A new drill hole magnetometer: preliminary results from the Tennant Creek area

A drill hole magnetometer system has been developed primarily to help in the search for gold bearing magnetite bodies in the Tennant Creek area in the Northern Territory. The probe contains three fixed orthogonal fluxgate magnetometers with three corresponding orthogonal inclinometers. The inclinometers are used to remove the effects in the magnetometer’s data produced by probe rotation and drill hole inclination. Readings are then corrected for drill hole deviation and the background field is removed to produce anomalous vectors. A drill hole surveyed at the West Gibbet Prospect at Tennant Creek shows the potential of the instrument in locating and defining magnetic bodies. In addition, the magnetometer is an extremely sensitive drill hole survey tool and can be used to obtain an idea of the magnetic susceptibility of rock units intersected by the hole.