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January - February 2015
MODERN QUARRYING
13
AT THE QUARRY FACE
Above:
The back area at
Zoutkloof which is filled with
water is the final 180 m depth
of mining. Here the limestone
deposit sits at 55
o
, and on the
sidewall, one can see the phyllite
which is screened out to the
waste dump in order to enhance
its quality. The area at the back
of the pit is overburden from
Vondeling, which has been
backfilled into the pit.
Centre:
The current Zoutkloof
pit is almost at the end of its life,
and is currently running at about
170 m deep. The aim is to mine
to a depth of 180 m with two
benches still being mined.
Left:
Close up view of the topsoil
and overburden, phyllite, granite
and limestone.
expand
PPC’s African footprint
He says the reserve quality is still high at this stage.
Looking at the Vondeling pit which com-
menced operation in 2007, the current depth is
50 m with planned mining until 2042. The final
depth then will be 200 m. The aerial map shows a
pink area, which was Phase One with a water canal
running through a portion of the planned mine
area. He says the new pit is roughly the same size
as Zoutkloof and has the same quality limestone
orebody.
The map shows the concurrent rehabilitation
taking place at Zoutkloof, and the overburden/
waste from the pit. “As we are opening up the new
pit, we are closing the old one. We will actually be
able to fill the whole pit and form a little bit of a hill.
We are currently at -60 m below sea level, and will
go down to -70 m.”
The old waste overburden dump has been
rehabilitated and the farmers renting the area have
planted wheat fields and are utilising the land for
agricultural purposes. There is no difference what-
soever between the natural and the rehabilitated
areas.
Diergaardt has been with the PPC group for
six years, having started off at PPC Riebeeck in the
Western Cape, then moving to the Eastern Cape,
followed by Dwaalboom in Limpopo Province.
He says he is very proud to be part of the tran-
sition phase at De Hoek, “which is very exciting
because we are closing one pit and opening up
another. Shale is also sourced from the De Hoek
operation, and Diergaardt says there are a lot of
shale reserves.
Showing
MQ
the two major shale deposits on
the aerial map, he says when mining in Vondeling
began; there was a lot of shale which was mined
when the pit was opened up. “There is a huge
stockpile in the pit area, and we are focusing on
that at the moment.
“What happened with the initial design which
went downwards is that after drilling we realised
that there was another limestone body sitting
closer to the surface, which means less overburden
stripping. This is why the river diversion plan came
in. The deeper deposit is sitting at a 55° angle, and
as you go eastwards it is getting deeper, so the
moving of the canal is critical for us to be able to
mine in that area,” he explains, adding that this will
be carried out by the end of this year.