Ultrasonic method for the exploration of the properties and structure of mineral layers

The method developed by the authors is based on the same principle as hydrolocation and ultrasonic flaw detection of metals using frequencies from 50 to 300 kc/s. The attenuation and velocity of wave as well as the location of the eventual inhomogeneities of the medium is determined on the basis of the size, shape and time of passing of the direct or reflected pulse. The experimental material, collected in the salt mines and quarries proves that the conditions of ultrasonic propagation in rocks are exceedingly more complicated and subject to changes, than in metals or water, but the range and accuracy of discernment is quite sufficient for practical aims. The measurements embrace the damping and velocity of ultrasonic waves in different rocky media. Various tests have also been carried out on detecting different types of inhomogeneities in layers of salt and rocks. General relations between parameters of ultrasonic propagation in those media and their structure, physico-chemical properties and types of discontuities are determined.