cyanide <0.005 - 1.04 mg/l (mean 0.38 mg/l). pH values of surface water samples collected ranged from 6.3 -7.3 (mean 6.7), EC 55.5 – 185.7 μS/cm (mean 116.8), TSS 10.7- 990 mg/l (mean 230 mg/l), arsenic 0.001- 0.021 mg/l (mean 0.021 mg/l), copper The study assessed the impact of an operating Tailings Storage Facility (TSF) of Adamus Resources Limited (Nzema Gold Mine) in the Ellembele District, Western 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 500m 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. Structured questionnaires were also administered to one hundred and twenty inhabitants living close to the TSF to solicit their opinion regarding the impact of the facility (TSF) on water quality in the communities out of which one hundred people responded. Results obtained from the analysis of water samples from the TSF-DW indicated that pH values range from 7.4 – 8.9 (mean 8.2), EC 1340 – 1630 μS/cm ( mean 1507.1 μS/cm), TSS 19 – 105 mg/l (mean 55.3 mg/l), arsenic 0.17 - 5 mg/l (mean 1.26 mg/l), cadmium 0.0001- 0.0004 mg/l (mean 0.0002 mg/l), copper 0.058 - 0.35 mg/l (mean 0.15 mg/l), mercury <0.0001 - 0.0002 mg/l ( mean 0.002 mg/l), Weak Acid Dissociable (WAD) cyanide <0.005 - 1.04 mg/l (mean 1.04 mg/l), total cyanide <0.0005 - 1.55 mg/l (mean 0.59 mg/l) and free cyanide <0.005 - 1.04 mg/l (mean 0.38 mg/l). pH values of surface water samples collected ranged from 6.3 -7.3 (mean 6.7), EC 55.5 – 185.7 μS/cm (mean 116.8), TSS 10.7- 990 mg/l (mean 230 mg/l), arsenic 0.001- 0.021 mg/l (mean 0.021 mg/l), copper mining industry’s best practices by ARL with regards to TSF management could also be a contributing factor to the quality of water bodies in close proximity to the facility. However, inhabitants living close to the TSF believe their water quality has been impacted adversely by the facility with five percent (5%) of the respondents relating the impact to smell, 78% to colour and 17% to odour.