White’s Electronics MXT 300 - Manual (Page 12)

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Chapter 4 MXT 300 Display
Prospecting MODE
The Prospecting MODE changes the display infor-
mation signifi cantly.
Gold in it's natural state can be any size and shape
from very tiny pinhead size fl akes 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 300 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 signifi cant
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 fl akes 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 indi-
cation can be different in different areas depending
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, aluminum, 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 re-
acts to gold. It is always a good idea to place a test
nugget just under the surface of the ground where-
ever 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 de-
pendability 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% prob-
ability of being iron. Remember when in doubt...
DIG. Use both the VDI and % IRON PROBABIL-
ITY. Dig often at fi rst, 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