Document mqwz9q67Nomep42VE3NY4qYGg

3W.5" R. I. 3465 UNITED STATES DEPARTMENT OF THE INTERIOR Harold L. Ickes, Secretary BUREAU OF MINES John W. Finch, Director KENT STATE UNIVERSITY 1/ 3 1850 022 840 046 September 1939 REPORT OF INVESTIGATIONS METHODS OF ROCK-DUSTING AMERICAN COAL MINES KENT STATE U US.. DOCS. KENT, OHIO BY J. J. Forbes SCF-FA-0603 After this report has served your purpose and if you have no further need for it. please return it to THE BUREAU OF MINES. USING THE OFFICIAL MAILING LABEL ON THE INSIDE OF THE BACK COVER. /