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Technical reviewGold
Cyanide monitoring continued for AngloGold Ashanti’s
metallurgical plants in southern Africa, Tanzania and
Mali, and this work will be extended to the Ghanaian
operations in the current year. Some preliminary work
was also done for Randgold Resources’ Loulo project
in Mali, which is scheduled to begin production in the
second half of 2005. Together with AngloGold Ashanti,
Mintek began a THRIP-funded project to investigate
various environment-related aspects of cyanide usage,
including the vapour pressure of HCN, the stability
of Prussian Blue-type precipitates in backfill, the
fate of thiocyanate in the environment, and cyanide
destruction by ultraviolet light. Work continued towards
the accreditation of analytical methods for cyanide, and
Mintek plans to apply for
ISO 17025 certification for
cyanide analysis later in
2005.
A programme of testwork was completed as part of the
pre-feasibility study on the Burnstone gold project (South
Rand) for Vancouver-based Great Basin Gold. The work,
which consisted of gravity separation and preg-robbing
tests on a composite sample of borehole cores, showed
that more than 90 per cent of the gold could be recovered
by gravity separation followed by carbon-in-leach. The
metallurgical testwork was carried out in conjunction with
MDM Ferroman, which is responsible for process and
plant design.
In early 2005, Great Basin initiated a feasibility study
on the project with the aim of reaching a development
decision within 12 months. Should the project go ahead,
Burnstone will be the first new gold producer on the
South Rand gold field in over 40 years.
Small-scale batch and continuous testwork, involving
milling and flotation to produce a copper concentrate
and leaching of the tailings for gold recovery, was carried
out for European Minerals’ Varvarinskoye project in
Kazakhstan. A bankable feasibility study was completed
by MDM Ferroman in November 2004, and construction
of the project is under way, with the first gold pour
scheduled for the end of 2006.
Gas-phase sampling
to determine cyanide
volitilisation rates
at a tailings storage
facility
Scale-up work on gold-based catalysts under Project
AuTEK 9
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RIP testwork using the Minix gold-selective resin was
carried out to recover gold from a copper leach residue
for Cominco Engineering Services Ltd.
Project AuTEK — the collaborative initiative to develop
novel industrial uses for gold and increase local
beneficiation — is now in its fifth year. The work on
catalysts for carbon monoxide oxidation has reached
product development stage. One of the potential
applications is in respirators, where the AuTEK catalyst
has the advantage of retaining its activity for much
longer than the conventional hopcalite catalyst, as well
as the ability to function in humid conditions. Prototype
respirators using the AuTEK gold-based catalyst will
be submitted to the NIOSH (US) for evaluation and
accreditation early in 2006, and the first commercial
production is expected in 2007.
Mintek now has the capacity to produce catalysts, in
batches of up to 20 kg, in a form suitable for a wide range
of industrial applications, and is ready to collaborate with
end-users in the pollution control, chemical processing
and fuel cell industries to design gold-based catalysts for
their specific needs.
Work on nano-monolayer-protected gold clusters for
drug delivery is in progress with the Universities of
Liverpool and Parma (Italy), and an investigation into the
manufacture of nanofibres by electrospinning has begun .
These materials have a very high surface area, and have
potential for use in biosensors as well as catalysts.
An investigation was conducted into the effects of
key growth parameters on the size and shape of gold
nanoparticles produced by biosynthesis. In order for
biosynthesis to compete with existing chemical and
physical methods, techniques need to be developed
that can control the particle size to a very narrow range,
as well as produce uniform shapes. A project was
begun with the University of the Free State to identify
the biomolecules that are responsible for the reduction
reaction and subsequent nanoparticle formation, which
could lead to a more controlled process. Another project,
at Rhodes University, is undertaking an initial screening
of micro-organisms for their potential for synthesising
platinum nanoparticles.
The AuTEK biomedical programme, which originally
focused on anti-tumour drugs, has broadened its
investigations to include anti-HIV and anti-malarial
agents, in collaboration with seven local and six
European universities. Screening work and toxicological
studies are continuing, and in-vivo testing will start
towards the end of 2005. Work has been initiated with
NECSA on radio-labelling to investigate the mode of
action of various compounds.
