Comminution Laboratory Services

Equipment and scale of operation• Bond Work Indices – for rod and ball mills.• JKTech drop weight tester and abrasion mill – the test provides

information on the breakage and abrasion properties of rocks, which can be used to simulate and design mainly crushing equipment and AG/SAG mills.

• SAG Mill Comminution (SMC) test, developed as a lower-cost precision technique to determine the impact breakage characteristics of drill core samples. SMC generates a drop weight index, which is a measure of the rock strength when broken under impact.

• Advanced Media Competency tests – these tests are conducted to evaluate the competency of the ore as the grinding medium.

• Grindmill tests – batch mill used for estimating breakage and selection function parameters, which can be used as an aid in mill design.

• Stirred milling tests – generally used for ultrafi ne milling, i.e. when product sizes below 10 μm are required.

• Scrubbing tests – these tests are normally conducted to remove coatings such as oxide coatings or clay layers from particles. Various scrubber parameters such as residence time, L/S ratio, scrubber speed, and charge level can be evaluated. The results obtained from the laboratory-scale scrubbing tests indicate the residence time and scrubbing parameters required to obtain a “clean” product. Confi rmatory pilot-scale scrubbing tests may then be undertaken to verify and fi ne-tune the scrubbing conditions.

Particle density and bulk density of samples• A Symantec Particle Size Analyzer is used for particle size analysis

from 850 μm to 0.1 μm in dry and aqueous suspensions.

A major partnership has been established with CSIR Miningtek and Rocklab, who carry out the following tests:• Bond Crushability (Impact) Work Index – this test provides

the energy requirements for a given crushing operation. The information is used by crusher manufacturers for crusher design and selection.

• Bond Abrasion Test – this test is used to obtain an indication of the

relative abrasiveness of an ore on a standard metal sample. The results can be used to estimate the relative steel ball, mill liner, and crusher liner consumption.

• Uniaxial Compressive Strength tests - The uniaxial compressive strength is a function of the maximum force recorded at the point of ductile-brittle transition of a sample under slow compression. The results are generally used in the selection of primary crushers and mineral breakers.

Mintek has established a strategic alliance with Orway Mineral Consultants (OMC) of Australia. Mintek conducts a suite of testwork as specifi ed by OMC, and the results are used in conjunction with OMC’s large database of ore types to characterise the likely behaviour of the ore in a mill, thus enabling a choice to be made on the type of milling circuit required.

Projects• Scrubbing projects on several kimberlite ores to determine the

optimal residence time required for effi cient scrubbing. • Testwork using the OMC procedure for several gold projects in

South Africa and West Africa, particularly Ghana. • General characterisation tests on gold ores, PGMs (UG2 and

Merensky), base metals (copper, zinc, iron) and industrial minerals. • Bench-scale comminution testwork for Everest South (Aquarius

Platinum), Two Rivers (Avmin), Blue Ridge (Cluff), Kalplats (Harmony).

• Grindmill testwork and simulation for BHP Billiton, Kumba Resources, Gold Fields and Polysius Krupp.

• Feasibility studies for Barrick Gold (Tanzania) and the Langer Heinrich uranium deposit in Namibia.

Key StaffJan Lagendijk - Chief Engineer. More than 15 years’ experience in the process industries. Musa Sadiki, National Diploma in Chemical Engineering, 6 years’ experience.Philemon Shalang - Chief Operator. More than 24 years’ experience in various mineral processing techniques.

Comminution Laboratory ServicesComminution Laboratory ServicesComminution Laboratory ServicesComminution Laboratory ServicesComminution Laboratory ServicesComminution Laboratory ServicesLaboratory-scale comminution techniques followed by computer simulation are becoming increasingly popular. Laboratory or bench-scale tests are relatively inexpensive, much quicker than piloting, and require only a small sample. Mintek offers a whole range of laboratory facilities and testwork to the mining and minerals industry. The results from these tests are used for general characterisation of ores, simulations, scale-up studies, and techno-economic evaluations.

