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January 2016
MODERN MINING
67
Top projects
COPPER
A Murray & Roberts
Cementation raise borer
working underground at
Palabora.
PALABORA OVER THE YEARS
1956 – Founded as Palabora Mining Company and began opencast mining
1996 – Construction begins on Lift I underground project
2002 – Production begins from Lift I block cave
2007 – Drilling starts on Lift II orebody
2011 – Business case study starts for Lift II project
2012 – Construction begins on Lift II twin decline to orebody
2014 – Feasibility study for Lift II completed
2015 – Shareholders approve final plan to proceed with Lift II project
2017 – First production expected from Lift II block cave
globally. Installing these units underground
reduces the need to pump water to the surface
for cooling; instead, upcast air is used to reject
heat in underground cooling towers and cool
air is blown down to the work face.
To match the capacity of the 17-t LHDs, the
crusher configuration will be different to the
four jaw crushers at Lift I. Rather, Lift II will
install two jaw-gyratory crushers – essentially
gyratory crushers with much larger throats
– capable of taking bigger lump sizes. With
a 2 000 t/h capacity and multiple tipping
points, these units will avoid any unproduc-
tive queuing when being fed by the 17-t LHDs
underground.
There are also to be some significant
improvements in the processing plant, accord-
ing to Flotation Plant Project Manager Willie
Laing. Most interesting among these is the
project’s use of sorting as a means of pre-con-
centrating ore and of improving the final quality
of concentrates. Palabora intends installing
optical ore-sorters to separate barren dolerite –
comprising 10-12 % of run-of-mine feed – from
copper-bearing material, a process made pos-
sible by the distinct colour difference between
these two rock types.
In addition, said Laing, tank cell technology
is to be introduced into the new flotation plant,
with the aim of improving recoveries from 80 %
to a targeted 88 % – delivering about 30 % cop-
per; magnetite recoveries will also improve
to 63-65 % iron in the final product. He said
extensive tests at mineral research group
Mintek, conducted with a specially installed
10 m
3
tank, showed the technology gave posi-
tive results, especially with lower grades.
Following the green light for Lift II’s imple-
mentation, employment expectations have been
understandably high in communities around
the mine – which have had to be carefully
managed by Palabora. According to Corporate
Affairs Manager Hulisani Nemaxwi, the mine
has leveraged the project’s employment impact
by reaching agreements with contractors
– where most of the new jobs have been gener-
ated – to ensure at least 80 % of non-skilled and
semi-skilled job opportunities will be filled by
local residents.
“We are also focused on upgrading skills
of workers, as well as developing local small
businesses to become reliable and sustainable
providers of services – both to the mine and
to other players in the local economy,” said
Nemaxwi. “We have spent about R160 mil-
lion over the past five years, and the results are
encouraging.”
As one of South Africa’s largest mining
development projects, Lift II must rank also as
one which generates considerable and much-
needed confidence in a mining sector under
almost unprecedented global and local stresses.
Retaining its focus on innova-
tion, and basing its decisions
on solid geological, min-
ing and metallurgical data,
Fouche emphasises that any
good project still relies on its
people.
“Many of the people who
were involved in Lift I are
now part of the Lift II project
team, giving the project vital
intellectual memory to ensure
that we can apply our lessons learnt and imple-
ment configuration changes,” he said.
Unique geology
Unlikemost of the world’s copper mines,
which mine their copper from porphyry
deposits, Palabora’s ore occurs in the
carbonatite formation known as the Pal-
abora Igneous Complex. The complex
also hosts a range of other minerals such
as phosphates, vermiculite, phlogopite,
magnetite, nickel, gold, silver, platinum
and palladium.