Mining operations generally produce lots of wastes, includingmine tailings, waste rock and assay crucibles. Tailings in particular act as amajor source of environmental contamination (Rouselet al, 2000). As a result, heavy metals may be solubilized as a result ofinadequate oxidation of the ore when there is continual bacteria action on thetailings(Jeng et al, 2005). Apartfrom this, flood damages and ground subsidence for example, have occurred atthe Obuasi mine several times due to unequipped, dilapidated facility forprevention of the damage. For instance, in 2005, incidents of tailings spillagedue to old dilapidated dams, each of which resulted in serious environmentalissues in Obuasi has been experienced and recorded (Bempah et al, 2013).
Such spillage can cause reduced productionlevels of farm produce (fear of farming on such lands due to contamination fromthe tailings) and reddish colour of vegetation in the area as well as thenature of some portions of the land could be affected (Kumi-Boateng, 2007). This problem of tailings disposal requires scientific andsystematical approach in reviewing the whole disposal of BIOX slurry totailings dam. The major problem with the discharge of the waste from thistechnology is the likelihood of some of the heavy metals leaching out to joinunderground water when there is dam breakdown or overflow. Un-oxidizedsulphides may be discharged which can result in continual oxidation, decreasingthe pH in the tailings environment with time.
Since the entire BIOX processoccurs at low pH, other heavy metals such as arsenic, iron, copper, cadmium,lead and zinc which are pushed to the tailings dam after neutralization may bemobilized and readily available in solution. Hence there is the need to look atthe stability of these metals in the tailings under different environmentalconditions. It is hoped that the understanding gained will help in theformulation of strategies, which will help to improve the discharge of tailingsfrom the BIOX process.
In this study, totalconcentrations of As and other selected heavy metals in mine tailings from thetailings dam of the Sansu Sulphide Treatment Plant at Obuasi, Ghana, underdifferent pH conditions will be determined.
