Magmatic sulphide deposits containing nickel (Ni) and copper (Cu), with or without (±) platinum-group elements (PGMs), account for approximately 60% of the world’s Ni production and are active exploration targets in the United States and elsewhere. On the basis of their principal metal production, magmatic sulphide deposits in mafic rocks can be divided into two major types: those that are sulphide-rich, typically with 10 to 90% sulphide minerals, and have economic value primarily because of their Ni and Cu contents; and those that are sulphide-poor, typically with 0.5 to 5% sulphide minerals, and are exploited principally for PGE.

The Eagle deposit and the Eagle East conduit zone are high-grade magmatic sulphide accumulations containing nickel-copper mineralization and minor amounts of cobalt and PGMs. The economic minerals associated with this deposit are predominately pentlandite and chalcopyrite.

Eagle and Eagle East are part of the same ultramafic intrusive complex and both host high grade primary magmatic nickel copper sulphide mineralization. Mineralization styles are similar at Eagle and Eagle East, consisting of ovoid to pipe-like bodies of mineralized peridotite with concentrations of sulphide mineralization along the base of the intrusion resulting in the accumulation of semi-massive sulphide, and a central core zone of massive sulphide.

Two types of potentially economic mineralization are found in Eagle and Eagle East: semimassive ........

The Eagle Mine is accessed via a main ramp, measuring 5.35 m high by 5.65 m wide and driven at a grade of -13%. The main ramp was driven to the 145 level, the lowest level and bottom of the Eagle Mine.

Mine production is made up of a combination of ore development through sill drifts or cuts (approximately 19%) and stope production (81%). The mining method selected for Eagle and Eagle East is the Transverse Sub-level Open Stoping (SLOS) method using a combination of cemented rock fill (CRF) and non-consolidated waste rock backfill. SLOS would also be used for any potential mining at Eagle East. This method provides the cost advantages of bulk mining, while maintaining a degree of selectivity and operational flexibility. The majority of the stopes will be mined as transverse bench and fill stopes, with some narrower zones of the orebody mined as longitudinal retreat stopes.

The Eagle orebody is accessed by the sub-level footwall drives driven off the main decline at 20 m to 25 m vertical intervals.

Stopes are designed to be 10 m wide and approximately 25 m high (corresponding to the top and bottom sub-levels). Stope lengths vary depending on the width of the orebody, however, due to geotechnical constraints, individual stope panels are limited to a maximum length of 20 m. The height and length of each stope panel is designed based on the hydraulic radius (HR) of the stope to limit sloughing from the walls and caving from the backs of the stop ........

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