Detecting Tips - Minelab GPX-4000 Quick Start Manual

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Detecting Tips

Follow these hints and
techniques for better
•
detecting and happy
prospecting that will help
you to utilise the power of
your GPX-4000.
For Maximum Gold
Recovery
•
Keep the coil as close
to the ground as
possible.
Listen carefully.
This is more important
than looking.
Slow down, do not
rush, take your time.
Have a positive mind
set, and imagine a
nugget at every next •
sweep!
Remember that
covering a small
section of ground
thoroughly will be
more productive than
randomly searching a
larger area.
Identifying Target Signals
Metallic targets will usually give a 'solid' sounding
signal when the coil is swept across the object
from any direction. A metallic target generally
produces a short, sharp and mostly symmetrical
signal. Ground noises usually give a broad uneven
signal when the coil is swept from different
directions and often may only give a signal from
one direction and no signal on the return sweep.
If you are not sure if the sound is ground noise
or a target signal, you should investigate. Scrape
a shallow hole about 70 - 100mm (2½" - 4") deep
over the suspected target. Sweep the coil over
the hole at the original ground level. Do not dip
the coil into the hole. If the signal has decreased
in volume or is less defined, it is probably ground
noise. If the signal remains the same or becomes
louder, it is likely a metallic target. If you are still
not sure, make the hole deeper and repeat the
process.
A 'halo effect', which may be built up around a
buried metal object, makes the object appear to
be larger to the detector than it actually is. This
will be reduced once the target is disturbed from
its position in the ground (e.g. a small object,
detected at a substantial depth, may be more
difficult to detect once disturbed from the ground
and lying in the loose dirt. If the object is reburied,
the 'halo effect' will not be present).
•
Do not try to eliminate what might appear to be
Big Gold
a faint, isolated ground noise by balancing the
Big Gold gives a much
detector over the target because you may be
different response to
'balancing out' the target response from a deeply
the smaller shallower
buried metallic target. It is better to Ground
pieces. The signal is
Balance around the target without going across it,
often quite broad, and
then switch to Fixed and try Pinpointing.
there is very little pitch
•
Dig all target signals, even in previously detected
variance.
areas. The GPX-4000 has superior ground
balancing and depth so it is possible to find
False Signals
new targets in well-worked areas where other
detectors have been unable to cope with the high
If false signals are
degree of mineralisation and/or salt.
occurring as you sweep
the coil, check that they
•
In some goldfields, a response may be received
are not produced by
from a concentration of orange/reddish dyke
any metal that you are
material or clay. Remember, a metal target will get
carrying, such as your
louder by moving the coil even centimetres closer.
pick, battery or steel toe
boots.
•
If detecting areas of extremely variable
mineralisation, detect along the ground contours
Move the coil closer,
rather than across them. This will often stabilise
and then further away
the effect.
from your body, in
order to check if the
•
In heavily mineralised areas the operator may
signals are coming from
need to sweep the coil 10 – 20 mm ( ½" – 1")
these items. If they are,
above the ground. This should give a more stable
increase the distance
Threshold and less ground noise.
between the coil and
these items. •
Very sudden or large changes in the mineralisation
of an area may produce a signal from the detector.
Avoid carrying metallic
Usually this signal is very broad, and often only
objects in your pants
present in one direction.
pockets as these are too
close to the coil.
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