For further information contact Jan Lagendijk - Chief Engineer, Comminution Laboratory ServicesTelephone +27 11 709-4550, Fax: +27 11 709-4427,e-mail: janl@mintek.co.za

Specialists in mineral andmetallurgical technology

Comminution Laboratory ServicesComminution Laboratory ServicesComminution Laboratory ServicesComminution Laboratory Services

Agit Singh - Manager: Minerals ProcessingTelephone +27 11 709-4339, Fax +27 11 709-4427,e-mail agits@mintek.co.za

Mintek200 Malibongwe Drive, Randburg, South AfricaPrivate Bag X3015, Randburg 2125 South AfricaTel: +27 11 709 4111www.mintek.co.za

Comminution Pilot Plant

Equipment and scale of operation• Concrete drying pad for ore drying and sizing, capacity up to

500 t of material.• Trommel screen for continuous classifi cation of ore from 150

mm to 50 mm.• Crushing and blending facility, consisting of a 20 by 10 inch

jaw crusher followed by a 2-foot standard head Symons cone crusher in closed circuit with a vibrating screen. Kilowatt-hour meters are used to measure the power consumption of the jaw and cone crushers. Access points are available to take belt cuts of all the streams in the circuit.

AG/SAG pilot mill• Internal dimensions: 1.7 m diameter by 0.6 m length.• Typical throughput: 0.5 to 1.5 t/h, depending on type of ore.• Accurate instrumentation for feed rate, charge mass and mill

power.

Pebble, ball, and rod mills• Internal dimensions: 0.86 m diameter by 1.5 m length

(smaller mills available).• Typical throughputs: 0.3 to 1.0 t/h depending on feed

material.• Accurate instrumentation for feed rate and mill power.• Various classifi ers are used with these mills, including

hydrocyclones, screens, and spiral classifi ers.• Pebble crushers are frequently used in certain AG circuit

options.

Major projects completed in the past few yearsEvaluation of AG, SAG, ball or pebble milling circuits for base metal ores:• Nkomati nickel project for Avmin, South Africa.• Agua Rica copper ore project for BHP Copper, Chile.Pilot-scale testwork to evaluate AG, SAG, ball or rod milling circuits on South African PGM ores:• Impala Platinum UG2 and Merensky ores.• Two Rivers (Avmin).• Everest South UG2 (Aquarius Platinum).• Ngezi (Zimbabwe Platinum Mines).• Winnaarshoek UG2 (Impala Platinum).Target gold project for Avgold, SA - evaluation of AG, SAG, ball and pebble milling circuits. Metallurgical audits of comminution circuits (Impala Platinum and Lonmin Platinum). Sampling campaigns, mass balance reconciliation, laboratory and pilot-scale testwork, steady-state computer simulations to evaluate possible circuit modifi cations to increase throughput and maintain or improve fi neness of grind.

Key StaffAdrian Hinde - Specialist: Particulate systems. More than 25 years’ experience in comminution R&D.Jan Lagendijk - Chief Engineer. More than 15 years’ experience in the process industries.A team of 7 operators headed by Patrick Tshisikhawe and Philemon Shalang, each with more than 15 years’ experience in the operations of metallurgical pilot plants and laboratory. equipment.

Comminution Pilot PlantComminution Pilot PlantComminution Pilot PlantComminution Pilot PlantComminution Pilot PlantComminution Pilot PlantMintek offers both bench- and pilot-scale testing facilities. The results from these tests are used for simulations, scale-up studies and techno-economic evaluations.

For further information contactAgit Singh - Manager: Minerals ProcessingTelephone: +27 11 709 4339Fax: +27 11 709 4427e-mail: agits@mintek.co.za

Specialists in mineral andmetallurgical technology

Comminution Pilot PlantComminution Pilot PlantComminution Pilot PlantComminution Pilot Plant

Mintek200 Malibongwe Drive, Randburg, South AfricaPrivate Bag X3015, Randburg 2125 South AfricaTelephone: +27 11 709 4111www.mintek.co.za

Flotation

EquipmentFully equipped fl otation laboratories for routine and specialised testwork.• Six Denver D-12 laboratory fl otation machines.• Leeds-design fl otation system.• Wemco and Agitair fl otation machines.• Full range of fl otation cells from 1 to 10 litres.• Facility to measure and record parameters such as sulphide

ion concentration, redox potential, pH, oxygen levels, xanthate concentration, and temperature.

