Core and Reaming Bit Studies in Yucca Mountain Tuffs

by Richard E. Gertsch, Colorado Sch of Mines, Golden, United States,
Jim F. McCormick, Colorado Sch of Mines, Golden, United States,
Eddie L. Wright, Colorado Sch of Mines, Golden, United States,

Document Type: Proceeding Paper

Part of: High Level Radioactive Waste Management 1993


The Site Characterization Project is a major part of the work in determining the suitability of Yucca Mountain as a potential high level waste repository. Over 100 exploratory drill holes for the Project will be drilled dry in order to limit contamination of the in-situ rock formations. Dry drilling is not a common practice and drill bits suitable for the application need to be developed. To increase penetration rate and bit life, the Department of Energy (DOE) instituted an extensive drilling program at the Colorado School of Mines (CSM) to test and evaluate full sized core and reaming bits. Current test results of the on-going program show that drill bits with aggressive profiles perform best. Stratapac core bits outperform small diamond bits. The gage areas need improvement. Core bits fail first at the outer gage, while the rest of the bit remains relatively intact. Alternating cone reamer designs perform better than designs with all cones facing inward, because they drill the inner gage core hole more effectively.

Subject Headings: Drilling | Radioactive wastes | Waste storage | Penetration tests | Waste disposal | Rocks | Site investigation

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