Name of the Project
Prieska copper/zinc project.

Location
Northern Cape, South Africa.

Project Owner/s
Orion Minerals.

Project Description
A bankable feasibility study (BFS) on the foundation phase of the Prieska project has confirmed the quality and scale of the project. The BFS evaluates the establishment of new mining operations at the Prieska copper mine, which has been closed since 1991.

The project has a maiden ore reserve of 13.62-million tonnes at 1.1% copper and 3.2% zinc for 143 000 t of contained copper and 433 000 t of contained zinc.

The BFS has also investigated the commercial viability of a mining plan for the foundation phase aimed at establishing mine infrastructure and operational capacity, which are intended to establish the platform for further mining of deposit extensions, and the exploration and mine development of neighbouring prospects.

According to the BFS, the foundation phase runs for 9.7 years of run-of-mine production at a design ore processing rate of 2.4-million tonnes a year. This phase targets the exploitation of those portions of the Prieska deposit that have been upgraded to indicated and inferred mineral resources from the first surface-based drilling campaign conducted from 2017 to 2018.

The production target comprises 65% probable ore reserves and 35% inferred mineral resources, with ore reserves predominating during the early stages of the mining plan. Underground and surface mining methods are planned to be used for the duration of the foundation phase, in conjunction with conventional froth-flotation concentration to produce differentiated copper and zinc concentrates for export.

Beyond the foundation phase, it is expected that mine-life extension will be underpinned by delineated mineral resources not yet incorporated into the mining plan, and known deposit extensions and existing pillars, which are expected to require low or no additional capital investment to extend the mine life. An estimated 9.7-million tonnes of indicated and inferred mineral resources, at grades of 1.1% copper and 3.6% zinc, remain outside the immediate mining plan, providing near-term potential to optimise mine plans to incorporate more of these resources into the foundation phase. Significant potential for nearby satellite deposits has also been identified.

Potential Job Creation
Not stated.

All-in Sustaining Costs/All-in Costs
Not stated.

Net Present Value/Internal Rate of Return
The project has a pretax net present value, at an 8% discount rate, of A$574-million and an internal rate of return of 38%, with a payback of 2.9 years from first production.

Capital Expenditure
The project has a peak funding requirement of A$378-million.

Planned Start/End Date
The production of first copper is scheduled to follow a two-year construction period.

Latest Developments
Orion Minerals has flagged a possible A$15-million in cost savings at its Prieska copper/zinc project, after identifying two new 3 600 kW mills that can be incorporated at the project.

The new mills are immediately available at a significant discount to similar mills, which would be available from manufacturers only on long order, the company has said.

The company has moved to secure specific mills required to release improvements identified in value engineering studies on the ore processing plant design and layouts.

Orion MD and CEO Errol Smart has said that securing the new mills facilitates the incorporation of a semiautogenous grinding (SAG) mill into the ore processing flowsheet, in place of the ball milling arrangement selected in the bankable feasibility study. This allows for significant operational flexibility and facilitating the processing of Prieska ore at a rate of up to 20% above design throughput, as well as capacity for future expansion.

Using the SAG mill also simplifies the plant layout and operations, reducing the upfront capital expenditure (capex) and the estimated operating costs, while removing the requirement for multistage crushing and screening of rock ahead of milling.

Overall, capex for the plant has now been reduced by about A$15-million, from the A$109-million originally estimated, while unit operating costs have been reduced by 5% from the base estimate of A$16.10/t.

Key Contracts and Suppliers
DRA Projects South Africa; A&B Global Mining; ABS Africa; BPDT & Co; Bluhm Burton Engineering & Ventilation Consultants; Beulah Africa; Cart Investments; Earth Science Solutions; Endeavour Financial Limited; Falcon & Hume Attorneys; Fraser McGill Mining & Minerals Advisory; Knight Piésold; METC Engineering Consultants; Mets Consulting South Africa; Patterson & Cooke; PCDS Consultants; Power Plant Electrical Technologies; Professional Cost Consultants; Questco; Shift Innovations; Steffen, Robertson & Kirsten South Africa; The MSA Group; Turnkey Civil (International) Group; VBKom Engineering Consultants; Z Star Mineral Resource Consultants (BFS); and Byrnecut Offshore (underground mine development and production).

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