Osisko Development (TSXV: ODV; NYSE: ODV) has provided an initial open-pit resource estimate for the Sapuchi, Golfo de Oro, California, High Life and Calvario deposits at its San Antonio project in Sonora state, Mexico.
Indicated resources total 14.9 million tonnes grading 1.2 grams gold per tonne and 2.9 grams silver for 576,000 oz. of gold and 1.4 million oz. of silver. An additional 16.6 million tonnes grading 1 gram gold and 3.3 grams silver for 544,000 oz. of gold and 1.8 million oz. of silver, were categorized as inferred.
The resource comprises oxide, transition and sulphide zones for each deposit using cut-off grades of 0.27 gram gold for oxide and 0.44 gram gold for transition and sulphide.
"The addition of this new resource further strengthens our portfolio for near term advancement and towards possible production. Osisko Development has made considerable progress at San Antonio in the past year with the construction of the leach pad, near-term processing of the stockpile and completion of a drill program to generate this initial resource," Osisko's president Chris Lodder said in a press release.
The resource estimate is based on 84,454 metres of current and verified historic drilling in 579 holes, of which 27,870 metres of drilling in 177 holes were drilled by the company in 2021. It covers a portion of the Sapuchi - Cero Verde trend that encompasses the five above-mentioned deposits (2.8 km along strike out of approximately 10 km).
According to Lodder, the company believes "there is potential to add to the mineral resource through continued exploration and drilling on the property."
The San Antonio project is a past-producing mine that went into receivership as an oxide copper mine. The gold potential of the asset, however, has never been properly evaluated. After acquiring the property in November 2020, Osisko has been focused on amending existing permits to transition the mine production to a gold heap leach operation.
Progress to date include construction of a leach pad and carbon in column plant to process stockpiled mineralized material, which totalled 1.1 million tonnes with an average grade of 0.57 gram gold. Processing of the stockpile began in late 2021, and currently, 680,000 tonnes of mineralized material has been placed and processed.