Abstract: A method and apparatus facilitating the event-synchronized recording of data at different locations, such as may occur at and within a borehole during a Measurement-While-Drilling (“MWD”) operations. In a seismic survey the method and apparatus uses three subsystems: 1) a seismic source; 2) a borehole receiver, and 3) a pinger. When used in a borehole containing a drill string, the pinger strikes or vibrates the drill string causing an acoustic signal to traverse the drill string. The signal reaches a borehole receiver where it is detected. The signal is also reflected back up the drill steering to a sensor, nominally an accelerometer sensor, associated with a pinger where it is time-stamped by inclusive timing circuitry.

Abstract: This system comprises means for standardizing the detected gamma spectrum and processing it by a reference spectrum. The lithology and/or the nature of the ores are determined, by a processing means, by comparison between the standard recorded spectrum and lithology and/or ore spectrum models contained in a library. The ore content, density and porosity can also be determined without supplementary measurements on the basis of the lithology and the nature of the ores.