San Antonio Project

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Mine TypeOpen Pit
StatusInactive / Suspended
  • Gold
Mining Method
  • Truck & Shovel / Loader
Mine Life... Lock
SnapshotIn 2019 Argonaut announced that the Mexican Environmental Authority had not approved its environmental permit for San Antonio Project due to its non-compatibility with a 2018 municipal zoning revision.

December 05, 2022, the Argonaut entered into the Option Agreement with Heliostar and Compañía Minera Pitalla, which holds the title to the San Antonio Gold Project. Under the terms of the Option Agreement, Heliostar has the Option to earn a 100% interest in and to the San Antonio Gold Project.

Development is currently paused due to a pending environmental permit. Heliostar will earn the option to acquire a 100% interest in the project by obtaining this permit.


Argonaut Gold Inc. 100 % Indirect
The Argonaut owns 100% of the San Antonio Project as its foreign operations in Mexico.

December 5, 2022 - Heliostar Metals Limited is pleased to announce that it has entered into a binding option agreement (the "Option Agreement") with Argonaut and its wholly owned subsidiary, Compañía Minera Pitalla S.A. de CV ("Compañía Minera Pitalla"), pursuant to which it has been granted an option (the "Option") to acquire a 100% interest in the San Antonio Gold Project. Both projects are located in Mexico.



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Deposit type

  • Breccia pipe / Stockwork
  • Orogenic


The mineralization has been identified over approximately 1.8 km of strike length at the Project and has been subdivided into four fault-bounded zones referred to as Los Planes, Intermediate, Las Colinas, and La Colpa, Los Planes is the best known of the areas and is the most densely drilled. Local normal and listric faulting displaces and truncates the mineralized zones (Herdrick, 2009). Much of the outcrop is covered by pediment that thickens to the east, featuring cobbles and boulders of schist and gneiss.

Los Planes
Mineralization extends along a north-south strike length of approximately 800 m. Drilling has encountered continuous mineralization to depths of 380 m from the surface. Mineralization generally varies between 1 and 20 m in thickness. Mineralization thickness is highly variable due to the stockwork-style of mineralization, and zones can locally coalesce into broader intervals over 100 m in thickness. Mineralization is interpreted to be open along strike to the north and at depth. Mineralization is hosted in diorites and gabbros within a large shear zone that dips between 75º and 45º to the west and horizontally to very shallowly to the east. The shear zone is broken into subunits that are defined by their structure, alteration, and degree of mineralization.

Las Colinas & Intermediate
Las Colinas and Intermediate zones appear to be genetically related, and are separated by postmineral normal faults that effectively truncate mineralization between the northern (Intermediate) and southern (Las Colinas) zones. The faults that bound Intermediate to the north and south dip away from each other at 50º to the north and 55º to the south, respectively. Known mineralization in the Colinas zone is truncated to the south by the mineral tenement boundaries. The deposits dip approximately 50º to 60º to the west, and are hosted in shear zones measuring over a km in strike length. Shear zones are generally competent in both zones, and is described as being composed of potassium feldspar and quartz in a matrix of sericite, chlorite, and quartz (AMEC, 2011). The mineralized zones vary in thickness, and are generally thinner to the south in the Las Colinas zone. Perhaps the most notable difference between the zones is the conspicuous absence of a well-developed stockwork zone at Las Colinas. Much like the mineralization at Los Planes, Au grades in the Intermediate zone are best associated with the stockwork zones characterized by elevated sulfide content.

La Colpa
Mineralization at La Colpa is interpreted to be a sheeted vein complex with intermediate stockwork zones. Due to the unpredictable nature of this mineralization, the number of parallel veins varies within the zone from two to six sequential structures. The stockwork zones are hosted in cataclastic units with a schist footwall, and are weakly chlorite/sericite altered. Originally, the mineralization was interpreted to be hosted in a shear zone dipping to the west at about 10º to 20º and composed of cataclasite and mylonite, with alteration dominated by sericite, silicification, and local K-feldspar. The dip of these units has been reinterpreted to be about 50º to 60º dip after more information was acquired in the recent expanded drilling program.



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Mining Methods


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Crushers and Mills


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CommodityUnitsAvg. AnnualLOM

Production Costs

Cash costs Gold USD 553.06 / oz *  USD
Assumed price Gold USD 1,355 / oz *  USD
* According to 2012 study / presentation.

Operating Costs

OP mining costs ($/t milled) USD 5.5 *  USD
Processing costs ($/t milled) USD  ....  Subscribe
G&A ($/t milled) USD  ....  Subscribe
Total operating costs ($/t milled) USD  ....  Subscribe
* According to 2012 study.

Project Costs

MetricsUnitsLOM Total
Initial CapEx $M USD  ......  Subscribe
Sustaining CapEx $M USD  ......  Subscribe
Closure costs $M USD  ......  Subscribe
Total CapEx $M USD  ......  Subscribe
OP OpEx $M USD  ......  Subscribe
Processing OpEx $M USD 198.6
Refining costs $M USD  ......  Subscribe
G&A costs $M USD 46.2
Total OpEx $M USD  ......  Subscribe
Income Taxes $M USD  ......  Subscribe
Net revenue (LOM) $M USD  ......  Subscribe
Operating margin (LOM) $M USD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M USD  ......  Subscribe
After-tax Cash Flow (LOM) $M USD  ......  Subscribe
Pre-tax NPV @ 8% $M USD  ......  Subscribe
After-tax NPV @ 8% $M USD  ......  Subscribe
Pre-tax payback period, years  ......  Subscribe

Heavy Mobile Equipment


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Mine Management

Job TitleNameEmailProfileRef. Date
....................... Subscription required ....................... Subscription required ........... Subscription required Subscription required Nov 22, 2023
....................... Subscription required ....................... Subscription required Subscription required Oct 10, 2012
....................... Subscription required ....................... Subscription required Subscription required Oct 10, 2012


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