Mine excursion
The two conveyor belts, which run parallel
to the decline shafts at Sibanye’s Bathopele
Mine, take the ore to surface.
shafts, which is Sibanye-Stillwater’s
most recently proposed acquisition,
and the company may soon take over
the operations (subject to various
outstanding conditions), which of
course includes infamous Marikana. To
the west of Sibanye-Stillwater’s current
operations is the other big name in
South African platinum producers,
namely Impala and Royal Bafokeng’s
Rasimone Mine.
Two shafts
The rich ore body at Bathopele is
accessed by two decline shafts: East
Shaft and Central Shaft. Two decline
conveyor belts run parallel to the
shafts, all the way to the bottom, where
it reaches a depth of about 600m.
The East Shaft of this fully
mechanised low-profile board-and-
pillar operation mines a single seam
of UG2 Reef at an average of about
1.95m stoping width (in some cases
the UG2 Reef can be as narrow as
80cm). The teams in the Central Shaft
operate in stoping widths of about
2.2m on average and they mine dual
seams of UG2 Main and Leader reefs.
Van Aswegen explains there is a waste
portion of about 1.3m between the two
seams; therefore, they take out both
seams. “If the internal waste portion
falls below 1.3m, we struggle to keep
it up with support and as a safety
precaution, we mine both reefs,” he
explains.
Each underground section at
Bathopele consists of 27 (nine per
shift) workers rotating on three shifts.
Each shift works 11.5 hours on a
two-shift cycle. The morning shift
starts a six o’clock in the morning to
half past five in the afternoon, and the
next shift works from six at night to
half past five in the morning. The nine
workers of the third shift are off duty
for a week. Each underground crew
covers about 2 250m and the targets
for the different teams are to install
seven roof bolts per hour and drill 20
holes per drilling rig, while the LHDs
have to move 10 loads of ore per hour.
To prevent bottlenecks at the
processing plant, Van Aswegen
says the mine has minimised its
underground waste and sends as little
waste as possible to surface. “When
we encounter a geological feature that
results in off-reef mining, we pack the
waste underground in the worked-out
areas and we don’t send it to the
concentrators. In addition, we have
re-engineered the tips and we scalp
about 7% of the tonnes that we break
off the grizzlies. These scalping tonnes
are also packed in the worked-out
areas,” Van Aswegen adds.
Steyn’s Section 10E
workstation
“There are eight working sections
and a development section on the
East Shaft,” says Steyn in a crouched
position at his workstation, 300m
underground. One section consists of
10–12 panels and the panel widths are
10m wide. “However, we can mine it
smaller up to 6m wide, depending on
the ground conditions,” says Steyn as
the noise from the LHDs dies down.
Every section has its own conveyor
belt that links with the main belt to the
surface. In other words, the conveyor
belt is moved as the miners advance
and is normally not further than 100m
from the face.
“In this section, there will typically
be one mechanised drill rig that is able
to drill a hole end of 3.2m. On average,
we achieve an advance of about 3.0m,”
explains Steyn. In addition, each
section has two roof bolters that install
the primary support of 1.6m fully
column Resinbolt. According to Van
Aswegen, these roof bolters have been
modified to enable them to insert long
anchors up to 3m as secondary support.
There are two LHDs in each section.
SEPTEMBER 2018 MINING MIRROR
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