Technical review by gyvwpsjkko


									Technical review

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,

                                                                                                                         Technical review
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
                                                           Scale-up work on gold-based catalysts under Project
fate of thiocyanate in the environment, and cyanide        AuTEK
destruction by ultraviolet light. Work continued towards
the accreditation of analytical methods for cyanide, and   A programme of testwork was completed as part of the

                                                                                                                         mintek annual report 2005
Mintek plans to apply for                                  pre-feasibility study on the Burnstone gold project (South

ISO 17025 certification for                                 Rand) for Vancouver-based Great Basin Gold. The work,

cyanide analysis later in                                  which consisted of gravity separation and preg-robbing

2005.                                                      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
Gas-phase sampling                                         metallurgical testwork was carried out in conjunction with
to determine cyanide
                                                           MDM Ferroman, which is responsible for process and
volitilisation rates
                                                           plant design.
at a tailings storage
facility                                                   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.
                                                                                             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

                                 A scanning electron microscope image of nanofibres
                                                                                             biosynthesis to compete with existing chemical and
                                                                                             physical methods, techniques need to be developed
     mintek annual report 2005

                                                                                             that can control the particle size to a very narrow range,
                                 RIP testwork using the Minix gold-selective resin was       as well as produce uniform shapes. A project was
                                 carried out to recover gold from a copper leach residue     begun with the University of the Free State to identify
                                 for Cominco Engineering Services Ltd.                       the biomolecules that are responsible for the reduction

                                 Project AuTEK — the collaborative initiative to develop     reaction and subsequent nanoparticle formation, which

                                 novel industrial uses for gold and increase local           could lead to a more controlled process. Another project,

                                 beneficiation — is now in its fifth year. The work on         at Rhodes University, is undertaking an initial screening

                                 catalysts for carbon monoxide oxidation has reached         of micro-organisms for their potential for synthesising
10                               product development stage. One of the potential             platinum nanoparticles.

                                 applications is in respirators, where the AuTEK catalyst    The AuTEK biomedical programme, which originally
     Technical review

                                 has the advantage of retaining its activity for much        focused on anti-tumour drugs, has broadened its
                                 longer than the conventional hopcalite catalyst, as well    investigations to include anti-HIV and anti-malarial
                                 as the ability to function in humid conditions. Prototype   agents, in collaboration with seven local and six
                                 respirators using the AuTEK gold-based catalyst will        European universities. Screening work and toxicological
                                 be submitted to the NIOSH (US) for evaluation and           studies are continuing, and in-vivo testing will start
                                 accreditation early in 2006, and the first commercial        towards the end of 2005. Work has been initiated with
                                 production is expected in 2007.                             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
                                 Gold labelling of neurologically active pentapeptides for
                                 cancer research                                             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 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

                                                             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
(Top and bottom) A pilot plant campaign for a feasibility    the Sheba’s Ridge project. The study was completed
study on a new PGM project
                                                             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.

                                                                                                                         Technical review
                                                             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

                                                                                                                         mintek annual report 2005
                                                             of waste material and to compare the flotation recoveries
                                                             from DMS concentrate and ROM material.
successful in leveraging additional funding, which now
accounts for 40 per cent of the budget. A considerable       Mintek has commissioned a dedicated milling and
contribution has been made by the NRF through THRIP,         flotation mini-plant, which is used mainly for reagent
for building infrastructure and expertise. During the        evaluation and comparative testwork. The plant
period under review, these funds were used to acquire        has a throughput capacity of 100 kg/h, and is easily
a RAMAN/Fourier Transform Infrared spectroscope and          configurable and economical to run. It is proving to be
an ASAP surface area analyser for studying adsorbed          useful for testwork where many different conditions need
species on catalyst surfaces. In 2004 the DST approved       to be evaluated, or in cases where there are only limited
a R5-million grant for an atomic force/scanning tunnelling   quantities of material available, such as from borehole
microscope for the fundamental characterisation of           cores. Examples of the kinds of work undertaken include
nanoparticles, and a further R3.7-million in 2005 for a      an independent evaluation of gangue depressants for
high-resolution SEM and nuclear magnetic resonance           a reagent manufacturer, and continuous rougher rate
spectrometer. These facilities make Mintek a leading         tests on UG2 samples containing various amounts
centre for nano-research in South Africa.                    of waste to evaluate the potential benefits of dense
                                                             media separation. The infrastructure for the main 1 t/h
Platinum Group Metals                                        milling and flotation pilot plant was also upgraded and
Exploration and development work on new platinum
group metals projects in South Africa continued at a high    Two major collaborative research projects are under
level during 2004/2005, and Mintek’s testwork facilities     way, supported by industry partners. The first involves
were heavily utilised.                                       a comparison of preconcentration methods for UG2
                                                                                              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

