Heavy metals mobility
progressively receive growing attention due to the growing scientific and
public awareness of environmental issues. First and foremost, ensuring
increased effective bioxidation shall reduce the probability increasing acidity
of tailings from the further oxidation of un-oxidised sulphide minerals.
Improvement in the process can be in areas of bacterial re-engineering and
particle size reduction.
Sstatistically, there is approximately
a 1?in?600 chance of a tailings dam failure in any given year, based on
historical performance over the period of record (Kuipers et al., 2015). While these numbers may seem small, their
implications are not.” In risk?based dam safety practice for conventional water dams, some particular
level of tolerable risk is often specified that, in turn, implies some
tolerable failure rate. Clearly, improvements to current practice provide an
essential starting point on the path to zero failures.
To achieve this objective, mining companies have to adopt the best
available tailings technology based on the principles of soil mechanics:
surface water from the impoundment.
unsaturated conditions in the tailings with drainage provisions.
Achieve dilatant conditions throughout the
The main goal of applying these
improvements is to reduce tailings dam failure. This can be achieved most
directly by storing the majority of the tailings below ground—in mined?out pits for surface mining operations or as backfill for
underground mines. Apart from this, surface storage using filtered tailings
technology is a prime candidate for this improvement.
tailings impoundments, constructing filtered tailings facilities on existing conventional
impoundments poses several technical hurdles. Chief among them is undrained
shear failure in the underlying saturated tailings. Attempting to retrofit
existing conventional tailings impoundments is therefore not recommended, with
reliance instead on best practices during their remaining active life.
For new tailings facilities,
improvements should be actively encouraged for new tailings facilities at
existing and proposed mines. Safety attributes should be evaluated separately
from economic considerations, and cost should not be the determining factor.