The Maggie Hays deposit is blind, with the top of the main disseminated sulphide zone commencing at a depth of about 200 m beneath the surface and the massive sulphides at a depth of about 350 m beneath the surface, as shown in the cross section along 82700N.

The main zone of the deposit is located at the base of the CUU in association with olivine orthocumulate and mesocumulate lithologies that have subvertical dips to the east and west. Structurally, the zone occurs at a local pinch out in the CUU against stratigraphically overlying BIF (to the west) and underlying felsic volcanics (to the east). The structural termination is controlled by an early thrust, which dips at about 50° to the east and plunges at about 45° to the south, thereby terminating the main zone of the deposit at depth. A second lower grade portion of the deposit, known as the southern zone, occurs several hundred metres to the south. The Maggie Hays North zone of the deposit is controlled by the same thrust, with the mineralisation totally hosted.

Main Zone:
• Located at the base of the CUU with the bulk of the deposit located between 200 and 500 vertical metres beneath the surface and over a strike extent of 600 m.
• Basal massive sulphide zone of 4-6% Ni, located towards the lower (down-dip) margin of the disseminated zone and the northern structural termination of the ultramafic.

Northern Zone:
• Hosted entirely by felsic volcanics with the mineralisation controlled by an early thrust fault. The zone dips at about 50° to the east and has a strike extent of about 800 m.
• Massive, stringers and breccia sulphides. The sulphides form as a matrix to felsic clasts.

Southern Zone:
• Located several hundreds of metres to the south of the main deposit in high-magnesium ultramafics.
• Up to 10% disseminated sulphides, similar to the main disseminated zone.

All ore will be extracted using mechanised underground mining techniques. Development will be undertaken using mechanised jumbo drills for drilling and ground support installation. Diesel underground loaders and trucks will be used for material movement. Stope ore will be extracted by reactivating the existing sub-level cave, supplemented with separate areas of longhole stoping using unconsolidated backfill. Concurrent mining fronts will be established through the use of cemented aggregate fill and in-situ sill pillars.

The Lower ore zone plunges 25 to 30| to the northeast, is undulating, and sometimes comprises multiple massive units, separated by ultramafic host. The Lower ore zone is mined by room and pillar methods with backfill.

The Upper ore zone has a variable dip but on average plunges 60| to the northeast, is thinner than the Lower ore zone, and is hosted in ultramafics. The Upper ore zone is currently mined by drift and fill methods. However the lower parts of the Upper ore zone are likely to be mined by long hole open stoping methods.

The Lake Johnston 1.5 million tonne per annum process plant includes a conventional 3 stage crushing circuit, 3 ball mills, 2 flotation circuits, multiple thickeners and 2 Larox filtration circuits and a large concentrate storage shed. The Primero Group engineering subcontractors have been commissioned by POS to progress preliminary engineering design for the processing of Lithium hosted pegmatites. An initial review of the concentrator will be focussed on a plant trial to process Lithium ores to produce a 6% spodumene concentrate.