The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
North of 60 Mining News - September 6, 2024
Fireweed continues to explore the untapped potential of MacPass, with drilling programs that are expanding both known resources and targeting new greenfield zones.
Deposit locations and simplified model of MacPass: pink lines show fault systems controlling the distribution of deposits, while pink plumes represent subsurface areas where early stratiform mineralization formed.
Fireweed Metals Corp. Sept. 5 announced a significant milestone with an updated mineral resource estimate for the company's Macmillan Pass project in Yukon, Canada, marking a 300% increase in zinc equivalent in the indicated resource category for Tom and Jason, and inaugural resource estimates for the Boundary and End Zone deposits.
Situated in eastern Yukon, approximately 200 kilometers (124 miles) from Ross River, the Macmillan Pass project spans 977 square kilometers (377 square miles) of largely under-explored terrain along the Macmillan-Hess fault corridor on the border of Northwest Territories.
Home to the Tom, Jason, Boundary, and End Zone deposits, exploration over the years has steadily revealed the possibility of MacPass being one of the largest undeveloped primary zinc projects in the world.
According to a 2018 resource estimate, Tom and Jason host 11.2 million metric tons of indicated resource averaging 6.59% (1.63 billion pounds) zinc, 2.48% (620 million lb) lead, and 21.33 grams per metric ton (7.7 million ounces) silver; plus 39.5 million metric tons of inferred resource averaging 5.84% (5.08 billion lb) zinc, 3.14% (2.73 billion lb) lead, and 38.15 g/t (48.4 million oz) silver.
Following a strategic focus on expanding known zones and exploring new targets, Fireweed's 2023 drill program built upon past successes at Tom, Jason, and Boundary, leading to the significant resource expansion now reported.
Based on 124,632 meters of drilling from 544 holes completed between 1952 and 2023, including both historical (pre-2017) and recent (2017-2023) work, the updated Macpass estimate reflects data up to and including drill hole TS23-009D2, which was completed on Oct. 15, 2023; the final database cut-off for the 2023 estimate was June 23, 2024.
As a result of all this work, four deposits at MacPass – Tom, Jason, Boundary, and End Zone – now host 56 million metric tons of indicated resource averaging 5.49% (6.78 billion lb) zinc, 1.58% (1.95 billion lb) lead, and 24.2 grams per metric ton (43.54 million ounces) silver; plus 48.49 million metric tons of inferred resource averaging 5.15% (5.5 billion lb) zinc, 2.08% (2.23 billion lb) lead, and 25.3 grams per metric ton (39.42 million ounces) silver.
If viewed from a contained zinc-equivalent standpoint, this represents a nearly 300% increase in indicated resources compared to its previous estimate.
"The delivery of the updated mineral resource estimate for the Macpass project marks another key milestone in demonstrating the exploration potential of the Macpass district," said Fireweed Metals Interim CEO Peter Hemstead. "The team has increased the contained zinc equivalent metal in the indicated resources category by approximately 300% and more than doubled the overall tonnage. The addition of Boundary Zone now positions Macpass as one of the world's largest undeveloped primary zinc districts."
Deposit locations and simplified model of MacPass: pink lines show fault systems controlling the distribution of deposits, while pink plumes represent subsurface areas where early stratiform mineralization formed.
Following this significant resource update, Fireweed has also applied new constraints for both open-pit and underground mining, designed to better define the most economically viable portions of the deposits.
By refining these models with sensitivity analyses and geological data, Fireweed is positioning itself to assess potential mining methods and costs, setting the stage for further exploration and technical studies, all aimed at advancing MacPass toward a clearer understanding of its economic potential.
"This resource is the culmination of six years of exploration success at Macpass, including an additional 43,000 meters of drilling at Tom, Jason, End Zone, and our discovery at Boundary Zone, which is one of the most globally significant zinc discoveries of the last 15 years," said Fireweed Metals VP Geology Jack Milton. "We have more than doubled the tonnage from our previously reported resource, increased the contained zinc metal by 83%, and added open-pit and underground mining volume constraints for reporting."
In addition to the resource update, Fireweed has made significant strides in understanding the metallurgical performance of MacPass mineralization.
Previous tests conducted on the Tom, Jason, and Boundary zones have demonstrated positive metallurgical outcomes, with high-grade concentrates and strong recoveries, including results from past programs disclosed in 2018 and 2022, where the deposits consistently produced favorable results.
In 2023, testing was carried out to assess the performance of the massive sulfide mineralization at Boundary Zone. Two composites from drill holes NB21-001 and NB20-004 were used for open circuit tests based on a flowsheet developed in 2022.
Those results continue to support the potential for high recoveries, reinforcing the viability of processing ore from Boundary, Tom, and Jason.
This deeper understanding of the metallurgical characteristics enables Fireweed to fine-tune future processing methods, which will be critical as the company moves closer to technical studies.
According to Fireweed, metallurgical variability will play a key role in determining the most efficient methods for ore extraction and processing. The continued success in testing suggests that these deposits are well-suited for economic development, with the company highlighting Boundary Zone's growing importance as they work to optimize both open-pit and underground mining scenarios.
Looking ahead, Fireweed is not only focused on the known resources but is also setting its sights on further exploration potential across the MacPass district.
"The deposits remain open along strike and at depth and, with the 2024 drill program (14,000 metres) not yet included in this MRE, there exists the potential for an increase to the resource as part of future technical work," added Milton. "In addition, we are undertaking a large and comprehensive regional exploration program to continue to provide a pipeline of high-quality targets for future testing."
The company's 2024 exploration campaign is targeting further expansion at Tom, Jason, and Boundary through step-out drilling, while new greenfield targets will be tested along the MacMillan-Hess fault corridor.
Additionally, the company will employ a combination of ground gravity geophysical surveys, soil sampling, and airborne geophysical methods, including electromagnetic and magnetic surveys, to refine and prioritize targets.
Moreover, the company is evaluating elevated concentrations of critical by-product minerals, including gallium and germanium, across the deposits.
"The potential for by-product gallium and germanium could enhance the Macpass district with further critical minerals exposure," said Milton.
These critical minerals, combined with the zinc, lead, and silver already identified, could further enhance the project's value and position MacPass as an important supplier of these strategically vital materials.
With its growing resource base and continued exploration, Fireweed is positioning itself to unlock the full potential of this district-scale project, advancing its development toward a more defined economic future.
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