ASX-listed Orion Minerals has provided an update on the progress of the Feasibility Studies for both the Prieska Copper Zinc Mine (PCZM) and the Okiep Copper Project (OCP), both located in the Northern Cape Province of South Africa.
The Company has appointed experienced international project manager, Nick Fouche, as PCZM Project Director to oversee the completion of the Feasibility Study.
Fouche is a highly regarded global mining executive with vast experience in the development of execution of major mining projects around the world. He was previously General Manager Growth 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.
Orion has also secured the services of highly respected LMMS Consultants to assist in expediting ongoing optimisation work for the PCZM Feasibility Study.
LMMS have been contracted for a three-month period from October 2024 to provide intensive input to optimise the PCZM BFS (see below). The consultant employees involved in the optimisation programme are Joe Luxford and Doug Syme, both of whom have worked on orebodies using the selected mining methods for PCZM, both in Australia and worldwide.
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.
PCZM Feasibility Study Optimisation
Orion recently completed an internal review of the PCZM Feasibility Study with input from LMMS and Fouche. This review 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.
The PCZM orebody is unique due to its laterally extensive but folded tabular structure. The dip of the orebody rotates through almost 3200 on mine scale and has true widths of 2m – 45m; however, due to folding, the horizontal spans can vary from 2m – 200m and the vertical height of mineralised blocks ranges from 2m – 200m.
In the Deeps section of the orebody, which has a Mineral Resource of 29 million tonnes at 1.2% Cu and 3.8% Zn (refer ASX/JSE release 18 December 2018), 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.
The different mining methods that have been selected require different mining equipment and different layouts of waste access development.
While some ore blocks may be extracted by more than one of the selected mining methods, 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 Capex, Opex 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.
The detailed mine scheduling requires multiple iterative scenario runs, which require manual intervention and detailed design finessing in addition to the use of standard computerised Mine Shape Optimiser (MSO) software. This is particularly the case in the zones where the geometry of the orebody requires mining methods to transition and where complete runs of the financial model are required to test the impact of the modifications.
The primary development and ventilation layouts also require optimisation for long-term use to extract the anticipated extensions of the orebody in the strike and parallel footwall orebody.
In addition, the geotechnical stress regime needs to be reviewed for different extraction schedules and mining rates, taking into consideration the geometry of mining void development.
LMMS have commenced detailed optimisation of the mine schedule, with the optimisation program expected to be completed in December 2024. This will be submitted for review by external experts at the earliest opportunity and then incorporated into the finalised PCZM Feasibility Study.
Considering potential December festive season disruption, the final Feasibility Study is expected to be ready for release in early Q1 CY2025.
New Okiep Mining (NOM), Flat Mines Copper Project
The first draft of the Flat Mines Feasibility Study was reviewed by The Minerals Corporation (TMC), which has been appointed as the debt financiers’ Independent Experts, in July 2023. TMC recommended some additional work requiring confirmation drilling.
The revised Flat Mines Feasibility Study is progressing well following the successful completion of an 11 hole, 5,800m confirmation drilling programme that was executed and reported between February 2024 and September 2024.
The drilling programme confirmed the Mineral Resource Estimates as previously reported which were incorporated in the initial life-of-mine (LOM) schedules.
The availability of drill core also afforded the opportunity for additional geotechnical appraisal and metallurgical test work.
Metallurgical test work has now confirmed historical data and recovery assumptions that were used the first draft of the Feasibility Study that was reviewed by TMC
Geotechnical test work of core and a review of detailed logging and mapping has also confirmed expectations of highly competent host rock, with minor modifications being recommended for stope designs to accommodate rare, minor fractures within the orebodies.
These revised stope designs are now nearing completion and will be incorporated in the financial modelling and submitted for external review by mid-November 2024.
This will pave the way for the expected release of the Flat Mines Feasibility Study in December 2024.
Orion’s Managing Director and CEO, Errol Smart, commented: “We are thrilled to welcome Nick Fouche as Project Director for the PCZM development. Nick was Project Director for the Feasibility Study and execution of the Palabora underground mining project and has unique experience that is applicable to Orion’s underground copper mining projects. His vast global experience includes roles with ERO Copper, South 32 and Rio Tinto as General Manager Growth. Nick is a fantastic addition to the Orion team, as we move towards the development phase at Prieska.
“We are also pleased to have secured the services of LMMS Consultants, 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 are 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 South 32, as well as for several junior mining companies.
“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. The Prieska Mineral Resource has unique geometry, being folded through dip rotations of almost 3200 and having mineralised true widths varying from 2m – 45m.
“While it has been relatively simple to select suitable mining methods to extract this superb 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 (MSO) 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.
“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.”