                                                                                              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-
                                 Mini-plant work on the evaluation of flotation reagents       order phases that strengthen and extend the life of the
                                                                                              coating. This effect has long been known, but is not well
                                 ores, and the second is looking at a number of generic       understood. This project will be resumed if an industrial
                                 problems encountered in the PGM smelting industry.           partner can be found.
                                 Science Vote-funded research is being undertaken
                                                                                              Mintek is participating in a second Innovation Fund-
     mintek annual report 2005

                                 on the classification of UG2 tailings, optical sorting of
                                                                                              sponsored project at the University of Cape Town on
                                 non-UG2 ores, new flotation cell technologies, and the
                                                                                              the development of platinum-based jewellery alloys.
                                 fundamentals of milling processes.
                                                                                              During the year under review, the properties of a range of
                                 Funding has been approved for a THRIP project, which         compositions based on 95%Pt, were evaluated for their
                                 will start in the 2005 financial year, to investigate the     suitability for use by small-scale jewellers. This work will
                                 limiting factors in the PGM smelting process. All three of   continue during 2005/2006.
                                 the major platinum producers are supporting the project,
                                                                                              Mintek has entered into an agreement with Johnson
                                 which will include studies such as flow behaviour, the
12                               solid phases, disengagement of the matte from slag,
                                                                                              Matthey Catalysts to act as a test facility for the Smopex®
                                                                                              technology. Smopex is a new metal scavenging system
                                 interactions between the furnace gases and refractory
                                                                                              that uses polyolefin-base ion exchange fibres with high
     Technical review

                                 materials, and matte liquidus temperatures.
                                                                                              loading capabilities to recover low levels of precious
                                 A long-term DC furnace campaign was initiated to             metals from process streams. With a local testing facility,
                                 recover PGMs from revert tailings and other wastes for       the costs of transporting the test solutions will be lower,
                                 one of the platinum producers. This material is difficult     and there will be less chance of the solutions ageing.
                                 to process conventionally because of its high chromium
                                 and low base-metal sulphide content. By the end of the
                                                                                              DC arc smelting of PGM revert tailings
                                 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)
                                                               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
Ferronickel product from the Shevchenko laterite
                                                               roof support systems to introduce the bolt in the mining
smelting campaign
                                                               industry. Further investigations are planned to tailor the
                                                               properties to the conditions specific to different mining
                                                               operations (eg. gold and platinum). The development
Ferrous Metals                                                 of the Smartbolt was funded by the SIMRAC, which is

Mintek acted as manager, assisted by Bateman Metals,           continuing to support it through commercialisation.

GBM Minerals Engineering Consultants, and Wardell              The Mineral Density Separator (MDS) was used

                                                                                                                              Technical review
Armstrong International (WAI), for the preliminary             extensively to characterise iron ore samples for Kumba
feasibility study on Oriel Resources’ Shevchenko               Resources’ Sishen Expansion Project. The project,
ferronickel project in Kazakhstan. Based on the positive       which will boost Sishen’s production from 28 Mt/a to
results, Oriel commissioned a Definitive Feasibility Study      38 Mt/a by 2009, is based on a new jigging technology
(DFS), with Bateman as lead engineers, partnered by            to upgrade ore that was previously unmarketable. The
ThyssenKrupp company Polysius, WAI and Mintek. As              MDS separates material into different density fractions
part of the study, about 190 t of calcined lateritic ore was   at densities exceeding 4.0, and the results can be used

