VANCOUVER (miningweekly.com) – TSX-V-listed junior Santacruz Silver Mining has discovered a new mineralised vein crosscutting the Membrillo silver/zinc/lead/gold vein structure, located about 4 km from the company's Rosario mill located near Charcas, San Luis Potosi, in Mexico.
Vancouver-based Santacruz on Monday said its mining activities at the Membrillo prospect have been focused on drifting to access the Membrillo vein that generally strikes northwest to southeast and dips about 45° to 60° to the southwest.
This underground development has intersected a previously unknown east to west striking vein structure that dips about 50° to 52° to the southwest and is infilled by quartz, carbonate and sulphide minerals. This previously unknown vein has been named the San Rafael vein.
"This is a very exciting development for Santacruz. Not only does the San Rafael vein potentially provide a new source of feed for our Rosario mill facility, at some of the highest grades that the company has ever assayed in the area, but there are three other areas on the Rosario property, where similar east-west post mineralised structures have been identified, but have never been systematically evaluated,” stated president and CEO Arturo Prestamo.
To date, the company has completed about 68 m of drifting on Level 1 along the San Rafael vein where the true width of the vein is about 0.5 m to 1.6 m wide.
Santacruz has received assay results for 41 chip samples completed across the San Rafael vein on Level 1. Within the first 33 m of Level 1, 26 chip samples returned assay results of trace to 0.64 g/t gold, trace to 154.29 g/t silver, 0.03% to 0.94% lead, and 0.28% to 24.65% zinc over sampling widths of 0.5 m to 4.2 m. This is followed by 35 m of higher-grade mineralisation, where 15 chip samples returned assay results of 0.28 g/t to 1.44 g/t gold, 55.26 g/t to 770.54 g/t silver, 0.12% to 15.92% lead and 4.23% to 20.09% zinc over sampling widths of 0.5 m to 1.6 m.
Santacruz noted that no historical drill holes were completed at the Membrillo prospect that have intersected the San Rafael vein, or other previous exploration activities on the San Rafael vein. The vertical and horizontal continuity of the San Rafael vein and the extent of mineralisation hosted by the vein structure is still unknown. Given that the San Rafael vein was intersected at a vertical depth of only 25 m below surface, Santacruz undertook a stripping and trenching programme to trace the surface expression of the San Rafael vein, for which results are still pending.
Ground conditions while drifting along the San Rafael vein are favourable with no rock bolting or other structural support required. The dilution while mining the San Rafael vein is expected to be 25% on drifts and 15% on stopes.
Prestamo added that the northwest to southeast veins have been the predominant focus of most historic exploration, but with the discovery of the San Rafael vein, Santacruz will broaden its exploration focus to evaluate the east to west structures on both the Rosario and Membrillo veins.
Meanwhile, Santacruz expects the drift to intersect the Membrillo vein close to where historic drilling has indicated higher-grade mineralisation to be completed within the coming weeks. The company plans to complete a ramp to access the San Rafael vein and the Membrillo vein from a sub-level 12 m below Level 1.
Feed from the San Rafael vein is now being transported to the Rosario mill.