The surface geology at Emily Ann is totally obscured by transported sediments and a thick saprolite profile extends down to about 80 m below the surface.

The deposit occurs in a complex geological setting, consisting dominantly of felsic volcaniclastics hosting subordinate discontinuous lenses of mineralised and barren ultramafics, which dip at between 40° and 60° to the east in the vicinity of the deposit. The ultramafics and associated nickel-sulphide mineralisation do not extend to the bedrock surface and are therefore totally blind. The deposit has been subdivided into two main mineralised structural domains, termed the upper mineralised horizon (UMH) and lower mineralised horizon (LMH).

The UMH has a strike extent of about 520 m and down-dip extent of up to 150 m. The mineralisation is highly variable and consists dominantly of disseminated to matrix pyrrhotitepentlandite and lesser stringer and massive sulphides. The proportion of massive sulphides increases downwards towards the boundary mylonite. The mineralisation in the LMH is of greater economic significance and consists of lenses of high tenor (8-14% Ni) massive nickel sulphides (pyrrhotite-pentlandite) distributed over a strike length of about 520 m and with a down-dip extent of about 270 m.

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 35 ........

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.

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