Heavy metals mobilityprogressively receive growing attention due to the growing scientific andpublic awareness of environmental issues. First and foremost, ensuringincreased effective bioxidation shall reduce the probability increasing acidityof tailings from the further oxidation of un-oxidised sulphide minerals.Improvement in the process can be in areas of bacterial re-engineering andparticle size reduction. Sstatistically, there is approximatelya 1?in?600 chance of a tailings dam failure in any given year, based onhistorical performance over the period of record (Kuipers et al., 2015). While these numbers may seem small, theirimplications are not.
” In risk?based dam safety practice for conventional water dams, some particularlevel of tolerable risk is often specified that, in turn, implies sometolerable failure rate. Clearly, improvements to current practice provide anessential starting point on the path to zero failures. To achieve this objective, mining companies have to adopt the bestavailable tailings technology based on the principles of soil mechanics: · Eliminatesurface water from the impoundment. · Promoteunsaturated conditions in the tailings with drainage provisions. · Achieve dilatant conditions throughout thetailings deposit The main goal of applying theseimprovements is to reduce tailings dam failure.
This can be achieved mostdirectly by storing the majority of the tailings below ground—in mined?out pits for surface mining operations or as backfill forunderground mines. Apart from this, surface storage using filtered tailingstechnology is a prime candidate for this improvement. For existingtailings impoundments, constructing filtered tailings facilities on existing conventionalimpoundments poses several technical hurdles.
Chief among them is undrainedshear failure in the underlying saturated tailings. Attempting to retrofitexisting conventional tailings impoundments is therefore not recommended, withreliance instead on best practices during their remaining active life. For new tailings facilities,improvements should be actively encouraged for new tailings facilities atexisting and proposed mines.
Safety attributes should be evaluated separatelyfrom economic considerations, and cost should not be the determining factor.