Corporate Profile

Mintek is South Africa’s national mineral research organisation and it is one of the world’s leading technology organisations specialising in mineral processing, extractive metallurgy and related areas. Working closely with industry and other R&D institutions, Mintek provides service testwork, process development and optimisation, consulting and innovative products to clients worldwide.

Publications/Presentations

Azerbaijan gold mine to use Mintek-designed resin

Posted on Nov 15, 2011

Anglo Asian Mining plc has selected the Mintek-developed DOWEX™ MINIX™ ion-exchange resin for gold recovery at its Gedabek (Gädäbäy) gold-copper project in Azerbaijan.

Gedabek, which is the first operating gold mine in the south-west Asian country, was officially opened and produced its first gold in May 2009. The operation consists of an open pit mine and heap-leach facility, with gold recovery by resin-in-solution and electrowinning. Copper production will begin shortly. The mine is expected to produce more than 300 000 ounces of gold during its initial six-year mine life.

Owing to the substantial copper grade of the ore, the copper concentration in the leach solution is about 100 times that of gold. “An ordinary ion-exchange resin would become loaded with copper, with very little capacity remaining for gold,” explained Dr Roger Paul, Mintek’s General Manager of Technology, who visited the mine in June to assist with optimising the gold recovery circuit. “The DOWEX MINIX strong-base resin, however, is extremely selective for gold over all other metal cyanide complexes, and is able to achieve high gold loadings under these conditions, resulting in a greatly improved gold recovery. The Gedabek plant is the first application of the resin in a leach solution containing such high copper concentrations, and we are very pleased with its performance.”

Several important classes of gold deposit contain appreciable quantities of cyanide-soluble copper minerals that can build up in the metallurgical process solutions, resulting in gold lock-up in the circuit and reduced recoveries. “The DOWEX-MINIX resin makes low-cost heap leaching viable where, due to technological or economic considerations, is not practicable to remove the copper by flotation or acid leaching prior to cyanidation,” said Dr Paul.

Gold recovery from cyanide leach solutions with anion exchange resins is commonly practiced in the CIS countries, and western gold mining companies are now beginning to realise the economic benefits of ion exchange. Resins are more versatile than activated carbon because they can be customised to improve features such as selectivity, loading capacity, and resistance to poisoning. They can also be eluted at much lower temperatures, and unlike activated carbon do not require thermal regeneration.

Originally envisaged as an alternative to granular active carbon for gold recovery, the DOWEX MINIX resin found its first niche application in recovering gold from carbonaceous preg-robbing ores. It is used in this role at Avocet Mining’s Penjom mine in Malaysia, and formerly at the Barbrook gold plant near Barberton in South Africa. The resin, designated XZ 91419, is manufactured and supplied under licence by the Dow Chemical Company.

Mintek technology successfully used in water-purification industry

Posted on Nov 15, 2011

Mintek has commissioned a Minfurn carbon-regeneration furnace at the Rietvlei water treatment plant near Tshwane in South Africa’s Gauteng Province.

The furnace, which has a capacity of 25 kilograms of dry regenerated product per hour, restores the efficiency of the granular activated carbon (GAC) that the plant uses to adsorb dissolved organic matter before the final chlorination step in the purification process.

This is the first adaptation of the Minfurn’s unique direct resistive heating technology to an area outside the gold industry.

The Minfurn was originally designed and developed by Mintek specifically for the regeneration of GAC used to adsorb gold from solution in the carbon in pulp (CIP) and carbon in solution (CIS) recovery processes. The furnace employs a technique of direct resistive heating by means of an electrical current passed directly through the carbon bed. This results in a high degree of regeneration efficiency, with significant advantages over other regeneration technologies including low consumption of electricity, ease of operation, minimal moving parts, and low maintenance.

About 30 Minfurns have been installed in industry, mainly at small and medium-sized gold mines in Latin America. Recently, further opportunities were identified for the application of the technology in two new industry sectors – potable water treatment and food processing.

