TIN: Stellar announces fresh project economics for Heemskirk
Heemskirk developer Stellar Resources has published a new scoping study for the Tasmanian tin project, incorporating the September 2023 MRE of 7.34 Mt at 1.04% Sn and updated cost estimates.
The proposed underground mine would produce approximately 350 ktpa ore from two of Heemskirk’s four deposits, producing 1,902 t tin-in-concentrate per annum over 12 years, 97% from indicated resources. Incorporating inferred resources would extend mine life to 22 years, with the potential for an accelerated schedule to increase mining capacity to over 750 ktpa ore for 13 years. Under the current plan, a small amount of mining of inferred resources is necessary to access the indicated resource.
Stellar Resources Executive Chairman Simon Taylor highlighted the low cost estimates of a capital cost requirement of A$71 million (approximately US$48 million) alongside a new AISC estimate of US$18,260/t tin produced. A base case at a tin price of US$28,000 was modelled for a post-tax NPV8 of A$75 million with payback over 3.5 years. A spot case at a tin price of US$32,000 yielded an estimated post-tax NPV8 of A123 million with payback over 2.8 years.
The processing plant flowsheet includes two-stage crushing, sulphide flotation, gravity separation, flotation of deslimed fines, acid leaching to remove carbonates present at Heemskirk, and final dressing using a second sulphide flotation and magnetic separation. The plant will require an upfront capital expenditure of A$45 million, and carries an estimated operating cost of A$43.5/t ore. Tailings will be thickened and pumped via a 6.7 km long slurry pipeline to a proposed disposal site within a natural valley away from observed endangered flora and fauna.
Over the mine life, head grade will average 0.78% Sn, with a 75% recovery rate, to produce a concentrate grading 49% Sn for sale to smelters in China or southeast Asia.
The company did not provide an estimated start-up year, but stated first concentrate sales would be expected to commence approximately 9 months from the start of decline development.
Stellar Resources has commenced data collection for a Prefeasibility Study investigating increased mining rates, plant capacity optimisations, incorporation of ore sorting, and alternative tailings management. Baseline work and studies have started for the environmental impact statement and environmental management plan, both required for final permitting. The updated scoping study provides very attractive cost estimates, with AISC placing in the lower half of forecasted mining costs and capex intensity firmly in the lower half of similar projects as calculated by ITA. Stellar Resources has attracted significant investment in 2024, and we look forward to further studies as the project progresses.
