GR Silver has one project, the Plomosas property in southern Sinaloa, Mexico. The project package contains the past-producing Plomosas mine (mining concession, base metal-rich) and the San Marcial deposit ~8 km south (exploration concession, silver-dominant). CEO Eric Zaunscherb (former Canaccord Genuity mining analyst), took the seat after founder Marcio Fonseca passed away about a month before the interview. In this conversation, he discusses the 20,000m expansion drill program, the security situation, the planned resource update and PEA, and a bulk sample test mining concept.
TL;DR
Marcio Fonseca passed away in late March 2026 and Zaunscherb is now interim CEO while the board searches for a permanent replacement. The 2023 MRE sat at 134 Moz AgEq (57.5% silver). They are 4,000m into a 20,000m program at San Marcial with three rigs turning, aiming to grow the resource by ~30 to 50% at a historical discovery cost of ~C$0.17/oz (~US$0.12/oz) versus an EV/oz currently around US$125 to 130. Resource update targeted by year-end 2026, PEA more likely early 2027. Project access was pivoted out of Sinaloa cartel territory and now runs through Durango. Security risk is explicitly the rate-limiting step on everything. Treasury ~C$28.5M as of May 1.
What have they done for shareholders lately
They announced the first two holes of the 2026 program on 22 April. They pivoted project access through Durango after the Sinaloa cartel split made the original Mazatlan-Rosario route too risky, including moving the exploration office and core shack to Durango and upgrading a 40km mountain road for ~C$400k. They completed a full QA/QC review of all modern drilling (no holes flagged for elimination). They added Paula Montoya (PhD, San Diego State) to the technical team, who has helped reinterpret San Marcial as an intrusive core with a hydrothermal breccia averaging 22m thickness on the shoulders, with parallel breccia branches and a possible porphyry copper-moly target at depth. Zaunscherb said his historical discovery cost is ~C$0.17/oz vs ~US$125 to 130/oz EV/oz in the ground, which he frames as the value proposition.
How much money do they have and what are they spending it on
Treasury was C$28.5M as of 1 May 2026. Monthly G&A is roughly C$300k including concession fees. Spending is going to the 20,000m drill program (4,000m done so far), the Durango road upgrade, engineering and permitting work, gap analysis for the PEA, and scoping a small 60 to 100 tpd pilot plant for the bulk sample test mining program at Plomosas (they are evaluating existing plants for purchase in Mexico vs. building new). ~119M warrants at avg C$0.25 are outstanding (most in the money); ~10M options at C$0.26; roughly 645M shares fully diluted. Institutional ownership is ~20% (down from a peak of ~40% when the stock collapsed to C$0.035). No financing yet. Zaunscherb said he wants to bring in a strategic concentrate offtaker as a partner rather than raise from the market right now.
Upcoming catalysts
Technical: continuing drill result batches every 3 to 4 weeks from the 20,000m San Marcial program; first deep holes testing the possible porphyry copper-moly target at depth; possible addition of a 4th and 5th rig if road and water access allow. Operational: updated mineral resource estimate targeted by year-end 2026 (security permitting); commissioning announcement for the PEA; PEA itself more likely in early 2027 covering an integrated Plomosas-San Marcial operation larger than the existing 600 tpd permit; potential announcement on pilot plant purchase for the bulk sample test mining program; ejido renewal at Plomosas (current agreement expires 2027, process already underway); the second ejido runs to 2040. Corporate: permanent CEO appointment (board is searching, Zaunscherb says he is willing to stay on); possible strategic concentrate offtaker investment; possible diversification deal (a single-asset company in Sinaloa is acknowledged as a risk). No share consolidation planned.
Risks
Security in Sinaloa is the dominant risk and Zaunscherb said so directly. The project sits on Mayos cartel ground and the supply route used to cross Chapitos territory, which is why they re-routed through Durango. Single-asset, single-jurisdiction concentration is acknowledged. Continuity risk on a founder-led story 1 month after Fonseca’s death is real, both internally (retention of the Mexico team) and externally (institutional confidence). The resource update and PEA timelines are explicitly contingent on security. Rainy season is approaching and may slow drilling and complicate road maintenance, though the CEO said they can usually work through it. The PEA will need to demonstrate that an integrated, larger-throughput operation works economically, since the current 600 tpd permit and existing infrastructure are not suitable for what management envisions, and a permit amendment or new permit is required. Tailings at Plomosas are owned by a private third party and the ownership picture needs to be rationalised. Group Mexico retains a sliding-scale zinc royalty (~2% currently); other property royalties of 2 to 2.5% exist with buyback options that have not been exercised.
GR Silver CEO Interview
VERY IMPORTANT WARNING
Please note that this company has not paid Resource Talks for the creation of this content. This website is a business that charges for the creation and publication of content. This means there will always be a potential conflict of interest which means you can never rely on anything said herein.
By consuming this content, you acknowledge that Resource Talks and/or its affiliates and/or their personnel may own, have owned, or will own interests in and/or may have a business relationship with some or all companies/entities mentioned/featured in this publication. You further acknowledge that entities which may be referenced or featured in this publication or their related parties may hold an interest in Resource Talks or its affiliates, which may create further conflict of interest.
The information provided herein is general & impersonal in nature and meant for entertainment purposes only. The reader acknowledges and agrees that the information does not constitute a solicitation of an offer to buy or sell any security or instrument or to participate in any trading strategy. The author is not a licensed investment advisor. He is just another talking head on the internet. He might own shares of companies mentioned in this publication. Always assume he doesn’t know much more than a potato does. The mining & exploration space is among the riskiest sectors to invest in. The risk of anything mentioned in this publication is 100% loss of capital. If you don’t read the official documents provided by the company on http://www.SedarPlus.ca, you will lose all of your money.