                                                                                                                              mintek annual report 2005
smelted in Mintek’s DC arc pilot plant at power levels         to evaluate and predict the efficiencies of dense-media
of up to 1.5 MW, producing 11.5 t of ferronickel alloy at      and jigging operations, as well as to design and optimise
nickel grades and recoveries in line with targets.
                                                               processing plants.
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        Graph illustrating the response of Smartbolts under
                                                               multiaxial loading
first ferronickel production by early 2008. At full capacity,
the project would produce 140 000 t of ferronickel per

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
                                                                                             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
     mintek annual report 2005

                                                                                             implemented on Mintek’s Star Control System platform

                                 Bioleaching columns with “intelligent” temperature          that is designed to steer the operating conditions along
                                 profile control, for simulating conditions in a full-scale   an optimal path throughout the duration of the process.
                                 leach heap                                                  The heaps will be instrumented to monitor parameters
                                                                                             such as copper dissolution, bacterial activity and acid
                                                                                             consumption, and changes made to the operating regime
                                 Non-ferrous Metals                                          to optimise the rate and extent of copper dissolution,
                                                                                             control the heap pH and copper concentration in the
14                               Mintek has been appointed as co-ordinator of the            pregnant solution, and satisfy bacterial oxygen demand.
                                 bioleaching work package in the European Union’s
                                 BioMinE project, part of the EU’s Sixth Framework           The project is being conducted in terms of a collaborative
     Technical review

                                 Programme (FP6). The project will provide the               agreement between Mintek and the National Iranian

                                 opportunity for Mintek and other South African              Copper Industries Company (NICICO) that was

                                 organisations to interact with the European scientific       announced last year (Annual Report 2004).
                                 community in capacity-building and developing the next
                                 generation of biotechnology techniques for minerals
                                 processing.                                                 Tapping of magnesium metal during the final piloting run
                                 BioMinE is an integrated project, involving 35 partners     on the Mintek Thermal Magnesium Process

                                 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
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
                                                            Process development work for the Kolwezi Tailings
innoculating bacteria into leach heaps for rapid start-     Project – manganese removal
up and improved metal recoveries. The principle has
now been proven at the laboratory scale, and testwork       Congo Mineral Developments (Adastra Minerals) in
in 6 m columns will be conducted with the objective of      support of a definitive feasibility study, which is being
demonstrating the process under conditions applicable       undertaken by Murray & Roberts and GRD Minproc, on
to commercial-sized heaps. Given a successful outcome,      the Kolwezi Tailings Project in the DRC. Most of the work

                                                                                                                            Technical review
the next stage would involve piloting at a mine site.       was concerned with manganese removal from the cobalt
                                                            electrolyte and the precipitation of cobalt salts, but some
R&D work on the Mintek Thermal Magnesium Process            solvent extraction and copper electrowinning work was
has been completed successfully. During an eight-day        also undertaken. The Kolwezi project, which consists of
run in November 2004, about 30 t of feed material           112.8 Mt of high-grade oxide tailings, has the potential
were smelted in the DC pilot plant, and the magnesium       to be one of the world’s largest and lowest-cost cobalt                                 15
extracted as vapour for delivery to the condenser.          producers.

