The concept of geometallurgy is being researched by State-owned mineral research council Mintek’s mineralogy division, owing to the global mining industry’s challenge to confront declining grades and low-grade orebodies.

The current lack of exploration, in addition to the finite number of high-grade mineral ores, has resulted in the need to enhance processing techniques to exploit these types of orebodies in an efficient, yet profitable, manner.

“Geometallurgy involves the synergistic application of geology, mining, geochemistry, mineralogy, metallurgical processing and economics to build models – usually spatial – that allow for a prediction of the key processing attributes of an orebody,” says Mintek mineralogy manager Nosiphiwo Nyamane.

Predictive models rely on the effective integration of various data types that consider ore variability and subsequent treatment options to improve the efficiency of sustainable mining and beneficiation activities for any given deposit, she notes.

Nyamane comments that geometallurgy is particularly important for older mining sectors that are at a fairly mature stage of development, including South Africa’s mining sector, as it can assist mining companies in addressing increasing operational costs and declining ore grades by alleviating challenges in their existing operating models.

Moreover, the increased application of geometallurgical modelling will absorb a wider range of specialists, such as geochemists and metallurgists, owing to the numerous data points that need to be included in a model. This will, in turn, increase opportunities for individual geologists and consulting companies.

Nyamane notes that there has been debate surrounding the geoscience industry and whether it has the skills and expertise to address the wider needs of society, such as securing energy sources or addressing the effects of climate change.

She notes that, as the geosciences offer numerous solutions to society’s challenges, geoscience skills are transferable to other economic sectors, like agriculture or banking. This transferability of skills, including in the international labour market, can create challenges for the mining industry in terms of the availability of specialists.

Employers in exploration engage geologists who specialise in geophysics, geochemistry and geohydrology, but the current drought in most of Southern Africa has led in particular to geohydrologists being in high demand, Nyamane notes. “Local and international consulting firms are employing more engineering geologists, geotechnical engineers and hydrogeologists,” she comments, adding that this could reduce the number of in-house specialists available to mining companies.

Further, she notes that the main challenge pertaining to the shortage of skills in geosciences is that experienced personnel are nearing retirement age, leaving younger, less experienced geologists to execute projects. Nyamane advises, however, that companies invest in succession planning to mitigate this skills challenge, in addition to coaching and mentoring programmes.

Mintek offers several bursaries to its employees to study parttime. During the 2015 financial year, about 150 bursaries were awarded to Mintek employees for undergraduate and postgraduate studies. It also has a Work-Integrated Learning programme that caters for diploma students and artisan learnerships, which are implemented in partnership with Sector Education and Training Authority the Mining Qualifications Authority.

Recent Projects
“The fragile mining sector economy in South Africa does not bode well for sustainable commercial revenue for Mintek on the local front, but Mintek has been fortunate to achieve a significant increase in its foreign revenue from various countries across the globe to compensate for the decreasing number of local work opportunities,” Nyamane highlights.

On the local front, though, the company is currently involved in the evaluation of processing options for uranium extracted from the low-grade Karoo sandstone deposit, located near Beaufort West, in the Western Cape. The project started last year, but the the process has been complicated by high acid consumption and the presence of significant quantities of molybdenum. However, Mintek has successfully developed and patented a novel technology to extract molybdenum from the uranium leach liquor before uranium recovery takes place.

Mintek has noted an increase in uranium-related activities, which has also become one of the largest growth areas for the company. Many of the deposits under investigation are relatively low grade and significant effort has been expended on developing a method to upgrade the ore.

A coal sorting project is also under way, with sensor-based sorting technology being used to upgrade the low-grade coal to meet the supply specifications for State-owned power utility Eskom. Mintek is undertaking the project in conjunction with State-owned energy-focused mining company African Exploration Finance & Mining Corporation. Additionally, the project will assess the feasibility of producing low-volume streams of high-grade coal.

Mintek is also undertaking a programme to assess options for the uranium-bearing Springbok Flats coal deposit, located north of Pretoria towards Hammanskraal.

International Geological Congress
Nyamane notes that the thirty-fifth International Geological Congress (IGC) will be the largest gathering of geoscientists ever held in Africa. “Therefore, it is important for Mintek to have a presence at such a conference and showcase its technologies.”

She states that the congress will allow for immediate and long-term brand benefits worldwide, specifically in Africa, while increasing Mintek’s credibility and visibility, as several staff members will also participate in the event’s technical presentations.

Mintek will showcase its technical divisions at the IGC, which will be hosted at the Cape Town International Convention Centre from August 27 to September 4.