|UNDER WATER TREASURE HUNTING
(My Colorado Adventure)
|by James Wark--former First Vice-President
Houston Gem & Mineral Society
This article appeared in the December, 2007
the HGMS BackBenders Gazette
(American Federation of Mineralogical Societies
First Place winner--Adult Articles published in 2007)
Prospectors have a saying that "Gold
is where you find it." Under water is
where you can find the greater amounts of
placer deposits. Back when the old timers
were panning for the color, they did not
have a way to get to the fissures and cracks
deep in the rivers. But with the invention
of the portable dredge, gold now can be found
where it was impossible for them to get to
back then. Be careful of boulders rolling
down your way, swift currents, and underwater
rock slides. Did I mention tree trunks? The
larger ones can take you and your dredge
out in one swift disastrous event—especially
if you are underwater. It's always best to
have a dive buddy with you.
The dredge I use is a Keene Engineering's Gold Dredge model 3500 series with a 5-horse power Briggs & Stratton gasoline motor, a diaphragm air compressor, and a 2" water pump. Let's not forget the sluice box with riffles and the pontoons on which it floats. Both the air pump and water pump are run with the motor. I picked it up at their warehouse in California in 1975. Then I immediately drove to the ghost town of Cripple Creek, Colorado and proceeded to dredge for gold—that elusive yellow metal. Gas was only about 85 cents a gallon then. The motor would run for about 2½ hours on 1 gallon of gas.
The air compressor will deliver breathing air under water at one atmosphere (33) feet. It delivers a maximum of 75 psi. This is called the Hookah Dry Air System Diving. Ingenious isn't it. So as long as your motor is running, you have an air supply. It's vastly superior to scuba as far as gold dredging is concerned for several reasons—no bulky tanks that restrict the diver in tight spaces, and you don't have to get the tanks refilled as you do with scuba. To refill scuba tanks could be a 100 mile or more roundtrip every day.
Be careful of underwater currents. They can surprise you and drag you downriver before you know it. The compressor pumps air into a hose, then to a receiver tank that holds approximately 60 psi and floats a few feet from the compressor. Then there area about 50 feet of air line that the breathing regulator is attached to. The air line is constructed of special vinyl plastic with an inside diameter of ¼ inch. Let's not forget
the harness that attaches to your back that keeps the regulator from being pulled from your mouth. Could save a few teeth as well. Don't want to spend your profits at the
dentist. Another great feature of the reserve tank is that in case of motor or compressor failure, it holds about one minute of air. To be safe on ascending back to the surface,
go one foot per second. Other equipment to bring along on the adventure is a diving mask and a diving suit. It gets cold in the water, as the stream or river water is usually from snow and ice melting way upstream. Another helpful hint: Don't drink the water when there's a herd of animals upstream.
The water pump works on the Venturi principle. The overburden never gets into the
water pump. It's like an underwater vacuum cleaner. Suction and water pressure bring
the material through the two-inch tube from the bottom and dump the material into the
sluice box on top of the water. The inside diameter of the intake nozzle is 1¾ inches.
If it were 2 inches, the hose would be continually clogged up. No surprise there. The
pump delivers approximately 75 gallons per minute. Also remember to prime the pump.
It's primed manually by rapidly moving the foot valve up and down under the water
line. Running the water pump dry for any length of time will put you in the market for
You have to remove the overburden first from the bottom of the river. The gold will
always be at the very bottom of the debris. Make sure your debris exit is on the other
side of your dredge, or you will have unwanted rocks hitting you up side your head
while you are underwater. And let the debris flow downhill so you will not have all the
underwater dust in your way. No more than a yard—on a good day—can be worked
with a hand-held gold-pan. A 2 inch dredge can easily do 2–3 yards in a hour.
Material is passed over a set of sluice boxes where the gold is trapped in the riffles and
the lighter materials are washed back into the stream. The sluice box will trap about
95% of the gold that enters it. Gold is eight times heavier then the ordinary sand,
magnetic black sand, and gravel found in your riffle board. It is found on and in
bedrock, in the crevices, and in cracks, soft spots, and potholes. Any crack big enough
for water to get into is big enough for gold to get into. A magnet will remove any
magnetic material. Gold will not stick to a magnet and is given a rating of 2.5 on Mohs
Scale of Hardness. This means that it is a soft metal. The miners of the past would use
mercury (called also quick silver) to get the small placer and flour gold from the riffle
board. This method is called amalgamation. Another is the scratch test. Take a pocket
knife and see if it scratches the surface. If it does you have struck gold. Pyrite is harder
and will not scratch.
At the writing of this article, spot on 24 carat gold is $807.00 a ounce. (Monex Trading)
When I was prospecting in the '70s, it was $35 bucks a ounce. I may be unavailable
this summer—busy in the mountains on another gold treasure hunting adventure
if the price stays the same or goes up as some predict. One thing I am proud to say is
that in the Lost Wax Casting division of the HGMS, I am the only person so far to
have cast gold rings from gold that I mined personally from the jealous gasp of Mother
Nature. My special thanks goes to my very knowledgeable instructors, Charlie
Fredregill and Tom Wright. My hat is off to the wizards of casting.
For me there is no greater thrill than the sound of gold nuggets hitting the container.
One thing I did learn was that if there is any doubt, it probably is not gold. Gold
flattens out after being hit with a hammer, while Pyrite shatters into a pile of broken
fragments. Pyrite is also appropriately named Fools Gold. On your larger nuggets,
don't test them by hitting with a hammer. You would have a chunk of gold that USED
to be a very prized specimen. Ouch!! Another trick of the trade that old timers used
was to drop the nugget into nitric acid. Gold looks like it's sitting in water. Pyrite starts
bubbling, smoking, and disintegrating before your eyes. IT IS NOT RECOMMENDED
THAT YOU DO THIS!!
I learned all of this and much more about gold mining from an old timer named Herb
Boone. He was a genius at gold mining. He was my dive buddy, mentor, and a descendent
from the prospectors of the 1880s in Cripple Creek's heyday. Unfortunately, he is
no longer with us. He took a treasure trove of information about gold mining plus
many tall stories to the grave with him with his unfortunate passing. Herb, I salute you
and thank you for sharing your vast knowledge so unselfishly with me. This article is
dedicated to you. Goodbye, my dear friend.