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Metal
Detecting
Metal
detectors and detecting have come a long way in recent years, and can be
very useful in giving you an indication of good spots to dig for gold.
As with computer software, each year sees new, improved metal detectors,
with more specialist models coming on the market. The Internet has
greatly increased our choice and it is well worth a browse to see what
is available. Get a good search
program on the job and you will have more than enough to choose
from. Models offered come from many manufacturers, Minelab, Fisher,
Tesoro, Whites, Garrett, and many others. They range from the top
Minelab model around $NZ5,795, to the Warehouse model at around $80.00.
Metal Detectors, and books on how to use them, along with gold pans and
accessories, are available from the Nature Discoveries shops, and from
Detection Solutions, 1/27 Fortunes Road, Pakuranga, Auckland.
Phone (09) 576 8000.
Nature
Discoveries have three shops: The Palms, Shirley Mall, on the corner
of Marshlands and Shirley Road, Christchurch. Phone (03) 385 1565
Meridian Centre, on the corner of George & Hanover Streets, Dunedin.
Phone (03) 477 1515, and North City Plaza, 4 Titahi Bay, Porirua.
Phone (04) 237 0237. Nature Discoveries in Christchurch also have a
metal detector that you can hire out.
Each
detector is different, but here are some principles that apply to them
all.
Decide how much area you
want to cover and stick to that. It is better to be methodical than
impulsive because then you can be sure of where you have or have not
been. Some treasure hunters take a ball of string and lay it out on the
area of beach or ground and divide it into squares with their string.
They then sweep their detector head over each square in turn, putting a
marker in the last one they swept if they go for a break. It is a very
effective way to find treasure but it’s not so easy when you want to
find gold in a creek bed. It’s hard to set out string squares in a
creek but you could try on some of the shingle beaches. Four pegs
marking off a square at a time would do the trick too. Just keep
bringing the far two pegs forward to mark off each new square as you
move backwards.
The
principle of the metal detector is simple. A coil of wire in the sensing
head is connected to an electronic circuit which senses any changes in
the electromagnetic properties of the coil. Under normal conditions, the
properties are stable, but when it is brought near any metal, they
change, and the differences are registered on a meter, usually with an
audible tone. A second method is to have one coil transmit a signal into
the ground, and a second coil to receive it. Under normal conditions,
the second coil is adjusted so that it does not receive any transmitted
signal. Only when something in the ground reflects the signal is it
detected.
More details
about this process in our book,
"Gold for the Taking."
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