Name of the Mine
Mercedes mine.

Location  
Sonora, about 250 km north-east of Hermosillo, Mexico, and 300 km south of Tucson, Arizona, in the US.

Mine Owner/s  
Bear Creek Mining Corporation.

Brief Description  
Mercedes is a fully mechanised, ramp-access operation that produces gold and silver. 

Eleven individual deposits have been mined or are currently in production, and seven additional deposits have been identified and are currently in the early exploration or drill definition stage. These deposits occur in three main areas: the prolific Mercedes trend – a major vein that hosts the Mercedes, Aida, Barancas, Gap, Laguna and Marianas deposits; the Rey de Oro area that hosts the Rey de Oro and Klondike deposits; and the Diluvio area that hosts the Diluvio, Lupita and San Martin deposits. 

Additional mineralised zones proximal to existing workings have been identified and are at the exploration or drill definition stage.

Brief History  
Exploration and small-scale mining activities have been undertaken in the Mercedes mine vicinity since the early 1900s. 

The mine has been in commercial production since 2011, under the ownership of Yamana Gold Inc from 2007 to 2016, Premier Gold Mines from 2016 to 2021 and Equinox Gold Corp from 2021 to 2022.

In December 2021, Equinox agreed to sell the Mercedes mine to Bear Creek Mining Corp. 

Primary Metals/Minerals  
Gold.

Secondary Metals/Minerals  
Silver.

Geology/Mineralisation  
The Mercedes mine is located in the north-western edge of the epithermal gold and silver deposits belt of Mexico.

The mine area is underlain by a thick succession of shallow-marine shelf carbonate and siliciclastic rocks ranging in age from Jurassic to Cretaceous, which have been moderately to strongly faulted and folded.

Andesitic flows and flow breccias have been deposited and preserved in at least three west-northwest thickening basins, on the margins of the north-west-trending arches. This andesite package, locally more than 500 m thick, and the contact zone with the underlying tuff, host all known economic epithermal vein deposits in the district.

A total of 16.5 km of gold/silver-bearing epithermal low sulphidation veins have been identified within or along the margins of the andesite-filled basins, which constitute the primary exploration target on the property.

Reserves  
Total proven and probable reserves as at December 31, 2021, were estimated at 2.22-million tonnes grading 3.75 g/t gold and 29 g/t silver.

Resources  
As at December 31, 2021, Mercedes had total measured and indicated resources of 2.55-million tonnes grading 3.81 g/t gold and 37.47 g/t silver. Inferred resources were estimated at 884 000 t grading 4.5 g/t gold and 41.02 g/t silver.

Type of Mine
Underground.

Mining Method  
Mechanised cut-and-fill.

Major Infrastructure/Equipment  
The Mercedes mine includes all surface and underground infrastructure necessary to operate the site. This comprises:

• a 2 000 t/d three-stage crushing and process plant.
• mine infrastructure – administrative office facilities, two camp facilities (exploration and mine personnel), mine operation and maintenance facilities (surface and underground), core storage and exploration offices, personnel change room facilities (mine dry), and lamp and safety rooms.
• tailings management infrastructure for surface disposal – two existing and a third one to be designed and built.
• a paste plant for underground backfill.
• two on-site batch plants for the preparation of shotcrete and for concrete as required.
• a water supply and treatment plant.
• electrical infrastructure and substation to meet site load requirements of about 14 MW.
• access roads connecting the site with public roads as well as internal roads connecting the different mine areas to the plant and to the other major infrastructure; and
• ore and waste stockpiles areas.

Prospects  
Bear Creek has started a programme to delineate new prospects, with the potential to lead to new mineral resources proximal to Mercedes’ current operations, to be followed by a second phase of work aimed at expanding the existing interpretation of the remainder of the Mercedes concessions with the aim of defining key mineralised systems and new mineralisation models. 

Contact Details 
Bear Creek Mining Corporation
Tel +1 604 685 6269
Email info@bearcreekmining.com

Sources
Bear Creek Mining Corporation. Website: https://bearcreekmining.com/