Giant and Hidden Gold Deposits, Wyoming

Ah, Atlantic City, my home away from home. While working at the University of Wyoming for the
 Wyoming Geological Survey, I mapped the South Pass Greenstone Belt and underground mines
from 1983 to 1988, and completed a 129-page summary book with a compiled 1:48,000 map.
While mapping for a few summers in the 80s, provided me access to many gold prospectors. Many
 evenings were spent sharing spirits in the Atlantic City Mercantile while listening to various stories
about the big one (nugget) that got away. But there were just as many evenings spent with a coyote
 choir on the plains near Lewiston where only myself and a few coyotes sang ballads to the local
prairie dogs, some crazy critter than ran laps around my tent, and ghosts from Lewiston. I thank
God for the opportunity to spend summers in this fantastic gold country. And I also need to thank
some of the locals for so many wild stories to tell around campfires and public prospecting talks.

Revised 2/18/2022. Wyoming is known for its detrital gold in paleoplacers. These are simply fossil stream placers deposited in the geological past that are now mostly high and dry. Mining these requires transporting water to the paleoplacer, or the paleoplacer to water.  

Where a paleoplacer consists of relatively unconsolidated gravel, it can be mined similar to a sand and gravel operation. If the operation is near a road, the sand and gravel can be used as a by-product for road construction. The opposite may also occur where gold can be extracted as a by-product of sand & gravel operations if it is found such operations have anomalous gold. Where paleoplacers are extremely old, such as in the Witwatersrand of South Africa, the gold is recovered from underground mines to depths of more than 13,000 feet.  

Ugh! Where are all the people coming from?
Small paleoplacers are found scattered around the Atlantic City area at South Pass and there are also likely overlooked paleoplacers. The closer these paleoplacers sit to gold-bearing shear zones, the better they should be. To find these on Google Earth, visit the to Atlantic City, Wyoming area. This is where I figured I would end up retiring after I got tired of the Wyoming Geological Survey, but already, the area is getting crowded. Just look at the populations signs!

Follow the Riverview Cutoff road south of town at an eye altitude of about 10,000 feet on Google Earth. Near GPS coordinates 42°28'45"N; 108°42’58”W close to the northern extent of one paleoplacer. As you look at the area on aerial photography, note rock foliation (lineation) disappears - this is because the very old (2.8 Ga) metamorphic rocks are buried by the much younger paleoplacer. On the ground, the paleoplacer has scattered, rounded, rocks that normally can not be seen on aerial photography; however, at 42°28'36"; 108°42’46”W a rounded, white boulder is actually visible on the aerial photos at an eye altitude around 8,300 feet. When you slowly back off the eye elevation to 17,000 or 18,000 feet, you will be able to see the extent of the paleoplacer (it is subtle, but its there). At the eastern extent of the paleoplacer is an old ditch dug by late 19th century to early 20th century prospectors presumably to transport water from Rock Creek to hydraulically mine parts of the paleoplacer and parts of Rock Creek. 

JP, Jim and me on Rock Creek, 2015. I'm the good looking 
wearing shoes.
A couple of years ago, I had the opportunity to consult on gold in Rock Creek. It was an eye-opener. This gold placer was mined from about 1933 until it closed due to an order filed at the outbreak of the second world war. It is apparent to me, that the early prospectors left behind considerable gold, not only because of the inefficiency of their processing plant, but also because of the poor mining practices where they covered areas of virgin ground with tailings, and left other parcels of virgin ground untouched altogether. When mining ended in 1942 due to the mine closure by the War Minerals Board, the placer operation never gold reopened, but the operation was in mineralized ground in 1942 that was minable at gold prices of only $35.50/ounce. To me, this deposit looks to be a very good placer particularly at today's gold prices.

Rock foliation in the Miners Delight formation seen on the side of hills from Rock Creek
(photo by the author).
A large paleoplacer (with reworked gold deposits, or placers) is found south of the South Pass greenstone belt. This is the Dickie Springs-Oregon Buttes paleoplacer and the greenstone belt continues under this large paleoplacer. In 1978, a few members of the US Geological Survey astounded the geological community when they suggested this paleoplacer contained as much as 28.5 million ounces of gold! If valid, that would make this one of the larger gold deposits in the US. But little exploration occurred on the gold deposit because of its size and lack of water. Even so, past information suggests that reworked portions of the paleoplacer near Dickie Springs (42°18'30"N; 108°51’48"W) has more than a million ounces of gold. This should provide an exciting gold prospecting opportunity. Not only is their gold in the paleoplacer, but in places it has been reworked by modern drainages and there should be ample amounts of gold in drainages in the area. 
Examination of the Dickie Springs gravel in
the Dickie Springs-Oregon Buttes paleoplacer 
south of South Pass at Dickie Springs (photo
by the author).

Gold has been mined in that region in the historical past as well as in recent years. To find Dickie Springs, do a Google Earth search for “Dickie Springs, Fremont County, Wyoming”. When you arrive at the spot, note that Dickie Springs sits in a drainage that flows to the northeast to the Sweetwater River at the edge of the exposed portion of the South Pass greenstone belt (and its not the only drainage). 

Now keep in mind: there is not only a world-class paleoplacer gold deposit siting along the southern edge of the South Pass greenstone belt, but there is also a hidden, world-class, lode gold deposit in this region that supplied the gold to the paleoplacer. This hidden source rock is very likely part of the South Pass greenstone belt, and greenstone belts are known for several major gold deposits worldwide. So, where is this deposit? 

Several years ago, Hecla Mining had a possible lead, but their project was terminated by company management. It will likely take detailed geophysical surveys and drilling to find it, or someone will have to get the Hecla report from the company files.

Dave Freitag shows a vial of gold recovered from his paleoplacer gold property at Dickie Springs
 (photo by the author).
Oregon Buttes lit up by the sun on the horizon. View from
South Pass (photo by the author).
Gold from the Dickie Springs paleoplacer - photo courtesy of Dr. J. David Love. 

Generalized map of Wyoming's ancient Precambrian rocks
showing location of greenstone belts in Wyoming.
South Pass lies in Western Wyoming at the southern
tip of the Wind River Mountains
Fisher dredge sits all alone on Rock Creek abandoned in 1942 when the War Minerals Board closed
all gold mining operations in the US to focus all energy on the war effort (photo by the author).
Just remember, this placer mine was economic at that time (gold price of $35.50). Compare to today's
gold price - no wonder why I think this mine should be started up again!

The author lectures to a group of gold prospectors about the geology and gold deposits of the
South Pass greenstone belt and associated paleoplacers (photo courtesy of David Miller).

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