International Silver, Inc. announced that it has concluded the metallurgical flotation and roast/leach testing programs of the Caselton Tailings. The Flotation test work of the tailings samples was conducted independently by HRL Metallurgical Testing under the supervision of Core Engineering in Townsville, Australia. The roasting and leach testing of the flotation concentrates was conducted independently by Hazen Research of Denver, Colorado.

The flotation testing of new drill samples taken from the Caselton Tailings confirmed expected recoveries of gold and silver. The grade of the tailings was re-confirmed to be an average of 0.964 grams of gold and 30.50 grams of silver per ton. An Independent report estimates a total of approximately 2.0 million tons of these tails are contained in the existing ponds.

The tailings also contain an average of 15.26% sulfur. All assays of both tailings head samples, flotation concentrates and residual tails produced in the testing program were determined independently by HRL and Hazen. Flotation testing demonstrated that the gold and silver are associated with pyrite and that with a mass pull of 43% in flotation, recovery will be 92% of gold and 82% of silver to a pyrite concentrate containing 37% sulfur.

The company anticipates processing 1,000 tpd of the tailings to produce approximately 430 tpd of pyrite concentrates grading 2.13 grams of gold and 59 grams of silver per ton of pyrite concentrate. Based on the initial bench scale testing the cyanidation circuit is expected to recover 70% of the contained gold and 82% of the contained silver. The company is proceeding with Pilot plant test work to confirm and attempt to improve these recoveries.

Flotation concentrate will be roasted in a fluid bed roaster and followed by cyanidation. In addition, the roaster gases will pass to a sulfuric acid plant to produce sulfuric acid. Based on the initial test results and an anticipated processing rate of 1,000 tpd, the company is projecting that the project will generate approximately 7,000 ounces of gold, 225,000 ounces of silver and 170,000 tons of sulfuric acid per annum.