Since GAC has an affinity for organic substances and repels water, it represents and effective way of separating traces of organic matter from water. “This is particularly important in the light of recent changes in raw water quality and supply in the southern African region,” said Hylton Gidish, Mintek’s product manager for the Minfurn. “Locally, acceptable final organics levels are 20 nanograms per litre. Previously, this level was relatively easily maintained by most water works in South Africa, but with recent deterioration in both quality and supply of raw water, increasing organic matter has begun to be a problem, particularly at the smaller plants.”

The Rietvlei plant, which produces 40 million litres of drinking water a day (about 6 per cent of Tshwane’s daily requirements), was the first plant in South Africa to apply a GAC filtration system for drinking water treatment. The project, which was completed in 1999, was awarded the SA Association of Consulting Engineers national award for technical excellence in 2000. The plant was recently singled out as the best medium-sized water purification facility in South Africa.

The Minfurn installation at Rietvlei presents an ideal opportunity for commercial demonstration of the technology in the potable water treatment industry. Similarly, a food-processing company in the USA has successfully tested a Minfurn for regenerating spent GCA used in the removal of unwanted colour from their lactic acid product.

“The GAC used in the water treatment and food industries is typically finer-grained and softer than the material used for gold recovery,” explained Gidish. “The Minfurn is ideally suited for these applications, since it results in minimal abrasion of the carbon, and hence fewer losses of fine material.”

Development work is ongoing at Mintek to adapt the Minfurn and the operating procedure to GAC samples with different physical and electrical characteristics, as well as in unexplored areas of GAC application.

Pretoria matric learners scoop top science award

Posted on Nov 15, 2011

Pretoria, Gauteng, emerged as victors of this year’s national Minquiz® Science Competition held at Mintek’s campus in Randburg on 27and 28September 2010. Each of the members of the winning team walked away with a half-ounce Kruger Rand sponsored by Rand Refinery Limited worth about R4 500 a piece, while each of the schools they represented received a cash prize of R3 250, sponsored by DCM Deco Metals.

The winners competed against more than 50 other finalists, studying Grade 12 Physical Science and Mathematics at school, who had advanced to the national competition following rigorous provincial competitions in July.

The competition was introduced by Mintek, a national science council and a global leader in mineral and metallurgical innovation, in 1988 with an aim to foster excellence in Mathematics and Physical Science at school and encourage learner interest in careers in Science, Engineering and Technology.

Myra Norman, a member of the winning team from Hoërskool Pretoria-Wes described the Miquiz, experience as “phenomenal”. “It was the first time I took part in a competition like this one. I want to thank Mintek and everyone who made this opportunity possible as this event has opened doors for various possibilities in science and engineering.”

Potchefstroom, North West, were runners-up. Each of its participating students received a portable educational microscope from Advanced Laboratory Supplies. Each school represented in the team received R2 250 donated by South African entrepreneur, Mark Shuttleworth, a previous Minquiz winner and now a patron of the competition. Sasol, Secunda came third and each of its participating students received a book prize donated by Apollo Scientific while each of the schools they represented received R1 250 from the Southern African Institute of Mining and Metallurgy (SAIMM). All the learners in first, second and third positions received a one-year subscription of Quest, a science magazine published by the Academy of Science of South Africa.

All learners who participated in the competition received a certificate of participation, an issue of Quest, Grade 12 Physics, Chemistry, Mathematics and languages study guides published by Proverto, and a Sasol encyclopaedia.

Craig Andrews, of Selly Park High School in the North West province, and Antony James Lake, of Fish Hoek High School in the Western Cape, were named top learners in the Platinum and Gold category (written test) respectively. They were each awarded a Netbook valued at R2 200 and a high-end Texas Instruments scientific calculator worth R2 300, respectively donated by UK-based GFMS and Oxford Educational Supplies.

Heather Elizabeth Rae, of Eunice High School in the Free State, and Lulama Applegreen of Sol Plaatjie Secondary School in the North West, were the top girl learners in the Platinum and Gold category (written test) respectively. They were each awarded a cash prize to the value of R1 000, donated by the Council for Scientific and Industrial Research (CSIR), on top of the Texas Instrument calculators.

All the Gold and Platinum category winners and their respective teachers received Texas Instruments top-end scientific calculators.

Thirteen learners obtained a Distinction Certificate (60-79%) and received Texas Instruments basic scientific calculators.

