Search U.S. government technical reports digitized or harvested by TRAIL.
Progress report on investigation of detachable rock-drill bits
Progress report no. 2 on investigation of detachable rock-drill bits
Progress report 4 on investigation of detachable rock-drill bits
Progress report no. 3 on investigation of detachable rock-drill bits
Operations at the Haile Gold Mine, Kershaw, S.C.
Bureau of Mines exploration of mercury deposits to June 30, 1944
Diamond-drilling blast holes, eastern Magnetite Mine A
Diamond drilling blast holes, Balmat Mine, St. Lawrence County, N.Y.
Diamond-drilling blast holes, eastern magnetite "Mine B"
Shaft sinking by diamond drilling, Bellefonte mine, National Gypsum Co., Centre County, Pa.
A skull breaker in a limestone quarry
Diamond drilling blast holes, Bell Mine, the Warner Co., Centre County, Pa.
Diamond-drilling blast holes, Bellefonte Mine, National Gypsum Co., Centre County, Pa.