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Snapshot
Location: Baja California Sur, Mexico
Ownership: 100%
Status: Development
Metals: Gold
Royalty: 0%
Overview
The San Antonio Project is a gold development project in the State of Baja California Sur, approximately 40 km southeast of the port city of La Paz. The mineral claims cover 23,284 ha with surface rights to 2,926ha.
Heliostar produced a Preliminary Econonomic Assesment Study for the project in 2025. The mine plan foresees an open pit mine feeding a heap leach to recover gold, producing 79koz Au/yr over a 14 year mine life at an all-in sustaining costs of US$1,063/oz. The forecasted initial capital cost of the mine is US $132 million, with a 2-year pre-production phase.
The study showed an after tax NPV5% of US$399m at $1,900/oz gold and an IRR of 40.7%. Heliostar is working on a path to get the state-level permits required for the project to move towards construction.
History
There are records of gold and silver mining in the district dating back to 1748. Modern exploration started in the 1970s with mapping, trenching and some limited geophysics surveys. Echo Bay Exploration but the first mineral resource out in 1996 with Pediment Gold releasing a Preliminary Economic Assessment in 2010 after conducting more than 71,000m of drilling to define the deposit. Argonaut Gold acquired the project in 2011and conducted more than 22,500m of additional drilling focused on deposit delineation, exploration, condemnation, and water source confirmation as well as doing metallurgical and environmental studies. In 2019, Argonaut applied for a mining permit to build an open pit mine at the site.
Heliostar acquired an option for 100% of San Antonio in 2023 and gained full ownership of the project in November 2024.
Location and Infrastructure
The project is located 40km southeast from the state capital of La Paz (pop. 250k) and just 8km from the historic mining town of San Antonio. La Paz is a major port city and has an international airport with regular flights to most major cities in Mexico as well as to Los Angeles. The project is accessible from La Paz via the paved, public Highway 1 with gravel roads providing vehicle access across the project area. A 34.5kVpowerline passes through the project area, however, there is no project specific infrastructure established at the site.
There are two ejidos present in the project area. Heliostar has a 30-year land occupation agreement with the San Antonio ejido (through to2039) over 260 ha. This covers the Los Planes and Las Colinas deposits of the project and some of the surrounding area.
Overview
The San Antonio Project is a gold development project in the State of Baja California Sur, approximately 40 km southeast of the port city of La Paz. The mineral claims cover 23,284 ha with surface rights to 2,926ha.
Heliostar produced a Preliminary Econonomic Assesment Study for the project in 2025. The mine plan foresees an open pit mine feeding a heap leach to recover gold, producing 79koz Au/yr over a 14 year mine life at an all-in sustaining costs of US$1,063/oz. The forecasted initial capital cost of the mine is US $132 million, with a 2-year pre-production phase.
The study showed an after tax NPV5% of US$399m at $1,900/oz gold and an IRR of 40.7%. Heliostar is working on a path to get the state-level permits required for the project to move towards construction.
History
There are records of gold and silver mining in the district dating back to 1748. Modern exploration started in the 1970s with mapping, trenching and some limited geophysics surveys. Echo Bay Exploration but the first mineral resource out in 1996 with Pediment Gold releasing a Preliminary Economic Assessment in 2010 after conducting more than 71,000m of drilling to define the deposit. Argonaut Gold acquired the project in 2011and conducted more than 22,500m of additional drilling focused on deposit delineation, exploration, condemnation, and water source confirmation as well as doing metallurgical and environmental studies. In 2019, Argonaut applied for a mining permit to build an open pit mine at the site.
Heliostar acquired an option for 100% of San Antonio in 2023 and gained full ownership of the project in November 2024.
Location and Infrastructure
The project is located 40km southeast from the state capital of La Paz (pop. 250k) and just 8km from the historic mining town of San Antonio. La Paz is a major port city and has an international airport with regular flights to most major cities in Mexico as well as to Los Angeles. The project is accessible from La Paz via the paved, public Highway 1 with gravel roads providing vehicle access across the project area. A 34.5kVpowerline passes through the project area, however, there is no project specific infrastructure established at the site.
