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Canada

Macmillan Pass Project

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Overview

Mine TypeOpen Pit & Underground
StagePreliminary Economic Assessment
Commodities
  • Zinc
  • Lead
  • Silver
Mining Method
  • Truck & Shovel / Loader
  • Alimak
  • Sub-level Retreat
  • Vertical Crater Retreat
  • Longhole stoping
  • Transverse stoping
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SnapshotMacmillan Pass is one of the largest undeveloped Zinc deposits in the world.

Owners

SourceSource
CompanyInterestOwnership
Fireweed Metals Corp. 100 % Direct

Contractors

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Deposit type

  • SEDEX

Summary:

The Tom and Jason deposits are examples of stratiform, strata-bound sediment-hosted, exhalative (“SEDEX”) zinc-lead-silver-barite deposits (Goodfellow et al., 1993; Leach et al., 2005; Goodfellow et al., 2007; Goodfellow, 2007).

Zinc-lead-silver-barite mineralisation at the Tom deposit varies from well laminated and stratiform (parallel to sedimentary layering) to a brecciated stockwork zone adjacent to the Tom normal fault. The Tom West and Tom East zones, both of which are exposed at surface, are interpreted to have formed one continuous strata-bound controlled lens prior to folding and faulting of the Tom Sequence, whereas the Southeast Zone is interpreted to have formed in a separate sub-basin to the main graben structure hosting the Tom West and Tom East zones (Goodfellow, 1991). All three zones have been affected by folding, with evidence for the possible development of a crenulation cleavage as opposed to the chaotic folding of laminae due to soft-sediment deformation. Ferroan carbonate alteration and quartz veining are common in footwall conglomerates near vent facies at Tom West.

The Tom West Zone dips 60° to the southwest, has a strike extent of approximately 1 km and extends up to 400 m down dip. It is about 40 m thick at its widest point and breaks into two discrete layers in the centre at depth. Contacts vary from transition over <1 m or are faulted and abrupt. The highest-grade portion of the Tom West Zone occurs along the southern and near surface portion of the zone where Pb+Zn grades exceed 10% with elevated silver. The Tom West Zone hosts the bulk of the resource at the Tom deposit.

The Tom West Zone can be divided into a series of mineralization facies (after Goodfellow, 1991; 2007) consisting of:
• Vent facies – Stockwork of pyrite, pyrrhotite, galena, sphalerite, with minor chalcopyrite, arsenopyrite and tetrahedrite with a gangue of ferroan carbonates, quartz and barite subdivided into five types, including an upper high-grade zone with 15–30% Pb+Zn, Ag between 150 g/t and 200 g/t and a low Zn/(Zn+Pb) ratio.
• Pink facies – Interbedded barite, chert, cream-coloured sphalerite, fine grained pyrite and black Bacarbonate, overprinted by pink and yellow sphalerite resulting in locally high grades in the range of 10–30% combined Pb and Zn.
• Gray facies – Interbedded pink sphalerite, fine grained galena and pyrite, white to pale gray barite, pale grey chert and grey to white Ba-carbonate/Ba-feldspar, typically with grades in the range of 4–5% Pb+Zn with negligible Ag.
• Black facies – Black mudstone and chert interbedded with barite, witherite (Ba-carbonate) and finegrained sphalerite, galena and pyrite, typically with grades in the 4–10% Pb+Zn range and a high Zn/(Pb+Zn) ratio.

The Tom East Zone occurs near the hinge of the anticline that has folded the originally planar deposit, and which plunges northward in this area. It consists of interbedded high-grade sphalerite, galena, barite and chert thought to have formed within the same stratigraphic interval as Tom West (McClay and Bidwell, 1986).

The Tom Southeast Zone is not exposed at surface, and consists of a tabular, stratiform body 0.5 m to 6 m thick with a strike length of approximately 400 m and a down-dip extension of at least 350 m dipping 60–70° to the east. It is located near the nose of the southeast-plunging Tom anticline on its eastern limb. Mineralisation consists of finely laminated sphalerite, galena, pyrite and black cherty mudstone (Goodfellow, 1991).

