Black Swan

  • 2.2Mtpa processing plant
  • Silver Swan underground 12.9kt Ni (grade - 9.5%)
  • Golden Swan underground 6.3kt Ni (grade - 3.9%)
  • Silver Swan Tailings - 6.2kt Ni (grade - 0.92%)
  • Black Swan Disseminated 181kt Ni (grade - 0.63%)
  • Southern Terrace remains prospective for additional high grade discoveries

History

The Black Swan Project is located approximately 600km east of Perth and 50km northeast of Kalgoorlie, Western Australia and 300kms South of Poseidon’s Windarra Nickel Project.

The project commenced operations in 1997 and operated continuously until 2008. The following production was achieved:

  • Black Swan Open Pit - 5.9Mt @ 0.7% Ni for 41kt Ni
  • Silver Swan Underground - 2.7Mt @ 5.1% Ni for 138kt Ni
  • Total production 179kt Ni concentrate

Fill the Mill Strategy

The Company continues to progress toward a commencement of mining and processing operations at Black Swan given the positive outlook for nickel with work continuing on the Bankable Feasibility Studies for the 1.1Mtpa and 2.2Mtpa throughput options.

The current process plant was built in 1996 and upgraded in 2007. It was put on care and maintenance in February 2009 following a period of low Ni prices.

2021 Black Swan Scoping Study

During the fourth quarter of FY21, GR Engineering Services (GRES) was commissioned to provide a
Scoping Study to evaluate the capital and operating expenditure (+/-20% accuracy) for commencing
operations at the Black Swan plant. Two processing plant configurations were considered for refurbishment:

Option 1: 150ktpa Silver Swan concentrator to treat high-grade sulphide ore.

Option 2: Black Swan concentrator de-rated to 1.1Mtpa utilising the 4.8MW SAG Mill in a Single Stage SAG Mill configuration to treat lower grade open pit disseminated ore, Silver Swan tailing, high grade ore and potentially ore from Windarra.

The key findings from the study were:

  • The 150ktpa Silver Swan concentrator can be refurbished for a capital cost of $13.4 to $15.9 million, subject to using contract crushing or utilising the existing Black Swan crushing capacity. The operating cost estimate was $79.09/tonne without contract crushing or $91.60/tonne utilising contract crushing.
  • The 1.1Mtpa Black Swan concentrator can be refurbished for a capital cost of $22.1 million, while the operating cost estimate came in at $29.39/tonne.
  • The study concluded that both concentrator refurbishment options would take approximately six months to complete.

2022 Black Swan Bankable Feasibility Study

to positive outcomes from the Scoping Study and the large (and growing) resource base at Black Swan, the Company is now studying two throughput options:

  • 1.1Mtpa throughput to produce smelter grade concentrate, key points as follows:
    • mixing Black Swan Disseminated serpentinite ore with Silver Swan high grade ore and Silver Swan tailings
    • produces a concentrate with an Fe:MgO of greater than 3:1
    • likely < 5 year project
    • low start-up capital
    • improved concentrate payabilities in recent years
  • 2.2Mtpa throughput to produce a rougher concentrate, key points as follows:
    • can process both higher talc content sepentinite and talc-carbonate disseminated ore
    • rougher concentrate can be processed to mixed hydroxide precipitate via pressure oxidation
    • longer life > 5 year project
    • potential for local downstream processing in Western Australia (i.e. Pure Battery Technologies proposed pCAM Hub in Kalgoorlie, or existing HPAL plants in WA.

Bankable Feasibility Studies (BFS) are currently in progress to evaluate commencing mining and processing operations at the Black Swan. The BFS will incorporate studies into the blending of mining inventories from several sources. The main source will be the lower grade disseminated ore (both serpentinite and talc-carbonate) from the Black Swan open pit. High-grade massive sulphides from the Silver Swan and Golden Swan will be included in the production blend assessment and Silver Swan Tailings. Ore sourced from Windarra, which is proposed to be hauled to Black Swan at a later point in the production schedule, will also be assessed.

The historical Silver Swan tailings located only 300 metres from the Black Swan concentrator could form a small proportion of the production blend (10-15%) in the 1.1Mtpa option given that this relatively high-grade nickel tailings resource has a high iron-sulphide content with a low level of MgO. This aspect of the Silver Swan tailings makes it attractive to include as a feedstock blend, to improve the final concentrate marketability to smelters. Noting the Fe:MgO ratio is an important criterion in a nickel concentrate specification, with penalties (and ultimately reject limits) applied if the specifications are not met.

The 675kt measured resource for the Silver Swan tailings, grading 0.92% Ni and 683 ppm Co, could be blended with other ore sources to ensure the final concentrate quality remains within the required specification with respect to the Fe:MgO ratio. The tailings are already at the target grind size, so the incremental cost to reclaim and process will be a small fraction of the overall operating cost. The proportion proposed to be added will not affect the 1.1Mtpa milling capacity option given the tailings are already ground to the target grind size and there is surplus flotation capacity within the Black Swan concentrator.

For the Fill the Mill Strategy, next steps include:

  • delivering an updated Black Swan Disseminated Resource (completed)
  • deliver the BFS on the two throughput options
  • update the Mining Reserves for the Open Pit and Underground Resources
  • making a Final Investment Decision (FID)
  • subject to FID, financing and undertaking all necessary development steps to restart operations
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