Applications:

• detecting magnetic ores or deposits
• bedrock features
• mineral exploration
• archaeology

Examples:

• geologic mapping
• location of buried tanks and drums
• hydrogeology
• engineering

Magnetic intensity measurements are taken along survey traverses (normally on a regular grid) and are used to identify metallic mineralization that is related to magnetic materials (normally magnetite and/or pyrrhotite). Magnetic data are also used as a mapping tool to distinguish rock types, identify faults, bedding, structure and alteration zones. Line and station intervals are usually determined by the size and depth of the exploration targets.

The magnetic field has both an amplitude and a direction and instrumentation is available to measure both components. The most common technique used in mineral exploration is to measure just the amplitude component using a proton precession magnetometer. The instrument digitally records the survey line, station, total magnetic field and time of day at each station. This information is typically downloaded to a computer at the end of each day for archiving and further processing.

The earth's magnetic field is continually changing (diurnal variations) and field measurements must be adjusted for these variations. The most accurate technique is to establish a stationary base station magnetometer that continually monitors and records the magnetic field for the duration of the survey. The base station and field magnetometers are synchronized on the basis of time and computer software is used to correct the field data for the diurnal variations.

Technical Papers (PDF)

• Time Domain EM and Magnetic Mapping of the Ferguson Lake Nickel-Copper-Cobalt-PGE Property

References

• Mining in Manitoba

Similar Service: Gravity Surveys

Click here to learn more about data processing for Magnetic Surveys.