“It was a rewarding experience and we learned a lot from Minquiz. I liked the energy, team spirit and also meeting new people who share the same goals as myself,” said Lulama Applegreen, from Sol Plaatjie Secondary School in Potchefstroom. She added learners felt very much inspired by the address of Professor David Block, the guest speaker at the event.

The University of the Witwatersrand academic excited the participating learners with his talk entitled “The Power of Vision”, which was sponsored by Anglogold Ashanti and Metrohm SA.

Concluding his address and urging the learners to espouse a “change in mindset” and strive for original ideas, Block said: “Every star is a star, and all beetles are born to scratch.” He added that the imprints of Minquiz “continue to blaze a most luminous legacy. Truly astronomical!” He also donated four copies of his latest coffee table book, “Shrouds of the Night”, which he co-authored with fellow astronomer, Professor Kenneth Freeman.

Background to Minquiz

Mintek hosted 56 top Grade 12 learners from schools across all nine provinces as they were competing against each other in the annual Minquiz ® Science Competition on 27and 28September 2010. Learners gathered at Mintek’s campus in Randburg from 14 provincial centres countrywide.

Participating in teams of four, the learners took part in an individual written test, followed by a team building activity which aimed to get each team working together in order to assess each other’s strengths and weaknesses. This was then followed by a live on-stage quiz where teams competed head-on, in a rigorous and nail biting Science and Mathematics competition.

This year, Mintek is proud to announce that the sponsors of the competition have donated prizes to the value of about R166 000, which was paid out to winning learners and schools in various categories. Mintek further invited potential sponsors to the event on 28 September to assess whether the competition fits into their company’s school engagement programmes, and whether the company wishes to support Minquiz next year as an anchor or prize sponsor.

To further inspire and revolutionalise the dreams and visions of our future Scientists, Technologists and Engineers in South Africa, Professor David Block, Director of the Anglo American Cosmic Dust Laboratory at the University of the Witwatersrand, was the guest speaker. Anglogold Ashanti and Metrohm SA generously sponsored the address by Professor Block.

Ms. Zimbini Zwane, Sasol’s Community and Government Relations Affairs Manager also addressed the learners. Sasol has come on board as an anchor sponsor of Minquiz in 2010.

Learners and schools won the following prizes:

Company

Prize Details

Value

DCM Deco Metals
  • Schools represented in first-placed team: R3 250 x 4
R13 000
Mark Shuttleworth
  • Schools represented in second-placed team: R2 250 x 4
R9 000
Southern African Institute of Mining and Metallurgy
  • Schools represented in third-placed team: R1 250 x 4
R5 000
Rand Refinery
  • Learners in first placed team: 4 x ½ ounce gold Kruger Rands
About R18 000
Advanced Laboratory Supplies
  • Learners in second-placed team: 4 x portable educational microscopes
About R2 700
Apollo Scientific
  • Learners in third-placed team: 4 x book prizes
R1 400
GFMS
  • Top learner in Gold and Platinum categories: 2 x netbooks
About R4 400
Council for Scientific and Industrial Research
  • Top girl learner in Gold and Platinum categories: 2 x R1 000
R2 000
Oxford Educational Supplies
  • Learners scoring 60-79% in written test: 50 Texas Instruments basic scientific calculators
  • Learners scoring 80% & above in written test: 10 Texas Instruments advanced scientific calculators
  • Learners with highest marks in written test (2 Gold & 2 Platinum): 4 Texas Instruments top-end scientific calculators
  • Teachers of learners with highest marks in written test (2 Gold & 2 Platinum): 4 Texas Instruments top-end scientific calculators
R56 900
ASSAf
  • Latest issue of Quest magazine to all participants
  • Learners in first, second and third place: 12 one-year Quest subscriptions
About R3 600
Proverto
  • Grade 12 Physics, Chemistry, Mathematics and languages study guides to all participants (learners & chaperones)
About R25 000
Sasol
  • Sasol encyclopaedia to all participants
About R10 000

 

For general information regarding sponsorship opportunities and Minquiz, please contact: Dominic Monama at: dominicm@mintek.co.za or Tel. 011 709 4139.