One of the major achievements of Project AuTEK has
been the establishment of a pool of skilled researchers
with strong international links. The number of researchers
has grown from five in the year 2000 to more than 50,
and collaborative links have been forged with nine local
universities and more than a dozen overseas in six
countries. Two PhD and eight MSc degrees have already
been completed, and another 30 postgraduate projects
are registered. AuTEK researchers have made 68
contributions in international journals and conferences.
The launch of AuTEK Americas is planned for late 2005.
AuTEK’s budget has grown from R1-million to just over
R14-million in 2005, and the project has been very
A scanning electron microscope image of nanofibres
Gold labelling of neurologically active pentapeptides for
cancer research
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successful in leveraging additional funding, which now
accounts for 40 per cent of the budget. A considerable
contribution has been made by the NRF through THRIP,
for building infrastructure and expertise. During the
period under review, these funds were used to acquire
a RAMAN/Fourier Transform Infrared spectroscope and
an ASAP surface area analyser for studying adsorbed
species on catalyst surfaces. In 2004 the DST approved
a R5-million grant for an atomic force/scanning tunnelling
microscope for the fundamental characterisation of
nanoparticles, and a further R3.7-million in 2005 for a
high-resolution SEM and nuclear magnetic resonance
spectrometer. These facilities make Mintek a leading
centre for nano-research in South Africa.
Platinum Group Metals
Exploration and development work on new platinum
group metals projects in South Africa continued at a high
level during 2004/2005, and Mintek’s testwork facilities
were heavily utilised.
A major piloting campaign was completed on a 500 t
bulk sample from a new project in the eastern Bushveld
Complex, to provide metallurgical data as inputs into the
feasibility study, and to determine the most appropriate
concentrator design and the performance criteria. Two
different MF2 configurations were evaluated, and the
minimum product specifications were attained with both
circuits.
Metallurgical variability testwork, to determine the
factors that influence metal recoveries, was carried out
as input to the pre-feasibility study by Ridge Mining on
the Sheba’s Ridge project. The study was completed
in March 2005, and Mintek will also be involved in work
for the bankable feasibility study on the project, which
is scheduled for completion by the end of 2006. Similar
work was performed for Aquarius Platinum’s Everest
South project - Mintek previously ran piloting campaigns
to determine the design parameters for the Everest South
concentrator, which is due to be commissioned at the end
of 2005.
Bench-scale investigations were done as part of the
pre-feasibility studies for African Platinum’s Leeuwkop
project, and for the Boikgantsho joint venture between
Anooraq Resources and Anglo American Platinum.
A major programme of work on PGM ores from many
different sources, was carried out to evaluate the use of
dense media separation (DMS) for the up-front rejection
of waste material and to compare the flotation recoveries
from DMS concentrate and ROM material.
Mintek has commissioned a dedicated milling and
flotation mini-plant, which is used mainly for reagent
evaluation and comparative testwork. The plant
has a throughput capacity of 100 kg/h, and is easily
configurable and economical to run. It is proving to be
useful for testwork where many different conditions need
to be evaluated, or in cases where there are only limited
quantities of material available, such as from borehole
cores. Examples of the kinds of work undertaken include
an independent evaluation of gangue depressants for
a reagent manufacturer, and continuous rougher rate
tests on UG2 samples containing various amounts
of waste to evaluate the potential benefits of dense
media separation. The infrastructure for the main 1 t/h
milling and flotation pilot plant was also upgraded and
modernised.
Two major collaborative research projects are under
way, supported by industry partners. The first involves
a comparison of preconcentration methods for UG2
(Top and bottom) A pilot plant campaign for a feasibility
study on a new PGM project
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ores, and the second is looking at a number of generic
problems encountered in the PGM smelting industry.
Science Vote-funded research is being undertaken
on the classification of UG2 tailings, optical sorting of
non-UG2 ores, new flotation cell technologies, and the
fundamentals of milling processes.
