Copperwood Deposit "The Copperwood project refers to a stratiform copper deposit in shales and siltstones of the lowermost Nonesuch Formation along a shallow-dipping southern limb of the westward-plunging Western Syncline in the Upper Peninsula.Within the deposit the company says copper occurs as very fine-grained chalcocite."Fully-diluted proven and probable reserves are 22.6 million tonnes of 1.37 percent copper and 4.2 grams per tonne silver and 4.6 million tonnes of 1.11 percent copper and 2.8 grams per tonne silver, respectively (total of 798 million pounds of contained copper and 3.5 million ounces of contained silver)," the company's release states. "The ore body contains little pyrite, the iron sulfide that most commonly becomes acidic." Williams says.Baja has a similiar soft rock deposit consisting of 1.33 percent copper in 7 horizontal clay beds that are currently being mined with continous mining machines and the ore will be stock piled pending completion of the plant currently under construction. Baja has Co, Zn, and possibly moly credits in their deposit while Copperwood has silver credits.You can see pictures of Baja's continous mining machines and also a video animation of a continous mining operation. Calcocite is a sulphide of copper as "Bobvee" correctly points out. This is an advantage as recovery rated are very high on this using standard grinding and flotation.