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Title: Drilling and coring methods that minimize the disturbance of cuttings, core, and rock formation in the unsaturated zone, Yucca Mountain, Nevada

Drilling and coring methods that minimize the disturbance of cuttings, core, and rock formation in the unsaturated zone, Yucca Mountain, Nevada A drilling-and-casing method (Odex 115 system) utilizing air as a drilling fluid was used successfully to drill through various rock types within the unsaturated zone at Yucca Mountain, Nevada. This paper describes this method and the equipment used to rapidly penetrate bouldery alluvial-colluvial deposits, poorly consolidated bedded and nonwelded tuff, and fractured, densely welded tuff to depths of about 130 meters. A comparison of water-content and water-potential data from drill cuttings with similar measurements on rock cores indicates that drill cuttings were only slightly disturbed for several of the rock types penetrated. Coring, sampling, and handling methods were devised to obtain minimally disturbed drive core from bouldery alluvial-colluvial deposits. Bulk-density values obtained from bulk samples dug from nearby trenches were compared to bulk-density values obtained from drive core to determine the effects of drive coring on the porosity of the core. Rotary coring methods utilizing a triple-tube core barrel and air as the drilling fluid were used to obtain core from welded and nonwelded tuff. Results indicate that the disturbance of the water content of the core was minimal. Water-content distributions in alluvium-colluvium were determined before drilling occurred by drive-core methods. After drilling, water-content distributions were determined by nuclear-logging methods. more » A comparison of the water-content distributions made before and after drilling indicates that Odex 115 drilling minimally disturbs the water content of the formation rock. 10 refs., 12 figs., 4 tabs. « less
Authors: ; ;
Publication Date:
OSTI Identifier:OSTI ID: 59845
Report Number(s):CONF-8511172--3
ON: DE86008851
DOE Contract Number:AI08-78ET44802
Resource Type:Technical Report
Resource Relation:Conference: Conference on characterization and monitoring of the vadose zone, Denver, CO (United States), 19-21 Nov 1985; Other Information: PBD: 1985
Research Org:Geological Survey, Mercury, NV (United States); Fenix and Scisson, Inc., Mercury, NV (United States); Reynolds Electrical and Engineering Co., Inc., Mercury, NV (United States)
Country of Publication:United States
Language:English
Subject: 58 GEOSCIENCES; 05 NUCLEAR FUELS; YUCCA MOUNTAIN; BULK DENSITY; MOISTURE; POROSITY; TUFF; BOREHOLES; NEUTRON LOGGING; ALLUVIAL DEPOSITS; DRILL CORES; ROCK DRILLING; HIGH-LEVEL RADIOACTIVE WASTES; RADIOACTIVE WASTE DISPOSAL; UNDERGROUND DISPOSAL; MOISTURE GAGES; AIR; DRILLING EQUIPMENT; DRILLING FLUIDS; PSYCHROMETRY; EXPERIMENTAL DATA; Yucca Mountain Project