Macmillan Pass Project

Project Details

  • Overview
  • NI43-101 Technical Report
  • Location & Climate
  • Geology


The Macmillan Pass Project, located in Canada's mining-friendly Yukon Territory, is host to large zinc-lead-silver deposits. The project is accessible via a 3km road from the North Canol Road off the Robert Campbell Hwy in the southeast Yukon. The territorial government is highly-supportive of the mining industry and the Yukon is one of Canada's top provinces for new mine developments.


  • The January 2018 Mineral Resource Estimate puts Macmillan Pass among the world’s most significant zinc resources
  • Fireweed’s Macmillan Pass Project includes the large zinc-lead-silver deposits known as Tom and Jason.
  • The Tom and Jason deposits contain a combined resource* of:
  • Significant exploration upside remains, including the potential to expand upon historic work and to utilize modern exploration methods in search of new discoveries.
  • Existing camp, road access and a government airstrip are already in place.
43-101 Technical Report

Development Summary

There has been a significant amount of historical exploration on the Tom and Jason properties commencing with the discovery of the Tom West Zone in 1951. This has resulted in the drilling of 128 holes on the Jason property for a total of 37,924 m and 212 holes on the Tom property, for a total of 33,495 m. In addition, an adit with approximately 3,423 m of underground development and a spiral decline were put into the Tom deposit to assist exploration and bulk sampling. Exploration effectively ceased on the properties after 1992. There has been minimal modern exploration on the properties since that time.

Mineralization Summary

HudBay Minerals Inc. commissioned a mineral resource estimate in 2007 that reported 6.43 Mt indicated resources at both Tom and Jason at 6.33% Zn, 5.05% Pb and 56.55g/t Ag, and 24.55 Mt inferred resources at 6.71% Zn, 3.48% Pb and 33.85g/t Ag (Click here to read cautionary statement regarding historic resources). Through a program of relogging and sampling historic core as well as new drilling, Fireweed Zinc plans to update the historical data and work towards publication of a current mineral resource estimate followed by a preliminary economic analysis of the project.

Please click here for the full 2017 technical report


Fireweed Zinc's Macmillan Pass Project is located in the south east of Canada's Yukon Territory, approximately 372 kilometers east of the capital city of, Whitehorse. The deposit is accessible from the North Canol Road off the Robert Campbell Hwy. Access to the Tom and Jason deposit areas is via networks of location gravel roads.

The government regional Macmillan Pass Airstrip is located on the property within three kilometers of the Tom camp and deposit and is capable of landing 18 passenger aircraft. Flight time to the capital, Whitehorse, is approximately one hour. Other regional airstrips exist, notably the Ross River Airport located one kilometer south of the town of Ross River.

The regional climate is characterized by annual precipitation of 600-700mm. Mean annual temperatures range from -5 to -8 degrees Celsius. Winters are characterized by relatively dry, cold conditions with mean temperatures of -20 Celsius in January. Summers extreme temperatures would range from -5 to 30 degrees Celsius in valley floors. The wettest months are in July and August with rainfall amounts of 60-90 mm.

Regional Geology

The Tom and Jason zinc-lead-silver deposits are proximal vent SEDEX deposits formed during Devonian rifting activity in the Selwyn Basin. The Selwyn Basin is one of the most productive basins for SEDEX zinc-lead-silver deposits in the world and hosts 12 large deposits including the Tom and Jason deposits. Regional past producers were Faro (aka Anvil), Grum and Vangorda. The Howards Pass deposit (aka Selwyn) is currently one of the world’s largest undeveloped zinc deposits1. SEDEX mineralisation of the Selwyn Basin occurs in four main districts of different ages: Anvil/Faro (Cambrian), Howards Pass/Selwyn (Silurian), Gataga/Cirque (Late Devonian) and MacMillan Pass/Tom-Jason (Late Devonian). Synchronous and genetically related Mississippi Valley Type zinc-lead mineralisation occurs in the carbonate platforms along the east side of the Selwyn Basin.

Click here for regional geology maps, mineralization models, and Tom and Jason deposit maps and sections

Figure: Macmillan Pass Local Geology

1 Source:https://

Tom Deposit Overview

Zinc- lead- silver- barite mineralisation at the Tom deposit varies from well layered to a brecciated stockwork zone adjacent to the Tom fault. The Tom West and Tom East Zones, both of which are exposed at surface, are interpreted to have formed one continuous lens prior to folding of the Tom Sequence. The Southeast Zone is interpreted to have formed in a separate sub-basin to the main structure hosting the Tom West and Tom East Zones. All three zones have been affected by folding.

The Tom West Zone dips 60 degrees to the southwest, has a strike extent of approximately one kilometer and extends up to 400m down dip. It is about 40m thick at its widest and breaks into two discrete layers in the centre. The highest grade portion of the Tom West Zone occurs along the southern portion of the zone where Pb+Zn grades exceed 10%. The Tom West Zone hosts the bulk of the historical resource at the Tom deposit.

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 a series of fault bounded pods of interbedded sphalerite, galena, barite and chert.

The Tom Southeast Zone is not exposed at surface, and consists of a tabular, stratiform body 0.5m to 6m thick with a strike length of approximately 400m and a down dip extension of at least 350m dipping 60-70º 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.

Jason Deposit Overview

The Jason deposit is hosted by a Devonian sequence disrupted by faulting and folded into a series of “upright tight west-trending, shallowly east-plunging folds". 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.

Click here for regional geology maps, mineralization models, and Tom and Jason deposit maps and sections.

Click here for NI4-101 disclosure and the Qualified Person information.