The increasing prevalence of new technology, and endeavours to boost environmental, social and governance (ESG) performance, are increasingly positively impacting on African gold mining, with many mining companies starting to embrace new technologies for process efficiency and reduced environmental impact, says metallurgical technology company GoldOre founder and CEO Adrian Singh.

“Technology advancement is the future, and this also applies to the development of process technology for recovery improvement on a gold plant,” notes Singh, adding that even the smallest improvement in gold recovery can translate into a significant profit, owing to the current gold price of just under $2 000/oz.

To this end, GoldOre offers its MACH Reactor technology that enables processing plants to increase gold recovery using pre-oxidation and boosted leach applications.

The MACH Reactor is the only hydrodynamic cavitation unit on the market used in the gold sector.

Cavitation benefits include the removal of obstructive passivation layers, as well as particle breakage for improved liberation. Boundary layers are also reduced to promote diffusion – the rate-limiting step for heterogenous gold leach reactions.

Moreover, the MACH Reactor is the only oxygen injection technology on the market which is completely self-aspirating, allowing for oxygen gas pressures of as low as 1 bar to be injected into the reactor.

“While competing technologies generate large bubbles that are centimetres in size, the MACH produces pico-bubbles so small that they are invisible to the naked eye to give the highest gas-dissolution efficiency,” Singh enthuses.

The technology can also draw air in from the atmosphere to aerate pulp if oxygen is unavailable.

Further, the MACH has a product life span to match that of the project, which Singh describes as a “phenomenal achievement”.

Compared with other technologies that generally only offer single capacity units of about 600 m3/h, the MACH Reactor is produced in a variety of different capacities, ranging from under 1 m3/h to over 3 000 m3/h, and is completely customisable in terms of capacity and materials of manufacture.

The reduction of cyanide consumption by as much as 30% also provides a significant cost benefit, considering cyanide is the most expensive reagent used on a gold plant.

Despite contributing towards ESG initiatives, as well as improving efficiencies, Singh laments that the African gold mining industry is slow to embrace the MACH Reactor.

“For African gold miners, increased ounces remain the primary objective, and this is often achieved at the expense of efficiency and sustainability factors as they strive to increase plant throughput at all costs.”

He describes the African gold mining industry as conservative in their slow embrace of technological improvements, which consequently creates a “major stumbling block” in bringing step-change improvements to their operations.

Hence, Singh argues that research and development (R&D) is necessary to allow for step-change improvements to process plants.

To this end, GoldOre has designed and built semi-pilot and laboratory-sized MACH test rigs that are used for in-house research with partnered institutions and for academic postgraduate studies.

Singh says GoldOre has used R&D to improve its technology offering to ensure that the MACH is always up-to-date with regard to identifying new applications in the gold mining industry, thereby paving the way for future growth.