Detecting Tips - Minelab GPX-4500 Instruction Manual

Detecting Tips

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Follow these hints and techniques to help you to
For Maximum Gold
utilise the power of your GPX-4500, to ensure that
Recovery
every trip is a success.
Keep the coil as
Identifying Target Signals
close to the ground
•
as possible.
Metallic targets will usually give a 'solid' sounding
signal when the coil is swept across the object from
Listen carefully.
any direction. A metallic target generally produces a
This is more important
short, sharp and mostly symmetrical signal. Ground
than looking.
noises usually give a broad uneven signal when the
Slow down, do not
coil is swept from different directions and often may
rush, take your time.
only give a signal from one direction and no signal
on the return sweep.
Have a positive
mind set and imagine
•
If you are not sure if the sound is ground noise or a
a nugget at every
target signal you should always investigate. Scrape
next sweep!
a shallow hole about 30mm (1") deep over the
Remember that
suspected target. Sweep the coil over the hole at
covering a small
the original ground level. Do not dip the coil into
section of ground
the hole. If the signal has decreased in volume or is
thoroughly will be
less defined it is probably ground noise. If the signal
more productive than
remains the same, or becomes louder, it is likely a
randomly searching a
metallic target. If you are still not sure make the hole
larger area.
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 re-buried 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 at depth
detector over the target; you may be 'balancing out'
gives a much different
the target response from a deeply buried metallic
response to the smaller
target. It is better to Ground Balance around the
shallower pieces. The
target, without going across it, then switch to Fixed
signal is often quite
and try Pinpointing.
broad, and there is very
•
Dig all target signals, even in previously detected
little pitch variance.
areas. The GPX-4500 has superior ground balancing
and depth so it is possible to find new targets in
False Signals
well-worked areas where other detectors have
been unable to cope with the high degree of
If false signals are
mineralisation and/or salt.
occurring as you sweep
the coil, check that they
•
In some goldfields a response may be received from
are not produced by
a concentration of orange/reddish dyke material or
any metal that you are
clay. Remember, a metal target will get louder by
carrying, such as your
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 need
signals are coming from
to sweep the coil 10–20 mm ( ½"–1") above the
these items. If they are,
ground. This should give a more stable Threshold
increase the distance
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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