METHOD AND APPARATUS FOR DUAL LOCATION SONAR MEASUREMENT OF CAVERNS

摘要

This invention relates to methods and apparatus for surveying caverns. More particularly the invention relates to methods and apparatus for surveying an underground cavern penetrated by spaced-apart boreholes including positioning a sound-transmitting device into one borehole and a sound-receiving device in the second borehole, transmitting sequential sound pulses by the transmitting device, reflecting the sound pulses from the cavern wall, receiving the sound pulses at the receiving device, and measuring the elapsed time between the transmission and receipt of sound pulses.