Funding has been approved for a THRIP project, which
will start in the 2005 financial year, to investigate the
limiting factors in the PGM smelting process. All three of
the major platinum producers are supporting the project,
which will include studies such as flow behaviour, the
solid phases, disengagement of the matte from slag,
interactions between the furnace gases and refractory
materials, and matte liquidus temperatures.
A long-term DC furnace campaign was initiated to
recover PGMs from revert tailings and other wastes for
one of the platinum producers. This material is difficult
to process conventionally because of its high chromium
and low base-metal sulphide content. By the end of the
period under review, over 5 000 t of a planned 10 000 t
had been processed. As well as being a major service
work project, this exercise is serving to demonstrate the
smelting stage of the ConRoast process, which involves
the smelting of primary platinum-bearing feed materials
in a DC arc furnace, with the PGMs collected in an
iron alloy. A paper entitled “DC arc smelting of difficult
PGM-containing feed materials” was presented at the
International Platinum Conference in September 2004.
The programme on the development of PGM-based
analogues of the nickel-based superalloys is now in
its fifth year. This work is supported by the three major
platinum producers Anglo Platinum, Impala Platinum and
Lonmin Platinum, with collaborating institutions being
Japan’s National Institute for Materials Science (NIMS)
and the universities of Bayreuth and Leeds. Significant
progress was made in the ThermoCalcTM work, and
investigations of the experimental phase diagrams are
ongoing, with the current focus on resolving anomalies
found in the binary diagrams. A major effort is being
made to identify a niche opportunity for testing prototype
alloys.
Mintek participated in an Innovation Fund project,
managed by the CSIR, on the addition of platinum to
coatings on nickel-based superalloys. The conventional
aluminising process produces a nickel aluminide
coating. Platinum additions result in a mixture of higher-
order phases that strengthen and extend the life of the
coating. This effect has long been known, but is not well
understood. This project will be resumed if an industrial
partner can be found.
Mintek is participating in a second Innovation Fund-
sponsored project at the University of Cape Town on
the development of platinum-based jewellery alloys.
During the year under review, the properties of a range of
compositions based on 95%Pt, were evaluated for their
suitability for use by small-scale jewellers. This work will
continue during 2005/2006.
Mintek has entered into an agreement with Johnson
Matthey Catalysts to act as a test facility for the Smopex®
technology. Smopex is a new metal scavenging system
that uses polyolefin-base ion exchange fibres with high
loading capabilities to recover low levels of precious
metals from process streams. With a local testing facility,
the costs of transporting the test solutions will be lower,
and there will be less chance of the solutions ageing.
Mini-plant work on the evaluation of flotation reagents
DC arc smelting of PGM revert tailings
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Ferrous Metals
Mintek acted as manager, assisted by Bateman Metals,
GBM Minerals Engineering Consultants, and Wardell
Armstrong International (WAI), for the preliminary
feasibility study on Oriel Resources’ Shevchenko
ferronickel project in Kazakhstan. Based on the positive
results, Oriel commissioned a Definitive Feasibility Study
(DFS), with Bateman as lead engineers, partnered by
ThyssenKrupp company Polysius, WAI and Mintek. As
part of the study, about 190 t of calcined lateritic ore was
smelted in Mintek’s DC arc pilot plant at power levels
of up to 1.5 MW, producing 11.5 t of ferronickel alloy at
nickel grades and recoveries in line with targets.
The DFS, which will be completed in the third quarter
of 2005, is based on a smelter plant with an initial
installed capacity of two 80 MW twin-electrode DC arc
furnaces, followed by a third furnace after the third year
of operation. Subject to a positive outcome, construction
could start during the second quarter of 2006, with the
first ferronickel production by early 2008. At full capacity,
the project would produce 140 000 t of ferronickel per
annum.
A “pre-concept” study was completed on the production
of ferrochromium at the Voskhod mine in Kazakhstan.
At the end of the year under review, Oriel commissioned
Mintek to carry out a scoping study to design and cost a
chromite beneficiation flowsheet.
