RT Web Page DB /z-wcorg/ DS http://worldcat.org ID 681260358 LA English UL http://catalog.hathitrust.org/api/volumes/oclc/29117505.html T1 Cost keeping for small metal mines A1 Pickering, J. C., PB Dept. of the Interior, Bureau of Mines : Supt. of Docs. [distributor PP Washington YR 1919