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COVER STORY
November 2016
MODERN MINING
23
a ventilation fan installation at Nchwaning III
shaft. The 460 kW centrifugal fan was installed
adjacent to the existing three fans. The
change-over of the surface fan intake from the
trifurcated inlet to a quadfurcated inlet was
successfully accomplished and the existing
fans returned to service as planned.
At Nchwaning II, the vertical shaft upgrade
has comprised refurbishment of the exist-
ing shaft steelwork, installation of new shaft
loading facilities and the replacement of the
existing 8-ton skips with new 14-ton skips. A
refurbished rock winder has also been installed
adjacent to the existing winder while the exist-
ing man winder was also upgraded. Also
required have been headgear and sheave altera-
tions to suit the new ropes, larger skips and
winder placement.
All design work pre-construction and engi-
neering support during the shaft upgrade was
done by WorleyParsons, with Assmang taking
direct charge of construction activities under
Hennie Wessels from Assmang.
The Gloria shaft stripping and second escape
package, together with the Nchwaning II head-
gear and shaft upgrade, were combined and
Group Five was awarded the contract in April
2015. Stefanutti Stocks Civils was contracted
to construct the winder house and Winder
Controls installed the winder.
Refurbishment of the Vecor rock winder
(to be used at Nchwaning ll shaft) was com-
pleted in June 2015 and the winder house in
August 2015.
A portion of the refurbishment of the shaft
steel work was carried out over weekends so
as not to interrupt mining activities. The major
work, which includes the replacement of the
loading boxes, sheave deck and all rock winder
guides, took place during a planned shut period
starting in March 2016.
The lifting of the 57-ton sheave deck took
place on 22 September 2016 using a 550‑ton
crane. All sheaves and related equipment have
been installed and aligned and roping up was
underway as this article was being written.
Commissioning, testing and licensing of both
winders and shaft systems will commence dur-
ing October and November 2016.
Considerable development work, of course,
forms part of the overall project. BRMO is
undertaking all the development and associ-
ated support work required at Nchwaning I
and III shafts ‘in house’ and is being assisted
by WorleyParsons, which is responsible for the
design, procurement and management of the
construction work. At Nchwaning II shaft, the
development has been contracted out to Aveng
Mining, which was due to complete its contract
during October 2016.
The development contract has included:
all satellite tips consisting of silos, tips, load-
ing facilities, top and bottom conveyors and
ramps between Seam 1 and Seam 2 reef planes
at Nchwaning II shaft; all transfer points; con-
veyor drives to Nchwaning I and II shafts; the
TMM workshop; and all crusher chambers.
Summing up WorleyParsons RSA’s involve-
ment in the BRP, Greyling says it demonstrates
the company’s abilities in virtually every
facet of underground mine construction and
development. “The Johannesburg office of
WorleyParsons RSA houses much of the mining
and shaft sinking expertise of the international
WorleyParsons group and in fact is the group’s
Global Centre for Excellence for precious
metals processing and underground mine
development,” he says. “All our skills have
been deployed at Black Rock and have contrib-
uted to what has been an extremely successful
project thus far.”
Photos: Charles Corbett on behalf of Assmang
Top:
The 11 m high graben
tie-in structure.
Above:
Conveyor in
progress from graben
tie-in to shaft system.