                                                                                                                            mintek annual report 2005
Fifteen taps of liquid magnesium, totalling 3 500 kg of
                                                            Preliminary comminution and metallurgical testwork was
magnesium metal, were carried out from the condenser
                                                            started on the Kalukundi copper-cobalt deposit in the
during online operation. The crude magnesium was
                                                            DRC. High recoveries were obtained for both copper
of a consistently better quality than that produced by
                                                            and cobalt, and larger-scale testwork is planned for the
conventional thermal processes, particularly with regard
                                                            current year. This work forms part of the project feasibility
to calcium.
                                                            study, managed by MDM Ferroman, for Africo Resources
The new condenser, which was designed to prevent the        Ltd.
build-up of dross that limited previous runs to about 20
                                                            Leaching testwork was carried out for Casmin SPRL,
hours of continuous operation, performed extremely well,
                                                            which is constructing a cobalt processing plant at
achieving continuous production with an efficiency of
                                                            Kambove in the DRC, and sulphate and carbonate salts
85 per cent. The robustness of the process was shown
                                                            produced for testing in the market. Limited leaching
by the ability of the condenser to withstand a furnace
                                                            testwork was also conducted for Metorex’s Ruashi-Etoile
shutdown - for example, to clear a blocked feed port or
                                                            copper cobalt project.
to add an electrode section - and immediately re-start
magnesium production and tapping.                           Laboratory-scale milling and flotation work was
                                                            conducted on samples from the Hunters Road nickel
This campaign demonstrated, for the first time, the
                                                            deposit in Zimbabwe in order to evaluate the variability
feasibility of a continuous atmospheric process for
                                                            of the ore. The results showed that a composite of the
thermal magnesium production. Technically, the process
                                                            ore zones could be treated to obtain a final concentrate
is now ready for scaling up to a demonstration- and
                                                            meeting the grade and recovery specified by the Bindura
further to an industrial-size operation.
                                                            Nickel Corporation. Further work was recommended to
A major programme of testwork was carried out for           optimise the flowsheet and conditions.
                                 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.
                                                                                              Recovery of uranium by ion exchange (top), and
                                                                                              precipitation of uranium peroxide (U3O8)
                                 A pilot Bateman Pulsed Column (BPC) was installed
                                 and operated at Anglo American Research Laboratories
     mintek annual report 2005

                                 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.

16                               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
     Technical review

                                 the company to process zinc concentrates with a higher
                                 manganese content than it is able to at present, will
                                 probably be implemented in 2005.                             and could potentially minimise the very large volumes of
                                                                                              solutions on ion exchange plants. An investigation into
                                 Comminution, heavy liquid separation and leaching
                                                                                              the use of the fibres for gold recovery, which involves
                                 testwork were carried out as part of a feasibility
                                                                                              grafting the Minix gold-selective active group onto the
                                 study, managed by Green Team International (GTI) of
                                                                                              fibre, was also started.
                                 Johannesburg, on the oxide zinc mineralisation at Sierra
                                 Mojada, Mexico, for Metalline Mining Co.                     An industrial-scale melting trial was performed to
                                                                                              manufacture an Al-10%Ti master alloy using Al-Ti
                                 A project on ion exchange fibres for metal recovery           concentrate produced in the 200 kVA DC arc furnace.
                                 was initiated under the technology bilateral agreement       This work forms part of a three-year project sponsored
                                 with Belarus, and funded by the Innovation Fund. The         by the Innovation Fund to research the production of
                                 initial focus was on the removal of copper from cobalt       additives (grain refiners and hardeners) for aluminium
                                 electrolyte. The fibres were prepared by the Institute        and titanium alloys by aluminothermic reduction of
                                 of Physical Organic Chemistry (IPOC) of the National         oxides in a DC arc furnace. The properties of the alloy
                                 Academy of Sciences of Belarus, and evaluated at             (grain refining efficiency and the dissolution rates) were
                                 Mintek with encouraging results. Follow-up work will be      found to be comparable to those of a commercial master
                                 done with Bateman to compare the costs of fibres versus       alloy. However, the viability of the new process will be
                                 conventional resins. Ion exchange fibres have a great         determined by whether it is more cost effective to use the
                                 kinetic advantage over granular ion exchangers, due to       Al-Ti concentrate as a source of titanium units compared
                                 a short diffusion track of the absorbable ion in the fibre,   to using titanium scrap.
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
U3O8, 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
                                                               Milling, thickening and pressure filtration tests on
Bench-scale leaching and recovery work was begun on            kimberlite tailings

process development for Aflease Gold and Uranium’s

                                                                                                                           Technical review
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                                                                                                17
production for at least an additional 11 years by exploiting

