Some Results of Acoustic Reflection Testing in Russian Potash Mines

Abstract

For several years, acoustic sounding has been used in the potash mines of the Upper Kama potash mining district to solve mining problems. Salt rock has a relatively low attenuation rate of elastic waves, thus making it possible to use high frequency acoustic signals for probing salt rock masses of substantial thickness. A custom-made, PC based acoustic aquisition system is used to generate a radio-impulse shaped signal and record the envelope at [Formula: see text] digitization rate. The operating frequencies are 10 or [Formula: see text]. Piezo-ceramic transducers are attached to the roof of the mine with specially designed poles. The acoustic reflection data are collected mainly by using zero-offset profiling and an expanding spread mode. The records are complicated with noise, so computer processing with correlation filtering must be used to remove the noise patterns. The acoustic reflection data obtained show a good level of agreement with synthetic seismograms calculated from the stratigraphy found in nearby boreholes (with depths ranging up to [Formula: see text]). The high-frequency acoustic reflection method has proven to be capable of mapping stratigraphic features of flat bedded and folded salt rock, and to locate zones of disturbed rock around mine openings.