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 3 km road from the North Canol Road off the Robert Campbell Hwy in 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. Find out more about the latest work being done on the property here.

Tom & Jason

  • Fireweed’s Macmillan Pass Project includes the large Tom and Jason zinc-lead-silver deposits.
  • The January 2018 Mineral Resource Estimate puts Macmillan Pass among the world’s most significant zinc resources.
  • The Tom and Jason deposits contain a combined resource of:
    • 11.21 Mt Indicated @ 9.61% ZnEq
      • 6.59% Zinc, 2.48% Lead, 21.33 g/t Silver
    • 39.47 Mt Inferred @ 10.00% ZnEq
      • 5.84% Zinc, 3.14% Lead, 38.15 g/t Silver
  • 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.

Boundary Zone

  • Drilling on Boundary Zone on the Nidd property in 2019 included intersections of:
    • 100 m of 7.94% Zinc from surface including 6.4 m of 42.49% Zinc within 230 m of 4.14% Zinc
  • The Nidd claims host established zinc mineralization in the Boundary Zone where historic drilling included intersections of
    • 224.0 m of 2.5% Zinc and 0.3% Lead, including 4.5 m of 16.4% Zinc, demonstrating potential for both bulk tonnage open pit and high-grade underground mineralization
  • With the acquisition of the Nidd claims, Fireweed owns all four known large zinc mineralized systems in the region – Tom, Jason, Boundary Zone and End Zone – as well as many other zinc exploration targets including the entire highly prospective “fertile corridor” of exploration targets extending from Tom to Boundary Zone and beyond.
  • The large Nidd property covers 7,393 hectares in 372 mineral claims which expands Fireweed’s claim holdings in the district to 544 square kilometers.
  • Previous work by Teck on the Nidd claims included 35 drill holes (many with significant zinc mineralization) as well as extensive geochemical and geophysical surveys that outlined additional exploration targets.

End Zone

  • End Zone is host to high-grade zinc-lead-silver mineralization. In 2018, drilling at End Zone intersected high grades including 11.08 m of 4.78% Zinc, 10.17% Lead, 87g/t Silver.

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, Jason, Boundary Zone & End Zone 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 mineralization 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 mineralization 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 mineralization 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 400 m down dip. It is about 40 m 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 Zinc+Lead+Silver 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 400 m and a down dip extension of at least 350 m dipping 60-70º to the east. It is located near the nose of the southeast plunging Tom anticline on its eastern limb. Mineralixation 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.


Boundary Zone & End Zone Overview

The Nidd property covers the western extension of the mineralized “fertile corridor” that is host to all four of the known large zinc mineralized systems in the Macmillan Pass Zinc District – Tom, Jason, End Zone and Boundary Zone (see attached map). This fertile corridor traces critical stratigraphic rock units, structural features and exploration targets from east of the Tom Deposit to west of the Boundary Zone over a length of at least 25 kilometres.

The most significant mineralization found to date on the property is the Boundary Zone where 24 historic core holes were drilled. Known mineralization is spread over an area two kilometres long and 200 to 800 metres wide with drilled mineralization in a central area 300 metres long and a true thickness of up to 285 metres of over 2% Zinc. The zone remains open to depth and along trend for further exploration. The Boundary mineralization consists of sphalerite-siderite-pyrite and minor galena in veins, stockworks, interstitial disseminations, and as replacement of matrix and clasts within diamictites and chert pebble conglomerates. 

The Boundary Zone is located adjacent to a major synsedimentary structure and contains large volumes of boulder diamictites indicating that the area underwent active tectonic extension during the formation of the basin, a similar setting to the Tom and Jason areas. The Boundary Zone area is part of a distinct sub-basin that contains significant volumes of strongly siderite altered basaltic pyroclastics and lava flows within the same Earn Group formation that hosts the Tom and Jason deposits. The presence of synsedimentary faulting, a distinct sub-basin, volcanic rocks, abundant zinc mineralization, and strong alteration indicate the area is host to a robust zinc mineralizing system.