PERTH (miningweekly.com) – A metallurgical optimisation upgrade at the Heemskirk tin project, in Tasmania, has resulted in a 34.2% increase in the project’s net present value (NPV), owner Stellar Resources reported on Tuesday.
A 2013 prefeasibility study had estimated that a $114-million investment would be required to support production of 4 327 t/y of tin-in-concentrate. At the time, the project was estimated to have a NPV of A$61-million, at a tin price of $25 500/t.
However, Stellar noted this week that optimisation studies had increased tin recovery by 4.5% to 72.8% across all of the Heemskirk deposits, and more specifically by 7.4% to 79.5% at the Severn deposit, increasing tin-in-concentrate production to 4 520 t/y, and increasing the project’s valuation to A$82.3-million.
“This is a significant milestone for the Heemskirk project for two reasons; firstly, it has demonstrated a step-up in recovery for Severn, the major deposit, and promises improvements for the other deposits, which to date have not been tested to the same degree,” said Stellar MD Peter Blight.
“Secondly, it has provided robust data for optimising design criteria and processing conditions ahead of a definitive feasibility study (DFS) to commence in 2015.”
Stellar would conduct an assessment of the operating and capital cost implications of the Severn results, and would apply lessons learnt at this deposit to other ore sources.
The company would also conduct pilot testing to support a DFS, as well as further variability testing.