• Procedures for conducting rougher rate fl otation tests and fi tting to rate models.

An extensive range of modular pilot-scale equipment for use on small (60 kg/h) and large (up to 1 t/h) fl otation plant runs for parameter investigations and plant design data-gathering exercises.• Autogenous mill (a bleed stream is fed directly into the fl otation plant).• A wide range of pilot-scale mills, that can be run in rod or ball mode,

with capacities from 250 - 1000 kg/h.• Two smaller mills, 0.6 m diameter by 1 m long, are used for smaller

scale testwork.• Stirred mill detritor.• High Pressure Grinding Roll (1 t/h).• A range of classifi cation systems (microscreens, spiral classifi ers,

sieve bends, and cyclones), conditioner types (Sala and Denver), and peristaltic pumps sizes for reagent delivery.

• Flotation cells for specifi c on-site applications.• One 18 l OK fl ash fl otation cell.• One Maxwell-type cell.• Two modifi ed single Sala 80 l cells with extra-large impellers.• Six 180 l tank cells, skid-mounted for on-site testwork.• Jameson cells and Multotech column fl otation cells can be hired as

required.• Flotation cells, modular, for general work.• Eight banks of 80 l Sala cells for rougher and scavenger fl otation, each

bank comprising four or six cells, all equipped with automatic level controllers.

• Six banks of 30 l Sala cells, usually used for cleaner fl otation, each bank consisting of two, four, or six cells.

• Six banks of Denver 11 l cells.• A dedicated 100 kg/h milling and fl otation plant is available for reagent

evaluation and comparative testwork.A full range of in-house analytical facilities is available, with turnaround times of between 3 and 8 hours. Plant runs can be scheduled for periods ranging from a few hours to continuous runs over several days.

A dedicated, experienced team is available to run the pilot plant and to manually measure all plant parameters. The plant is usually sampled manually every hour, and the data is processed through commercial mass-balancing packages.The pilot plant is set up so that air fl owrates and bubble sizes in the cells can be measured. This is useful for modelling purposes. The plant is controlled via the Mintek FloatStar system, which reduces start-up time and allows tight level control at setpoints. This reduces variations in the data due to plant disturbances, and allows study of the effects of small level changes.

Recent projectsBase metals• Nkomati (Ni-Cu-PGMs) - major pilot-plant campaign to derive

concentrator design parameters for expansion. On-site piloting (at Tati Nickel) to recover precious metals from Activox® residues.

• Bindura Nickel – process design. • Marakand Minerals – Cu-Pb-Zn recovery.

Platinum-group metals• Bushveld Complex — Process development for Mototolo (Anglo

Platinum/Xstrata), Blue Ridge and Sheba’s Ridge (Ridge Mining), Everest South (Aquarius Platinum), Leeuwkop (Afplats), Boikgantsho (Anooraq/Anglo Platinum), Elandsfontein (Eland Platinum), Smokey Hills (Platinum Australia), and Tussenkomste (Platmin).

Other deposits• Process development for Kalplats (Platinum Australia/ARM).

Miscellaneous testwork• Independent evaluation of gangue depressants for a reagent

manufacturer. • Continuous rougher testwork on UG2 ores. • Comparison of PGM fl otation recoveries from DMS concentrates and

ROM material.

Key StaffMike Bryson - Specialist. PhD in Chemistry on fl otation reagents. Ten years’ R&D experience on the fundamentals of fl otation chemistry before taking responsibility for all sulphidemineral fl otation process development work at Mintek. Has supervised many major pilot-plant projects on the fl otation of sulphide, gold and PGM ores.Dhiraj Maharaj. BSc Chem. Eng. Five years’ experience in developing process fl owsheets for a range of PGM and base metal projects.Ravi Roy. BSc Chem. Eng. Four years’ experience in fundamental aspects of fl otation processes.

FlotationFlotationMintek can develop and evaluate fl otation procedures for new ores, according to specifi c product grade and recovery requirements, by applying our expertise on the selection of plant confi guration, reagents, and conditions, and by running extended pilot-scale testwork. We also offer a consultancy service to help existing plants improve their operations.

