Name of the Project
Prieska copper/zinc project.

Location
Northern Cape, South Africa.

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

Project Description
An updated bankable feasibility study- (BFS-) 20 has confirmed the potential of Prieska to underpin a significant near-term, low-cost, copper/zinc development project, with exceptional opportunities for future growth.

The updated BFS on the foundation phase of the project proposes the development of a new 2.4-million-tonne-a-year copper/zinc mining operation at the brownfield project.

Underground and surface mining methods are planned to be used in conjunction with conventional froth-flotation concentration to produce differentiated copper and zinc concentrates for export.

Peak production is estimated at 23 000 t/y of copper and 88 000 t/y of zinc.

The life-of-mine (LoM) has been extended by two years, from 9.7 years to 11.5 years.

Material changes in the updated BFS, compared with the 2019 BFS plan, include:

• reducing the mine dewatering timeline and supplementing the treatment of that water,
• incorporating additional mineral resources into the mining plan that will increase the mine life by two years,
• a more conservative timeline to ramp up to steady-state production,
• prioritising the early mining of high-grade zones in the mining sequencing,
• adopting semiautogenous grinding mills in the processing flowsheet,
• an owner-miner operating philosophy for underground mining,
• using an experienced contractor to operate the processing plan, and
• a change in the key operational infrastructure being supplied by third-party financing and in the supply of select key operational infrastructure.

The mining methods for the project remain unchanged, compared with those stated in the 2019 BFS. Tunnel development remaining from the previous mining operations allows for early access to underground production mining areas. It is planned that a combination of longhole open stoping with fill and drift-and-fill mining methods will be used, supported with paste backfill.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has a net present value, at an 8% discount rate, of A$779-million, compared with A$574-million in the 2019 BFS, and an internal rate of return of 39%, compared with 38%, in the 2019 BFS. Payback from first production is estimated at 2.4 years, a decrease of five months.

Capital Expenditure
Market intelligence firm S2 Research noted in May 2022 that the peak funding requirement of Orion Minerals’ Prieska project had decreased from R2.4-billion to R2.25-billion. This has reduced the funding risk of the project.

In a prior note, S2 anticipated that Orion would need R2.7-billion to develop and optimise the Prieska mine.

Planned Start/End Date
Orion Minerals is targeting production startup in 2024, market conditions permitting.

Latest Developments
Orion Minerals has awarded a six-month trial mining contract to P2 Mining, a subsidiary of South African mining contractor Newrak Mining Group, to undertake the early works trial underground mining programme at the Prieska copper/zinc mine.

The trial mining will target the +105 Level Crown Pillar, using conventional and alternative underground mining methods.

The trial mining will comprise 120 m of footwall ramp development, before accessing the high-grade supergene ore of the +105 block with ore development along strike for 150 m on either side of the primary access as the primary in a cut-and-fill mining cycle.

The contract also covers the opening of the 143 Level historical stope draw-points for selective loading and hauling to surface of broken ore remaining in the stopes, as well as to perform bulk sampling and metallurgical trials on the material.

If successful, this exercise will continue to build a stockpile on surface for future processing once the concentrator plant is commissioned.

Newrak will operate a trial fleet of ITC equipment, together with a full conventional mechanised mining fleet to compare efficiencies during the trial mining phase.

The contractor will operate a fleet of conventional load, haul and dump loaders, as well as a continuous loading machine, which was recently introduced to the South African market and secured by Orion on demonstration rental.

The ITC120 continuous loader is expected to contribute to improved efficiencies in mucking operations and to accelerate access tunnel development and ore drive development.

“This is a tremendously exciting period for Orion as we move to active trial mining at Prieska and start our transition from developer to operating mining company. We have spent the past two months completing essential preparations, such as installing underground refuge chambers, upgrading hoisting capacity of the emergency escapeway to surface, and sourcing and installing key ventilation equipment.

“With these essential safety and environmental preparations now complete, we can finally mobilise the mining contractor to commence drilling, blasting and hauling ore to surface,” says Orion CEO and MD Errol Smart.

Key Contracts, Suppliers and Consultants
Companies involved in the BFS included A&B Global Mining; ABS Africa; BPDT & Co; Bluhm Burton Engineering & Ventilation Consultants; Beulah Africa; Cart Investments; DRA Projects South Africa; Earth Science Solutions; Endeavour Financial Limited; Falcon and Hume Attorneys Inc; Fraser McGill Mining & Minerals Advisory; Knight Piésold; METC Engineering; Gariep Mining and Exploration Services; Mets Consulting South Africa; Patterson and Cooke; PCDS Consultants; Power Plant Electrical Technologies; Professional Cost Consultants; Promethium Carbon; Shift Innovations; SRK Consulting; Strategy4Good; The MSA Group; Turnkey Civil (International) Group; VBKom Engineering Consultants; Whittle Consulting; Z Star Mineral Resource Consultants; and P2 Mining (early works trial underground mining programme).

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