The Siviour graphite project is an open-pit mining development in the Eyre Peninsula, Australia. The mine is being developed and operated by Renascor Resources through its subsidiary Ausmin Development, which holds complete ownership of the project.
Siviour is recognised as the world’s second-largest reported proven graphite reserve and the largest outside of Africa, with an anticipated mine life of 40 years and potential production of up to 150,000 tonnes of annum (tpa) of graphite concentrates.
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The project is estimated to require a start-up capital of A$114m ($79m). It is expected to generate approximately $260m annually in export revenue, enhancing Australia’s international competitiveness and potentially establishing the country as a future leader in the sector.
Siviour project location
The Siviour project is situated within Renascor’s Arno project on the Eyre Peninsula, South Australia. The site is approximately 15km west of Arno Bay, 120km north-east of Port Lincoln, and 150 km south-west of Whyalla.
Geology and mineralisation
The geology is based on the Hutchison group rocks, with the graphite mineralisation hosted within Mesoproterozoic metasedimentary rock sediments of the Hutchison Group.
Mineralisation at Siviour occurs within a sequence of schist, micro-gneiss, and metasedimentary rocks, presenting a simple tabular geometry. The main host is a 30m thick band of pelitic schist that occurs within a thick calc-silicate sequence.
Reserves at Siviour
The proven and probable reserves at Siviour were estimated at 61.8 million tonnes (mt), grading 7.0% total graphitic carbon (TGC), with a total contained graphite of approximately 4.3mt as of August 2023.
Mining method at the Siviour graphite project
The selected approach for mining is conventional open-pit mining, with truck and shovel operation. The majority of overburden will be excavated by drill and blast techniques, except for approximately 15% of alluvial material that can be freely dug.
The mining strategy involves conventional excavation methods using trucks and excavators, with drilling and blasting for the extraction of fresh and partially weathered rock, as well as ore. Mining operations are expected to be carried out in 10m x 10m blocks on 2m benches.
The mining fleet will consist of a Komatsu PC2000 200t excavator, HD785 haul trucks with a capacity of 60m³, and a Komatsu WA500-7 wheel loader.
The definitive feasibility study (DFS) plans for the acquisition of the mining fleet, which includes additional equipment such as a Komatsu GD655_5 Grader, Komatsu HM400_3MO Water truck, Komatsu WA 320PZ IT tool carrier, and Komatsu D275AX Dozer, through a hire purchase agreement. Other ancillary equipment will be bought outright.
Mining operations are set to run 24/7 to quickly reach high-grade ore, then scale back to day shifts only in years two and three. Mining operations would return to a 24-hour operation in year five, aligning with the expansion of the processing plant to 1,650ktpa.
Ore processing
The DFS proposes the construction of two processing plants, each with a capacity of 825 kilotonnes per annum (ktpa), culminating in a combined capacity of 1,650ktpa.
The processing plants are designed to extract graphite concentrate through froth flotation. The mined ore will undergo a two-stage crushing process followed by grinding, flotation, filtering, drying and sizing, before being packaged for shipment.
The run-of-mine (ROM) ore will be crushed in a primary jaw crusher with the oversize further crushed by a secondary pebble crusher.
The crushed ore will be conveyed to a primary rod mill to achieve the desired flotation feed size. The mill oversize will be recycled to the mill feed, while the fines will bypass the primary mill to prevent overgrinding.
The flotation and regrind circuits will include desliming, roughing, scavenging, multiple cleaning stages, and regrind stages. The cleaning circuit will screen concentrate after the second cleaning, with larger flake material moving directly to filtration and drying.
The finer product will undergo additional regrind and cleaning to enhance purity. The design aims to maximise the retention of coarse flake graphite with a minimum purity of 94% to 96% TGC.
The final product will be filtered, dried and sorted into different-size fractions before being placed in bins and packaged into one-tonne bulk bags according to product specifications.
Battery anode material production
Renascor plans to establish a facility to produce battery anode material, converting graphite concentrate into purified spherical graphite (PSG) using an environmentally friendly, hydrofluoric acid (HF)-free purification process.
The graphite concentrate will be micronised, spheronised, and purified to more than 99.95% TC for export to lithium-ion battery anode manufacturers, catering to the electric vehicle market.
Renascor has secured offtake agreements for PSG with companies such as POSCO, Mitsubishi Chemical, Hanwa, Shanxi Minguang New Material Technology (Mingunag), and Jiangxi Zhengtuo New Energy Technology (Zeto).
The Australian Government, through its Critical Minerals Facility, approved a loan facility of A$185m ($121.5m) for the battery anode facility.
Site infrastructure
Lucky Bay, the closest port to the project site at approximately 60km, is the preferred port. The port, currently under development, is expected to be operational when production starts at Siviour. If Lucky Bay is not ready, concentrates will be transported by road to Port Adelaide, about 500km away.
Electricity will be sourced from an existing 33kV grid operated by SA Power Networks, with plans to enhance and extend the power line by approximately 12.5km. The project will benefit from a low environmental footprint, with approximately 70% of electricity supplied from renewable sources in South Australia.
Water will be provided by a reverse osmosis plant located approximately 12km from the Siviour site on the Spencer Gulf, subject to planning and approvals.
Contractors involved
Optiro, a mining consultant, provided the mineral resource estimation of the project.
Goudie Hall Consulting was responsible for the metallurgical test work. Optima Consulting and Contracting handled the mining and mine design aspects.
The engineering of the mineral processing and plant design was a collaborative effort between Royal IHC and Wave International.
AMC Consultants and Wave International carried out geotechnical analysis for the mine. The latter was also in charge of the infrastructure and tailings management for the project. Groundwater Science, a hydrogeological consultancy, conducted the hydrogeological studies.
The environmental permitting process was managed by JBS&G Australia. Logistics were overseen by an individual expert, George Wilby. Financial analysis was provided by BurnVoir Corporate Finance and Wave International.
Engineering consultant ANZAPLAN completed advanced mineral processing trials for the project.
