ASX- and JSE-listed Orion Minerals has started a series of field trials for the treatment of minewater at the Prieska copper/zinc mine in South Africa’s Northern Cape province, using a proprietary electrolytic technology to produce saleable products.

The process has the potential to extract valuable products such as calcium and magnesium, for agri-nutrient use, from water pumped out of the underground mine at Prieska, the company says.

In addition, other products with potential for by-product sales in the chemicals industry will also be extracted by the process.

The trials have begun as Orion prepares to start dewatering the underground mine and

implement other key elements of its early production plan as it advances the Prieska mine towards production.

The water treatment trials are being undertaken in collaboration with Free Radical Process Design (FRPD), a South Africa-based technology company which has developed a proprietary process and equipment for the continuous extraction of metals and other valuable minerals from water using electrowinning via a rotating cathode (electrosoftner).

The electrosoftner is said to have the potential to extract iron hydroxide, hydrogen, calcium, magnesium and base metals such as nickel, zinc and copper from contaminated mine water.

The ability to harvest the agri-nutrients at the Prieska mine, which is located in a region where renewable energy is abundant and where irrigation agriculture is a core industry – has the potential to offer important host-community development opportunities, Orion posits.

It explains that this would also advance the company’s vision of establishing a ‘green’ footprint for the Prieska project with broad stakeholder benefits as part of its objective to have a world-class environmental, social and governance framework to support its operations.

The beginning of the field trials follows the success of laboratory scale test work, where water samples from Prieska were analysed and passed through an electrosoftner demonstration unit, producing precipitates of iron hydroxide, calcium hydroxide/carbonate and magnesium hydroxide, while concentrating sodium hydroxide that can be bled off as a liquid from Prieska’s mine water.

“We are particularly pleased to have the opportunity to collaborate with South African technology developers, Free Radical Process Design, who have worked with The University of Pretoria to develop an innovative technology that could have a global impact in the treatment of contaminated minewater and which is directly applicable to our Prieska mine dewatering challenge.

“We look forward to trialling the Rotowinner technology to treat our Prieska mine water, while simultaneously recovering ‘clean and green’ agricultural nutrients and delivering treated water which would be available for community agriculture purposes,” enthuses Orion CEO and MD Errol Smart.

In addition to agricultural nutrients, other products that are are used in the chemical industry, can potentially be extracted using the Rotowinner technology, opening up interesting future by-product sales opportunities, he adds.