Mintekker cycles 24 hours to raise funds against childhood cancer

Posted on Nov 15, 2011

Mintek employee Chris Fletcher completed 24 hours of continuous cycling on Friday, 29 October at Mintek’s Randburg campus in a charity feat aimed at raising funds for children with cancer.

Riding a stationary bicycle, Fletcher (52) covered an equivalent of about 392.6 km since he started on Thursday at 13h00 and he burnt about 12 670 kilocalories in the process. Fletcher’s feat is part of a fundraising initiative for CHOC, the South African Childhood Cancer Foundation.

Fletcher is a member of the CHOC Cows, a group of about 130 cycling enthusiasts, who are targeting to raise R4.1-million in 2010 in order to fund the upgrade of the paediatric oncology ward at the Chris Hani-Baragwanath hospital, and also if possible, at the Charlotte Maxeke Academic hospital.

Fletcher hopes to raise a total of about R25 000 from this “spinnathon” event at Mintek alone. Apart from staff and business divisions, Mintek’s corporate clients and visitors to the campus have also pledged their sponsorships.

Various options in which sponsors could donate funds included:

  • straight donations, regardless of time or distance covered;
  • sponsorship on a per kilometre basis up to a specified maximum; or,
  • sponsorship per 20, 50 or 100 kilometres or part thereof.

Fletcher also used this event as a warm-up for the Momentum 94.7 Cycle Challenge later this month in Johannesburg.

Materials for H2S environments – cracking the problem

Posted on Nov 15, 2011

Mintek, South Africa’s national mineral technology institute, has developed a unique laboratory facility for testing the susceptibility of alloys to corrosion and hydrogen-induced cracking under the conditions known as “sour service”.

“This type of cracking has been responsible for numerous equipment failures worldwide, resulting in serious health and safety consequences as well as environmental incidents, damage to equipment and downtime,” said Deon Slabbert, co-ordinator of Mintek’s Metals Technology Centre (MTC).

Sour service, or wet hydrogen sulphide (H2S), environments are commonly encountered in the petrochemical industry. The corrosion of steel under these conditions generates hydrogen, which when absorbed by the steel can lead to crack development and eventual failure in pipelines, pressure vessels, and related plant equipment.

“The presence of H2S can cause metallic materials to fail by several mechanisms, and testing of materials to determine their suitability for sour service is critical for both producers and users,” explained Slabbert. “South Africa’s petrochemical refiners – Chevron, SAPREF, Engen, NATREF and SASOL – all specify the use of materials resistant to hydrogen-induced cracking to avoid in-service failures. Seamless pipes are also produced locally for oilfield applications, and these products need to be certified as resistant to hydrogen-induced cracking and in many instances to sulphide stress cracking as well.

“There are several international standards and material recommendations aimed at preventing failures in sour service, and working groups and research projects are active internationally to extend our knowledge in this area. However, owing to the extreme conditions employed in these tests, which involve the exposure of specimens in an acidified brine solution saturated with H2S for up to 30 days, few laboratories are equipped to conduct such investigations”.

The MTC at Mintek is the only laboratory in South Africa that provides this service to industry. The purpose-built facility is constructed to world-class standards, incorporating dedicated stainless-steel equipment and additional safety features beyond those that are required in the standard procedures.

Samples are prepared for metallographic examination using automated equipment, and a specialised spreadsheet has been designed to calculate the critical parameters that must be within specified limits.

“Since commissioning of the facility in 2005, we have tested more than 1 400 samples without incident, owing to the dedication and attention to detail of the staff,” said Slabbert. “As a result, most materials used in South Africa, and also those exported, specifically for sour service, are now accompanied by a Mintek report certifying that the material has been tested and is resistant to hydrogen-induced and sulphide stress cracking.”

Mintek’s MTC also offers other corrosion tests and a wide range of investigations to solve materials-related problems in industry.

For more information about Mintek’s MTC and its services, contact Melanie Smit at Tel: +27 11 709 4501 or e-mail melanies@mintek.co.za

Applications for prospecting, mining permits and mining rights

Posted on Nov 15, 2011

Please note that as from 15 April 2011 all applications for prospecting, mining permits and mining rights will only be accepted in electronic format.

Visit www.dmr.gov.za for more information