Composite map of 600 acre magnetic survey showing ferrous geology (red bands) relative to background magnetic field shown in blue.
Scott conducts a magnetic survey in the rugged terrain of the Limestone Hills, near Townsend, MT to locate UXO.
Rob and Cy looking for high iron-content strata in the Limestone Hills near Townsend, MT.
Big James Grimes braving a cold day with the magnetometer near Townsend, MT
UXO Detection and Characterization
Both magnetic and electromagnetic methods are used to detect Un-Exploded Ordinance. Each are suited to particular geologic and cultural situations which must be considered.
A survey of the magnetic total field in a given area will reveal a dipole for a magnetic object. This is very useful for UXO detection considering UXO anomalies have predictable dipoles. However, if the soil is magnetic, dipoles can be partially or completely obscured.
In magnetic soils an electromagnetic survey of the area is ideal. During an EM survey, an an electric current is used to charge the earth. This creates a temporary magnetic field which can be measured after the current is discontinued. The strength of this decaying magnetic field can be measured to interpret metallic objects from the surrounding soil. More specifically, this method is known as Time Domain Electro-magnetics.
The EM-61 used to conduct a time-domain electromagnetic pipeline survey.
Magnetic field crew led by Mason Porter (M.S. Geophysics, Montana Tech) conducts a UXO survey in the North Helena Valley.
Kim collects magnetic data in the Limestone Hills
3D rendering of magnetic data of a 25m x 25m area, the large spike at the right indicates a strong dipole and a likely UXO target.