Name of the Project
Cosmos Odysseus nickel project.

Location
Odysseus is located on a granted mining lease that is part of the high-grade Cosmos nickel complex, which is situated 30 km north of Leinster, in Western Australia.

Project Owner/s
Western Areas.

Project Description
A definitive feasibility study (DFS) has confirmed the project as a robust, ten-year operation producing 130 000 t of contained nickel in concentrate from ore reserves of 8.1-million tonnes at a nickel grade of 2%.

Odysseus will be accessed through a new single ramp decline that starts from the existing AM5/6 decline development. Compared with the central spiral decline proposed in the 2017 prefeasibility study (PFS), the ramp decline from the AM5/6 infrastructure minimises the full-face development required to access the Odysseus orebodies, reducing the development timeframe by six months, compared with that of the prefeasibility study (PFS).

While the existing decline development will need to be rehabilitated to a relatively lower take-off point, since it passes directly through existing AM5 infrastructure, it also creates the option of potentially mining the AM5 and AM6 deposits, which contain an indicated mineral resource of 2.2-million tonnes grading at 2.6% nickel.

No evaluation or study has been completed for the AM5 and AM6 deposits, and any potential benefits do not form part of the Odysseus DFS. Early concurrent and later mining options will form part of further study work.

The primary mining method will be single-lift longhole open stoping with paste fill, accessed through transverse ore drives (west to east) on a 50 m cross-cut spacing. The South and North orebodies will be mined in a top-down, centre-out sequence. Compared with the PFS, which had proposed a bottom-up approach, the top-down approach, combined with the quicker ramp access, allows for quicker accessing of the ore.

The existing Cosmos processing plant will undergo a $36-millon expansion and refurbishment to increase mill throughput from its previous nameplate capacity of 450 000 t/y to 900 000 t/y.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has an estimated pretax net present value, at a 7% discount rate, of $418-million and internal rate of return of 28% at a $7.50/lb nickel price, with a 3.5-year payback from the start of production.

Capital Expenditure
Preproduction capital expenditure is estimated at $299-million, including contingency.

Planned Start/End Date
First nickel concentrate is scheduled for the December 2022 quarter.

Latest Developments
Western Areas has started the development of twin declines at its Odysseus mine, at the Cosmos operation in Western Australia, awarding contractor Barminco a A$200-million contract.

The development and production contract at the Odysseus mine will run over a five-year period, and followed on from earlier rehabilitation work that the contractor completed at the mine.

Meanwhile, dewatering and rehabilitation of the main access decline have been completed, and work has started on the main decline and return airway full-face development.

“We have reached a critical milestone with the firing of the full-face development of the Odysseus decline, which is now heading across to the orebody. A significant amount of preparation and support work has been delivered across the site to reach this milestone,” Western Areas MD Dan Lougher has said.

“We now have our eye on the delivery of the first ore tonnes mined from underground in the first quarter of 2022,” he adds.

The refurbishment of the Cosmos concentrator is expected to start in the third quarter of 2022, and first nickel concentrate is targeted for the second quarter of 2023.

Key Contracts, Suppliers and Consultants
GR Engineering Services (process plant design, engineering, associated infrastructure); Piran Mining (mine planning and optimisation); KCSA Geomechanics (geotechnical engineering); Golders (geotechnical engineering); Dempers & Seymour (mining rock mass modelling); Itasca Australia (geotechnical modelling and geotechnical peer review); RSV SA (shaft engineering and design); Outotec (paste fill engineering, plant design and testing); OZ Vent (mine ventilation); ALS Metallurgical Services (metallurgical testwork); Groundwater Resource Management (hydrogeology); Big Dog Hydrogeology (hydrogeology peer review); MYR Consulting (risk assessment); Mining Access Legal and MMTS (tenement management services); SRK Consulting (geological model); Project Support (mining tender and infrastructure cost management); and Project Consultancy Services
(power study); and Barmico (development and production contract).

Contact Details for Project Information
Western Areas, tel +61 8 9334 7777, fax +61 8 9486 7866 or email info@westernareas.com.au.