December 4, 2017. Thompson Falls, Montana. United States Antimony Corporation (“USAC”, NYSE American “UAMY”) reported that SEMARNAT (the equivalent of the U.S. EPA) has issued USAMSA (a wholly owned subsidiary of USAC) the permit for a cyanide leach plant for the Puerto Blanco mill in Guanajuato, Mexico.
The plant is designed to recover gold and silver from the pilot flotation mill tailings of the Los Juarez gold-silver-antimony deposit in Queretaro, Mexico. The deposit is 3.5 kilometers in length and over 1 kilometer in width. It has all the signature elements of the Carlin gold mine and the Robert’s Mountain over-thrust belt in Nevada. The deposit has been owned by two major mining Companies but has never gone into production due to the complex metallurgy. USAC has solved the metallurgical problem with the floatation product by adding an alkaline leach circuit. A second issue was that the mill only recovered 30 to 50% of the gold and 60 to 80% of the silver in the flotation concentrate. Test work showed that these values could be recovered by a cyanide leach of the mill tailings. USAC has finally gotten the permit for the cyanide leach after many years. Construction of the leach circuit has commenced. Initial projects will include a plastic liner for the tailings pond and construction of the leach plant building. In Montana, construction of leach plant equipment is underway.