20 F1A4 Operator Instructor Notes and Syllabus
Minelab Countermine Division
Safety through Excellence
at picking the exact centre of your target. If you have an odd shaped target it may have two
centres or be a pipe. You should still be able to pick the centre of the mass.
•
Two targets resolution.
Your aim here is to show how to map two targets laid within close
proximity to each other showing the actual shape on the ground of the dual targets. Use the
pinpointing procedure mentioned above.
•
Similar looking targets but opposite tones.
Use two coins that look similar but react differently
to each other. This is to demonstrate how the tones can provide some information about target
conductivity. For example the coins, although they look the same, are different in composition. In
Rwanda they use this feature to identify specific mines. A VS50 sounds much different than a
Type 72. Again it is not fool proof, but when combined with local experience it is a useful capability
for the operator.
•
Large Target.
When you have a large metal target such as a metal anti-tank mine the extreme
edge of detection will appear to be very large and in fact it is a long way from the outer edge of the
target let alone the centre of it. To help you find the centre of large targets you can use the
following technique. Hold the detector by the handle at 90° to the ground and at chest height.
Lower the Coil towards the ground directly above the area you believe to be the centre of the
target. Slowly reduce the height of the Coil towards the ground until you hear the first sign of a
response in the Earset. After receiving this initial response you can then move the Coil around this
general area, keeping it at the same height, to ascertain the centre by listening for slight
fluctuations in the pitch of the tone. From these changes in pitch you will quickly ascertain where
you believe the centre of the target mass is.
•
Water.
Dig a hole and fill it with water (or use a plastic bucket without a metal handle) and show
the F1A4 is not affected by operating in a wet environment. Place a target in the bottom of the
hole or under the bucket and show your students that there is no loss of sensitivity.
•
Soil sifting.
The Monoloop Coil offers an excellent benefit when searching an area for a target,
which you anticipate to be fragmentation. Rest the Coil on a known clean piece of ground close to
the area to be excavated. As you remove soil from the area place that soil onto the Coil and wait
for a response. If no response occurs, brush the soil off and do it again with another sample.
When presenting this instruction make sure you have put a small piece of metal in the area to be
excavated. Initially, show the students the detector alarming on a target in the ground then
proceed to find it using this process.
Piece of wire.
Have available a piece of wire that can show the students the conductivity of a
target. The wire needs to be about 60cm long and quite thin. Firstly ask the class if they believe
that a metal piece of wire will make the detector alarm, some will say yes. Holding the wire out
straight, pass it over the Coil. It will not make a sound. Join the wire together into a figure of eight
and pass it across the Coil again. It will now alarm with a moderate volume level. Unwind it from
the figure of eight and turn it into one circle and pass that across the Coil. This will provide you
with the strongest response. Now turn the circular piece of wire at 90 degrees to the Coil and note
that the response is weaker. This demonstration shows that a given mass of metal will have
differing levels of detection depending on its shape. Damaged or corroded mines may detect
differently depending on the extent of damage or corrosion, or the way they lie in the ground.
