Mt Thirsty is Australia’s most advanced genuine cobalt project with a Pre-Feasibility Study (PFS) completed in 2020.
The Mt Thirsty Project is located approximately 16km northwest of Norseman, Western Australia and is close to all necessary infrastructure (rail, road, power, gas, water, townsite, fibre optic and seaport). The Project is a 50/50 Joint Venture between Greenstone (a 100% subsidiary of Horizon) and Conico Ltd.
COBALT-NICKEL OXIDE DEPOSIT
The Project hosts the Mt Thirsty Cobalt-Nickel Oxide Deposit which represents an excellent long-term, low cost, cobalt production opportunity.
The deposit is flat lying, continuous and thick starting from near surface to around 70 metres below surface. Due to intense oxidation, the deposit is very soft and fine grained.
PRE-FEASIBILITY STUDY (PFS)
The Mt Thirsty PFS returned a positive pre-tax Net Present Value with a low capital cost of A$371 million (including indirect costs, growth allowance, owner’s costs and 10% contingency) (refer to Greenstone Minerals Limited (GSR) ASX announcement dated 20 February 2020). The project is expected to produce 19.1kt of cobalt and 24.8kt of nickel as a Mixed Sulphide Product (MSP) over the 12 year life of mine, a product that is of strategic interest to many multinational mining, refining and trading companies as it is suitable for the production of metals, chemical and battery markets.
NICKEL SULPHIDE MINERALISATION
In addition to the Cobalt-Nickel Oxide Resource, the Mt Thirsty Project has proven potential to host primary nickel sulphide mineralization at greater depths within the same ultramafic sequence which hosts the near surface oxide deposit.
The thick sequence of altered olivine-rich, cumulate-textured ultramafic rocks contain semi-massive, stringer and disseminated nickel sulphide mineralisation. The footwall contact where the best concentration of nickel sulphides might be expected has been systematically tested with RC and diamond drilling. RC drilling to date has returned nickel sulphide intersections including 6m @ 3.4% nickel, 2m @ 5.9% nickel, 2m @ 3.5% nickel and 1m @ 4.0% nickel (refer to Greenstone (GSR) ASX Announcements 31 August 2010, 2 September 2010, 18 November 2010).