JOHANNESBURG (miningweekly.com) – Platinum group metals (PGMs) producer Sedibelo Platinum Mines Limited has announced the expansion of operations at Pilanesberg Platinum Mines into contiguous deposits of Sedibelo Central, Magazynskraal and Kruidfontein – known as the Triple Crown properties – with an estimated resource base in excess of 60-million four-element (4E) PGM ounces, considered one of the world’s largest undeveloped PGM deposits.

The predominantly shallow deposits will enable safe and sustainable mining activities for potentially more than 60 years. The approved expansion will be funded through Sedibelo’s existing cash resources and future cash flow. The first ounces from Triple Crown are expected to be extracted in 2023.

The Triple Crown expansion will be mined simultaneously with ore from the existing openpit upper group two (UG2) reef and Merensky operation, utilising two separate decline shaft systems.

The existing Pilanesberg Platinum Mines’ concentrator plant has the capacity to be used to process the Triple Crown ore as well as ore from the openpits. With minimal reconfiguration, the Triple Crown UG2 and Merensky ore will be blended and processed through the existing Merensky plant, thereby reducing capital expenditure as well as lowering operating cost significantly.

Sedibelo’s current workforce of 1 500 employees is expected to grow significantly as the Triple Crown operations develop. More than 60% of the current work force is from the local communities. Sedibelo expects that the new positions will also be taken up by local employees predominantly. 

Sedibelo also announced the construction of a 110 000 t beneficiation plant at Pilanesberg Platinum Mines, employing cost- and energy-efficient Kell technology .

Kell reduces energy consumption by some 82% with the associated significant reduction in carbon emissions, also improving recoveries and lowering operating costs. Benefitting from being robust in operation, Kell is unconstrained by concentrate grade, is insensitive to chrome levels as well as being resistant to other impurities.

Hence, using Kell will improve the economic return of the Triple Crown expansion and is an integral part of Sedibelo’s future development.

Kell’s carbon dioxide (CO₂) emissions from concentrate to final refined metals are only 19% of the CO₂ emissions caused by the current smelting/refining route.

Kell emits zero sulphur dioxide (SO₂) and converts the sulphide minerals into a stable and benign gypsum product and its water consumption is negligible.

Sedibelo shares an interest in Kell South Africa with the Industrial Development Corporation and founder Keith Liddell through Lifezone.

Arne Frandsen, chairperson of Sedibelo, commented: “Today is a significant day in Sedibelo’s history. We are opening our next door 60-million-ounce Triple Crown deposit, thereby securing the future of Sedibelo for many decades to come. The construction of our Kell Plant will allow us to produce metal and lower our cost profile further. Equally important, it will reduce our carbon footprint and water usage significantly. We trust our environmentally friendly platinum group metals will become an important part of future electrification and the “green revolution”, used in fuel-cells around the world.”  

Erich Clarke, CEO of Sedibelo, commented: “We are proud and excited to now be breaking-ground in our contiguous Triple Crown orebody, which we can extract sustainably at a low cost profile with our efficient workforce. The benefits for our stakeholders, including our host communities, will be many and last for generations to come.” 

Liddell added: “I developed Kell Technology as a cost-efficient alternative to the conventional smelting of PGMs. We are excited to now proceed with the construction of the Kell plant at Pilanesberg Platinum Mines. The benefit for Sedibelo and the industry will be significant; delivering beneficiation, energy and cost advantages as well as a reduction in CO₂ and SO₂ emissions”.  

Sedibelo, which has assets on both the western and eastern limbs of the Bushveld Complex, has produced around 1.5-million ounces of 4E PGMs since it commenced mining in 2008. Sedibelo’s total resource base exceeds 90-million ounces of 4E PGMs.

Sedibelo has operated in 2020 with zero fatalities, zero reportable lost-time injuries and no reportable environmental incidents.

KELL TECHNOLOGY

The far-reaching Kell process comes at a third of the capital cost of smelting/refining and at half of its operating cost.

End products can be customised and the proposed Sedibelo Kell plant will be producing refined 99.95% PGM metal products.

Locked up ‘work in progress’ PGMs inventory is 90% lower, releasing working capital and shortening payment pipelines from several months for smelters down to a month or so. In fact, for a mining company that is currently selling concentrate, the release of locked up working capital can pay more than half of the cost of a Kell plant.

Kell’s ability to recover cobalt has resulted in discussions with South African companies that are potentially interested in manufacturing electric vehicle (EV) batteries domestically in South Africa.