Mintek is in the final phase of a three-year project, funded
by the Innovation Fund/NRF, to develop a low-nickel
austenitic stainless steel for structural applications.
Welding, corrosion, and cold formability tests were
completed, and industrial scale-up trials (approximately
2 t) were carried out in order to validate the properties
achieved in laboratory. Prototype fasteners were
produced from some of the industrial bars by hot forging
and thread cutting, in order to demonstrate the properties
of the alloys. Overseas visits have been made to several
stainless steel manufacturers in order to identify a partner
with which to commercialise the alloy.
Trials of the “smart” rockbolt or SmartboltTM, which
undergoes a phase transformation when strained and
can thus be monitored to provide warning of impending
dangerous rock conditions, continued at a deep-level
gold mine. Mintek is negotiating with a manufacturer of
roof support systems to introduce the bolt in the mining
industry. Further investigations are planned to tailor the
properties to the conditions specific to different mining
operations (eg. gold and platinum). The development
of the Smartbolt was funded by the SIMRAC, which is
continuing to support it through commercialisation.
The Mineral Density Separator (MDS) was used
extensively to characterise iron ore samples for Kumba
Resources’ Sishen Expansion Project. The project,
which will boost Sishen’s production from 28 Mt/a to
38 Mt/a by 2009, is based on a new jigging technology
to upgrade ore that was previously unmarketable. The
MDS separates material into different density fractions
at densities exceeding 4.0, and the results can be used
to evaluate and predict the efficiencies of dense-media
and jigging operations, as well as to design and optimise
processing plants.
Ferronickel product from the Shevchenko laterite
smelting campaign
Graph illustrating the response of Smartbolts under
multiaxial loading
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Non-ferrous Metals
Mintek has been appointed as co-ordinator of the
bioleaching work package in the European Union’s
BioMinE project, part of the EU’s Sixth Framework
Programme (FP6). The project will provide the
opportunity for Mintek and other South African
organisations to interact with the European scientific
community in capacity-building and developing the next
generation of biotechnology techniques for minerals
processing.
BioMinE is an integrated project, involving 35 partners
from 14 different countries, that focuses on innovative
biotechnology-based processes for recovering or
removing metals from primary and secondary materials.
The primary objective of the bioleaching package is
to provide solutions to the technical constraints that
currently limit the broader commercial applications
of bioleaching technologies. R&D activities focus on
improvements in the performance and cost-effectiveness
of bioleaching processes, the wider application
of bioleaching to low-grade, complex and waste
metal resources, and innovations that will minimise
environmental impact and enhance sustainability.
In addition to the EU FP6 funding, Mintek’s contribution
to BioMinE is also being supported by a major strategic
investment by the DST. The ability of Mintek and
other South African organisations to participate in
and to compete for funds under the EU’s Framework
Programmes is facilitated by the SA-EU S&T Co-
operation Agreement signed in 1996.
Large-scale piloting of Mintek’s heap bioleaching
technology for primary copper sulphide ores is scheduled
to begin at the Sarcheshmeh Copper Complex in
southern Iran in the second half of 2005. Mintek has
completed a detailed engineering design of the plant,
and three pilot heaps, each of about 25 000 t, are under
construction with leaching of the first heap scheduled
to start in October. As part of the preparations for the
campaign, two 6 m columns with “intelligent” temperature
profile control, which simulates the temperature regime
within a full-scale heap, were run at Mintek under the
conditions that will be employed on-site.
The process has been designed utilising state-of-the-art
mathematical modelling of the transport phenomena in
heaps, and a control strategy has been developed and
implemented on Mintek’s Star Control System platform
that is designed to steer the operating conditions along
an optimal path throughout the duration of the process.
The heaps will be instrumented to monitor parameters
such as copper dissolution, bacterial activity and acid
consumption, and changes made to the operating regime
to optimise the rate and extent of copper dissolution,
control the heap pH and copper concentration in the
pregnant solution, and satisfy bacterial oxygen demand.
The project is being conducted in terms of a collaborative
agreement between Mintek and the National Iranian
Copper Industries Company (NICICO) that was
announced last year (Annual Report 2004).
