Laminco tests San Antonio

Plans to develop the Luz del Cobre copper deposit as an in situ leaching operation are on hold as Laminco Resources (TSE) evaluates the potential for bulk-tonnage gold mineralization.

Luz del Cobre forms part of the 50-sq.-mile San Antonio property in Mexico’s Sonora state, where reverse-circulation drilling is assessing gold-mineralized trends.

Drill results from the Cerro Sapuchi and Trion zones, along with geological mapping, suggest that copper mineralization at Luz del Cobre is hosted in the same rocks. The two zones are segments of a structure believed to extend eastward to Luz del Cobre for a minimum strike length of 54,000 ft. Limited surface sampling on the outer edges of Luz del Cobre returned up to 0.03 oz. gold per ton, while a single hole drilled in the centre encountered an overlying cap grading 0.044 oz. over 90 ft.

The deposit hosts about 13.5 million tons grading 0.46% copper. Initially Laminco proposed recovering copper sulphate through an in situ operation, which would have involved injecting a weakly acidic leaching solution through a series of small-diameter holes drilled from surface. The leached copper mineralization was to be collected in a series of underground crosscuts and drifts.

Laminco is adding a second drill rig to the San Antonio property. One will drill stepout and infill holes on the California and Cerro Sapuchi-Trion-Luz del Cobre zones; the other will test exploration targets. These targets include the sedimentary units adjacent to the 3,300-ft.-long Realito shear-breccia zone, and the Tigre ridge, 4,000 ft. west of, and on strike with, the Main California zone.

Among the best holes from a drill program along the California trend is No. 77, which stepped out 400 ft. east of previous drilling and encountered 65 ft. grading 0.048 oz. at a depth of 125 ft.

A stepout hole in the Main California zone (70 ft. south of hole 67) returned 735 ft. of 0.054 oz. (including the intervals grading 0.13 oz. over 135 ft. and 0.095 oz. over 215 ft.) for hole 78. The previously reported hole 67 returned 685 ft. of 0.041 oz. (including 0.068 oz. over 190 ft. and 0.1 oz. over 145 ft.).