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Field Testing
Minelab’s GP3000
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CHRIS GHOLSON |
In 1892, a young and hopeful
Albert Gaston set off across the vast Western Australian desert
in search of gold. News spread like wildfire about a fabulous
gold strike near the present day town of Coolgardie; destined to
become one of Australia’s richest deposits. Spurred on by the
new discovery, Gaston with only a few shillings in his pocket
loaded his meager belongings into a makeshift wheelbarrow and
walked the two hundred miles separating York and Coolgardie. It
was a gruelingly long journey, water was extremely scarce and on
several occasions he nearly perished. In his autobiography
Coolgardie Gold (a personal favorite), he reminisced
of the first sight to greet his eyes in this new gold-rush town.
It was a verse he saw carved into the trunk of a tree, which
read:
Damn Coolgardie! Damn the
track!
Damn it there and damn it back!
Damn the country! Damn the
weather!
Damn the goldfields all
together!
Not exactly words of encouragement
for someone that had just walked 200 miles! I am certain that
had the disgruntled fellow who scratched these words been
swinging Minelab’s newest and finest gold machine, the GP3000,
his poem would have read much differently!
New Features of the GP3000:
Although nearly identical in
appearance, the GP3000 has several new features not found on the
GP Extreme. These include: Low-Noise circuitry, new battery
harness, Smart Point diagnostic port, longer lasting 12A/Hr Gel
Cell battery, and a heavier bungee cord. The new Low-Noise
circuitry is a valuable addition because it results in a
smoother more stable threshold, enhancing the operator’s ability
to hear faint signals caused by small and deep targets.
The new Smart Point is a diagnostic test port to help Minelab
technicians troubleshoot problems quicker and efficiently should
your 3000 ever need service. Like its predecessor, the 3000 also
boasts Dual Voltage Technology (DVT). DVT refers to changes in
the voltage used to create the electro-magnetic field
transmitted from the coil into the ground. Minelab engineers
discovered that by using two different voltages the possibility
of magnetic saturation of the ground was lessened. Thus,
detectors using DVT have an increased ability to balance out
ground mineralization proving increased depth and greater
sensitivity compared to other detectors.
The 3000 is a fairly complex metal
detector and it would be difficult for me to cover each and
every control within the confines of this rather short article,
so I have decided to only go over those which I feel are of the
utmost importance.
The first is the Level Adjust.
This knob is an important but often misunderstood control on the
3000. It influences the level of discrimination by adjusting the
amount of sensitivity to ferrous targets. The Level Adjust also
affects auto ground tracking even when the discriminator is
turned off. When fully clockwise there is less likelihood of
balancing out a faint deep target. This happens because the
ground tracking needs to be paused when hunting using the
discriminator. It has been my findings, as well as my colleagues
in Australia, that this knob plays a crucial role in locating
deep or faint targets. When turned fully anticlockwise, a weak
target is enough to pause (or stop) ground tracking. This is
very useful when chasing large nuggets at depth. When turned
fully clockwise, the 3000 requires a much stronger signal to
pause ground tracking. This means that a very faint target may
be balanced out in Tracking before the operator even hears it. I
strongly suggest running this knob between 11 and 12 o’clock
when the Balance switch is set in the Tracking position. The
Level Adjust will not affect the machine when placed in the
Fixed position.
Discrimination: The 3000
has a fairly good discriminator; perhaps one of the better
Minelab have made. There are two wires inside the cable of a DD
coil. One sends information from the control box to the coil
then into the ground (Transmit) and the other collects
information from the ground and sends it back to the control box
(Receive). Using this ability, the 3000 can analyze information
and decide on the conductivity of a given target and give a
reasonably accurate indication if it is ferrous or non-ferrous.
Unfortunately the discriminator doesn’t match the 3000’s
performance; this is because a large target is needed to give
reliable discrimination. In other words, it works really well on
rusted cans and other “big” iron rubbish, but has no power
against smaller ferrous items like boot tacks. When a target is
received, try sweeping the coil quickly across the target from
side to side; this will give a more reliable discrimination
result. Remember, if the signal doesn’t blank both ways there is
doubt, and the target should be investigate
Tune: I include this
feature because of a common misconception that this button is
used to set the ground balance. This feature has nothing to do
with the balance, but is instead used to combat the effects of
external interference and should only be used when really
needed. I strongly advise tuning with the coil in the same
position as you would when detecting. Ground balance the
detector to the soil your working in at the time, then place the
coil on the surface of the ground and depress the tune button
and wait for it to cycle. Do not move the coil while this is
happening, as any signal picked up will affect the final outcome
of the tuning process. When the tuning is completed (signaled by
three sharp beeps) and re-ground balance. Do not try to tune out
moving objects such as airplanes.
