EQUIPMENT FOR ULTRASONIC INVESTIGATION IN MINES

Equipment for ultrasonic investigations in mines is described. The tra nsmitter supplies an amplitude modulated sinewave power signal to the transducer. Special transducers using a piezoceramic ring were develop ed and these transducers are also described. The receiving system prod uces three analogue outputs - the level of the receiving signal, its p hase and the phase of the amplitude modulation. These outputs are led to the surface of the mine and conditionally collected by a computer. This method allows us to determine the damping coefficient of the rock , the velocity of the ultrasound and its changes. The results of the l ong-term investigation are compared with other measurements in the sam e location.