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Title: Feasibility study of an earth melting penetrator system for geoprospecting tunnel right-of-ways
Authors: Westinghouse Electric Corporation. Advanced Energy Systems Division.
Soils and Pavements Laboratory (U.S.)
Black, D. L.
Keywords: Drilling
Soil penetration
Earth melting penetrators
Subsurface exploration
Feasibility studies
Right of way
Geophysical exploration
Geophysical surveys
Rock melting penetrators
Underground openings
Publisher: Geotechnical Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Description: Technical Report
Abstract: The Earth Melting Penetrator (EMP) is a concept utilizing high-temperature penetrator tips at the leading end of a length of nonrotating stem to melt earth materials in its path and leave an open hole for geologic exploration purposes. The early proof-of-concept testing was performed by the Los Alamos Scientific Laboratory. Westinghouse Corporation Advanced Energy Systems Division developed a conceptual design and cost estimate for a technically feasible EMP system (including heater, core handling, power transmission, and power generation subsystems) capable of penetrating a 3-mile long right-of-way path through rock and soil and recovering a 3-in.-diam core from that hole. The heater tip is an annular extended surface tungsten body heated to 2300°C by pyrographite resistance elements. A special annular configuration downhole electrical transformer was designed to convert 1.25 mw of electric power from high voltage-low current transmission mode to low voltage-high current heater mode. A special power generation and control system using paralleling and load sharing between three 680 Hz, 900 kw diesel-powered generators was designed. Tip-steering techniques were established. Several tip-location (guidance) schemes were examined, and it was found that an inertial system would be best but was outside the current state of the art and that a combination electrolitic level-compass scheme would be marginally adequate but technically feasible. Furthermore, providing sufficient (6300 SCFM) air at the tip to preserve components and cool the core would require more power than the electrical system. It would be simple to provide sufficient water (14 gpm), but its proximity to high-level electrical circuits necessitates special design considerations. A downhole propulsion system is described. The EMP system is technically feasible at a total system projected cost of $4,000,000.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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