Insensitive to the chrome content in the concentrate, Kell ensures that there are no harsh penalties when chrome levels are exceeded.

Kell produces refined metals at the mine site and thus generates more skilled jobs at the mine site.

Overall metal recoveries are comparable with traditional smelting-refining and in some cases higher.

The proposed Pilanesberg Platinum Mines plant has already obtained its environmental approvals.

HYDROMETALLURGY ECLIPSES PYROMETALLURGY

Kell is essentially a hydrometallurgical process, involving key elements being leached and re-leached.

There is a little pyrometallurgical bit in the middle involving material being put through a kiln to render the precious metals leachable again after having taken up base metals, but this involves only heating and not smelting.

Metaphorically speaking, the pyrometallurgy, through smelting, is the big sledgehammer being used to crack the nut and it smashes it to smithereens as a way of extracting benefit out of it.

“What we do is, with a pair of nutcrackers, just open it up and then extract the kernels out,” Liddell explained to Mining Weekly during a Zoom interview earlier this year, in which he let it be known protection of the technology has been enhanced by four new patents granted globally, one for refractory gold concentrates that enables production of refined gold at the mine site without use of cyanide. Lithium, too, is in the development company's sights.

But the immediate strong focus is on the PGMs sector: “We’ve been extremely busy in essentially engaging the overall PGMs industry in Southern Africa but also to some extent globally. We’ve been developing feasibility studies, scoping studies and test work, batch test work, pilot test work and continuous test work.

“The industry is now well informed about Kell and in specific terms its operating costs and capital costs in relation to their own operations and they’re all waiting for the outcome from our first commercial installation.

“It’s the classic that we always see with new technology into the conservative mining industry – ‘don't be first but make damn sure you're second’.

“We appreciated that many years ago when we tied up with Sedibelo and Pallinghurst, and quickly after that the Industrial Development Corporation, because we knew we had to have a Kell plant working on a mine somewhere before the balance of the industry would accept it.

“Sedibelo particularly is a company that wants to take its Pilanesberg Platinum Mines and vertically integrate it to produce some PGM metals and base metals at the mine site.

“In the last couple of years, and particularly this year, we further optimised the engineering into a fully modular plant format that includes PGMs refining and base metal refining,” Liddell said.

Several independent studies completed confirm the substantial decrease in CO₂ and SO₂ emissions from Kell compared with smelting and refining. "So, if the industry wishes to reduce the carbon footprint of its products, or rather, if the buyers of PGMs want lower CO₂ inputs, then Kell is the obvious solution, Liddell said.

While there are zero SO₂ emissions from Kell, many PGM smelters, and even new ones, burn the sulphide minerals to form SO₂ that is released directly into the atmosphere.

With the help of acid plants and wet scrubbers, PGM companies are abating sulphur emission, but this does not remove 100% of the SO₂, even though it comes at considerable capital and operating cost, Liddell noted.

UPPER GROUP TWO REEF

Kell’s insensitivity to the chrome content in the concentrate does not limit the rate that UG2 reef, currently favoured by mining companies seeking optimum palladium and rhodium output, can be processed.

“We don’t care what the chrome content is in Kell feed as the chromite passes through the process undigested,” Liddell pointed out.

Moreover, base metal refining and PGMs refining are integrated directly into the Kell process, again at the mine site.

The Kell plant design for Pilanesberg Platinum Mines will produce final refined platinum, palladium, rhodium 99.95% metals and gold 99.99% sponge, in addition to London Metal Exchange-grade nickel/cobalt/copper cathodes.

The materially lower cost of Kell has been demonstrated over a number of studies now, for different users and all types of concentrate, embracing UG2, Merensky, Platreef and Great Dyke reef.

RECOVERY OF COBALT

The existing smelters and refineries in South Africa burn off most of the contained cobalt. In contrast, Kell recovers over 95% of the contained cobalt to refined metal product.

“There have been discussions with potential domestic South Africa companies that are interested to manufacture EV batteries domestically in South Africa. That is very interesting to us as the hydrometallurgical process provides a competitive advantage to customise the final end products into battery precursors such as nickel, cobalt and manganese.

“For instance, EV battery manufacturers in South Africa will be constrained in sourcing cobalt from outside South Africa, and recovery of cobalt from South African PGMs is of interest to them.

“Our initial Kell plant at Pilanesberg will have a cobalt recovery section, but more as a test facility to start with since the feeds to that plant, being UG2, are quite low. But we do see opportunity for a battery precursor, or even battery manufacturing plant to be sited next to a Kell plant,” Liddell said.