Mactung Project

NWT & Yukon, Canada

The Mactung Project is the world’s largest high-grade tungsten deposit*


The Mactung Project straddles the Yukon-Northwest Territories boundary and is located within the traditional territories of the Kaska Dena Nation and the First Nation of Na-cho Nyäk Dun and in the Sahtu Settlement Area.  It is adjacent to Fireweed’s flagship Macpass Project and is accessible via the North Canol Road, and by air via the Macmillan Pass aerodrome.
After discovery in 1962, extensive drilling, engineering, metallurgy, geotechnical, and environmental studies were completed over the next decades in support of a Feasibility Study (2009) and positive Yukon-based mine project assessment (2014).


2023 Activities
  • Mactung acquisition in June
  • New resource estimate confirms project hosts the world’s largest high-grade tungsten deposit*
  • Programs to inform mine plan and project permitting:
    • Drilling for metallurgical sample analyses
    • Year-round water and hydrological studies
  • Regulator and Indigenous engagement
Why Mactung?


  • The U.S., Canada and the EU have designated tungsten a critical metal. It has extreme physical characteristics necessary for many industries.


  • China controls most of the world’s tungsten deposits and production, creating risks to the west in a changing world.


  • Recent world events have sharpened the focus of western governments on critical metals, creating an opportunity to create a reliable western source of tungsten.


A 2023 Technical Report announced updated mineral resources for Mactung.  The mineral resource totaled 41.5 Mt Indicated Resource at 0.73% WO3 and 12.2 Mt Inferred Resource at 0.59% WO3. It is estimated that there is the potential for an Exploration Target at Mactung of between 2.5 and 3.5 Mt at a grade of between 0.4 and 0.6% WO3 in addition to the current Mineral Resources disclosed (see Fireweed news release). These results make it the world’s largest high-grade tungsten deposit.*

  • Five holes were completed by Fireweed in 2023 to support metallurgical studies and improve definition.
  • ~650 m of untested strike length between the resource and where the skarn units crop out out at surface provide exploration upside.
  • Updated resource by Fireweed metals in 2023 of 41.5 Mt at 0.73% WO3 indicated and 12.2 Mt at 0.59% WO3 inferred.
2023 Mineral Resource Estimate:
Classification Cut-off Grade WO₃ Tonnage (tonnes) WO₃ Grade (%) Contained WO₃ (mtu⁵)
Indicated (underground) 0.5 12,168,00 1.05 12,789,000
Indicated (open pit) 0.25 29,319,000 0.59 17,367,000
Total Indicated (OP+UG) 0.5/0.25 41,487,000 0.73 30,156,000
Inferred ⁽⁴⁾ (underground) 0.5 2,817,000 0.73 2,066,000
Inferred ⁽⁴⁾ (open pit) 0.25 9,430,000 0.55 5,139,000
Total Inferred⁽⁴⁾ (OP+UG) 0.5/0.25 12,247,000 0.59 7,205,000
  1. All mineral resources have been estimated in accordance with Canadian Institute of Mining and Metallurgy and Petroleum (“CIM”) definitions, as required under National Instrument 43-101 (“NI43-101”).
  2. Mineral resources are reported in relation to a conceptual pit shell and underground mining volumes to demonstrate reasonable prospects for eventual economic extraction, as required under NI43-101; mineralization lying outside of the pit shell or underground volumes is not reported as a mineral resource. Note the conceptual pit shell and underground volumes are used for mineral resource reporting purposes only and is not indicative of the proposed mining method; future mining studies may consider underground mining, open pit mining or a combination of both. Mineral resources are not mineral reserves and do not have demonstrated economic viability. Mineral resource estimates do not account for mineability, selectivity, mining loss and dilution. All figures are rounded to reflect the relative accuracy of the estimate and therefore numbers may not appear to add precisely.
  3. Open pit (OP) mineral resources are reported at a cut-off grade of 0.25% WO3. Underground (UG) mineral resources are reported at a cut-off grade of 0.5% WO Cut-off grades are based on a price of US$240 per mtu of WO3 concentrate and a number of operating cost and recovery assumptions (see Table 5).
  4. Inferred mineral resources are considered too speculative geologically to have economic considerations applied to them that would enable them to be categorized as mineral reserves. There is also no certainty that these inferred mineral resources will be converted to the measured and indicated categories through further drilling, or into mineral reserves, once economic considerations are applied. The Inferred Mineral Resource in this estimate has a lower level of confidence than that applied to an Indicated Mineral Resource and must not be converted to a Mineral Reserve. It is reasonably expected that the majority of the inferred Mineral Resource could be upgraded to an Indicated Mineral Resource with continued exploration.
  5. A metric tungsten unit (mtu) is 10 kilograms of tungsten trioxide (WO3).


Fireweed Metals Files Technical Report for its Mactung Project on SEDAR

Fireweed Announces Near-Term Plans for Mactung Project

Fireweed Metals Announces Mineral Resources for the Mactung Project: the Largest High-Grade Tungsten Deposit in the World*

Fireweed Announces Signing of Definitive Agreement on Mactung Project


  1. * References to relative size and grade of the Mactung resource in comparison to other tungsten deposits in the world are based on review of the Standard & Poor’s Global Market Intelligence Capital IQ database

Technical information on this page has been approved by Fireweed’s VP Geology, Dr. Jack Milton, P.Geo. (BC), a ‘Qualified Person’ as defined under Canadian National Instrument 43-101. For full disclosure please visit our cautionary statements page

For details, see Fireweed news release dated June 13, 2023 “Fireweed Metals Announces Mineral Resources for the Mactung Project: the largest High-Grade Tungsten Deposit in the World” and the technical report entitled “NI 43-101 Technical Report: Mactung Project, Yukon Territory, Canada” with effective date July 28, 2023 filed on