Method for locating underground anomalies by diffraction of electromagnetic waves passing between spaced boreholes

Patent · Tue Jul 17 04:00:00 EDT 1979

OSTI ID:5378381

Lytle, R J; Lager, D L; Laine, E F; Davis, D T

Underground anomalies or discontinuities, such as holes, tunnels, and caverns, are located by lowering an electromagnetic signal transmitting antenna down one borehole and a receiving antenna down another, the ground to be surveyed for anomalies being situated between the boreholes. Electronic transmitting and receiving equipment associated with the antennas is activated and the antennas are lowered in unison at the same rate down their respective boreholes a plurality of times, each time with the receiving antenna at a different level with respect to the transmitting antenna. The transmitted electromagnetic waves diffract at each edge of an anomaly. This causes minimal signal reception at the receiving antenna. Triangulation of the straight lines between the antennas for the depths at which the signal minimums are detected precisely locates the anomaly. Alternatively, phase shifts of the transmitted waves may be detected to locate an anomaly, the phase shift being distinctive for the waves directed at the anomaly. 9 claims.

• Assignee: Dept. of Energy
• Patent Number(s): US 4161687
• OSTI ID: 5378381
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420206* -- Engineering-- Mining & Drilling Equipment & Facilities-- (1980-1989)
BOREHOLES
CAVITIES
DETECTION
DRILLING EQUIPMENT
DRILLS
ELECTRICAL SURVEYS
ELECTROMAGNETIC SURVEYS
ELECTRONIC EQUIPMENT
EQUIPMENT
GEOPHYSICAL SURVEYS
OPERATION
SUBTERRENE PENETRATORS
SURVEYS
TUNNELS