Status IN PRODUCTION
Location Sonora, Mexico
Production ~50,000 oz / yr1
Reserves 325 koz @ 3.90 g/t gold
M&I Resources 551 koz @ 4.10 g/t gold2
Mining styleopen-pit heap leach
Upside Potential Expand throughput toward 80-90 koz / yr
Mercedes is an underground gold-silver mine located in the State of Sonora in northern Mexico, approximately 250 km northeast of Hermosillo, Mexico and 300 km south of Tucson, Arizona. Operations are exploiting low sulfidation quartz veins and quartz veinlet stockwork for gold and silver using underground modified overhand cut and fill, narrow vein longitudinal longhole mining, and longhole open stoping methods at an ore extraction rate of approximately 2,000 tonnes per day. Processing is by wet milling with a Merrill-Crowe recovery system. Equinox Gold acquired Mercedes in April 2021 through its acquisition of Premier Gold Mines.
Mercedes was placed on care and maintenance in April and May 2020 as the Mexico-wide government-mandated restrictions related to COVID-19. A phased re-start of the mine began in June 2020, prioritizing completion of key access ramps to the Diluvio West and Lupita Extension stoping areas, and definition drilling at Marianas, Diluvio West, and San Martin.
Mercedes mined a total of 106,597 tonnes during Q3 2020 compared to 163,030 tonnes during the same quarter of the previous year. The main driver behind the decrease in tonnage during the period was a restructure of the mining zones, from an average of six zones in 2019 to two main areas, Diluvio and Lupita, in the third quarter of 2020. This change had a positive impact, with a considerable reduction in tonnes of waste, increase in the average of gold grades from 2.94 g/t in Q3 2019 to 3.37 g/t in Q3 2020, and a decrease in costs. Due to the lower tonnage extracted from the mines, the plant has changed its operational schedule with an average of 20 operational days per month and 10 days off. This new schedule has allowed an optimization of the reagents, electricity and maintenance.
Located within two northwest trending anticlines, the andesite sequence hosts all the economically important epithermal veins and Au-Ag resources identified on the Mercedes property. Gold-silver mineralization on the Mercedes property is primarily epithermal low sulphidation. A total of 14 fissure vein zones with a cumulative strike length of 12.35 km of gold-silver-bearing veins occur over a vertical range greater than 600 metres, with lengths from 100 m to 3 km. Gold and silver-bearing vein/stockwork zones (up to 100m width) occur at Diluvio.
Several exploration targets exist on the property with the potential for mine life extension. In addition to identifying potential targets close to existing infrastructure on the property, Equinox Gold expects to explore along the several kilometres of the unexplored main northwest vein systems that the existing mines sit on, as well as other regional targets.