Oxidation of sulfide ore bodies; 1, Geochemical environments in terms of Eh and pH

In the first paper, field measurements in mining districts of the western United States, experimental observations, and theoretical considerations bearing on the mechanism of oxygen reduction are reported, leading to the formulation of an Eh-pH diagram indicating probable ranges of Eh and pH values of natural aqueous systems in the weathering environment and in the depth environment (the latter characterized by the absence of free oxygen). In the second paper, results of electrode potential measurements of copper, lead, iron, silver, and zinc sulfides in aqueous solutions are discussed and a procedure outlined for identifying first-step oxidation or reduction reactions of sulfide minerals.