Ground Balance Type; Ground Balance Procedure For Specific - Minelab GPX-4000 Quick Start Manual

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Ground Balance Type

(Ground Balance, pg. 38)
Range
Factory Preset
General
This is the best Ground Balance Type for use in over
90% of goldfield soils and uses the conventional
automatic Tracking on the previous Minelab model,
the GP3500. In Tracking, General Ground Balance
samples variations in the ground mineralisation and
sets a continuously changing average of the Ground
Balance level. General Ground Balance is ideal for
most mineralised grounds and is the preferred
Ground Balance Type for soils that have highly
variable mineralisation.
Specific
This is a special Ground Balance Type for use in
areas of highly magnetic, iron-rich soils. Use of
Specific Ground Balance will allow you to keep the
coil closer to the ground and allows Monoloop
coils to be accurately Ground Balanced in areas
that would normally be too 'hot' for their use. The
Tracking function in Specific is more conservative
than in General, and will pause on even the faintest
response, removing the risk of 'Tracking out' faint
signals.
The disadvantage of using Specific is the possibility
of more ground noise in variable soils. It is
recommended that the operator be more active in
checking their Ground Balance setting by stopping
periodically and raising and lowering their coil,
and listening to any variations. Ideally, Specific
Ground Balance should only be used in soils that are
reasonably uniform or non-variable.
Specific, General
General
Ground Balance Procedure
for Specific
When moving to a new area, the first Specific
Ground Balance must be done with the Ground
Balance switch – not the Quick-Track button.
1 Find a clear area of ground
without any targets.
2 Change Ground Balance to Fixed.
3 Hold the coil 300mm–450mm
(12"–18") above the ground.
4 Change the Ground Balance
switch to Tracking. You will hear a
high pitched Threshold that only
lasts 1 second.
2 3 4
Fixed
Tracking
5 When the low pitch tone begins,
immediately start lowering and raising
the coil over the ground. Try to lower
the coil parallel and as close to the
ground as possible without touching it.
6 Continue moving the coil up and down
until the audio has stabilised and any
ground noise has stopped. When there
is no longer a change in the Threshold,
the detector is 'Ground Balanced'.
7 Change the Ground Balance back to
Fixed and commence detecting.
5 7
Tracking
Time
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