San Antonio

Key Facts
Location Baja California Sur, Mexico
Ownership 100%
Status Advanced Exploration
Mine Type Open pit, heap leach
Metals Gold
Acquisition December 2009

San Antonio Gold Resource Estimates at $1,500 Gold1

Category Tonnes
Au Grade
Au ounces
Measured & Indicated 65.0 0.86 1,735
Inferred 6.2 0.34 67

1 Mineral Reserves and Mineral Resources have been estimated as at December 31, 2019 in accordance with NI 43-101 as required by Canadian securities regulatory authorities. Mineral Resources are presented inclusive of Mineral Reserves. Numbers may not sum due to rounding.

The M&I Mineral Resources and Inferred Mineral Resources for the San Antonio Project set out in the table above were taken from the San Antonio Technical Report. The Mineral Resources were estimated at a gold price of $1,500 per ounce using a cutoff grade of 0.11 g/t Au for oxide and transition and 0.15 g/t Au for sulphide.


The San Antonio Gold Project is located on the Baja California Peninsula, adjacent to the historic mining town of San Antonio and 40 km southeast from the port city of La Paz. Good gravel roads traverse most of the project area and a high voltage power line crosses through it. The 100% owned project covers a large land package of favorable geological trend. In the late 1990s Echo Bay Mines Ltd located and partly tested the Colinas gold resource and in 2007-2008 Pediment Gold Corp. discovered and defined a significant gold resource at Los Planes.


The basement rocks of the Baja California Sur region are comprised of a chain of Mesozoic granitic bodies and accompanying late Paleozoic to Mesozoic metasedimentary roof pendants. The structural geology of the region is dominated by Mesozoic aged large-scale low-angle thrust faulting featuring cataclasites, mylonites and mineralized stockwork zones that host silver and gold mineralization. Shear zones related to thrust faulting exceed 200 metres in thickness and are regionally traceable over 40 kilometres.

Due to the paucity of outcrop within the San Antonio Project, geological interpretations are primarily based on drill data. The primary rock units within the San Antonio Project belong to the basement of the Baja California Sur, and include:

  • Diorites and gabbros: usually coarse grained, contain abundant hornblende or augite and are darkcolored.
  • Biotite–hornblende quartz diorites: abundant hornblende and minor quantities of magnetite
  • Biotite granodiorite–granite with a weakly porphyritic character.

The San Antonio Project geology is defined by mineralization hosted in a regional shear zone, possibly a Mesozoic-age thrust fault. The shear dips to the west at about 45° and is dominated by stockwork, cataclasites and mylonites.

Gold mineralization on the San Antonio Project has been identified along a 1.8 kilometres strike length and has been subdivided into four fault-bounded zones, which have been named Las Colinas, Intermediate, La Colpa, and Los Planes.

Los Planes is the best known of the deposits to date and is the most densely drilled. The Los Planes mineralization extends along a north-south strike length of approximately 800 metres. Drilling has encountered continuous mineralization to depths of 380 metres from the surface. 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. Two of these subunits, referred to as the Hanging Wall and stockwork/cataclastite zones host the great majority of the gold mineralization. Mineralization is intimately associated with sulphides, although near-surface oxidation affects Los Planes to depths in excess of 100 metres along faults and fracture zones.

The Las Colinas and Intermediate zones appear to be genetically related and are separated by postmineral normal faults. The deposits dip approximately 50º to 60º to the west and are hosted in shear zones measuring over a kilometre in strike length. The mineralized zones vary in thickness and are generally thinner to the south in the Las Colinas zone. Mineralization at the La Colpa zone is interpreted to be a sheeted vein complex with intermediate stockwork zones. The La Colpa occurrence consists of a number of parallel veins and stockwork zones that dip at about 50º to 60º to the west. The mineral deposits of the San Antonio Project are considered to be mesothermal or of orogenic origin.


The nearby Triunfo district is thought to have produced around 115,000 ounces of gold and approximately 21 million ounces of silver through 1914.

Other production was from the nearby El Tule area, where a flotation mill was operating at some point during the this time.

The government geological branch, Consejo De Recursos Minerales, carried out work in the 1970s, consisting of mapping, trenching and limited magnetic and induced polarization ("IP") surveys which covered portions of the San Antonio Project.

The most recent production in the district was gold produced by Minera Tepmin at the Testera Mine, located approximately 10 kilometres south of San Antonio. This mine processed approximately 50 tonnes per day and operated intermittently between these years. There is no recorded production from the current project area.

A Canadian-based company, Viceroy Resource Corp., began investigation of the Paredones Amarillos area south of the San Antonio Project in about 1990.

Echo Bay Exploration Inc. ("Echo Bay") acquired the Paredones Amarillos area from Viceroy Resource Corp. through a joint venture.

During the approximate period from 1993 to 1998 Echo Bay carried out detailed geologic studies which led to both RC and core drilling on multiple targets. Echo Bay left the area at the end of 1998.

Exploration work by Pediment staff in the area commenced in 2005. Activities until 2010 included data review, rock chip and grab sampling of old trenches and workings, soil sampling, reconnaissance IP geophysical surveys, RC and core drilling, mineral resource estimation and metallurgical test work. Third-party studies in relation to socio-economics, hydrogeology and geotechnical were also commenced.

A preliminary economic assessment ("PEA") was commissioned from AMEC in 2010 by Pediment Gold Corp.

Argonaut published a resource estimation completed by AMEC.

Argonaut published a PEA completed by SRK Consulting Inc

Technical Reports