Corner Bay tables estimate for Alamo Dorado

Consultants for Corner Bay Minerals (BAY-T) have calculated reserve figures and a pit design for the Alamo Dorado silver-gold deposit in Sonora state, Mexico, showing a minable reserve of 49.7 million tonnes grading an average 0.2 gram gold and 52 grams silver per tonne.

The reserve estimate is part of a prefeasibility study by Arizona-based Mintec that included resource and reserve calculations and a pit design. The proposed pit has a stripping ratio of 0.4-to-1.

Alamo Dorado’s resource, in all categories, is estimated at 74.8 million tonnes grading 41 grams silver and 0.16 gram gold. That resource figure includes the minable reserve.

The current drill lines at Alamo Dorado are 50 metres apart, and Mintec classified mineralization within 30 metres of a drill hole as measured, within 60 metres as indicated, and beyond 60 metres as inferred.

Mintec’s prefeasibility study predicts a mining cost of US90 cents per tonne and a cash production cost of US$1.71 per oz. silver. The open pit would feed a heap-leach recovery operation, but two streams of material would go the leach pads: a higher-grade stream with 65-95 grams silver per tonne, and a lower-grade stockpile with 11-12 grams. Mintec’s design has the pit being excavated in three phases, with the first taking just under a quarter of the deposit at a stripping ratio of 0.17-to-1.

The prefeasibility study assumed average recovery of 70% for both silver and gold, though Mintec used a lower (60%) recovery figure for the low-grade stream. Column-leach tests will determine whether or not the assumptions are valid; so far, four large-diameter drill holes have been completed and the samples are being crushed and prepared for testing.