UNDERGROUND MINE TESTS OF REAM
Ream is a unique method of rock breaking using high energy projectile impact. This report describes the most recent in a series of tests demonstrating mining applications for the ream method. In an underground limestone mine at Greer, W. Va., ream was used to drive a short tunnel and drill a large diameter borehole. Along with breakage data from these tests, the goal of the program was to examine environmental problems which might result from the use of cannons underground. A total of 103 shots was used to advance a 14-1/2-feet high by 10-feet-wide face a distance of 5-1/2 feet. It is estimated that the 9.3-pound-concrete projectiles launched at 5,000 feet per second will break an average of 0.78 tons of limestone or 67 percent of the 1.125 tons of granodiorite broken in previous tests. The 9-inch-diameter borehole was drilled horizontally by repeated axial impact for 7 feet, 2-1/2 inches by 21 shots giving an average of 4.12 inches per shot. Scaling this result to compressible impact energy yields an estimated 5.8 inches per shot for a 12.8-inch diameter hole compared with 8 inches per shot for a 16-inch-diameter hole in granodiorite.
Physics International Company2700 Merced
San Leandro, CA USA 94577
Bureau of MinesC Street Between 18th and 19th Streets, NW
Washington, DC USA 20241
- Lundquist, R
- Publication Date: 1976-11
- Pagination: 46 p.
- TRT Terms: Boreholes; Drilling; Excavation; Excavation and tunneling; Feasibility analysis; Fracture mechanics; Guns; Mufflers; Rocks; Tunneling; Weapons
- Geographic Terms: West Virginia
- Old TRIS Terms: Excavation technology; Hypervelocity impact; Hypervelocity projectiles
- Subject Areas: Bridges and other structures; Geotechnology; Railroads; Security and Emergencies;
- Accession Number: 00166262
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: BuMines-OFR-91-77 Final Rpt.
- Contract Numbers: H0252011
- Files: TRIS
- Created Date: Sep 20 1977 12:00AM