For further information contactMike Bryson - SpecialistTelephone +27 11 709-4446, Fax: +27 11 709-4427,E-mail: mikeb@mintek.co.za

Specialists in mineral andmetallurgical technology

Agit Singh - Manager: Minerals ProcessingTelephone +27 11 709-4339, Fax: +27 11 709-4427,E-mail: agits@mintek.co.za

Mintek200 Malibongwe Drive, Randburg, South AfricaPrivate Bag X3015, Randburg 2125 South AfricaTel: +27 11 709 4111www.mintek.co.za

Physical Separation

ServicesHeavy Liquid Separation and Dense Media SeparationA laboratory is set up to carry out preliminary “sink-fl oat” separations up to densities of 4 g/cm³. Density classes with intervals of 0.05g/cm³ can be evaluated. The data is used to construct washability curves. From these tests, investigative projects are designed to treat bulk samples in the 2-5t/h DMS cyclone plant, which operates, using either cyclones 250 mm or 350 mm in diameter. The plant is able to treat samples from 100 kg to 100 t in the larger pilot applications. Both density beads and Heavy Liquid Separation analyses on the sink and fl oat fractions are used to confi rm the separation density. Projects on diamondiferous gravel, andalusite, iron, PGMs, gold, copper-nickel, and chromite ores have been run successfully.

Other GravityMintek has a range of bench and pilot-scale equipment, including:• Wilfl ey shaking tables (one-eighth and half-size).• A variety of spiral concentrators, including a large diameter coal spiral that

can be run either in batch mode or continuously at solids feed rates from 1 t/h to 4 t/h.

• Fines separators such as the Falcon, 3 inch and 7 inch Knelson concentrators, as well as a laboratory Superbowl laboratory and pilot jigs. The pilot units use the unique Apic air-pulsed technology. They operate at up to 35 t/h and can treat material as coarse as 35 mm. These jigs are electronically controlled, and are mobile.

• Mineral Density Separator for characterising samples into closely spaced density fractions. The results could be used to assist in plant performance, as well as to evaluate the amenability of using Jigging as a processing option.

• laboratory and pilot Linatex T-type classifi er treating up to 1 t/h solids, and Eriez Crossfl ow.

• Laboratory Mozley multigravity separator.• Kipp Kelly pilot air (pneumatic) table feed rate ±100-300kg/h.

Classifi cationWet and dry classifi cation is carried out using a variety of equipment:• Standard laboratory sieve shakers.• Pilot screening facilities, including a number of 36 inch diameter Sweco

screens and double deck Rotex screen.• Hydrocyclone pilot plant incorporating 25 mm, 65 mm, 100 mm, and

150 mm diameter cyclones.• Air classifi er used for dry classifi cation down to 5 μm.

Electrostatic separationMintek has a bench-scale Ultrastat separator, an improvement on the standard plate separator, which is available for laboratory scale testwork.

Magnetic separationMintek has a laboratory rare-earth oxide permanent high-intensity roll separator for dry separation, with barium ferrite, samarium cobalt, and neodymium boron iron rolls. A pilot separator with two rolls treating a nominal 300 kg/h is also equipped with barium ferrite and neodymium magnets. Wet, fi ne magnetic separation is done on bench and pilot scale, using low-intensity drum separators. Wet, high intensity magnetic separation (WHIMS) is done at both laboratory and pilot scale (Jones pilot-scale separator).

Optical sortingA novel optical sorting technology has been successfully tested for the cost-effective upgrading of gold, platinum-group metal (UG2), base metal and industrial minerals ores. A full-scale unit is on site, capable of handling particle sizes of 20-100 mm at throughputs of up to 30 t/h.

Coal preparationMintek undertakes testwork on the upgrading of coal to a saleable product using dense media, centrifugal separation, jigging, spirals, and T-classifi ers, using either bulk or laboratory-scale samples. Other services include process simulation, total plant audits, and coal laboratory audits.

Recent Projects• Picobello Andalusite - Spain.• Mooinooi Chromite - testwork to upgrade recovery plant following

changes in mining methods.• Kumba Resources - characterisation of iron ores during development of

the Mineral Density Separator.• Saudi Arabia - pilot-scale testwork on phosphate ore upgrading in

conjunction with Bateman.

