United States

Eagle East Expansion Project

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Overview

Mine TypeUnderground
 Archived Information
Commodities
  • Nickel
  • Copper
  • Cobalt
  • Gold
  • Silver
Mining Method
  • Longitudinal retreat
  • Bench & Fill
  • Transverse open stoping
Backfill type ... Lock
Mine Life... Lock
ShapshotThe first ore from Eagle East ore body was mined and delivered to the mill on September 30, 2019.

Owners

SourceSource
CompanyInterestOwnership
Lundin Mining Corp. 100 % Indirect
Eagle Mine LLC (operator) 100 % Direct
The Eagle East project is 100% owned and operated by Eagle Mine LLC, an indirect wholly owned subsidiary of Lundin Mining Corp.

Deposit type

  • Magmatic

Summary:

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 (SMSU) sulphides and massive sulphides (MSU). Disseminated mineralization is also encountered in the peridotite intrusive, however, because it is not economic, the mineralized peridotite with disseminated sulphides has been considered as an intrusive and not a mineralized unit.

Sulphides are deposited as dense droplets in the primary magma due to decreased flow rate in the magma, or a change from laminar to turbulent flow due to changes in the conduit geometry. Multiple pulses occur in the same plumbing system, resulting in three discrete mineralization types which typically have hard contacts. The mineralizing intrusion is Mineralized Peridotite (MPER), which transports sulphides within large volumes of magma, and in this way is able to transport significant quantities of dense sulphides upward through the crust in a diluted form. This results in the conduits between mineralized zones consisting of barren peridotite or weakly mineralized peridotite, such as the upper zone of Eagle East.

Typical mineralization zoning at both Eagle and Eagle East consists of a mineralized peridotite conduit with a core of SMSU and a base of crosscutting MSU that also sills out into the surrounding sediments. The massive sulphide remains liquid for a significant time, so it is able to crosscut other units after emplacement is complete.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Production

CommodityProductUnitsLOM
Nickel Metal in concentrate t 48,117
Nickel Metal in ore t 56,784
Copper Metal in concentrate t 46,030
Copper Metal in ore t 47,233

Operational metrics

Metrics
Daily milling rate 1,615 t *
Waste tonnes, LOM 1,008 kt *
Ore tonnes mined, LOM 1,544 kt *
Total tonnes mined, LOM 2,552 kt *
Tonnes processed, LOM 1,544 kt *
* According to 2017 study.

Production Costs

CommodityUnitsAverage
Credits (by-product) Nickel USD -3.87 / lb *  
C1 cash costs Nickel USD 3.68 / lb *  
C1 cash costs Nickel USD -0.19 / lb * **  
Assumed price Nickel USD 7.5 / lb *  
Assumed price Copper USD 3 / lb *  
* According to 2017 study / presentation.
** Net of By-Product.

Operating Costs

Currency2017
UG mining costs ($/t milled) USD 64.7  
Processing costs ($/t milled) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe

Project Costs

MetricsUnitsLOM Total
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Pre-tax NPV @ 8% $M USD  ......  Subscribe
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Heavy Mobile Equipment

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Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Sep 21, 2020

Aerial view:

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