These
goldfields can be accessed from the American River Bikeway or by
parking near Sunset Avenue and Main Ave N38 39.251 W121 12.579. A
walk along easy fire roads and trails bring you to the
coordinates.
The Mississippi Bar has been extensively dredged
for gold. Dredging uses massive buckets on a conveyor belt style
system to dig up ancient river sediments. The machinery is located
on a floating barge since the digging extends below the water table
and creates a pond. As the barge digs it way forward it constantly
sits in its own pond. The gold is separated from the tailings (all
the other rock) on the barge and the tailings are piled up beside
the barge in tall linear piles as it moves along. The coordinates
are on one of these piles of tailings.
In a single year, each dredge could excavate 26 million cubic
yards of material. That is equivalent to a 100 football fields
filled two stories high. The tailing piles around the coordinates
are only a small portion of the area that has been dredged along
the American River. On the south side of the river there is another
field of these tailing piles that extend almost 3 miles away from
the river and are almost 5 miles long.
The source of the gold along the American river is a placer
deposit. A placer deposit is a natural concentration of a mineral
by erosional forces, typically river water. In this case, gold was
eroded out of the Mother Load gold deposits in the Sierra Nevada to
the east. The ancient American River transported the gold
downstream where it was deposited on the inside of meaner loops, in
covered rock holes, and other typical gold traps.
The density and chemical inertness of gold are the primary
characteristics that create gold placer deposits. Gold is a very
dense metal. For that reason, gold will get lodged in the river
bottom wherever the current slows down even slightly and will work
its way down below other rocks. Gold is also inert which means it
does not react with other compounds. Thus gold will remain gold
pretty much no matter what else comes in contact with it.
Logging requirements:
Send me a note with :
- The text "GC1CXXE Mississippi Bar Placer Deposit" on the first
line
- The number of people in your group.
- At the primary coordinates,
- Describe the size of the rocks in the tailings pile.
- What is the height of the pile from the water level to the top
of the pile
- At the secondary coordinates (N38 38.871 W121 12.422)
- What would account for the feature at these coordinates.
The following sources were used to generate this
cache:
- Cal Sierra Development Inc., History,
http://calsierradevelopment.com/
- Step by step River Gold Formation,
http://www.e-goldprospecting.com/html/gold_step-by-step.html DEREK
WILTON, Placer gold deposits, Pt. 1, October 6, 1997, The Northern
Miner,
http://www.northernminer.com/Tools/Geology101/geo101pg2.asp
