Assessment of Pollution Potential of Cyanide-Bearing Tailings Dam

This study ascertained the types of chemical species that are formed in tailings material of gold leaching plants and assessed their short and long term pollution potential capabilities. The results revealed that chemical, biochemical and geochemical reactions were occurring in the tailings material; producing complexed cyanides, bicarbonates and nitrates which accumulate with depth in the tailings material while ammonium, carbonate and sulphate ions decreased with depth. Heavy metal accumulation particularly Mn, Pb, Zn Cu, Fe were also observed to increase with depth. It was concluded that the cyanide bearing tailings material has short term pollution potential of free cyanides, ammonium ions, sulphates ions and a long term risk of, complexed cyanide, nitrate and increase in water hardness due to bicarbonate ion. Heavy metal pollution and a decrease in pH are also possible

Some Environmental Issues of Inland Valleys: A Case Study

Inland valleys have complex geo-ecological systems and hence biochemical accumulation of heavy metals in soils is inevitable.Such a situation can affect crop physiology and produce quality. This study was therefore carried out to ascertain the extent of heavy metal accumulation in Anum inland valley which fringed a mining concession at Konongo in Ghana. The study revealed that accumulation of heavy metals particularly iron and lead occurred in soils and crops, a phenomenon that can result in reduction of crop quality and yield from such valleys. The concentration of lead in the rice tissue was between 2 mg/kg and 13 mg/kg while that of iron was between 1400 mg/kg and 4500 mg/kg. The study concluded that inland valleys can be real environmental liability because produce from such valleys can be polluted and hence can be a source of social conflict particularly when they fringe mineral concessions as the adverse impacts could be unfortunately attributed to mining activity and similar land uses. Hence, development of a mine in such areas requires a comprehensive environmental impact assessment to ascertain the environmental quality of the adjoining inland valleys to prevent social conflict with the host community

Studies on Arsenic Release and its Mitigation from Tailings Dam Using Nanomagnetite Particles

Knowledge of the geochemistry of As in tailings material after beneficiation of gold-bearing sulphidic ores is necessary to comprehend the nature, stability and mobilization of As into the geo-environment and its subsequent mitigation during storage. In this study, XRD combined with reflected light microscopy and SEM-EDX were employed to carry out studies on the min-eralogical composition of As in a tailings material. Arsenic-rich solutions were generated from the tailings material using de-ionised water to ascertain As mobilisation. The remediation kinetics of the soluble As was carried out using nanomagnetite (Fe3O4). The XRD and SEM- EDX analyses showed that the major source of As in the tailings material is arsenopyrite (FeAsS). The study further confirmed that the residual As mineral in the tailings material is capable of decomposing during storage and can be subsequently mobilised into the geo-environment. It was established that nanomagnetite can efficiently re-move As from tailings leachates; preferably at pH between 6 and 7 and Langmuir isotherm best described the sorption process while the Gibbs free energy of the sorption was found to be -12.1026 KJ/mol. Thus, nanomagnetite can be used to mitigate arsenic foot-prints from tailings dam

Management of Acid Mine Drainage within a Wetland in the Tarkwa Area

Acid Mine Drainage (AMD) is an environmental phenomenon that is being experienced by some surface mining companies in Ghana. Consequently, there is the need to generate information and expand local expertise base in handling this phenomenon. This work explored the sustainable anaerobic wetland mitigation method for the management of this phenomenon.Results of water analysis showed that the pH at the acidic effluent discharge area is 4.4 but then it increased gradually to pH of 7.5 in the wetland. The study identified a sulphate reducing bacterium (Desulfovibrio desulfuricans) inthe wetland, whose activity produced OH- ions that raised the pH of the acidic effluent resulting in the precipitation of heavy metals like iron, lead and nickel. Consequently, if the natural anaerobic remediation is engineered, the effluent from the AMD can be treated and discharged without causing any significant adverse impact to the geo-environmen