MAGNETOMETER SURVEYS IN MINERAL EXPLORATION Magnetometer surveys have been used for many years as a reliable and well-established first step in mineral exploration, says Burns in a phone interview. A magnetometer is a passive sensor that measures variations in the Earth’s magnetic field. Depending on data quality, the recorded results can provide a picture of what lies beneath the surface. While we often hear terms like LiDAR, photogrammetry, and thermal imaging in connection with drone missions