Secondary use of tailings (slimes) dam material in Gauteng
Province, South Africa – a serious challenge for soil and sediment
contamination.
Waste material from mining and smelting is often deposited on tailings
and slimes dams. This is a comparatively cheap and easy
method as compared to underground storage. These deposits are
not only an eyesore but threaten the environment. Toxic compounds
are continuously fed with seepage water into groundwater aquifers
and underlying soil while wind blows fine material into the vicinity
and may well contaminate larger areas with heavy metals, radionuclides
or organic compounds. At the same time, however, older
tailings represent mineral resources – due to inefficient extraction
technologies in the past, it is often well worth the effort to mine the
tailings with modern technology.
This is why many tailings are used as secondary mineral resources.
They are mined by using high-powered water jets. The newly formed
sludges are being pumped through open canals over kilometers to
the next ore dressing plant. Then the cycle starts all over again,
because the remaining sludge will be pumped onto modern slimes
dams – for the next generation. Photo: Jörg Matschullat. Cover design:
Edwin Grondinger.
