Abstract: A mobile geophysical instrument produces geophysical data sets each associated with a position computed by use of a position sensor. A variable time delay results between a time when data for each geophysical data set is collected and a time when a position associated with each geophysical data set is recorded. A module receives distance transducer data and includes circuitry configured to generate a module signal based on trigger signals from the distance transducer and a calibration value. A data acquisition system (DAS) receives geophysical data sets from the geophysical instrument, positioning data from the positioning sensor, and the module signals. The DAS generates a DAS timestamp in response to each module signal and associates the DAS timestamp with each geophysical data set and a position associated with the geophysical data set, so as to substantially eliminate the variable time delay.

Abstract: The mass of stockpiled materials is determined from detailed measurements of the elevation of the pile surface at many points and the measurement of the gravitational field along several profile lines across the surface of the stockpiled material. The elevation measurements allow the calculation of the pile volume. Measured gravity values are adjusted using standard gravity corrections in such a manner as to imply all gravity data are collected along the same reference datum. Variations in the corrected gravity values are assumed to be caused solely by the pile material. The gravity measurements are interpreted using analytical and statistical methods to determine the volume-average bulk density value of the pile material. The pile volume is multiplied by the volume-average bulk density to obtain the weight of the stockpiled material.