Abstract: A borehole deviation monitor comprises a probe body adapted to be lowered in a borehole and including two inclinometers mounted in an orthogonal configuration to provide simultaneous X and Y axis inclination signals indicating the dip angle of the borehole with respect to the vertical and two triaxial magnetometers to provide reference signals indicating the azimuth angle of the borehole. The magnetometers are separated by a predetermined distance along the axis of the probe. A cable takeup winch mechanism is provided to lower the probe body into the borehole by predetermined increments equal to the distance between the two magnetometers. A control and data storage station is connected to the two inclinometers and magnetometers for reading and storing the data collected at each incremental distance and for correcting the azimuth reading given by the top magnetometer by substracting any difference in readings between the two magnetometers at the previous position of the probe.

Abstract: An accelerometer for blast monitoring comprises at least one piezoelectric transducer having a piezoelectric membrane attached along the edge thereof to the sidewall of a suitable container and mounted for free movement in such container for generating a high impedance electrical output signal upon deformation of the piezoelectric membrance by vibration during a blast, a high to low impedance converter connected to the piezoelectric membrane for converting the high output impedance of the piezoelectric membrane into a low impedance signal for transmission through long cables to recording equipment, and means for encapsulating the piezoelectric transducer and converter into epoxy or other solid material to minimize response of the transducer to surrounding acoustic signals.