Manufacturers globally are expressing concern over China’s dominance of strategic elements including rare earths used in a technologies such as electric vehicles, electric motors, batteries, aircraft, wind turbines and mobile phones.

“China’s monopoly of rare earths raises the question of supply vulnerability. The Chinese government’s move to electric vehicles could make China a net importer of rare earths soon, further disrupting supplies,” says Steenkampskraal Holdings chairperson Trevor Blench.

The Steenkampskraal rare earths mine in the Western Cape, owned by developer Steenkampskraal Holdings, is aiming to be a building block in a global rare earths supply chain independent of China.

“Just a few decades ago, the US was the world’s largest rare earths producer. The erosion of its production and shift to China is a complex story, but the common thread across our growing minerals-import dependence is a regulatory approach to mining that has seen investment flee despite world-class resources. For example, the US possesses 13 percent of global rare-earth minerals reserves, with significant deposits in California, Alaska, Idaho, Montana and Missouri. Yet increased import reliance has become a national security issue,” say US defense publication, Defense News.

“Whether it’s the advanced electronics and control systems in F-22 and F-35 aircraft, night vision devices, guidance, targeting systems, or dozens of other critical defense technologies, they’re all built with rare earth components. While the U.S. has a small strategic reserve of some of these minerals — to provide a short-term supply for our military supply chain — we have allowed ourselves to become unnervingly comfortable in China’s vise,” the publication says.

Most rare earth deposits globally have an average in-situ grade of between 1% and 2%. “When these other deposits are mined, the recovered grades are even less because the in-situ mineralised material will be mixed with material such as waste rock that has little or no economic value. Hard-rock monazite deposits, such as the deposit at Steenkampskraal, generally have much higher grades than beach sand deposits,” explains Mr Blench.

Rare earths in India, Australia and many other countries are mainly contained in monazite that is disseminated in heavy mineral sand deposits, where typically the rare earth grade is less than 1%. In China, the largest source of rare earths is situated at an iron-ore mine that contains bastnaesite and where rare earths are produced as a by-product.

“The rare earths resource at Steenkampskraal has been confirmed with an NI 43-101 Mineral Resource Estimate as the highest-grade deposit in the world, at an average of 14.4%. The rare earth grade in some areas is as high as 45% total rare-earth oxides. The recovered grade after dilution will be about 10%,” explains Mr Blench.

Mr Blench notes that the mine’s estimated total cost to produce mixed rare earth carbonate, which includes mining, beneficiation and chemical processing, but not the separation of the individual oxides, will be about $3.00/kg, which could be the lowest in the world.

The current design has been developed to make optimum use of the existing underground infrastructure. “Steenkampskraal is a former producing mine, with Anglo American having mined it for ten years in the 1950s and 1960s. A shaft, developed stopes, ore blocks, underground stockpiles of ore and much of the infrastructure are already in place. Our mine plan will make the most of the existing infrastructure, which will save us about 80% of mine construction costs,” Mr Blench notes. He adds that the company only has to invest the remaining 20% of the required capital for the underground mining operations to start operations.

“To make the mine operational again, the detailed engineering design of the processing plant needs to be completed. Management also plans to complete a bankable feasibility study (BFS) in the next six to nine months. We will know then what the capital budget will be which we currently estimate will have a capex of around R500-million,” he says.

“When the BFS is completed, we will raise the finance to finish the necessary addition to the mine, the processing plant and the infrastructure. Construction is estimated to take about 12 months.”

“Due to Steenkampskraal’s high-grade resource, it will have low operating costs. To produce one ton of rare earths we will need to mine about 10 tons of ore. Most other rare earth projects are required to process between 50 tons and 100 tons of ore to produce one ton of rare earths. This is because of the low grades of those resources,” says Mr Blench.

Steenkampskraal technical manager Witker Zimba explains that the mine design is based on conventional stoping techniques, tramming ore to the bottom of the incline shaft and hoisting the ore up the incline shaft. With a target production rate of 2 700 t/y of mixed rare-earth oxides, about 30 000 t/y of ore will be mined and processed, after allowing for ore dilution during the mining process.

Processing
“The high grade and small tonnage means that mining costs will be relatively low. At this rate of production, the mine life based on the presently known resource will be about 25 years,” he says. The processing route will use gravity separation and flotation to produce a high-purity concentrate that will contain about 90% monazite.

A concentrate containing copper, gold and silver will be produced as a by-product during this phase. The monazite concentrate will be chemically cleaned to remove residual apatite and sulphide contamination, after which it will be treated with caustic soda to render the rare earth elements soluble in a dilute acid solution.

The cerium will be removed from the mixed rare-earth salts at Steenkampskraal and refined for sale in South Africa. The cerium-depleted mixed rare-earth carbonate will be sold to companies that separate the individual rare-earth oxides.

Rare Earth Uses
Rare earths are used to make strong permanent magnets, which in turn, are used in electric motors that provide power for appliances, robots and electric vehicles (EVs).

“The most important application now is for electric vehicles with global production and sales of EVs are growing. The increasing demand for rare earths in all industries means immediate demand for the mine’s production,” Mr Blench says.

“Renewable energy is another key rare earth application. Magnets used in wind turbines are also made from rare-earth elements. Neodymium magnets, for example, are used in industries such as medical equipment and renewable energy producers. Wind turbines rely on high-strength neodymium magnets,” he says.

Product of Thorium
With the quality and grade of the feed material being so high, Steenkampskraal also has the potential to be one of the lowest-cost producers of thorium in the world. As part of its thorium strategy Mr Blench says the mine plans to supply thorium oxide to Thor Medical for the production of medical isotopes.

Thorium is the only natural source of medical isotopes used in targeted alpha therapy (TAT), a treatment for several types of cancer. Thor Medical in Norway is developing these treatments for cancer.

In addition, Steenkampskraal, together with thorium research company Thor Energy completed a five-year qualification programme in April 2018 for thorium as a nuclear fuel, focusing on the commercialisation of thorium as a fuel supplement in conventional nuclear reactors. Thor Energy is developing a nuclear fuel technology based on thorium as an alternative to uranium.

“Thorium fuel can use either uranium or plutonium as the fissile driver material. It is environmentally safer and extremely difficult to use to make a nuclear weapon. “In addition, the thorium fuel cycle is cleaner than that of uranium.”

“In contrast, uranium produces plutonium and minor actinides in its waste, and plutonium can be used to manufacture a nuclear weapon. These minor actinides remain radioactive for thousands of years. The thorium fuel cycle produces no plutonium and hardly any minor actinides, making the end product significantly safer and would almost eliminate the risk of nuclear proliferation,” explains Mr Blench.

Waste from the thorium fuel cycle contains mainly fission products that lose most of their radioactivity in a relatively short time, thereby substantially reducing the problems associated with the management and storage of nuclear waste. We see great potential for thorium as a safe supplement for uranium as a nuclear fuel, Mr Blench adds.

The Colorado School of Mines in the US published a report – ‘Thorium: Does Crustal Abundance Lead to Economic Availability?’ – in October 2014. The report includes studies of where the thorium would be sourced and states that the Steenkampskraal mine will be the lowest-cost producer of thorium in the world, with an estimated production cost of $3.56/kg.

“China, India and Turkey have declared thorium as part of their national power policy. Once the mine is in production, we will be able to increase output in a relatively short time to meet this demand,” he concludes.