Fireweed Zinc expands Boundary Zone at Macmillan Pass

Drilling at the Tom deposit at Macmillan Pass in 2019. Credit: Fireweed Zinc

After a long wait caused by assay lab backlogs, Fireweed Zinc has reported the first two of nine holes drilled last year at the Boundary Zone, part of its 940-sq.-km Macmillan Pass project in the Yukon.

Both holes in the 2,948-metre drilling program, completed in October, intersected wide zones of high-grade replacement-style and vein and breccia-hosted zinc mineralization.

Highlights include 212.7 metres of 4.42% zinc, 0.08% lead and 10.7 g/t silver in hole NB20-001. Within that intercept, a 5.8-metre section returned 25.58% zinc, 0.14% lead and 44 g/t silver.

Hole NB20-001 cut 246.7 metres of 2.6% zinc, 0.06% lead and 5.9 g/t silver from surface, including 5 metres of 23.62% zinc, 0.22% lead and 53.7 g/t silver.

“These first assays have been a long time coming due to slow turnaround at the lab while they operate under Covid-19 limitations,” said Fireweed Zinc’s CEO Brandon Macdonald, in a release. “The assays reported here are from the first two holes drilled in the central Boundary Zone area in 2020. We are pleased to see more good grades extending this wide zone of mineralization with very high-grade sections to depth in the central Boundary Zone area. Overall, a belated but great start to the 2020 drill assays.”

The infill and stepout drilling at the deposit has expanded known mineralization about 150 metres at depth and to the northeast, and about 360 metres to the west (assays are pending for this area).

Mineralization in the Boundary Zone extends to about 300 metres depth and is hosted in a 230-250-metre thick stratabound sequence with vein stockworks, breccias.

A resource estimate for Boundary Zone has not yet been completed, but the company believes it has potential to be mined as an open pit with a low stripping ratio, and by upgrading the ore through low-cost ore sorting.

Macmillan Pass hosts indicated resources of 11.2 million tonnes grading 6.59% zinc, 2.48% lead and 21.33 g/t silver for 1.6 billion lb. zinc, 600 million lb. lead and 7.7 million oz. silver. Inferred resources add 39.5 million tonnes grading 5.84% zinc, 3.14% lead and 38.15 g/t silver for 5.1 billion lb. zinc, 2.7 billion lb. lead and 48.4 million oz. silver. The resources, contained in the Tom and Jason deposits, are based on a $65 per tonne net smelter return (NSR) cut-off.

A preliminary economic assessment completed in 2018 outlined an open pit and underground operation with an 18-year mine life and a preproduction price tag of $404 million.

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