Metallurgical Fracture Simulation Tests Validate Prefeasibility Results

 

VANCOUVER - Excelsior Mining Corp. reported the final metallurgical results for the Gunnison Copper Project in Arizona. These comprehensive results will be incorporated into a full Feasibility Study scheduled for completion in 2016. Results indicate that copper leaches rapidly and relatively uniformly across all rock types.

Forward modeling of the recovery time curves and acid consumption curves (see graphs) indicate average acid consumption at 100% acid soluble copper recovery (approximately 70% total copper recovery), would be in the range of 8 to 10 pounds of acid consumed for every pound of copper cathode produced. This is consistent with the previously reported Prefeasibility Study that used approximately 8.1 pounds of acid consumed for every pound of copper cathode produced.

Stephen Twyerould, President and CEO said, These results are completely in-line with the results from our 2014 Prefeasibility Study and fully support the industry leading economics that define our Gunnison Copper Project. We remain excited by the rapid advancement of the Project and the use of this new data in our upcoming Feasibility Study.

The fracture simulation leach tests were designed to simulate the leaching of copper from a fracture surface as would occur during in-situ recovery operations at the Gunnison Copper Project. Natural, mineralized, fracture surfaces were taken from drill core representing the major rock and mineralization types found in the deposit. Samples were then embedded in acid resistant epoxy such that all un-natural surfaces of the core were covered by epoxy and the natural, mineralized, fracture surfaces were left exposed to the leach solution. The samples were placed in an approximately 9 foot long by 10 inch wide clear Perspex box with the un-coated mineralized fracture surfaces facing upwards, and the rest of the sample surrounded by epoxy, thereby restricting the leaching process to the fracture surfaces. A clear Perspex lid was placed on top of each box with minimal void space between the lid and the fracture surface. Mature raffinate, at 15 grams per liter acid concentration, was delivered at one end of the box, fully saturating the core, and moving across the fracture surface in a controlled manner, thereby producing copper-rich leach solution that was collected and sampled at the other end of the box.