Name of the Mine
Cozamin mine.

Location  
North-north-west of Zacatecas City in the mineral-rich state of Zacatecas, in Mexico.

Mine Owner/s  
Capstone Copper Corp.

Brief Description  
Cozamin is a copper/silver underground mine with a surface milling facility.

Brief History  
Cozamin has been continuously operated under Capstone since late 2006, when it started commercial production at 1 000 t/d. At the time, it had a three-year mine life in reserve, however, successful exploration has extended the life-of-mine until 2030.

Primary Metals/Minerals  
Copper.

Secondary Metals/Minerals  
Silver, lead, and zinc.

Geology/Mineralisation  
The Zacatecas mining district covers a belt of epithermal and mesothermal vein deposits that contain silver, gold and base metals (copper, lead and zinc). The district is in the southern Sierra Madre Occidental physiographic province near the boundary with the Mesa Central physiographic province, in north-central Mexico. The district occurs in a structurally complex setting, associated with siliceous subvolcanic and volcanic rocks underlain by sedimentary and metasedimentary rocks.

All mineralisation at Cozamin occurs in veins, and fracture-controlled systems of veinlets. Currently mined mineralisation at Cozamin is best described as intermediate sulphidation. The copper-rich intermediate sulphidation mineralisation is an early phase that is enveloped, overprinted or brecciated by zinc-rich intermediate sulphidation mineralisation.

Cozamin’s dominant mineralised vein systems include the Mala Noche vein (MNV) and the Mala Noche footwall zone (MNFWZ). On the surface, the MNV is mapped for 5.5 km across the property. It strikes about east-west and dips on average at 60° to the north. There are several shafts that provide access to historical workings, the largest historical area being the San Roberto mine and the second largest area being the San Rafael mine. 

Current exploration efforts are focused on the MNFWZ west target and other brownfield targets in the property. MNFWZ is open locally to the south-east and north-west and down-dip (at depth), while MNV is open locally to the east and west and down-dip (at depth).

Reserves  
Total proven and probable reserves as at December 31, 2023, were estimated at 8.89-million tonnes grading 1.62% copper, 0.58% zinc, 0.33% lead and 44 g/t silver.

Resources  
As at December 31, 2023, Cozamin had estimated measured and indicated resources of 18.07-million grading at 1.5% copper, 1.13% zinc, 0.44% lead and 46 g/t silver. Inferred mineral resources were estimated at 11.84-million tonnes grading 0.69% copper, 2.03% zinc, 0.86% lead and 38 g/t gold.

Type of Mine
Underground.

Mining Method  
Ore has been extracted primarily using longitudinal longhole open stoping with unconsolidated waste fill. With the introduction of pastefill in 2023, several mining methods are used, including longitudinal and transverse open stoping, and mechanised cut-and-fill.

Major Infrastructure/Equipment  
The mine includes a shaft, access ramps, ventilation system, a paste backfill plant, a process facility, national grid electrical power, pipelines, crushing and conveying facilities, maintenance facilities, administrative offices, roads, run-of-mine stockpile, a tailings filtration plant and a tailings storage facility. 

Prospects  
Cozamin continues to look for opportunities that will provide a pathway to increase mine production in the future to better use the installed mill capacity of 4 400 t/d.

Contact Details
Capstone Copper Corp. 
Tel +1 604 684 8894 
Email info@capstonecopper.com

Sources
Capstone Copper Corp. Website: https://capstonecopper.com/