tailings
A typical hydraulic recovery mining project.
higher tonnages and a higher rate of dam wall rise can
be achieved.”
Turning to the use of flocculants, Marais indicates
that the Golder office in Perth is undertaking a study
into the application and benefits of using flocculants,
especially in the dry areas of Australia to reduce wa-
ter content in the material deposited in tailings dams.
However, it is unlikely that flocculants would be used
in the dry areas of South Africa.
The use of thickened tailings for underground
backfilling is being undertaken in some South Afri-
can mines to improve safety by providing additional
support and to allow the mining of expanded faces
and pillars.
“We have expertise in the design of paste plants
to thicken tailings during which cement is added to
strengthen the material. Usually the coarse fraction of
tailings with higher strength is used as an aggregate
and the fines are sent to the tailings dam. The chal-
lenge is to build a tailings dam with a stable outer
wall when up to 20 per cent of the more stable coarse
material has been removed from the tailings stream.
We have upped the game with these tailings facilities
by introducing and maintaining high levels of elec-
tronic and human surveillance to identify early indi-
cators of possible safety issues,” says Marais.
The South Deep mine takes about 3 % of total tail-
ings to underground. High tailings volumes, high
costs and environmental issues limit the use of tail-
ings material underground. With environmental is-
sues a local imperative, the seepage of wet mass
through the underground rock face into the under-
ground aquifer is among the challenges faced by
mines that utilise bagged and cemented tailings as
support mechanisms.
Photos courtesy of Fraser Alexander and Golder Associates
Editor’s note: Since this article was written, it has been an-
nounced that Gold One is to merge its 74 % interest in Rand
Uranium (and Ezulwini) with Sibanye Gold for a consider-
ation of 17 % of Sibanye Gold ordinary shares.
