ON SITE
one stage, for a two week period, we
had a breakdown almost every day. To
continue production you have no choice
but to throw money at the problem
otherwise everything stands,” he says.
After wages and diesel, repair and
maintenace is the biggest cost driver on
the mine.
“If a company owns its own fleet and
does all the maintenance work in-house, it
is important to allocate a budget for each
machine. It is also extremely important to
employ top mechanics and have a network
of alternative suppliers other than the actual
OEMs. Furthermore, make sure you hire
the best and experienced operators who
not only know the machines they work
on, but can also operate a variety of other
equipment. One also needs to keep the
haul roads in good condition,” Blackmore
advises.
From strength to strength
Despite adverse economic conditions,
AST’s operation has gone from strength
to strength. Van Dykspruit quarry is on
the doorstep of Petra Diamonds’ Cullinan
mine in Gauteng. Cullinan is currently
expanding their underground operations,
which requires a significant amount of
high-quality sand and aggregates for their
structural concrete. The mine delivers
more than 3 000 tonnes of high grade
silica sand to Cullinan’s batching plant
per month. In the batching plant, the
sand is mixed with quartzite stone and
cement to produce an extremely strong
72MPa concrete that is pumped to the
underground workings along a 2km
feeder route, where it is used mostly in
spraycrete to strengthen the integrity of
newly developed underground tunnels.
The concrete is also used for causeways
and other infrastructure both underground
and on surface.
Blackmore says that the resource at
Van Dykspruit is low in clay content and
therefore ideal for the type of product
Cullinan demands. “If the sand contains
a high percentage of clay, the concrete
requires more water and cement,
increasing the client’s costs substantially.
After processing the run-of-mine sand, the
silica sand at VanDykspruit contains only
2.4% of materials passing 75µ, making
the processed sand a higher quality in
comparison to other sand deposits in the
area,” Blackmore explains.
Supplying Cullinan with sand is not the
only market for AST’s silica and quartzite.
The mine was initially developed because
of its strategic location close to the rapid
urban sprawl of Pretoria East and the
township of KwaMhlanga. Furthermore,
the construction of the Moloto corridor
road, which will run from Pretoria to
KwaMhlanga, is expected to generate
increased demand for road construction
materials, and AST is gearing up to supply
all the industry requirements in the area.
Quartzite the next target
Surface-lying sandstone currently being
mined and processed at Van Dykspruit,
overlies a bedrock of quartzite that will be
AST’s CDE Evowash plant arrived in South Africa in seven 40ft
containers from Northern Ireland three years ago.
16
OCTOBER 2019
www.equipmentandhire.co.za