Name of the Project
Prieska copper/zinc mine (PCZM).

Location
Northern Cape, South Africa.

Project Owner/s
Diversified metals explorer and developer Orion Minerals.

Project Description
The Prieska copper mine is located on a significant volcanogenic massive sulphide deposit. The fully permitted mine, which last operated in 1991, has a Joint Ore Reserves Committee-compliant resource of 31-million tonnes at 1.2% copper and 3.6% zinc.

A definitive feasibility study published in March 2025 has confirmed the potential to develop a long-life, financially robust mining operation through a two-phase development strategy aimed at derisking the development pathway and fast-tracking value-creation from a safe, modern, long-life, mechanised, underground base metal mine.

The project has the potential to develop into a long-life, financially robust mining operation with a yearly steady-state production of 22 000 t of copper and 65 000 t of zinc, the company points out.

The initial Upper-Level phase is based on mining near-surface supergene sulphide ore, which is accessible from an existing decline. 

The Deeps phase will start after the completion of mine dewatering, refurbishment of the main shaft and construction of the mining infrastructure. Mining of the Deeps has a life-of-mine (LoM) from first production of 11 years and will overlap with the past 2.2 years of the Upper-Level mining. This gives a combined LoM of 13.2 years.

The planned operation starts with the Upper-Level phase, which will run for 4.3 years, based on mining supergene and oxide ore close to surface that will be accessed from an existing decline. During the Upper-Level mining phase, pumping in the main shaft will be undertaken to dewater the mine, which is currently flooded to 265 m below surface. Following the dewatering will be the refurbishment of the main shaft and construction of the mining infrastructure. 

The Deeps underground mining will start from the twenty-eighth month of the project, with production overlapping with the last 2.2 years of the Upper-Level mining. The combined operation is planned over 13.2 years of production at an ore processing rate of 240 000 t/y for the Upper Levels and 2.4-million tonnes a year for the Deeps. 

Ore from the Upper Levels and Deeps mining will feed separate froth-flotation processing plants to produce a copper concentrate with important gold and silver by-product credits from the Upper Levels, and separate copper and zinc concentrates from the Deeps. Small amounts of gold and silver will be recovered in the Deeps copper concentrate as by-product credits.

Potential Job Creation
About 200 to 300 jobs are expected to be created during the early mining phase and about 800 at full production.

Net Present Value/Internal Rate of Return
The project has a net present value, at an 8% discount rate, of A$797-million and an internal rate of return of 31%, with a payback of 5.8 years from the start of construction.

Capital Expenditure
The project will require total capital expenditure of A$607-million. Expenditure to achieve first concentrate production in the initial Upper-Level phase is A$49-million.

Planned Start/End Date
First production from the Upper-Level phase is expected 13 months after the start of construction.

Development and production mining at the Deeps will start in month 28 and build up over a further 27 months to a steady-state rate of 200 000 t a month or 2.4-million tonnes a year.

Latest Developments
Orion Minerals’ Prieska copper/zinc mine has received a prospective financing and offtake uplift through the signing of a nonbinding term sheet with a wholly owned subsidiary of Glencore, involving financing of $200-million to $250-million and concentrate offtake for the asset. 

The mine financing will be made available in two tranches, the first $40-million of which will be for the construction and startup of Prieska’s Uppers, and the second $160-million to $210-million for the construction and startup of Prieska’s Deeps.

Moreover, up to $50-million of the second tranche may be drawn early to start early works on the Deeps.

The arrangement with the subsidiary of the global diversified London- and Johannesburg-listed Glencore, a miner and marketer of more than 60 commodities, was announced by Orion on September 17.

Conditions precedent to funding under the facilities include Glencore completing a due diligence. Drawdown will be based on milestones for each tranche to be agreed upon during the due diligence process, with first drawdown targeted for November.

Key offtake terms include the offtake of 100% of bulk concentrates from the Uppers for five years, 100% of copper concentrates from the Deeps for ten years, and 100% of zinc concentrates from the Deeps for ten years.

The proposed Glencore funding will enable Orion to transition to producer status with a binding agreement expected over the next four to six weeks.

The first tranche enables Orion to move swiftly into first production and first cash flow from mining of the Uppers at Prieska, and the early drawdown of the second tranche allows for Orion to start early works on the Deeps in accordance with the DFS, Orion CEO Tony Lennox has indicated.

Glencore has followed Prieska’s progress for some time and Glencore copper marketing’s Toby Spittle expressed commitment to completing the due diligence expeditiously “and seeing Prieska recommence production as soon as possible”.

South Africa’s State-owned Industrial Development Corporation (IDC), has expressed excitement about the prospects of advancing the project to implementation through its acting divisional executive of industrial projects and property development Rian Coetzee.

In an interview with Mining Weekly earlier this year, Lennox emphasised the closeness of Orion from transitioning to producer status. “We’ll do so in a considered and detailed manner, but rest assured, we’ll be producing concentrate by the end of next year,” he has forecasted.

“When we have the Prieska Uppers running, we'll be looking to ensure there’s a smooth transition into the mother lode of Prieska, the Deeps, and in parallel with that, will be finalising optimisation around the Okiep region.

Key Contracts, Suppliers and Consultants
Fraser McGill Mining & Minerals Advisory; METC Engineering; Gariep Mining and Exploration Services; Patterson and Cooke; Power Plant Electrical Technologies; Prysm; Professional Cost Consultants; Z Star Mineral Resource Consultants; P2 Mining a division of Newrak (trial underground mining contract); FlowCentric; EcoElementum; Sasol ENAEX; Solar Mining Services; Aquaplex; Partzone; Quebar; UMS Shaft Sinkers; LMMS Consultants (optimisation programme); and Practara Metals and Mining Advisory (independent technical experts).

Contact Details for Project Information
Orion Minerals, tel +27 11 880 3159 or email info@orionminerals.com.au.