DEPARTMENT OF THE INTERIOR FRANKLIN K. LANE, SECRETARY BUREAU OF MINES RECOVERY OF ZINC FROM The Bureau of Mines, in carrying out one of the provisions of its organic act-to disseminate information concerning investigations made-prints a limited free edition of each of its publications. When this edition is exhausted, copies may be obtained at cost price only through the Superintendent of Documents, Government Printing Office, Washington, D. C. The Superintendent of Documents is not an official of the Bureau of Mines. His is an entirely separate office and he should be addressed: SUPERINTENDENT OF DOCUMENTS, Washington, D. C. The general law under which publications are distributed prohibits the giving of more than one copy of a publication to one person. The price of this publication is 20 cents. 2 First edition. March, 1919. CONTENTS. Page. Zinc ores and concentrates suited to retort smelting. Zinc losses in mining and milling... Zinc recovery by different concentration processes. Loss of zinc in lead smelting.... Scope of investigations at Salt Lake City station... Mechanical concentration of zinc sulphide ores.. History of early mining in Park City. Daly-Judge milling practice... Slime treatment at the Daly-Judge... Silver King Coalition milling practice... Mills on tailing flats below Park City. Big Four Exploration Co. mill. Flotation of zinc sulphide ores. Magnetic roasting and separation...... Experiments at Salt Lake City station.... Description of roaster and magnetic separator. Zinc-iron middling from Utah-Apex mine, Bingham, Utah.... Ores from the Consolidated Nevada-Utah and the Green- wood mines, Pioche, Nev ...... Zinc-iron middling from Broadwater mill, near ParkCity, Utah. Ore from Carlyle mine, Steeplerock, N. Mex.. 47 49 49 51 53 |