Interview with Erin Zaunscherb, Chairman & CEO of GR Silver Mining Ltd.
Our previous interview: https://www.cruxinvestor.com/posts/gr-silver-mining-tsxvgrsl-high-grade-silver-strike-opens-up-expansion-potential-7893
Recording date: 29th April 2026
GR Silver Mining (TSXV:GRSL) is a silver-focused exploration company advancing the San Marcial project in Sinaloa, Mexico. The company holds 134 million ounces of silver equivalent in resources, has historically added ounces at a cost of US$0.12 per ounce, and is currently executing a 20,000-metre drill programme designed to grow that resource base materially. For investors, the combination of a large existing resource, a low discovery cost, an expanding geological model, and a structured near-term catalyst pipeline defines the investment case.
The project's geological setting is more complex and more prospective than the headline resource alone suggests. San Marcial sits within a breccia system hosted by an intrusive body, of which only approximately 20% of the perimeter has been tested. The remaining 80% of that perimeter represents high-priority exploration ground in analogous structural positions to existing high-grade mineralisation. Beyond the main breccia, geological mapping has identified parallel breccia bodies forming concentrically around the intrusive core, showing elevated gold. Surface sampling further toward the intrusive centre has detected copper and molybdenum, raising the possibility of a porphyry mineralisation model at depth. Within the main breccia itself, four to five distinct mineralisation pulses have been identified, adding vertical scale to the system.
Early results from the current drill programme are consistent with these interpretations. Hole 2601 returned 6.5 metres grading 500 grams per tonne silver, including 1.2 metres of 1,600 grams per tonne, with a notable 61-metre interval at depth confirming the system remains alive well below current resource boundaries. Hole 2603 returned 15.6 metres of 351 grams per tonne silver from 200 metres, including 2.5 metres at 1,400 grams per tonne. Drilling is now on holes 10, 11, and 12. The full 20,000-metre programme is targeting completion in the second half of the year, to be followed by a resource update and the commissioning of a PEA.
A separate but strategically connected element is the planned bulk sample test mining programme at the Plomosas mine, which sits on the same land package. With 7.4 kilometres of existing underground development and permits already in place, Plomosas offers a low-capital pathway to early cash generation and, more importantly, to demonstrating operational credibility with Mexican regulators. San Marcial currently holds exploration concession status, which carries a permitting timeline of five to seven years under conventional processes. A positive track record at Plomosas could shorten that meaningfully, with direct implications for the project's net present value.