Bioleaching columns with “intelligent” temperature
profile control, for simulating conditions in a full-scale
leach heap
Tapping of magnesium metal during the final piloting run
on the Mintek Thermal Magnesium Process
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The programme, which will run for about 18 months, is
aimed at proving the technology at a large scale, and
generating reliable operating information for commercial-
scale operations.
Mintek, in association with an industry partner and
funded by BioPAD, is engaged in a major R&D project
on the tank bioleaching of zinc sulphides. Various
microbiological and engineering strategies have
been examined with the aim of significantly reducing
processing costs, and progress on the engineering
side has led to a patent application for a novel bioleach
process configuration.
A second BioPAD-funded project involves the
development of a novel and effective technique for
innoculating bacteria into leach heaps for rapid start-
up and improved metal recoveries. The principle has
now been proven at the laboratory scale, and testwork
in 6 m columns will be conducted with the objective of
demonstrating the process under conditions applicable
to commercial-sized heaps. Given a successful outcome,
the next stage would involve piloting at a mine site.
R&D work on the Mintek Thermal Magnesium Process
has been completed successfully. During an eight-day
run in November 2004, about 30 t of feed material
were smelted in the DC pilot plant, and the magnesium
extracted as vapour for delivery to the condenser.
Fifteen taps of liquid magnesium, totalling 3 500 kg of
magnesium metal, were carried out from the condenser
during online operation. The crude magnesium was
of a consistently better quality than that produced by
conventional thermal processes, particularly with regard
to calcium.
The new condenser, which was designed to prevent the
build-up of dross that limited previous runs to about 20
hours of continuous operation, performed extremely well,
achieving continuous production with an efficiency of
85 per cent. The robustness of the process was shown
by the ability of the condenser to withstand a furnace
shutdown - for example, to clear a blocked feed port or
to add an electrode section - and immediately re-start
magnesium production and tapping.
This campaign demonstrated, for the first time, the
feasibility of a continuous atmospheric process for
thermal magnesium production. Technically, the process
is now ready for scaling up to a demonstration- and
further to an industrial-size operation.
A major programme of testwork was carried out for
Congo Mineral Developments (Adastra Minerals) in
support of a definitive feasibility study, which is being
undertaken by Murray & Roberts and GRD Minproc, on
the Kolwezi Tailings Project in the DRC. Most of the work
was concerned with manganese removal from the cobalt
electrolyte and the precipitation of cobalt salts, but some
solvent extraction and copper electrowinning work was
also undertaken. The Kolwezi project, which consists of
112.8 Mt of high-grade oxide tailings, has the potential
to be one of the world’s largest and lowest-cost cobalt
producers.
Preliminary comminution and metallurgical testwork was
started on the Kalukundi copper-cobalt deposit in the
DRC. High recoveries were obtained for both copper
and cobalt, and larger-scale testwork is planned for the
current year. This work forms part of the project feasibility
study, managed by MDM Ferroman, for Africo Resources
Ltd.
Leaching testwork was carried out for Casmin SPRL,
which is constructing a cobalt processing plant at
Kambove in the DRC, and sulphate and carbonate salts
produced for testing in the market. Limited leaching
testwork was also conducted for Metorex’s Ruashi-Etoile
copper cobalt project.
Laboratory-scale milling and flotation work was
conducted on samples from the Hunters Road nickel
deposit in Zimbabwe in order to evaluate the variability
of the ore. The results showed that a composite of the
ore zones could be treated to obtain a final concentrate
meeting the grade and recovery specified by the Bindura
Nickel Corporation. Further work was recommended to
optimise the flowsheet and conditions.
Process development work for the Kolwezi Tailings
Project – manganese removal
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Preliminary work was done for Mopani Copper Mines
(Botswana) on the development of a flowsheet for the
purification of cobalt electrolyte, and piloting work is
planned for 2005.
A number of concentration methods, including magnetic
separation, heavy media separation and flotation, were
tested for upgrading samples from Caledonia Mining’s
Nama cobalt project in northern Zambia.
