Aachen high shear reactor technology increases throughput, gold recovery

Mineral processing technology provider Maelgwyn Mineral Services Africa (MMSA) has developed its Aachen High Shear Reactor technology to such an extent that it has emerged as a key component in hydrometallurgical processes for several leading gold mining companies in Africa, says MMSA business development manager Juan van der Merwe.

The company offers mineral processing technologies, as well as a dedicated metallurgical testwork facility, which functions as a platform from which to test its proprietary technologies on the ore of potential clients and as an independent commercial laboratory that services the minerals processing industry.

“The Aachen technology efficiently achieves high-level oxygen mass transfer and has proven to be highly successful, particularly in the gold mining sector. Slurry is pumped from the process tank through the reactor where oxygen is introduced at high shear and velocity in a specially engineered aerator system.

“The purpose of deploying the Aachen technology is to assist in realising hidden potentials in reagent savings, gold recovery or throughput increases.”

Van der Merwe says MMSA has commissioned more than 50 units of the Aachen reactor technology on the continent, working with several high-profile mining companies across several jurisdictions, each of them having to deal with a different set of challenges.

London-listed gold miner Randgold Resources, a major client of MMSA, is using Aachen oxidation technology at its Loulo and Morila mines, in Mali, at its Tongon operation, in Côte d’Ivoire, and at the Kibali gold mine, in the Democratic Republic of Congo.

He adds that the company also provided the technology to Liberian gold miner Avesoro Resources’ (formerly Aureus Mining’s) New Liberty gold mine and to South African gold miner Pan African Resources at its Barberton Mines operation, where the Aachen reactors are used in the cyanidation circuit and are also used to support the cyanide detoxification processes.

MMSA is also working on several tailings reclamation projects in South Africa and aims to use Aachen oxidation technology and Imhoflot pneumatic flotation in the various reclamation processes. Van der Merwe says, while a number of these projects are still in development phase, it plans to commission several new installations within the next six months.

The Imhoflot pneumatic flotation technology, developed and commercialised by Maelgwyn Mineral Services, offers a reduced footprint and lends itself to retrofitting into existing plants to increase performance.

Van der Merwe highlights that the technology is well suited for use in a modular plant concept to recover valuable components from tailings, either from processed material or existing tailings dumps.

“The modular design of the distribution unit, aeration unit and separation cell allows for the easy assembly and replacement of parts, while the complete process is maintenance friendly, being mostly confined to the pump and aeration unit, which requires occasional and simple replacement of standard wear parts”.

Although the Imhoflot pneumatic flotation and Aachen reactor technologies enable MMSA to provide world-class mineral processing services for African mining firms, “the company has built its reputation on much more than these technologies”, he states.

Challenge Considerations

Van der Merwe notes that working in Africa entails having to deal with several challenges. “The risks associated with operating in Africa abound, hence we need to be consistently developing our technology to outpace competition. This is one aspect of the Aachen and Imhoflot technology side on which we are continually improving.”

He indicates that many of the sites where installations are made are in remote regions, with civil and political unrest. The constant threat of mosquito borne diseases and the recent Ebola outbreak in West Africa also present challenges.

However, MMSA has not allowed these challenges and the difficult operating conditions in the global mining industry of recent years to “stand in its way” to make a return on investment, says Van der Merwe.

“Along with our technologies, the driving force behind our success is a flexible and un-bureaucratic management. Combined with the ability to conduct testwork on site, we provide clients with the tools to implement the resultant solution and, thereafter, reap the benefits,” he concludes.