Gold Fields Results |
9
Improvements as a result of this blueprint project will enter realisation
stage from the September 2013 quarter.
The South Deep Business Improvement team is planning to complete
its setup during the September 2013 quarter and to support other
significant improvement projects from the December 2013 quarter
onwards.
Progress against the Mine Health and Safety Council (MHSC)
milestone, that no machine or piece of equipment such as pneumatic
development rock drills, pneumatic stope rock drills, hydropower rock
drills and drill rigs, fans and winches 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) decreased from 3.2 per cent in the March quarter to 2.8
per cent in the June quarter. Silencing of equipment is ongoing, with
continued focus on defective silencers on equipment. The percentage
of employees exposed to >85dB (A) decreased from 56.7 per cent in
the March quarter compared with 52.4 per cent in the June quarter.
This measurement is without ear protection, which is currently
provided and almost universally used.
The Group continues to pursue best practice in the area of dust
control in accordance with the MHSC. In order to improve upon dust
exposure targets, the following core initiatives are ongoing:
· Real time dust monitoring;
· Foggers/water mist spray systems at dust sources;
· Dust allaying at internal tips;
· Installation of water blasts in all working areas; and
· Footwall dust allaying.
West Africa region
Tarkwa
BPR initiatives are ongoing. The major BPR projects for 2013 include:
·
Extending life of heavy mining equipment, including tyre life,
through improved haul road conditions;
·
Increasing CIL throughput through the installation of a tipper car
on the North heap leach crusher conveyor to supplement the CIL
feed rate. The current circuit is limited by the feeding equipment
capacity into the primary crusher. The cross over from the North
heap leach crusher will assist in maintaining and increasing the
ore stockpile levels for feeding into the primary crusher and
increase the CIL milling rate from 1,460 tonnes per hour to 1,500
tonnes per hour. On an annualised basis this equates to an
increase in the milling rate from 11.9 million tonnes per annum to
12.3 million tonnes per annum;
·
Acceleration of waste strip 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. This project has
the potential to increase the annual mining volume by an
estimated 10 per cent; and
·
The purchase of an additional front end loader to improve loader
availability in the optimisation of crusher throughput from ore
rehandled from the ROM-pad.
The tipper car on the North heap leach crusher conveyor to
supplement the CIL feed rate was commissioned in May 2013. Since
inception of the haul road improvement campaign, average tyre-life
has increased from 4,250 hours to 5,200 hours in the June quarter.
Damang
BPR initiatives are ongoing. The major BPR projects for 2013 include:
· Continued savings from owner mining and maintenance initiatives
implemented in early 2011;
· Optimisation of the plant circuit to achieve the maximum recovery
rate of 89 per cent under current blend conditions which include:
· Installation and commissioning of the intensive leach reactor
(ILR) which was completed in the December 2012 quarter.
The unit is performing as expected with higher recovery rates
being achieved on the gravity concentrate. The ILR replaced
the Gemini shaking table used for treating gravity concentrate
from the Knelson concentrators. The use of intensive
cyanidation as applied in the ILR unit increased the recovery
of gold from gravity concentrate from 70 per cent (using a
gravity shaking table) up to 98 per cent. This reduced the
circulation of gold into the circuit from gravity concentrate
tailings and improved overall plant gold recovery;
·
Commissioning of the pre-leach thickener (PLT) project to
improve control of the circuit water balance and optimise
gravity circuit feed rates was completed in July 2013. The
inclusion of the PLT allows for the operation of the second
gravity concentrator, and at the same time improving leach
feed density control;
·
An additional CIL leach tank to take the number of leach tanks
from 7 to 8, is being added to the circuit to improve the
residence time and recoveries and circuit reliability, planned
for the end of the September 2013 quarter; and
·
Other smaller plant circuit optimisation projects, including
oxygen addition optimisation, are planned for 2013.
Australasia region
St Ives
BPR initiatives are ongoing. The major BPR projects for 2013 include:
·
Renegotiation of major site contracts resulted in a 27 per cent
reduction in the Cave Rocks development contract rates and a 30
per cent reduction in surface haulage costs. Benefits are expected
from the September 2013 quarter. Expected annualised savings
are approximately A$14 million;
·
Continued roll-out of the management operating system (MOS):
Operating centres have now been established across all operating
units to improve the effectiveness of daily production meetings
and to discuss key productivity metrics for the previous 24 hours.
Short and medium-term planning and execution processes are
being refined and standardised across open pits and underground
mines as the primary means to improve operating stability and
predictability;
·
Completion of the installation of personal protective equipment
(PPE) dispensing machines. Anticipated savings are
approximately A$600,000 per annum; and
·
The project to reduce operational damage to heavy mining
equipment in the underground mines has resulted in a 27 per cent
decrease in downtime hours and a 48 per cent decrease in
damage incidents year to date.
Agnew
BPR initiatives are ongoing. The major BPR projects for 2013 include:
·
Running of two mills as opposed to one, supplementing Kim ore
with remnant Songvang ore to maintain throughput at 130 tonnes
per hour or 87 per cent use of capacity as well as toll treating to
recover some additional costs. Currently approximately 1 million
tonne of the 1.2 million tonne capacity is being utilised;
·
A shotcrete/fibrecrete trial for support replacing the more standard
meshing and bolting methods of ground support. The trial was
completed and a final report is being generated. Early indications
are that cost benefits and productivity improvements may exceed
the original estimates;
·
Trialing the use of emulsion instead of ANFO: ANFO and
emulsion are explosives used in the blasting process. ANFO is a
mix of Ammonium Nitrate (94%) and fuel oil (6%) and has a solid
consistency. Emulsion is a blend of Ammonium Nitrate and a mix
of fuel oil, wax and other ingredients; giving it a more paste like
consistency. It has up to 48 per cent move explosive power than
ANFO. Results from the trial indicate around 10 per cent reduction
in dilution. This has significant cost and capacity benefits through
the whole mining process. The improvements are a consequence
of the ability to control explosive density and power when using
emulsion. Other positive features associated with emulsion are
that it is waterproof and does not dissolve in wet conditions
(ANFO is water absorbent) and as the charge up hose required
for the delivery of emulsion into the blast holes is much smaller
than the hose required for ANFO, there are less hole blockages
and drill holes are consistently fully charged; and
·
The new development contract continues to be monitored to
ensure savings are being realised. Renegotiated rates on the new
development contract are 12 per cent lower than those in the
expired contract. The new development contract commenced in
March 2013.