At the end of the period under review, Vancouver-based
Formation Capital Corp. commissioned Mintek to develop
a hydrometallurgical flowsheet for its Idaho Cobalt Project
(ICP). The ICP, a high-grade primary cobalt deposit
unique to North America, is currently in the bankable
feasibility and advanced permitting stage of development.
A pilot Bateman Pulsed Column (BPC) was installed
and operated at Anglo American Research Laboratories
to compare the performance with conventional mixer-
settlers for extracting zinc from pregnant leach solution
generated by leaching Zincor tailings. The chemical
performance of the extraction and stripping circuits in
both equipment configurations was identical, and it
was demonstrated that the BPC is a viable alternative
contactor to mixer-settlers in terms of recoveries.
Removal of manganese from zinc electrolyte using
air/SO2 on a large batch scale was tested successfully
for Kumba Resources. This technology, which will allow
the company to process zinc concentrates with a higher
manganese content than it is able to at present, will
probably be implemented in 2005.
Comminution, heavy liquid separation and leaching
testwork were carried out as part of a feasibility
study, managed by Green Team International (GTI) of
Johannesburg, on the oxide zinc mineralisation at Sierra
Mojada, Mexico, for Metalline Mining Co.
A project on ion exchange fibres for metal recovery
was initiated under the technology bilateral agreement
with Belarus, and funded by the Innovation Fund. The
initial focus was on the removal of copper from cobalt
electrolyte. The fibres were prepared by the Institute
of Physical Organic Chemistry (IPOC) of the National
Academy of Sciences of Belarus, and evaluated at
Mintek with encouraging results. Follow-up work will be
done with Bateman to compare the costs of fibres versus
conventional resins. Ion exchange fibres have a great
kinetic advantage over granular ion exchangers, due to
a short diffusion track of the absorbable ion in the fibre,
and could potentially minimise the very large volumes of
solutions on ion exchange plants. An investigation into
the use of the fibres for gold recovery, which involves
grafting the Minix gold-selective active group onto the
fibre, was also started.
An industrial-scale melting trial was performed to
manufacture an Al-10%Ti master alloy using Al-Ti
concentrate produced in the 200 kVA DC arc furnace.
This work forms part of a three-year project sponsored
by the Innovation Fund to research the production of
additives (grain refiners and hardeners) for aluminium
and titanium alloys by aluminothermic reduction of
oxides in a DC arc furnace. The properties of the alloy
(grain refining efficiency and the dissolution rates) were
found to be comparable to those of a commercial master
alloy. However, the viability of the new process will be
determined by whether it is more cost effective to use the
Al-Ti concentrate as a source of titanium units compared
to using titanium scrap.
Recovery of uranium by ion exchange (top), and
precipitation of uranium peroxide (U3O8)
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Industrial Minerals
Metallurgical testwork was carried out on about 6 t of
ore from the Langer Heinrich uranium project in Namibia
in support of the bankable feasibility study, conducted
by GRD Minproc, for Australian company Paladin
Resources. The work included feed preparation by
scrubbing and attritioning, alkaline (carbonate) leaching
at atmospheric pressure and elevated temperature, ion
exchange and precipitation of uranium peroxide. The
calcined products generally contained about 90 per cent
U3O
8, and complied with published specifications for
uranium concentrates. At the beginning of May 2005,
Paladin approved the development of the project, which
will be the first conventional uranium mining operation to
be developed outside of Canada in the past twenty years.
Uranium production is scheduled to begin in September
2006.
Bench-scale leaching and recovery work was begun on
process development for Aflease Gold and Uranium’s
Dominion uranium project.
Laboratory-scale work was undertaken for AngloGold
Ashanti to assist with upgrading the uranium circuit
at Vaal River Operations. AngloGold Ashanti plans to
upgrade the South Uranium Plant to maintain uranium
production for at least an additional 11 years by exploiting
the by-product uranium reserves associated with its new
Moab Khotsong Shaft.
The movement and handling of radioactive material in
South Africa is subject to the Nuclear Energy Act (NEA).
