Extracting PGMs from chromite
tailings at Kroondal - a world first
The new chromite-tailings retreatment plant for the recovery of
platinum-group metals (PGMs) at Aquarius Platinum's Kroondal mine
near Rustenburg, South Africa, designed, manufactured and erected
by BATEMAN, is thought to be the first PGM-flotation plant in the
world to process chrome-mine tailings.
According to Gert Ackerman, Managing Director of Aquarius Platinum
(South Africa), the concept is simple, the engineering straightforward
and the economics compelling. For a capital expenditure of about US$5M,
Aquarius will initially be adding 20 000 ounces to its PGM production,
while simultaneously cleaning the environment by putting discard material
to good use.
The feed to the plant comprises a mixture of about 60% of newly generated
tailings (a grade of 4 g/t of PGMs) piped through a 2 km pipeline
from the neighbouring Kroondal Chrome mine, owned by Xstrata. The
remaining 40% is dump material (a grade of 3 g/t of PGMs) trucked
in from various dumps in the Rustenburg area, most of them belonging
to Bayer"s Rustenburg chrome operation.
The plant design is simple and straightforward and its footprint has
been concentrated within an area of only 20 m by 50 m. The front-end
of the plant screens and scalps the dump material. Initially no crushing
or milling is required, but plans are in hand to add a mill later
this year.
The wet and dry feeds are mixed in a tank and the combined stream
is passed through conventional tank-type flotation cells, supplied
by BATEMAN, which also supplied the flotation-air blower. There are
four stages of roughing and six of cleaning and the layout makes use
of the slope of the land at the site so that the tank cell pairs are
terraced, reducing the height that would normally be required by a
conventional plant.
The retreated tailings are pumped to Kroondal's tailings facility.
The concentrate containing 150 g/t of PGMs is sold in accordance with
off-take agreements.
When the plant is in steady-state production, it will run on a four-shift
basis, with three people manning each shift.
The project is a joint venture of the RK1 Consortium, comprising
Aquarius Platinum (SA) Corporate Services (a wholly owned subsidiary
of Aquarius )(50%), GB Mining & Exploration SA(25%)and Sylvania
South Africa(25%). Aquarius is managing and operating the project
on behalf of the consortium.
More information may be obtained from Dirk Schenk, General Manager,
Special Projects, on +27-11-899-2735 or email specialprojects@batemanengineering.com.