Key StaffHeloise Thiele - Group Head. Eight years’ experience in projects on industrial minerals, including heavy mineral sands, andalusite, chromite, iron and manganese ores.Carl Bergmann - Specialist.Danie van Wyk - Specialist.The Physical Separation Group consists of fi ve engineers, and about 15 technicians and operators.

Physical SeparationPhysical SeparationPhysical SeparationPhysical SeparationPhysical SeparationPhysical SeparationMINTEK has 70 years’ experience in developing techniques for the physical separation of metallic and non-metallic minerals. South Africa’s andalusite industry was founded on work done at Mintek. More recently, dense-media separation (DMS), has been incorporated into platinum-group metals fl owsheets, to separate barren waste rock from ore prior to milling. The benefi ciation of chromite using gravity separation and DMS, and vermiculite upgrading by dry separation techniques, have become important activities.

For further information contactHeloise Thiele - Group HeadTelephone : +27 11 709-4469Fax : +2711 709-4427e-mail : heloiset@mintek.co.za

Specialists in mineral andmetallurgical technology

Physical SeparationPhysical SeparationPhysical SeparationPhysical Separation

Carl Bergmann - SpecialistTelephone : +27 11 709-4529Fax : +2711 709-4427e-mail : carlb@mintek.co.za

Danie van Wyk - SpecialistTelephone : +27 11 709-4455Fax : +2711 709-4427 e-mail : danievW@mintek.co.za

Mintek200 Malibongwe Drive, Randburg, South AfricaPrivate Bag X3015, Randburg 2125, South AfricaTel: +27 11 709 4111 www.mintek.co.za

Sample Preparation

Facilities– Concrete drying pad for bulk sample drying and sorting

– maximum capacity 500 t.– Pilot-scale crushing and screening plant, consisting of a 20

inch by 10 inch jaw crusher followed by a 2-foot Symons cone crusher in closed circuit with a vibrating screen. The maximum reduction ratio is from -150 mm to -6 mm.

– A variety of small crushers are also available - jaw, roll, cone, and pulverisers for handling small samples up to 50 kg. Samples up to 2 t can be treated with jaw crushers and roll crushers.

– In large-scale testwork, screen analysis can be carried out using large screens or a rotary trommel screen.

– In small-scale testwork, particle size can be determined using normal wet and dry screening techniques down to 38 mm. Sub-sieve sizing to produce size fractions for chemical analysis is performed using a Cyclosizer.

– A Particle Size Analyser is used for size analysis down to 1 μm.– Ceramic and steel mills are available for dry batch milling.– Samples up to 200 kg can be blended using a double cone

blender.

– Larger samples up to 100 t have been blended using a layering technique similar to the stacker/reclaimer system used in industry. This technique is recommended for preparing representative feed for pilot plant campaigns.

Facility Capacity – Grind ROM ores to below 38µm.– Handle 3 tons per day.– All types of ores can be handled and processed in this

facility.

Other Capabilities– Viscosity measurements.– Particle density and bulk density of samples.– Preparation of standard analytical samples.– Air classifi cation.

Key StaffWalter Coko - Group Head. Seven years’ experience in minerals handling and sample preparation. This includes both bulk and laboratory samples.

Sample PreparationSample PreparationSample PreparationSample PreparationSample PreparationSample Preparation

Mintek has a fully equipped sample preparation facility. Its function is to provide support for small, medium, or large-scale operations both inside and outside Mintek with respect to sample preparation. This includes crushing, milling and blending of samples.

For further information contactWalter Coko - Group HeadTelephone: +27 11 709-4437Fax: +27 11 709-4427e-mail: walterc@mintek.co.za

Specialists in mineral andmetallurgical technology

Agit Singh - Manager: Minerals ProcessingTelephone: +27 11 709-4339,Fax: +27 11 709-4427,e-mail: agits@mintek.co.za

Mintek200 Malibongwe Drive, Randburg, South AfricaPrivate Bag X3015, Randburg 2125 South AfricaTel: +27 11 709 4111 www.mintek.co.za