48 Garrett Metal Detectors
AT Gold
™
49
•
Ground balance the
AT Gold
as often as necessary
as the
ground conditions are heard to change (excessive noise,
etc). Gold nuggets are generally found in areas of high iron
mineralization where the ground conditions can change
frequently.
•
Determining ground mineralization level:
It is important to
understand the soil conditions of your hunting environment.
To determine how mineralized the soil is, begin by ground
balancing the
AT Gold
. (refer to Ground Balance section for
how to ground balance.)
After ground balancing, gauge the concentration of ground
minerals by manually increasing or decreasing the ground
balance setting by 5 to 10 points and "pumping" the coil
to check the ground response. If the ground response is
minimal, then the area contains low ground mineralization. In
areas of high ground mineralization, an increase or decrease
of just 1 to 2 points on the ground balance setting will quickly
produce a significant ground response.
•
Tips for locating targets amongst hot rocks or terra
cotta:
Hot rocks are any rocks that contain enough iron
minerals to make the detector sound off. A hot rock is more
conductive that the surrounding soil (i.e. its ground balance
is lower than the surrounding soil) and it will therefore sound
like a good target. The mineralization levels of terra cotta can
often create a positive target response like hot rocks.
A cold rock, or negative hot rock, is less conductive and/
or more ferrous than the surrounding soil (i.e. its ground
balance is higher than the surrounding soil) and it will
ADVANCeD TIPS AND TeCHNIQueS
therefore produce a negative response. Depending upon
your threshold level, this negative response will produce a
central silent response preceeded and followed by positive
responses (i.e., sounds like a double response). Because
of this central negative response, cold rocks can mask the
presence of good targets.
There are methods to reduce the effects of hot rocks,
terra cotta or cold rocks based upon the level of ground
mineralization that is present.
In lightly mineralized ground, it is possible to ground
balance the
AT Gold
to the hot rocks or terra cotta since
ground balance is less critical in areas of light mineralization.
Be aware, however, that the combined Target ID might be very
low (e.g. a gold nugget and a hot rock together may register
between 10 and 15 on the Digital Target ID). Therefore, Iron
Discrimination levels must be reduced in order to ensure
detection of good targets covered by the hot rock.
In more highly mineralized ground, the operator must either
contend with the hot rocks or switch to a Discrimination Mode
and introduce a minimal amount of IrON DISC. Hot rocks
usually have a very low Digital Target ID (often less than 10),
so very low levels of IrON DISC should be used. Tiny gold
pieces may also have a very low Digital Target ID in highly
mineralized ground, so take caution in applying much IrON
DISC to avoid also eliminating the tiny gold.
•
Searching for meteorites:
With its high frequency, true All
Metal Mode, adjustable threshold, ground balance and its
sensitivity to low conductivity metals, the
AT Gold
is also a
very effective meteorite detector. The majority of meteorites
are found in deserts and other arid climates where they are
best preserved.
Since most meteorites include high concentrations of
