Acoustic Cross-borehole Apparatus for Determining in Situ Elastic Properties and Structural Integrity of Rock Masses.
19th U S Rock Mech Symp Stateline Nev 5/1-3/78 Mackay Schl of Mines Reno Pp 121-129 :121-129
Mining exploration, development, and design require in situ testing instrumentation to measure geotechnical properties on a scale that takes into consideration heterogeneities in the rock mass. An acoustic device that propagates high-frequency stress waves between boreholes in rock separated by distances from a few to tens of meters was designed, developed, and performance-tested for applications in mining that require assessment of elastic properties and integrity of rock masses. Components of the system include a unique, portable pulser; inflatable, piezoelectric, borehole transmitter, and receiver probes; a downhole amplifier; and signal monitoring and measurement components. The probes are designed to operate in either dry or wet, nominally nx-size boreholes. Results are given for performance tests in a large granite block; in concrete; in deep, verticle boreholes in copper conglomerate at an open pit mine; and in shallow inclined boreholes in a copper porphyry at an underground mine. Several applications of the apparatus in mining research are given.
19th U.S. Rock Mech. Symp., Stateline, Nevada, 5/1-3/78, Mackay Schl. of Mines, Reno, Pp 121-129