- About 10,000 m of GR Silver Mining’s 20,000 m San Marcial drill program will be step-out drilling, management said.
- Step-out holes reported September 8 extended the breccias at least 300 m southeast and 75 m down-dip beyond the 2023 resource boundary.
- The company puts its historical discovery rate at about 4,000 ounces of silver equivalent per meter drilled, against about 1,000 for the peer group.
- The company labels 80% of the San Marcial chargeability anomaly untested.
- The company is targeting a resource update in the first half of 2027.
GR Silver Mining Ltd. (TSXV: GRSL | OTCQX: GRSLF | FRA: GPE) is drilling 20,000 m at its San Marcial silver discovery in Sinaloa, Mexico, and about 10,000 m will be step-out drilling to test whether the mineralized system extends beyond the 2023 resource. Management ties added ounces to that step-out footage, and the company is targeting a mineral resource estimate update in the first half of 2027.
The 2023 Resource Boundary & the Step-Out Evidence
GR Silver’s 100%-owned Plomosas Project has a 2023 resource of 77 million ounces of silver (55 million indicated and 22 million inferred), or 134 million ounces of silver equivalent. San Marcial, a resource area within the project, holds 46 million ounces of indicated silver and 14 million ounces of inferred (52 million and 16 million ounces of silver equivalent).
Step-out drilling tests whether mineralization continues past that boundary. On September 8, 2026, GR Silver reported 2 step-out holes that extended the mineralized breccias at least 300 m to the southeast and 75 m down-dip beyond the 2023 resource boundary. The known strike length is now approximately 1 kilometer.
GR Silver ties the high-grade zones to intersections of northeast-southwest structures with northwest-southeast and east-west breccias, and says silver grades tend to decrease outside those intersections.
Step-Out Footage & Added Ounces
President and Chief Executive Officer of GR Silver Mining, Eric Zaunscherb, separated the program’s total footage from the footage that adds ounces:
“We’re drilling 20,000 meters. If all of that were step-out, then sure, you’d be adding a lot of oz, but it’s not. There would be 10,000 of that.”
GR Silver puts its historical discovery rate at about 4,000 ounces of silver equivalent per meter drilled, against about 1,000 for the peer group. It plots itself against 5 peer companies (Prime Mining, Silver Tiger, Guanajuato Silver, Blackrock Silver and Vizsla Silver). It takes its own data point from its May 3, 2023 technical report, which prices silver at US$22.00 per ounce.
Management said the rate is based on history and is not a prediction of future results. The company has not published an ounce figure for the update.
Untested Ground & the Resource Update
The company labels 80% of the San Marcial chargeability anomaly, a geophysical target, untested. Separately, management said it has examined about 20% of the periphery around the intrusive body at the center of the system. The first describes untested ground, and the second is the share of the periphery examined so far.
The company lists 5 planned catalysts: the 20,000 m drill program, an updated mineral resource estimate, a preliminary economic assessment, a bulk sample test mining program, and pilot plant engineering at the former Plomosas mine.