HIGH PROFILE
A conveyor belt has been constructed at
Palabora for effective concrete delivery down to
the shaft sinking teams
hole; our blasting efficiency is, therefore,
electronically managed. This move to real-time
data acquisition has been well developed in our
lateral mining sections, and we are now moving
this to shaft sinking.
Cameras are installed on all conveyances and
on the stage so we can visually track all bank
activities. This further enhances our
management system and safety culture, allowing
us to identify where continuous improvements
can be made. Using this visual medium, we
analyse processes and incidents to remove any
tasks that raise the risk level. These
improvements are then built into our standards
and operating procedures.
M&R Cementation
underlines expertise
In the second of our exclusive shaft sinking project
profiles, IM puts questions to Graham Chamberlain,
Project Executive Mine Development, Murray & Roberts
Cementation, about the contractor’s work on the Palabora
copper project in South Africa
Project: Sinking of ventilation shaft for
Palabora Copper, a mine in the town of
Phalaborwa in South Africa’s Limpopo
province.
Client: The mine is owned by Palabora Mining
Company, part of the HBIS Group.
Scope: The contract is for a 1,200 m deep
ventilation shaft with a lined diameter
of 8.5 m – part of the development of
a new LIFT II underground block cave
mining area.
The shaft will be developed to a final
blind sink depth of 1,190 m and a drop
raise will take it to its final depth. By
early-2020, pre-sinking had been
conducted to a depth of 50 m, with
the use of a special shaft sinking
gantry. A surface headgear and winder
installation has been constructed to
facilitate the slow sink to 200 m and
the main sink, using Murray & Roberts
Cementation’s modified shutter and
lining methods.
Timeline: The project began in February 2019
and will continue until the September
quarter of 2022.
IM: What innovations has the company employed
to ensure it sticks to the budget and timeline set
out by the client?
GC: We continuously innovate our use of
equipment and upgrade our skill levels to
optimise productivity while ensuring the highest
levels of safety. The drill rigs we use today are in
their fifth generation of development, and are now
entirely hydraulic and operated remotely. They
have higher penetration rates but are much
quieter.
The drill rigs are nested into drill towers on
surface, and are extracted from shaft bottom
between drilling cycles so that all the
maintenance can be done safely and efficiently in
a suitable location outside the shaft. While
working, the robotic booms can be manoeuvred to
any position in the shaft for drilling.
We make use of explosive delivery pods codesigned
by a specialist explosives OEM and
ourselves – containing sensitised emulsion – that
have allowed us to shorten our cycle times. In line
with the Murray & Roberts strategic focus on
automation and real-time information, we get
immediate data on how many holes we have
charged and the volumes and density in each
IM: What safety procedures has the company set
up to enable work to continue even with social
distancing measures in place?
GC: All the regulated restrictions to prevent
COVID-19 transmissions are observed on site. This
is made easier by the fact most work is currently
outdoors, and the automation and mechanisation
of operations has meant smaller teams of higher
skilled staff. Everyone is trained in what is
required, and a compulsory pre-shift briefing is
held each morning before work starts to allocate
tasks and highlight risks. No-one reports to work
if they have not been through the briefing, or they
pose a potential risk to themselves and their
team.
With Zero Harm as our guiding principle, we
have removed people from the contact area,
preferring to deploy machinery in these high-risk
areas. We no longer conduct cleaning using
cactus grabs or rocker shovel loaders. Loading is
done, in this instance, by excavators hoisted in
and out of the shaft for the cleaning activity. For
larger shafts, we use clamshell muckers fitted to
the stage. Loaded kibbles are tipped out in the
headgear using an automated tipping
arrangement.
An important aspect of our safety protocol is
that we do not allow parallel activity if there are
people working at different heights in the shaft.
Where there is a team working at the bottom, no
work takes place above them, to ensure no
injuries in the case of falling items. Specialised
personal protective equipment – suited to
different tasks – is also vital to our safety regime.
Noise attenuation, for instance, is addressed first
at source and then by a double solution including
personalised ear plugs and earmuffs.
The outcome of our commitment to safety is
easily visible in the safety results we achieve,
where we commonly achieve 400-500 consecutive
LTI-free shifts.
76 International Mining | SEPTEMBER 2020