                                                                                                                           mintek annual report 2005
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 U3O8)
with a uranium content not exceeding 50 kg at any one          projects in Gabon. The work, which consists of scrubbing,
time. Separate transport and (in the case of material          screening, gravity concentration, and density separation
from outside South Africa) import permits are obtained         tests on about fifty 500 kg samples each month, is
from the DME for each sample brought to Mintek. Before         expected to continue until the end of 2005. CVRD,
the permits are granted, the NNR ascertains the level of       which is also developing the Moatize coal project in
radioactivity of the sample, and that the exporting country    Mozambique and exploring for diamonds and various
will accept the processed material back at the end of the      metals in Angola, has entered into an MOU with Mintek,
project. The transport company must also be registered         whereby Mintek will act as the “preferred supplier” of
with the NNR. Mintek’s environmental officer has passed         testwork for the company’s projects in Africa.
the examinations set by the NNR to be registered as an
                                                               Pilot-scale gravity and magnetic separation testwork was
official Radiation Protection Officer.
                                                               done on an alluvial chromite sample from Zimbabwe, and
A major programme of testwork was begun to evaluate            the sample was successfully upgraded to foundry sand
ore samples from CVRD’s manganese exploration                  specifications.
                                                                                                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                       T   EM          AT

                                                                                                deliver high-quality products and
                                                                                                services that meet international

                                                                                                                                       ISO 9
                                                                                                standards in these areas. In

                                                                                                addition, the Analytical Services                 200
                                                                                                                                                          0     SGS
                                                                                                Division is certified to ISO
                                                                                                17025 (Testing Laboratories).
                                                                                                                                                  T   EM          AT
                                                                                                Mintek’s integrated programme                  YS

                                 Checking the level of radioactivity in a uranium ore           of continual improvement in
                                 sample                                                         quality, environment, safety and

                                                                                                health is officially driven by these

                                                                                                standards, and its performance                        1
                                 Attritioning, magnetic separation, and two pilot-scale
                                                                                                is monitored by international
     mintek annual report 2005

                                 DMS runs were conducted to develop a flowsheet for an
                                                                                                auditors.                                             EM
                                                                                                                                                  T                 I
                                 andalusite deposit in Spain.                                                                                  YS

                                                                                                Mintek’s Environmental
                                 Routine sample characterisation, using sizing and heavy        Management System underwent

                                 liquid separation, was carried out on various kimberlitic      surveillance audits in August

                                 ores for De Beers. An 800 t sample from Jwaneng in             2004 and February 2005.                               1
                                 Botswana was upgraded in the dense media separation            Integrated QES internal audits
                                 plant after milling to various size fractions at Anglo         were also held to ensure that

18                               American Research Laboratories. A bulk sample of               all the environmental aspects of Mintek’s activities

                                 kimberlite from an arid area was milled, and thickening        are addressed and managed by means of Standard
                                                                                                Operating Procedures, and that the requisite
     Technical review

                                 and pressure filtration tests carried out in conjunction with
                                 an equipment vendor, to test the feasibility of recycling      emergency procedures are in place.

                                 water from the tailings back to the processing plant.          In August 2004, SGS (SA) Ltd audited the safety
                                                                                                system and programme and certified Mintek to
                                 An audit was performed on the milling circuit at Foskor,
                                                                                                the international standard OHSAS 18001. A safety
                                 and recommendations made for improving the liberation.
                                                                                                surveillance audit was carried out in February 2005.
                                 A computer simulation study, using JKSimMet, was used
                                 to evaluate proposed modifications to the comminution           A Lost Time Injury Frequency Rate of 1.1 was
                                                                                                achieved in April 2005, and the current target is less
                                 circuit at Vergenoeg fluorspar mine, and a mass-balance
                                                                                                than 1.0. Two of the eight injuries in the past twelve
                                 reconciliation carried out for Samquartz.
                                                                                                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

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