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Accurate directional borehole drilling: a case study at Navajo Dam, New Mexico.

Kravits SJ; Sainato A; Finfinger GL

Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9102, 1987 Jan; :1-25

https://www.cdc.gov/niosh/mining/works/coversheet1440.html

10005752

This report describes a project conducted by the Bureau of Mines in which the accurate directional drilling of a borehole was demonstrated with the objective of intercepting a designated target. The project was conducted at Navajo Dam in northern New Mexico at the request of the Bureau of Reclamation. Borehole survey and drill logs are provided in an appendix. The trajectory of the demonstration borehole was designed to intercept a 5-ft-radius target at the final or "punchout" distance of 885 ft. The elevation of the borehole at this distance was within the target; the borehole punchout coordinates were 8.81 Ft southwest of the target. As a result of the demonstrated accuracy, the Bureau of Reclamation has contracted the accurate drilling of boreholes as long as 600 ft from the inside of a short tunnel, to control water seepage in the right abutment. This resulted in a substantial cost savings compared to the original plan of constructing a longer tunnel and drilling 150- ft boreholes.

Surface-mining; Surface-properties; Underground-mining; Mining-industry; Coal-mining; Room-and-pillar-mining; Tunneling; Construction

19870101

IH; Report of Investigations

1987

PB88-232152

A03

RI-9102

PRC

Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9102

NM; PA