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Gold Fields Results
Progress against the Mine Health and Safety Council (MHSC)
milestone, that no machine or piece of equipment may generate a
sound pressure level in excess of 110dB (A) after December 2013, is
ongoing. The number of measurements expressed as a percentage
of noise measurements of machinery and equipment emitting noise in
excess of 110dB (A) was reduced to 0.6 per cent from 0.8 per cent in
the December quarter. Silencing of equipment is ongoing with
continued focus on replacing blocked and/or damaged silencers on
machines. A further measure to identify sound pressures above 85dB
(A) has been introduced and currently the percentage of employees
exposed above this level is 62.4 per cent. This measurement is
without ear protection. Thus far, empirical studies indicate that with
the proper use of ear protection no employee will be subject to a
sound pressure level in excess of 85dB(A). A project to measure
exposure whilst using hearing protective devices to provide
verification is set to start in June 2012.
Of the individual gravimetric dust samples measurements taken
during the March quarter, 1.5 per cent were above the occupational
exposure limit of 0.1 milligrams per cubic metre, thus meeting the
target of not more than 5 per cent of individual samples above the
occupational exposure limit of 0.1 milligrams per cubic metre.
In order to improve upon these dust exposure targets, the Group
continuously refines interventions, which include:
·
Building health rooms at the training centres to coach
employees on potential exposures and wearing of respiratory
personal protective equipment;
·
Using foggers, a water mist spray system, to trap dust particles
liberated from tipping points to prevent dust from entering the
main air stream;
·
Installing dual stage tip filter units, where the filters are
equipped with an additional layer of filtration material to improve
the efficiency of old technology filter bags in order to increase
dust filtration;
·
Managing the opening and closing of ore transfer chutes
between levels so that they remain closed when not in use to
reduce airborne dust entering the work place;
·
Treating footwalls with binding chemicals sprayed from a
specially designed car pulled by a loco to prevent dust from
being liberated into intake air ways; and
·
Analysing individual filters to assist in determining exposure
levels.
West Africa region
Tarkwa
BPR initiatives are ongoing. The major BPR projects for 2012 include:
·
Commissioning and integration of the secondary crusher at the
CIL plant. This is expected to achieve a 5 per cent improvement
in the milling rate from 950,000 tonnes to 1 million tonnes per
month. The secondary crusher was commissioned in the March
quarter and debottlenecking is in progress. The ramp-up of the
secondary crusher is planned at 75 per cent of nameplate
capacity for the June quarter, with full production from the
September quarter;
·
Waste strip acceleration. This is planned to be achieved
through the implementation of a larger sized load and haul fleet.
The improved flexibility is also designed to ensure a continuous
ore supply to the plant. Commissioning of the larger sized load
and haul fleet is scheduled for the December quarter;
·
The construction and commissioning of an in-pit satellite fuel
farm. The benefits that will accrue include shorter haul
distances for refueling, fuel burn cost savings and improved
productivity. Construction and commissioning is scheduled for
the June quarter and full implementation is scheduled for the
September quarter. This initiative is expected to deliver
approximately US$30 million in cost savings over the life of
mine; and
·
Various other initiatives totaling around US$20 million were
planned across the mine.
Larger sized load and haul fleet has been ordered with the associated
infrastructure requirements currently under construction. Construction
of the in-pit satellite fuel farm is nearing completion. Cost savings of
US$7 million were achieved in the March quarter on various smaller
initiatives.
Damang
BPR initiatives are ongoing. The major BPR projects for 2012 include:
·
Continued savings from owner mining and maintenance
initiatives implemented in early 2011; and
·
The implementation of an additional shift which will provide
flexibility to accelerate waste stripping and increase mining
volumes to ensure a continuous ore supply to the plant. The
new shift will also improve the utilisation of mining equipment.
Implementation was completed in the March quarter with the full
productivity benefits anticipated to be realised from the June
quarter onwards.
The introduction of owner mining has resulted in a decrease in mining
costs from US$4.35 per tonne, which was the contractor cost per
tonne prior to conversion to owner mining, to US$3.22 per tonne.
Added to this, the additional shift has resulted in an increase in
tonnes mined from approximately 6 million tonnes per quarter to 8
million tonnes per quarter, reducing costs further from US$3.22 per
tonne to US$2.75 per tonne mined.
Australasia region
St Ives
Towards the end of 2011, an in-house business improvement team
was established at St Ives and the transition to owner miner for
underground stoping was fully implemented. Business improvement
projects were introduced at Lefroy mill and include coarse ore
stockpile management, which allows for a manual feed at times of
crusher downtime to ensure the correct mining mix of coarse and fine
ore is delivered to the mill, the introduction of lead nitrate into the
milling circuit to improve recoveries and at the heap leach, a diverter
gate and belt magnets were commissioned allowing a continuous
feed to the pads, where previously the feed was temporarily stopped
to clear adverse material. These initiatives were effective in
increasing ore tonnes processed from an average of 1.68 million
tonnes per quarter for the 12 month period ended September 2011 to
1.77 million tonnes per quarter achieved over the last two quarters.
Ongoing projects from 2011 resulted in sustained savings of around
A$6 million for the March quarter.
New business improvement projects for 2012 are planned to generate
savings of A$16 million for the year. During the March quarter the
pipeline of new projects already generating cash is estimated at
around A$1 million. In addition, St Ives focused on the
implementation of semi-automatic production drills which allow a
single hole to be drilled on an automatic setting without an operator
being there to change rods. This would be required every metre and a
half if done manually. The intervention reduces drilling time, as drilling
is autonomous without losing production time. Estimated savings of
A$1 million are expected from this project from the June quarter.
At the open pits, the owner operator project is progressing well. A
fleet of Komatsu equipment has been ordered with the first delivery
scheduled for the end of the September quarter. This project is
expected to reduce open pit operating costs significantly and has the
potential to increase open pit reserves.
Agnew
At Agnew, new business improvement projects with planned benefits
of A$8 million have been identified for 2012.
The ventilation fan installation carried over from 2011, has resulted in
improved access to development areas because of enhanced airflow
and lower underground temperatures.
Projects which commenced during the quarter, from which benefits
are yet to accrue, include a change-over from ANFO (Ammonia
nitrate – fuel/oil) technology used to charge the drill holes for blasting
to emulsion charging, which unlike ANFO is pumped under pressure
to provide a more competent blast especially in wet holes. This is
expected to provide greater blasting efficiencies within the Waroonga
mining environment. In addition, an optimisation project to reduce
cycle times of dump trucks from Waroonga underground to the mill
was also introduced during the quarter.