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Southern Silver offers Cerro Las Minitas PEA with $349 million NPV, 60-month payback

View of the Cerro Las Minitas polymetallic project showing historic workings at the Bocona zone. Credit Southern Silver Exploration

Southern Silver Exploration (TSXV: SSV) has released the preliminary economic assessment (PEA) for its 100%-owned Cerro Las Minitas silver project about 70 km northeast in Durango State, Mexico. The PEA puts the gross revenues over 15 years of mining at $3.7 billion.

The study puts the after-tax net present value (5% discount) at $349 million and internal rate of return of 179% using silver at $21.95/oz., copper at $3.78/lb., lead at $0.94/lb., and zinc at $1.33/lb.

The initial capital requirement is $341 million for a large-scales underground mine. Annual silver-equivalent production will average 14.2 million oz. (5.8 million oz. silver yearly) at an all-in sustaining cost of $13.27/oz. silver-equivalent sold. Silver will represent 42% of revenues, and zinc will represent 39% of revenues. An additional $168 million is anticipated for sustaining capital.

The Cero Las Minitas project has an indicated reserve of 12.3 million tonnes averaging 106 g/t silver, 0.16% copper, 1.3% lead, and 3.3% zinc, containing 42.1 million oz. silver, 44 million lb copper, 358 million lb. lead, and 895 million lb. zinc. The inferred resource is 29.6 million tonnes averaging 117 g/t silver, 0.23% copper, 1.2% lead, and 2.3% zinc, containing 73.6 million oz. silver, 98 million lb. copper, 500 million lb. lead, and 1.01 billion lb. zinc. Only sulphide mineralization was included in the study.

Southern Silver anticipates there is further exploration upside at the project. Current drilling and confirmed extensions to the Mina La Bocona and Skarn Front deposits, neither of which is included in the resources.

The mining plan foresees the use of longitudinal and transverse long hole stoping methods. Two separate portals are proposed, one to access the Blind-El Sol and Skarn Front deposits, and the second to access the La Bocona and South Skarn deposits.

The mineral processing plant will have a 4,500 t/d nominal capacity. The process consists  of primary crushing, a 15,000-tonne run-of-mine stockpile, reclaim and secondary crushing, closed circuit ball milling, and sequential copper-lead-zinc flotation circuit producing three filtered concentrates for sale.

A portion of the tailings will be returned to the mine as cemented paste fill, and the remainder will be dry stacked on the surface.