Buchans–Mary March: Flagship VMS Discovery Project
The Buchans Mine ranks among the highest-grade polymetallic deposits ever mined: 16.2 Mt at 14.5% Zn, 7.6% Pb, 1.33% Cu, 126 g/t Ag and 1.37 g/t Au between 1928 and 1984. Canstar holds 145.6 km² of contiguous ground across the district that produced it, approximately 20 km east of the old mine.
A system already proven at Mary March
A 1999 discovery hole intersected 9.63 m grading 4.2 g/t Au, 122.1 g/t Ag, 10.1% Zn, 1.8% Pb and 0.64% Cu, the highest-grade drill intercept in the Buchans belt outside the mined deposits. Trenching in 2025 exposed mineralization at surface, with boulder grab samples returning up to 23.7% Pb, 9.15% Zn and 5.7% Cu. A hydrothermal alteration footprint traceable across roughly 4 km² marks the scale of the system. Grab samples are selective by nature and not necessarily representative of mineralization on the property.
Modern tools, applied for the first time
Ahead of drilling, Canstar relogged 14,400 m of historic core across 43 holes, submitted approximately 1,100 lithogeochemical samples, completed four geophysical surveys (LiDAR, magnetics, deep IP and borehole EM) and cut nine trenches. The output is a three-dimensional geological model of the district, further sharpened by a machine-learning targeting layer developed with TerraAI.
Drilling
The first drill program at Mary March since 2019 commenced in June 2026, funded by earn-in partner VMS Mining Corporation. In July 2026 the program intersected a potential VMS feeder zone — approximately 118 m of copper- and zinc-bearing stringer and disseminated mineralization within intervals totalling approximately 270 m of altered rhyolite (see news release of July 8, 2026). Visual observations are not a substitute for assay results; assays are pending.
The VMSC earn-in
VMS Mining Corporation may invest up to C$12 million at the project level to earn up to a 65% interest in the Mary March and Buchans projects, across three phases — C$4.0 million advanced to date. Every exploration dollar is spent at the project level, limiting equity dilution to Canstar shareholders; Canstar retains at least a 35% interest with pro-rata rights.
Historic production and pre-Canstar exploration results are historical in nature, have not been verified by a Qualified Person, and are not necessarily indicative of mineralization on the Company’s properties.