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Remotely placed reinforced concrete columns for point support through boreholes.
Burnett-M; Burnett-JM; El-Korchi-T
Washington, DC: U.S. Department of the Interior, Bureau of Mines, AML 02-95, 1994 Nov; :1-55
The subject of this report is the development, fabrication and testing of a system to place a reinforced concrete column in abandoned mines through a bore hole. The report covers the design and development of a mechanical device to place very low slump cable reinforced concrete in an annular ring so as to build a cylindrical wall from floor to roof remotely through an 8-in diameter borehole. The diameter of the annulus is about 8-ft at the roof and 20-ft-diam at the floor in a 6-ft-high mine. Concrete point support columns were built at the Subsidence Abatement Investigation Laboratory (SAIL) and at the Mine Roof Simulator (MRS) at the U.S. Bureau of Mines. Testing at the MRS indicates that full scale concrete support columns can support in excess of 20,000,000 lbs. The testing demonstrated that cable reinforcement is possible but not cost effective. Additional concrete added to the support to increase the strength is less costly than the cable. A concrete support column was built in an abandoned mine in Preston County, West Virginia as a field demonstration.
Abandoned-shafts; Boreholes; Columns-supports; Mines-excavations; Mining-engineering; Reinforced-concrete; Reinforcement-structures; Reinforcing-materials; Remote-control; Simulation; Soil-subsidence; Structural-engineering; Measurement-equipment; Concretes
Final Contract Report
NTIS Accession No.
Washington, DC: U.S. Department of the Interior, Bureau of Mines, AML 02-95
DC; CO; WV
Burnett Associates, Inc., Glenwood Springs, CO