DEPARTMENT OF THE INTERIOR FRANKLIN K. LANE, SECRETARY BUREAU OF MINES VAN. H. MANNING, DIRECTOR THE HISTORY AND DEVELOPMENT OF GOLD DREDGING IN MONTANA BY HENNEN JENNINGS WITH A CHAPTER ON PLACER-MINING METHODS AND OPERATING COSTS BY CHARLES JANIN (Papers read at the Second Pan American Scientific Con- 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 publícation to one person. The price of this publication is 30 cents. II First edition. July, 1916. CONTENTS. Gold dredging in Alder Gulch and Ruby district. Organization of Conrey Placer Mining Co.. Detailed descriptions of Conrey dredges. Steam dredges No. 1 and No. 2...... Page. Character of gold recovered... Comparative efficiency of different types of dredges. Data on cost of dredging in Montana............. Accounting methods used by Conrey Co. Operating report for electric dredges.. Object of detailed cost statements. |