The Nieves project is a low sulfidation epithermal silver deposit hosted in three east-northeast trending, steeply south dipping vein systems with alteration and mineralization bearing strong similarities to the Fresnillo silver deposit.
The most economically significant mineralization occurs in anastomosing carbonate-quartzsulphide veins that have been defined over a total strike length of 3.8 kilometers by 54,814 meters of drilling in 187 holes. The system develops to a maximum true width of in excess of 200 meters and has a proven down dip extent of approximately 525 meters.
The carbonate-quartz-sulphide veins contain the best grades of silver, gold, lead and zinc. This vein type consists of calcite that is partially to totally replaced by grey to white, chalcedonic, fine-grained quartz veins and veinlets. Individual veins vary in size from a few centimetres in width with a few up to 1.5 m wide with up to 50% sulphide minerals. Sulphides include pyrite, stibnite, sphalerite, galena, chalcopyrite and the silver sulphosalts: proustite, pyrargyrite, jamesonite and scarce tetrahedrite.
The central and most important of the three vein systems is the Concordia-San Gregorio-Dolores system which includes both the La Quinta and Gregorio North zones. Mineralization along the Concordia-San Gregorio-Dolores vein has a known total strike length of 1,300 meters and a true width up to 100 meters. The mineralized zone in the Gregorio North area is approxim ........
