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Chapter 4 MXT Display
Prospecting MODE
The Prospecting MODE changes the display infor-
mation significantly.
Gold in it's natural state can be any size and shape
from very tiny pinhead size flakes to large placer
gold nuggets as well as veins of various size in
quartz rocks. The Prospecting MODE takes these
facts into consideration and changes the display
accordingly. When prospecting an operator must
expect to dig nonferrous (not of iron) trash metals
such as aluminum foil, lead, and small brass. Any
of these metals can and do elicit the same response
as gold and MUST BE DUG. Attempts should be
made to avoid only IRON targets and only when
possible. The MXT displays information which is
intended to help the user determine whether the
target is NON-IRON (dig) or IRON (don't dig). In
heavy mineralized ground tiny pieces of gold can
sometimes look like IRON to a metal detector and
small pieces of IRON can look like gold. The VDI
numbers and Iron Probability scale both provide
help in determining when to dig.
The Prospecting MODE provides four significant
display indications.
1. VDI - The VDI number is listed on the display
and referenced on the label below the display. Gold
can indicate anywhere from slightly negative to +80
on the scale, however, most small nuggets indicate
in the -20 to +40 range. Metals that indicate above
+80, or below -20 are highly unlikely to be gold
unless they are conglomerated with highly unusual
alloys. If the VDI number tends to jump back and
forth from small negative numbers to small positive
numbers it is usually a small piece of some metal
and should be investigated by digging. Remember,
small flakes of gold in bad ground can read into the
small negative range. A magnet on your digging
pick can sort out a small shard of iron quickly.
2. IRON TARGET? - Indicates the likelihood the
target is ferrous (iron) expressed in a %. This
indication can be different in different areas de-
pending upon the degree of mineralization. As a
general rule targets registering 60%, 70%, 80%,
90% are going to be iron. 80% and over will
produce the audio grunt in the primary (Trigger
Center) mode. Targets that register 10%, 20%, 30%
or 40% are going to be gold or (lead, copper, alumi-
num, brass). All targets registering 50% or below
should be investigated.
As mentioned under the VDI section, iron ground
mineralization can distort the way the detector
reacts to gold. It is always a good idea to place a
test nugget just under the surface of the ground
whereever you are going to be prospecting and note
how it reacts to the IRON TARGET %. This will
give you a gauge as to what to expect. The degree
of dependability is affected by ground minerals and
the size of the target. It is not uncommon for a
small piece of gold in very bad ground to read 70%
probability of being iron. Remember when in
doubt...DIG. Use both the VDI and % IRON
PROBABILITY. Dig often at first, till you get a feel
for the area and accuracy in that ground.
NOTE: The display reading above would indicate a
target with a proper VDI number for gold and a low
enough iron target percentage to dig.
Mode toggle
switch Down for
Prospecting