Deposit Type
Magmatic sulphide deposits containing nickel and copper, with or without PGMs, account for approximately 60% of the world’s nickel 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 sulphide rich and sulphide poor. Sulphide rich deposits typically have 10% to 90% sulphide minerals and have economic value primarily because of their nickel and copper contents. Sulphide poor deposits typically contain 0.5% to 5% sulphide minerals and are exploited principally for Platinum Group Metals (PGM).

The Eagle and Eagle East deposits are sulphide rich and high-grade magmatic sulphide accumulations containing nickel-copper mineralization and minor amounts of cobalt and PGMs. The economic minerals associated with these deposits are predominately pentlandite and chalcopyrite.

The mineralization process common to all primary magmatic sulphide deposits consists of: 1) Metal-rich ultramafic magma intruding into the crust, typically in an extensional environment; 2) Sulphur saturation through geochemical contamination by crustal rocks resulting in primary sulphide droplets forming; 3) Metal enrichment of sulphides by interaction with large volumes of subsequent magma flow; and 4) Deposition of sulphides by density settling where magma flow slows due to structural traps or major changes in the geometry of the plumbi ........

The Eagle Mine is an underground mine producing about 2,000 tpd of high-grade nickel-copper ore. The ore is hauled to surface in diesel-powered trucks via the ramp and then trucked to the Humboldt processing plant at a separate site.

Mining Methods
Eagle Mine uses three mining methods, TSLOS, LSLOS and D&F. Combinations of all three methods are used in Eagle, Eagle East, and the Keel Zone.

Transverse Sublevel Open Stoping (TSLOS)
The portion of the deposit between two sublevels is mined by dividing the ore into alternating primary and secondary stopes, extending in parallel from the footwall to the hangingwall. The stopes in Eagle Zone are 10 m wide and range in height from 18 to 29 m, depending on the sublevel internal. The stopes in Eagle East Zone are also 10 m wide but range in height from 25-28 m.

In wider parts of the deposit, the stopes are not mined as single excavations extending from footwall to hangingwall. Instead, each one is divided into panels, thereby limiting the length of the opening to a maximum of 32 m. This distance is based on the ability to complete the stope cycle in less than 60 days at typical mucking and backfilling rates. Multiple panels are mined one after the other in a retreating fashion from the hangingwall to the footwall.

The primary stopes are mined first, leaving ore pillars of the same dimension between primary stopes that will subsequently be mined as secondary stopes. Then, the mined- ........

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