Green copper and clean smelting and refining are envisaged at Orion Minerals’ quickly advancing base metals mines in South Africa’s well-endowed Northern Cape province, which has historically produced 2.5-millon tons of copper until base metal mining ceased there several decades ago.

The fully permitted and already reviving Prieska mine will begin producing its first saleable copper and zinc 12 to 18 months after finalising its total funding requirement, which is estimated at from R3-billion to R4-billion.

“First focus was to prove the ore. We’ve done that. Second focus was do the bankable studies; we’ve done that. Third is build the mines and produce concentrates that are saleable, and then the fourth one will be putting those concentrates in a local smelter or refinery,” Orion CEO Errol Smart said during a South Africa-Australia webinar covered by Mining Weekly.

Regarding Orion putting up a smelter, Smart said: We would lean away from smelting. We’ve done a lot of work on metal vapour refining. We’re doing a lot of work on hydrometallurgical leaching.

“We would prefer to go away from energy- intensive smelting. It’s difficult to build an environmentally friendly smelter, but it is quite viable to build an environmentally friendly metal vapour refinery or leach plant, and that’s what we will probably look at in the future. We’ve got a whole team working on that. We’re looking at the optimised case,” he said during question time.

Renewable energy is on the cards: “We’re in advanced discussions with a few renewable energy power producers and one is offering 90% certified renewable energy at a cost 20% lower cost than the Eskom supply cost.

“So, essentially, we will be producing certified green copper on our side. That’s a huge opportunity and when speaking to the offtakers and debt financiers that green, ESG, credibility is very important,” he emphasised.

Power utility Eskom is scheduled to turn on the mine’s 15 MW of electricity input next Wednesday.

Trial mining has been under way for some time, with drilling and blasting taking place daily, and about 30 000 t of ore is already on surface.

The existing shaft, which descends to 1 100 m, has multiple underground roadways that reach down to the deepest ore at 1 250 m.

Orion has been conducting bankable studies since 2019 and is putting the finishing touches to updated versions.

Mine chambers at Prieska, which were blasted in the 1970s, have held their ground and no meshing and lacing, nor rock anchors, are required.

“This ground is standing fantastically well and what we’ve proven is that in the area where we’re going to mine, we can put in big machines, we can get economies of scale, and we can get the mining happening,” said Smart.

“We can run 4.5 m by 4.5 m development ends, and we can get efficiency in scale of mining.

“We’ve also proven that we can handle events of nature, a one- in-100-year rainfall event.

“We’ve put flood control measures in place, and we’ve shown that there will not be no unplanned flooding.

“The nine-billion cubes of water in the mine must be pumped out and the pumps to do this have been put in place,” said Smart.

The construction of a water retention dam will be completed in the next few months and the reverse osmosis plant is scheduled to be in place next year as an additional water control measure.

A 15 MVA grid power supply system has been constructed and 4 km dual water and tailings pipeline has been established to the tailings facility.

Besides Prieska, the Johannesburg Stock Exchange- and Australia Stock Exchange-listed Orion is also advancing the Okiep copper project, which has produced nearly two-million tons of copper historically under previous Newmont and AngloVaal ownership.

These projects are gaining strong momentum at an ideal time in a district that has produced at an average grade of 1.9% copper. For many decades, it produced more than 20000 t/y of copper from the existing plant facilities.

At Okiep, which is known for its high grades, Orion drilled one of the highest- grade intersections that has been drilled in the world, 50 m at 5% copper.

“There’s high-grade ore here that hasn’t been mined, and we’ll be proving it as we go,” he said.

Okiep is awaiting a water right and sign off on the engineering design of the tailings facility.

“Over the last nine years, Orion has done a consolidation of the most prospective brownfields projects and many of
the best greenfields areas. We’ve put that together over here, and those are the projects moving forward.”

The company has spent this year finalising optimised feasibility studies, while 160 people are active on site at Prieska, where having plants in place and production commencing at the end of next year is envisaged.

“There are very few opportunities in the world where there are mines that are fully permitted, they can come into production in 12 to 18 months, and they’ve got a big growth profile in front of them, and that’s where we are.

“This Prieska mine is a brownfields project. It was a large mine in its time. It used to have a processing plant with a capacity of three-million tons a year. It processed very successfully, produced very good concentrate. There are a lot of knowns and a lot of the infrastructure was in place, and that’s what’s helping us to accelerate this project,” Smart outlined.

The historic mining happened in ore that was dipping towards the north-east. At about 950 m depth, the orebody suddenly goes to a reversal and it dips to the south- west, and it becomes very flat dipping. That’s historically where AngloVaal stopped mining. AngloVaal mined from 105 m below surface to 970 m below surface.

There were 42 known mines in the district, more than three-quarters of them on Orion properties.

There are 1700 outcropping mafic orebodies that could have ore, and about 200 of those have got copper showings.