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32 Independence Group NL
CONSUMABLES
The main consumables at the mine are diesel, lime,
cyanide, carbon and water.
An on-site diesel-fuelled power station provides 40 MW
installed capacity. APA Group is currently constructing a
pipeline from Murrin Murrin to Tropicana to deliver gas.
Once complete, the existing diesel generators will be
replaced with gas-fired generators and so reduce both cost
of operation and the mass of emissions.
Relatively little water enters the pit voids from
groundwater seepage or rainfall. Water is supplied by
borefields, which are used to extract water from nearby
aquifers. In the 2014 calendar year a total of 4,362,473 kL
was abstracted from the process water supply bore field
plus an additional 532,488 kL which was abstracted from
operational bores. At stages during FY2015 the processing
facility was constrained due to a lack of water. This
occurred because there was a lower than predicted level
of water available from existing borefields; a lower than
predicted level of water in the open pits; and periods of
intensive water usage during construction of the tailing
storage facility. Water security has recently been achieved
by drilling additional bores. Water from the tailings storage
facility is recovered and recycled.
WASTE
The key waste streams from the mine are waste rock and
tailings. In addition to the gold bearing ore, waste rock is
extracted from the various pits. This rock (predominantly
ferrunginous cherts) contains some material that is
classified as potentially acid forming (PAF). Such material,
if left unmanaged and exposed to the elements, can
generate an acidic discharge that can cause downstream
impacts on biota and groundwater. Given this, the waste
rock dumps have been designed and are being constructed
to ensure the PAF material is blended with the neutralising
waste rock. This combined material is placed away from
what will be the final slopes of the waste rock landform.
Tailings are a thick water-based suspension of fine
crushed rock, sand, and clay produced from the
processing plant once the gold has been recovered. This
waste is pumped to the tailings storage facility, which is
designed to allow the tailings to settle and form a ‘beach’
that drains to a central pond. Ponded tailings liquor is
recovered and returned to the processing plant. Tailings
are cyclically deposited so the beaches evaporatively dry
and enable the dried tailings to be progressively stacked
higher. A key environmental consideration in this part
of the process is the presence of weak acid dissociable
cyanide in the tailings liquor.
The project development has required the clearance of
2,451 ha of natural bush to date. This includes both
mining and exploration disturbance but excludes open pit
disturbance.
A small volume of both putrescible and hard waste is
disposed of in the onsite landfill.
NATIVE TITLE
The Tropicana Gold Mine is wholly within the area of the
former Wongatha Native Title Claim (WC99/001). While
this claim was dismissed by the Federal Court in 2007,
AngloGold Ashanti continues to work closely with the
claimant group and other interested parties.
The most substantive nearby Aboriginal communities are
located at Laverton and Cosmo Newberry, both of which
are approximately 220km west-north-west of the site;
Coonana, which is approximately 225km south-west; and
Tjuntjuntjarra, 250km to the east. There are no pastoral
land holdings within the project area.
LIFE OF MINE
At present the expected life of mine for the mine is eight
years, based on current reserves. A mine closure plan has
been developed and is updated every three years.
A WA School of Mines graduate (BEng Mining
Engineering) with 3.5 years industry experience.
Having finishing his degree David started work as
an underground truck driver in 2012 and went on to
complete his introductory time underground including
in a variety of roles like nippering, service crew,
charge up, bogging and long hole drilling.
“I like my job not just because this is what I
want to do, but because the people I work
with really look after each other. As a mining
engineer, there are many challenging tasks
such as drill and blast design, magazine
management, and weekly scheduling to
name a few … it is all a good opportunity to
learn.”
Yingpeng (David) Wei
Mining Engineer
Jaguar Operation