11 F1A4 Operator Instructor Notes and Syllabus
Minelab Countermine Division
Safety through Excellence
Twenty six
Twenty
seven
If the ground is mineralized, the ground will also provide a response after each pulse
that will also decay over time. In conventional detectors, the interference from the
ground cannot be removed unless the sensitivity of the detector is decreased.
Twenty eight
Demonstration of Ground Balance.
The best method is to use a “mineralized rock” to demonstrate the false alarm as
follows (Note: a mineralized rock that the detector has not been balanced to is
required):
•
Without the mineralized rock, use the Test Piece (or some minimum metal mine
fuse/firing pin) to demonstrate the soft response from the detector.
•
Holding the metal target under the mineralized rock, pass both under the Coil.
The response from the mineralized rock should mask the target (this will not
happen if the target is a large piece of metal as the response to that will be
louder).
•
Remove the target and pass only the mineralized rock under the Coil to show
that the response remains the same as before.
•
Carry out the ground balancing procedure (do not go into detail as this is
explained in Lesson 4) – note the response from the mineralized rock
disappears.
•
Pass the mineralized rock under the Coil to show there is now no response.
•
Place the target under the mineralized rock and pass it under the Coil – only a
response from the target will be audible.
Note: If this demonstration is conducted inside a classroom, electrical interference from
lights, air conditioners etc may cause a warbling noise from the detector. If this
happens complete the Noise Cancel procedure to reduce/eliminate the interference. If
this does not work, the demonstration may have to be conducted outside in a location
away from electrical power sources.
Twenty nine
QUESTIONS
Students shall be able to explain the principles of metal detection and MPS technology.
