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, Government Printing Office, 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. First edition. July, 1918. Screen analyses of materials containing lead carbonate-Continued. Roasting and leaching of argentiferous oxidized ores of lead........ Tests of material from mine in Tintic district. Tests of material from mine in Park City district.. Tests of material from tailings dump.... Conclusions from results of tests.... Use of oxidized agents............... Additions of sulphur or sulphur compounds. Conditions essential for good roasting...... Materials to which process may be applied.. Sulphidizing with dry hydrogen sulphide.. Former attempts to use hydrogen sulphide.. Results of tests and discussion of results.... Summary of conclusions from results of dry sulphidizing Sodium sulphide for sulphidizing.. |