The Sherlock Bay nickel-copper-cobalt deposit (“Sherlock Bay” or “Deposit”) is located in the Pilbara region of northwest Western Australia, within / proximal to the Scholl Shear Zone, a major regional strike-slip fault that traverses the north-western margin of the Caines Well Granitoid Complex in the West Pilbara Craton. Much of the deposit is covered by a veneer of sheetwash sediments averaging ~12 m thick. The mineralised horizon is spatially associated with intermediate to felsic metavolcanic rocks, metasedimentary rocks and mafic-ultramafic intrusions - including the Sherlock Intrusion located immediately to the south and spatially (and genetically) associated with the Deposit.

The mineralised horizon is a steeply dipping banded quartz-magnetite-amphibole schist (also referred to as a siliceous banded iron formation or amphibole-bearing chert). There is broad correlation of Ni, Cu and Co grade to sulphide content with the main species being pyrrhotite (+/- pentlandite), pyrite and chalcopyrite.

Sherlock Bay includes two nickel sulphide deposits, Symonds and Discovery, both of which are tabular and trend northeast-southwest within an overall 1.5km strike length mineralised zone within the Scholl Shear Zone corridor. Each deposit is approximately 600m to 800m in strike length, approximately 15m to 20m wide and dip almost vertically to depths in excess of 500m. The deposits remain open down-dip/plunge.

The mineralisation is associated with a laminated silica-chlorite-carbonate-amphibole-magnetite assemblage within the host “chert” horizon. Ni-Cu-Co bearing sulphides occur as fine disseminations, veins, coarse blebs or within the bands apparently replacing magnetite. Nickel grades broadly correlate with pyrrhotite content. The entire chert unit is rarely completely mineralised, with nickel grades dropping to near background towards the “footwall” (south) in upper levels or “hangingwall” (north) at depth. The dip of the mineralised chert changes from steep west to steep east with depth – apparently correlating with an increase in grade down dip/plunge.

The Sherlock Bay deposit has a drilled strike extent of 1.7 km EW and a maximum vertical depth of 600m. The true thickness of the mineralisation ranges from 10 m to 30 m.

Initial study was completed in 2005, that included one open pit, with a saddle between the Discovery and Symonds deposits and two, decline based, underground mines utilising sub-level caving (“SLC”) methods.

The second study in 2018 applied a regularisation dilution model to the open-pits optimisation, which had the effect of incorporating an additional 2Mt (total 6.36Mt) of lower grade “ore” at the ore-waste boundary, which has had the effect of reducing overall open-pit grade by 16% to a realistic 0.31% Ni.

Waste to ore ratio for the open pits is approximately 5:1 after applying overall slope angles of 40° (batter angles 65° and 5m berms every 20m).

The 2018 study has incorporated the underground model from the 2005 study which includes separate declines to access the Discovery and Symonds lodes, accessed from a single portal within Symonds open pit. Mining to be conducted from the top down, to provide early higher-grade feed for the plant, utilising the SLC method with 25m sub-level spacing. Production blast holes are drilled as up-holes from one level to the other and mined in a retreating manner from the limits of the orebodies. The mining rate assuming mining the two resource zones (Discovery and Symonds) at the same time, is 1Mtpa production from each (total 2Mtpa).

The combined project (2018) includes two, optimised, open pits that would operate for up to 5 years and overlap with the underground development and establishment of SLC operations from year 3. The underground mines continue for the remaining 8 years of a 10-year mining plan, producing 2.0Mtpa of “ore” per annum once full production levels are reached.

Previous processing studies were based on processing 2Mtpa of ore grading 0.53% Ni, 0.13% Cu, 0.03% Co in a flowsheet comprising heap leaching of ore followed by solution neutralisation, copper cementation, to produce a separate copper product and precipitation of nickel and cobalt as a mixed hydroxide product (“Mixed Hydroxide” or “MHP”) containing about 44% Ni and 2% Co (dry basis).

The heap leach flowsheet was based on the BioHeap column leaching testwork on the Sherlock Bay sulphide mineralisation by Pacific Ore Technology (“POT”) in 2005 to 2008. The POT patented BioHeap process involved the use of saline tolerant bacteria to be sourced from the Sherlock Bay site. Nickel extraction ranged in testwork from 60% to over 90% with the highest nickel extraction reported in tests with a pH<1.8 at low pH and low Cl levels. Recoveries are expected to scale-up to average >80% in the highly saline conditions (27,500ppm Cl) expected at site.

The project design and cost ........