San Francisco Mine, Sonora, Mexico

by | Feb 25, 2021

Micon has worked with successive owners of this property since 2005, when it wrote the qualifying report on this property for Timmins Gold Corp. (Timmins) which later changed its name to Alio Gold Inc. (Alio). Micon continues to work with the current owners, Magna Gold Corp. (Magna).

The San Francisco Mine currently contains two major open-pits and extensive heap-leach pads located along Mexican Highway 15 between Hermosillo and Santa Ana. The mine, which was first operated between 1995 and 2002, was originally reopened in April, 2010, by Timmins and again by Magna in 2020 after Alio had placed the mine on residual leach at the end of 2019.


Micon Gold Consulting Case Study

Gold mineralization occurs in granitic gneiss and the deposit contains principally free gold and occasionally electrum. The mineralogy, the possibility of associated tourmaline, the style of mineralization, and fluid inclusion studies suggest that the San Francisco deposit may be of mesothermal origin.

Over the years, Micon has been able to track progress with development of the mine and processing infrastructure, to assist the owners and provide recommendations to guide exploration and mine planning. Commencing with a NI 43-101 Technical Report in 2005, Micon has now completed 17 separate assignments at the property describing its mineral resources and open pit reserves for processing by heap leaching.


The most recent updates followed the change of ownership in 2020, when consideration was also given to underground mining for a portion of the process feed, and a further study for the new owners is currently in progress. Micon will continue to assist and advise Magna on an as needed basis.

Micon Technical Report Case Study

San Francisco Mine as Viewed from Highway 15 Driving South from Santa Ana.

Micon Technical Report Case Study

View of the San Francisco Pit, March, 2020.

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