In its endeavours to develop its Prieska copper/zinc mine (PCZM) and the Okiep copper project (OCP) – both located in the Northern Cape, of South Africa – copper-focused developer Orion Minerals has appointed a project director and consultancy to progress feasibility studies for both projects.

As such, international project manager Nick Fouche was appointed in October as PCZM project director to oversee the completion of the feasibility study, while LMMS Consultants was appointed by Orion at the same time, to assist in expediting ongoing optimisation work for this feasibility study.

Fouche brings vast experience in the development and execution of major global mining projects, having been growth GM for HBIS Palabora Mining Company, where he oversaw the development of the last major copper mine in South Africa. He has also held senior roles with South32, MMC Mining, Rio Tinto and, most recently, Piedmont Lithium.

LMMS has been contracted for a three-month period from October 2024 to provide intensive input to optimise the PCZM bankable feasibility study, with the consultancy employees involved in the optimisation programme being Joe Luxford and Doug Syme, both of whom have worked on orebodies using the selected mining methods for PCZM, both in Australia and globally.

They were also both key members of the Palabora mine planning and execution teams and therefore understand the South African operating environment with local challenges and opportunities, notes Orion.

“Nick Fouche has unique experience that is applicable to Orion’s underground copper mining projects,” says Orion MD and CEO Errol Smart.

“LMMS Consultants is the same expert mining team that contributed to the success of the Palabora Copper Mine Lift 2 development project – the last big underground copper mine developed in South Africa.

“LMMS is recognised internationally for their specialist expertise in underground bulk mining applications and consult on high-profile large mining project development optimisations for major mining houses such as BHP, Rio Tinto and South32, as well as for several junior mining companies,” he adds.

Considering potential December festive season disruption, the final feasibility study is expected to be ready for release early in the first quarter of 2025.

In terms of feasibility study optimisation, a review by LMMS and Fouche highlighted the potential to unlock additional upside in the project by undertaking a further optimisation of the mine design and scheduling for the Prieska Deeps orebody.

Unique Orebody Requires Special Approach
Orion notes that the PCZM orebody is unique owing to its laterally extensive, but folded, tabular structure. The dip of the orebody rotates through almost 320º on mine scale and has true widths of 2 m to 45 m; however, as a result of folding, the horizontal spans can vary from 2 m to 200 m and the vertical height of mineralised blocks ranges from 2 m to 200 m.

In the Deeps section of the orebody – which has a mineral resource of 29-million tonnes, grading 1.2% copper and 3.8% zinc – the complex geometry of the mineral resource results in the need for multiple mine stoping methods to extract the ore of varying dip and thicknesses.

While some ore blocks may be extracted by more than one of the selected mining methods, Orion notes that each will deliver different waste dilution tonnes and therefore influence run-of-mine grade and require different development intensity.

The combination of these three factors may materially impact capital expenditure, operating expenditure and operating revenue in any given period.

The detailed layouts, planning and relative scheduling have been identified as factors that can materially impact peak funding and operating cash-flows, and which therefore require increased focus on optimisation.

“A recent review of the Prieska financial model with input from LMMS and Nick has highlighted the potential to unlock additional upside at Prieska by further optimising mine design and scheduling,” notes Smart.

He adds that while it has been relatively simple to select suitable mining methods to extract this orebody, the iterative process required to optimise the appropriate mining methods in different mining areas to achieve optimum ore recovery and cash-flow is proving time consuming.

“The additional optimisations now underway will require several iterative runs using mine shape optimiser software with manual adaptation of development layouts to connect mining areas using different mining methods. This time-consuming process can only be executed by suitably experienced mining engineers,” explains Smart.

“When building large, long-life mines with large specialist mining fleets, getting the best combination of mining methods and primary development layouts is critical to maximise long-term project execution and financial returns. In the case of PCZM, unlocking the potential upside from additional optimisation studies outweighs the earlier completion of a feasibility study.”