Volume: The beauty of this
feature is that you can adjust it for loud target noises without
affecting smaller ones; this is a very handy feature when gold
is buried deep in trashy environments. The volume only acts on
the louder target noises, helping to prevent deafening blasts
from large shallow objects.
Field Test:
In mid September 2003 my father
Steve Gholson, our hunting partner “Montana” Dansie, and myself
decided to sit in a truck for 14 hours in order to put the 3000
through its paces on some of the nastiest ground northern
Nevada. Our final destination was the famed dry placers
surrounding the town of Winnemucca. The spot we had in mind was
as rich in gold as it was noisy ground! The first real problem
was an underlying lens of highly mineralized “red” dirt. As if
the iron-rich red dirt was not enough, the soil also contained
high levels of salt which was visible in many places as a
threatening white crust. When put together, these two elements
formed an all but impenetrable barrier of noise. With the VLF
machines this ground was virtually impossible to work, as was it
with some of the previous Minelab SD models.
So, just how did the blue wonder
from Down Under fare? Like a charm!!! Even in this inhospitable
soil, the 3000 ran as smooth as a freshly spun piece of silk.
The newest version of the GP was so stable, the three of us were
able to swap out the stock 11” DD coils for the much larger
diameter Nugget Finder® monoloop coils, enabling us
to cover more ground and enhance sensitivity towards smaller
nuggets. In this part of the country there was little that
seemed to upset this detector. It preformed just as the
manufacturer had claimed and netted us a touch over 2 ½ ounces
of beautiful yellow nuggets. Most of our gold was found in
virgin ground, however all of the larger pieces came from old
patches, many of which had been worked for years with VLF
machines and more amazingly, with SD2100s!
Conclusion:
Before the likes, I will give you
my two dislikes. The first is price. At $3,495.00, this machine
carries the highest suggested retail price of any handheld metal
detector on the market. The second is size and weight. For as
much technology that was put into the inside, a little more
could have been spent on the outside. I think the control box
could easily be reduced to half its’ present size with zero loss
in performance. A reduction in bulkiness would certainly attract
those that have grown to love the airy, featherweight feel of
their VLF.
Okay, now for my likes. The first
is depth. One of the things I love best about the 3000, is its’
ability to achieve incredible depth on a broad spectrum of
target sizes. It cannot only pick out larger nuggets at depth,
but it really shines through on those small bits as well. I have
been absolutely amazed on more than one occasion when I have dug
beyond the 9-10” mark for a measly old-timer boot tack!
Definitely a double thumbs up in this department! The crisp
sensitivity of this unit is sure to catch the attention of even
the most anti-PI operator on the planet. Using smaller diameter
monoloop coils, I have recovered “nuggets” so tiny they could
not even trigger my digital scale! The decision to eliminate the
two-piece and o-ring for a solid upper shaft was also a nice
touch. Thanks guys for getting rid of those creaking shafts!
Those that are familiar with the GP Extreme will no have trouble
becoming familiarized with this newer model. To a brand new user
this machine may look scary, but it is in reality one of the
easiest gold machines to learn and operate. Once tweaked to an
operators’ particular taste, there are few adjustments that need
to be fiddled with out in the field other than the Balance
switch.
I have not written this article to
sway you. The decision to purchase, or not purchase this product
must be based entirely upon your own research. I will however
share with you my own personal situation and let you draw your
conclusions from there. As a serious electronic prospector I
rely on new technology to give me every advantage possible on
the goldfields. As more and more people are getting involved
with prospecting a quality machine has never been more
important. I choose to use the GP3000 because it excels in the
two areas I value most: sensitivity at depth and mineral
immunity. Even if I only gain a half inch more it could mean the
difference between hearing that 1-ounce nugget or leaving it
behind for someone else. Inevitably something better will come
along and I will switch up, but until then I will continue to
swing it religiously.
If the 3000 is beyond your
financial grasp, do not lose hope of finding gold. There is
another quality that I did not mention which is just as
important. The quality is persistence, and that my friends lies
within the operator, not a metal case. I wish all of you the
very best of luck with all your detecting! For more information
Minelab’s wide range of products, please visit their website at:
www.minelab.com, or by phoning 1-866-646-3522.
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