Mintek is registered with the National Nuclear Regulator
(NNR), and is authorised by the DME to possess and
process source material (natural uranium ore or U3O
8)
with a uranium content not exceeding 50 kg at any one
time. Separate transport and (in the case of material
from outside South Africa) import permits are obtained
from the DME for each sample brought to Mintek. Before
the permits are granted, the NNR ascertains the level of
radioactivity of the sample, and that the exporting country
will accept the processed material back at the end of the
project. The transport company must also be registered
with the NNR. Mintek’s environmental officer has passed
the examinations set by the NNR to be registered as an
official Radiation Protection Officer.
A major programme of testwork was begun to evaluate
ore samples from CVRD’s manganese exploration
projects in Gabon. The work, which consists of scrubbing,
screening, gravity concentration, and density separation
tests on about fifty 500 kg samples each month, is
expected to continue until the end of 2005. CVRD,
which is also developing the Moatize coal project in
Mozambique and exploring for diamonds and various
metals in Angola, has entered into an MOU with Mintek,
whereby Mintek will act as the “preferred supplier” of
testwork for the company’s projects in Africa.
Pilot-scale gravity and magnetic separation testwork was
done on an alluvial chromite sample from Zimbabwe, and
the sample was successfully upgraded to foundry sand
specifications.
Milling, thickening and pressure filtration tests on
kimberlite tailings
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Attritioning, magnetic separation, and two pilot-scale
DMS runs were conducted to develop a flowsheet for an
andalusite deposit in Spain.
Routine sample characterisation, using sizing and heavy
liquid separation, was carried out on various kimberlitic
ores for De Beers. An 800 t sample from Jwaneng in
Botswana was upgraded in the dense media separation
plant after milling to various size fractions at Anglo
American Research Laboratories. A bulk sample of
kimberlite from an arid area was milled, and thickening
and pressure filtration tests carried out in conjunction with
an equipment vendor, to test the feasibility of recycling
water from the tailings back to the processing plant.
An audit was performed on the milling circuit at Foskor,
and recommendations made for improving the liberation.
A computer simulation study, using JKSimMet, was used
to evaluate proposed modifications to the comminution
circuit at Vergenoeg fluorspar mine, and a mass-balance
reconciliation carried out for Samquartz.
Quality, environment and safety
Mintek holds certification for the ISO 9001 (Quality),
ISO 14001 (environment), and OHSAS 18001
(Safety and Health) standards,
confirming its commitment to
deliver high-quality products and
services that meet international
standards in these areas. In
addition, the Analytical Services
Division is certified to ISO
17025 (Testing Laboratories).
Mintek’s integrated programme
of continual improvement in
quality, environment, safety and
health is officially driven by these
standards, and its performance
is monitored by international
auditors.
Mintek’s Environmental
Management System underwent
surveillance audits in August
2004 and February 2005.
Integrated QES internal audits
were also held to ensure that
all the environmental aspects of Mintek’s activities
are addressed and managed by means of Standard
Operating Procedures, and that the requisite
emergency procedures are in place.
In August 2004, SGS (SA) Ltd audited the safety
system and programme and certified Mintek to
the international standard OHSAS 18001. A safety
surveillance audit was carried out in February 2005.
A Lost Time Injury Frequency Rate of 1.1 was
achieved in April 2005, and the current target is less
than 1.0. Two of the eight injuries in the past twelve
months were reportable injuries. A behavioural safety
programme was introduced in 2004, and further
reductions in the accident rate are anticipated.
The CDFR target was reduced from 15 per cent
to 10 per cent in September 2004. The new target
was consistently achieved until January 2005, when
some issues regarding deliveries and invoicing
increased the CDFR. These issues were identified
and corrective action taken, and Mintek’s Corporate
Quality team continues to closely monitor these areas
to ensure that services to clients remain at a high
standard.
Checking the level of radioactivity in a uranium ore
sample
SGS
SYSTEM CERTIFICATION
ISO
14001
SGS
SYSTEM CERTIFICATION
ISO
18001
SGS
SYSTEM CERTIFICATION
ISO9001:2000
18
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