Metal detectors and
magnetometers are used to locate buried metallic objects
like underground storage tanks and piping. A Geonics EM-61 is a high-resolution
time-domain electromagnetic metal detector that detects both ferrous and
non-ferrous metallic objects. It can detect a 55 gallon drum buried 3 meters
deep. This unit has a focused one-meter footprint and is best used to define
targets at known sites or in areas with nearby cultural interference such as
fences, buildings, or power lines.
ECHOTECH has combined this precision instrument with a real-time
sub-decimeter differential global positioning system (GPS) and designed a
non-conductive deployment trailer which allows us to collect continuous
EM-61 data over large acreages very rapidly. Data can be collected with
this system along one-meter separated profiles at a rate of 2 acres per hour!
The EM61 Survey at the Mosby Jet Fuel Refinery located buried underground
distribution piping and associated containment vessels. Some of the
detected 3 inch pipe was buried 8 feet deep. Many of the metallic objects
were undetected prior to conducting this survey.