Magmatic nickel-copper-platinum group element (PGE) deposits occur as sulphide concentrations associated with a variety of mafic and ultramafic magmatic rocks. The magmas originate in the upper mantle, and an immiscible sulphide phase occasionally separates from the magma as a result of the processes occurring during emplacement into the crust. The sulphide phase generally partitions and concentrates nickel, copper and PGE elements from the surrounding magma. The heavy sulphide droplets once concentrated and separated from the magma tend to sink towards the base of the magma, and form concentrated pockets or layers of sulphides that crystallize upon cooling to form mineral deposits.

The Dumont mineral deposit comprises olivine + sulphide cumulates that comprise differentiated layers of the Dumont sill, an Archean komatiitic intrusion contained within the Archean Abitibi Greenstone Belt of northwestern Quebec. As such, it is usually classified (Naldrett, 1989) with its most analogous counterpart, the Mt. Keith mineral deposit located in the Agnew-Wiluna Greenstone Belt within the Archean Yilgarn craton of West Australia.

Nickel-bearing sulphides and a nickel-iron alloy are enriched (grades > 0.35% nickel) in stratiform bands within the dunite subzone and are also broadly disseminated at lower concentrations throughout the dunite and lower peridotite subzones. The number and thickness of these bands varies from place to place in the deposit. Nickel sulphid ........

The Dumont pit will ultimately measure approximately 4.9 km along strike, 1.4 km at the widest point and reach a maximum depth of 520 m below surface. A total of 2,080 Mt of material will be excavated, using large surface mining equipment that will operate at high production rates.

The pit is comprised or three distinct areas:

• The “Quarry”, at the south east limit of the deposit hosts the only outcrop and is thus where mining initiates. The Quarry is initially excavated to a volume of approximately 5 Mm3 and serves as contingent storage for water during the period the Main Pit is operational. Following completion of operations in the Main Pit, the Quarry is expanded to its full limits of approximately 30 Mm3.
• The “South-East Extension” (SEE), measures approximately 92 Mm3. Development of the SEE commences immediately following that of the Quarry, from which it is separated by a saddle of rock. After the SEE reaches its final limits, it is backfilled to just below surface with waste rock from the Main Pit.
• The “Main Pit” represents approximately 85% of the total excavation.

The ore body is covered with overburden of varying depth. Overburden, which comprises 8.3% of the total material that will be excavated, is comprised of differing material types. Overburden will be stripped in advance of the ore mining operation and impounded in different areas depending on the geotechnical parameters of the specific material type. Waste roc ........

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