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Additional Information
Applications
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Magnetic Method
The magnetic method is a very popular and inexpensive approach for near-surface metal detection. Engineering and environmental site characterization projects often begin with a magnetometer survey as a means of rapidly providing a layer of information on where utilities and other buried concerns are located. It is also very popular in the unexploded ordinance arena, as multiple sensors can be mounted on unmanned, remote-controlled vehicles. Several acres can be investigated in a single day by a single operator on foot or from a vehicle.
 The principal of operation is quite simple. When a ferrous material is placed within the earth's magnetic field, it develops an induced magnetic field. The induced field is superimposed on the earth's field at that location creating a magnetic anomaly. Detection depends on the amount of magnetic material present and its distance from the sensor. 55 gallon drums can be detected at burial depths of up to 20 feet. Two sensors are often used to record a gradient measurement to improve the capability of locating small, shallow objects and as a means of estimating depth of targets. The anomalies are typically presented on color contour maps.
Common uses of Magnetometers include:
- locating buried tanks and drums
- fault studies
- mineral exploration
- mapping unexploded ordinance (UXO)
- mapping buried utilities, pipelines
- buried foundations, fire pits for archeological studies
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