(USGPO: Washington, DC), 1936. Paperback. Very Good. Item #21-1945
9 x 5.5", recent plain tan wraps, 169pp. Ink name of the author printed on the front cover else very good condition. Some of the contents: milling of copper sulphide ores, present method of concentrating copper ores, microscopic analysis, dewatering of concentrates and tailings. Very SCARCE.