The Jason Main Zone is located on the northern limb of the east-plunging Jason syncline, while the Jason South Zone occurs on the southern limb. The South Zone consists of two separate horizons whereas the Main zone is defined by a single horizon. These two separate zones are likely connected through the hinge of a syncline, but this has yet to be demonstrated through drilling. These horizons can be divided into several distinct mineralisation facies (zones), including (after Turner, 1991):
• Pb-Zn-Fe sulphide facies – Massive, banded sphalerite-galena and galena-pyrite overlain by debris flow deposits containing clasts of earlier deposited massive sulphides.
• Barite-sulphide facies – Interbedded fine-grained sphalerite, galena, barite, chert and ferroan carbonate forming the bulk of the mineralisation at Jason.
• Quartz-sulphide facies – Interbedded sphalerite, pyrite, quartz and carbonaceous chert with quartzcelsian (barium feldspar) bands in the lower lens.
• Massive pyrite facies – Massive pyrite beds interbedded with sphalerite, galena, chalcopyrite, pyrrhotite and quartz located near the Jason Fault.
• Ferroan carbonate facies – Massive beds of siderite and ankerite up to several metres across with irregularly distributed galena, sphalerite, pyrrhotite, pyrite, quartz, muscovite and pyrobitumen; spatially associated with a breccia pipe.

Reserves

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Mining Methods

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Comminution

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Processing

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Production

CommodityProductUnitsAvg. AnnualLOM
Zinc Metal in concentrate M lbs 1873,395
Zinc Concentrate kt 1472,638
Zinc Payable metal M lbs 1592,887
Lead Metal in concentrate M lbs 1061,940
Lead Concentrate kt 791,422
Lead Payable metal M lbs 1011,833
Silver Payable metal koz 25,774
Silver Metal in concentrate koz 2,05337,191

Operational metrics

Metrics
Daily ore mining rate 4,900 t *
Daily milling rate 4,900 t *
Daily milling capacity 5,000 t *
Stripping / waste ratio 5 *
Waste tonnes, LOM 24,680 kt *
Ore tonnes mined, LOM 32,656 kt *
Total tonnes mined, LOM 53,590 kt *
Tonnes milled, LOM 32,656 kt *
* According to 2018 study.

Production Costs

CommodityUnitsAverage
Assumed price Lead USD 0.98 / lb *  
Pre-tax break-even price Zinc USD 0.8 / lb *  
Assumed price Zinc USD 1.21 / lb *  
Assumed price Silver USD 16.8 / oz *  
* According to 2018 study / presentation.

Operating Costs

Currency2018
OP mining costs ($/t mined) CAD 4.45 *  
UG mining costs ($/t mined) CAD  ....  Subscribe
OP mining costs ($/t milled) CAD  ....  Subscribe
UG mining costs ($/t milled) CAD  ....  Subscribe
Processing costs ($/t milled) CAD  ....  Subscribe
G&A ($/t milled) CAD  ....  Subscribe
Total operating costs ($/t milled) CAD  ....  Subscribe
* According to 2018 study.

Project Costs

MetricsUnitsLOM Total
Pre-Production capital costs $M CAD  ......  Subscribe
Sustaining CapEx $M CAD  ......  Subscribe
Closure costs $M CAD  ......  Subscribe
Total CapEx $M CAD  ......  Subscribe
OP OpEx $M CAD  ......  Subscribe
UG OpEx $M CAD  ......  Subscribe
Processing OpEx $M CAD 748.5
G&A costs $M CAD 338.6
Total OpEx $M CAD  ......  Subscribe
Mining Taxes $M CAD  ......  Subscribe
Income Taxes $M CAD  ......  Subscribe
Total Taxes $M CAD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M CAD  ......  Subscribe
After-tax Cash Flow (LOM) $M CAD  ......  Subscribe
Pre-tax NPV @ 0% $M CAD  ......  Subscribe
Pre-tax NPV @ 8% $M CAD  ......  Subscribe
After-tax NPV @ 0% $M CAD  ......  Subscribe
After-tax NPV @ 8% $M CAD  ......  Subscribe
Pre-tax IRR, %  ......  Subscribe
After-tax IRR, %  ......  Subscribe
Pre-tax payback period, years  ......  Subscribe
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Required Heavy Mobile Equipment

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Personnel

Mine Management

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