There are two ejidos present in the project area. Heliostar has a 30-year land occupation agreement with the San Antonio ejido (through to2039) over 260 ha. This covers the Los Planes and Las Colinas deposits of the project and some of the surrounding area.
Geology
The regional around the project consists of basement granites overlain by marine sedimentary sequence capped by younger volcanics. The youngest rocks are a series of basalt flows. Two separate intrusive complexes (hosted in schists and gneisses) are the other major geologic features that define the region. Sands and gravels are widely present at surface, limiting outcrop.
At the project area, an intrusive complex of gabbro to diorite typically hosts mineralization in the San Antonio area. These are usually coarse grained, contain abundant hornblende or augite and are dark-coloured. Diorites and quartz-diorites are common in the hanging walls and footwalls of the deposits.
The mineralized zones are typical mesothermal vein-style or orogenic style gold deposits found along a regional shear thrust fault dipping45 degrees to the west. Gold mineralization is defined over 1.8 km of strike length with the four deposits (Los Planes, Intermediate, Las Colinas, and La Colpa) separated by local normal and listric faults. The blocks formed by these faults progressively drop to the northeast along northwest-trending structures.
Mineralization consists primarily of gold occurring with disseminated and veinlet sulfides that are associated with cataclasite. Quartz veining is widespread. The sulphides are often present in brittle structures including cracks, faults, joints and micro-fractures. Oxidation can reach 100 m in depth, most prominently along fault zones.
Production Plan
Heliostar released a Preliminary Economic Assessment for the project in January 2025. This envisions a truck and loader open pit mine feeding a 11ktpd crushing circuit with crushed material stacked on a heap leach pad and irrigated. The pregnant process solution would be processed through an ADR plant on site with loaded carbon shipped to La Colorada for final gold extration. The study shows inital capital foof139m to put the 78.6koz/yr mine into production at a site-level AISC of $21.15/t processed or $1,063/oz produced over a 14 year mine life.
Mineralized material from the would be drilled and blasted from three pit areas. The Los Planes producing the bulk of the feed with four pushback phases planned. Overall, the mining operation would have a strip ratio of 3.2:1. Mining will be done by a contractor supplying their own mobile fleet of primary equipment.
Crushing would be done through three phases producing a 19mm product. Feed from the pit would progress through a primary jaw crusher, a secondary cone crusher and the one of two tertiary cone crushers. This would produce a 19mm product to which lime would then be added to control the pH before being conveyed to and stacked on the pad before being irrigated.
After percolating through the pad, the process solution would be directed to an ADR plant to produce carbon loaded with gold. This would then be transported to La Colorada for final recovery of the gold into dore bars.
Growth
Opportunities exist to expand the known limits of mineralization at San Antonio by exploring along strike of key structures defined by drilling and by testing other subsidiary mineralized trends where they appear to extend beyond the deposit limits. Prospects include:
- Las Colinas South, where mineralization is open at the surface to the south
- Los Planes West, where the hanging wall mineralization to the west is poorly defined
- Los Planes East, where mineralization is open on the eastern margin of the apparent fold axial plane
- La Colpa, where multiple mineralized corridors with varying orientations are open and untested by drilling beyond the current deposit limits.
Mineralization remains open to the north and down plunge at Los Planes. Mineralization hosted in an apparent fold hinge, and the main shear structure hosting the cataclasite, are unconstrained by drilling down plunge to the north.
Most of the exploration has focused on the areas immediately around the San Antonio deposits. There controlling, regional northwest structure remains open along trend for expansion. In additions, much of the wider Project area remains underexplored and hosts numerous historical mining centres that represent opportunites for additional resource growth.
All technical information on the San Antonio Project is based on a technical report entitled “San Antonio Project, Baja California Sur, Mexico, NI 43-101 Technical Report on Preliminary Economic Assessment” with an effective date of November 30, 2024, filed on SEDAR by Heliostar on January 13, 2025 (the “San Antonio Technical Report”). The technical report for the San Antonio Project was prepared for Heliostar Metals Inc. by Mr. Todd Wakefield, RM SME, Mr. Richard Schwering RM SME, Mr. Jeffrey Choquette, P.E., Mr. Carl Defilippi, RM SME, and Ms. Dawn Garcia, CPG. and all are independent of the Company.
NI 43-101 Technical Report - January 2025
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