Paper No. 10
Presentation Time: 10:45 AM
THE COPPERWOOD PROJECT: THE NEXT NEW COPPER MINE IN MICHIGAN
Orvana Resources US Corp’s Copperwood deposit is located in Gogebic County, Upper Peninsula, Michigan. This sedimentary stratiform copper deposit is hosted by rocks of the Mesoproterozoic (1.1 to 1.0 Ga) Midcontinent Rift. Reported Canadian National Instrument compliant Proven and Probable Reserves, fully diluted, are 27.2 million metric tonnes averaging 1.33 % Cu and 3.9 ppm Ag for contained metal of 798 million lbs of Cu and 3.4 million oz of Ag. The host rocks are black to light-gray shales and siltstones of the basal Nonesuch Formation; mineralization consists of chalcocite as 5 to 50 micron disseminated grains and as concentrations along bedding planes. The tabular, copper-bearing sequence lacks significant basal undulations, averages 2.5 meters thick and dips from 8 o to 12o northward on the southwestern limb of the Western Syncline. Only one minor low-angle reverse fault has disturbed the section. The deposit is overlain by laminated siltstones (Nonesuch Formation) and underlain by red-bed sandstones, conglomerates, and minor siltstones (Copper Harbor Formation). Based on evidence from nearly 200 drill holes, chalcocite at Copperwood replaced syngenetic pyrite during diagenesis and incipient lithification of the host sediments as a result of upward-moving, copper-bearing basinal waters that emanated from the underlying red-bed paleoaquifer. The mineralized zone at Copperwood is stratigraphically equivalent to that at the White Pine Mine (~ 4.5 billion lbs Cu and 50 million oz of Ag mined 1953-1996), but Copperwood lacks the structural complexity and the hydrothermal overprint manifested by the native copper mineralization characteristic at White Pine. In fact, the lack of a hydrothermal overprint distinguishes Copperwood from most other examples of reduced-facies, sediment-hosted copper deposits (Kupferschiefer type). Copper mining in the Upper Peninsula of Michigan has been dormant since 1996, but Copperwood is poised to become the next new copper mine in Michigan.