Monday, July 25, 2011

The Crescent Creek Placers©

View of Crescent Creek and the Henry Mountains, looking west.
     The Henry Mountains are found in southern Utah, midway between Lake Powell and Hanksville. These mountains are an oasis of water and shade in an otherwise forsaken desert. The tops of the mountains are heavily timbered and there are green meadow filled basins surrounded by pines and aspens. Deer and other wildlife are abundant, and the nation’s only free roaming herd of buffalo can be seen around the base of the mountains.

     There are several accounts of the discovery of gold in the Henry’s placing the discovery of gold between 1885 and 1890. It is probable that the discovery of gold in the Henry’s is related to the development of the Glen Canyon Placers. While the gold was abundant, it was also fine and hard to recover. Prospectors, disappointed with the prospects in Glen Canyon, spread out across the country. In trying to locate other sources of gold, some prospectors worked their way up the Dirty Devil River to the base of the Henry Mountains; where, on the east flank of Mount Ellen, they found gold in Crescent Creek. They were able to  follow the trail of gold up to lode gold and copper deposits in what is now Bromide Basin.1  Early miners also found signs of the Spanish—an arrasta was found, and John Fremont found the skeleton of a burro—still carrying saddlebags full of high-grade ore in 1853.2  

     This lode was fairly high grade—but was also shallow—and the mines soon failed. Tens of thousands of years of erosion, however, left wide spread placers in a large alluvial fan around the eastern base of Mt. Ellen. Crescent Creek has carried the gold bearing sediment from Bromide Basin to the benches, where it formed a placer deposit that is large enough to be measured in square miles. Since the time of the original deposition, Crescent Creek has cut down through the gravel, reconcentrating the gold and creating a narrow, steep walled canyon that heads east away from the mountain and drains into North Wash. North Wash then drains into the Dirty Devil River. Butler Creek to the north and Copper Creek to the south, also cut through the margins of this placer, and as a result carry some limited values in gold.

          The gold here is high karat gold—heavy and rich in color. It is also chunky and large—coming in grains, wires and large flakes. In the original deposit, the gold is distributed quite uniformly across the placer, with a concentration of gold found “in black-sand streaks at the base of the fanglomerate gravel,”3 as it was described in Johnson’s Placer Gold Deposits of Utah. Where Crescent Creek has cut through the alluvial fan, the gold has been reworked. Because the amount of water flow is low—even in spring run-off—the gold tends to be spotty. It is generally moved only in flash floods. These flash floods are common—coming several times a year, principally during the monsoon season at the end of July and August.

          In the bottom of the wash, the gold tends to be right on bedrock, leaving the overburden barren.  And while some gold can be found just about anywhere that you find bedrock, the floods have formed rich pockets along the way.  The Crescent Creek placers are considered to be one of Utah’s few commercial grade placers, but they are marginal and difficult to work at a profit. A mining company has a lease on almost all the placer ground. Their claims are well posted and run from North Wash all the way to Bromide Basin. Another company (Unico Mining) currently holds lease on the lode mines in the basin.

Panning Crescent Creek with my son, Dalton.

     Because of the number of people that visit the area, a public panning area has been provided on Crescent Creek. It is well marked and is actually one of the better gold producing areas on the creek. When I first worked the area, I was working the stream sediments, as I didn’t see much bedrock exposed on the creek bottom. I was getting some gold, but it was fine and far between. Another prospector who was in the area came over and showed me the trick to the gold. I hadn’t realized it, but the bedrock in the public panning area is a soft clay—alternating gray or black bands—and by digging along the contact of this clay and the gravel I found large flakes of gold and small pickers. I was not getting rich, but it was certainly enough to keep me interested.

Map of the Crescent Creek Area.

     A few weeks later, while working an unclaimed area at the bottom of Crescent Creek, I found a fairly good pocket of gold and filed a claim on some of the last remaining land in the canyon. Instead of the black and gray banded clay that we found up at the Public Panning area, we had a soft, brightly colored orange/red clay, alternating with a hard but brittle dark red mudstone. The rich gold we found was on top of this soft orange colored clay. The work was slow and water was difficult to come by, but by using primarily a shovel and pan, we pulled about ¼ oz of gold out of this small stretch creek over the next several weekends.

     Crescent Creek is a perennial stream—but as you pull away from the mountain the creek bed goes dry, the water flowing under the abundant gravel in the area. The area we were working has shallow bedrock, and as such, has some water year round. The water here doesn’t flow except during spring runoff. In this area, it is more of a seep—just enough to keep the ground muddy. When we want to pan, we need to dig a hole and let the water seep in. Then as we pan, we need to keep mucking out the hole. It also took some time to clean the gold out of the sticky clay.

     Along Crescent Creek, the gold can be found associated with barite sand. The barite sand is a white to very pale yellow coarse-grained sand and is fairly heavy. If you are not finding much barite sand, you probably aren’t getting much gold either as they tend to settle in the same places.

Gold and barite sand.

     There isn’t much black sand in these placers and on our claim there is almost none. The black sand is more commonly found in the bench placers above the wash (in fanglomerates), and related to the original alluvial fan.

     Crescent Creek sits at the bottom of a steep walled wash—and as was already mentioned, it is prone to flash floods. In this area, they are fairly common. While we were there in the late spring we saw a brief storm that brought strong winds and heavy rain. It lasted for only about twenty minutes. About a half an hour after the rain stopped, we noticed a puddle creeping down the riverbed—and about two minutes behind it was a fast moving river. This trickle of a stream not even ¼ inch deep turned into a fast moving creek six to eight inches deep and about eight feet wide—and it flowed fast for over an hour, with a residual flow that lasted most of the night.

     These flash floods can be dangerous, but they can also move a lot of material—including gold. By putting a sluiced box into this flood, we were able to pick up some nice pieces, without shoveling any dirt.
The first year we were there, we worked a stretch of river between six and eight feet wide, about seventy feet long, with bedrock ranging from three inches to one foot deep and pulled out about ¼ oz of gold.

     When we returned the next spring, we could not find any sign of our previous activity. Everything we had done was washed away, including the two foot high dams we built to collect water; the large piles of tailings (we had to muck out our panning holes); and the five foot deep test hole that we dug about ten feet to the side of the shallow bedrock that we had worked. It didn’t take long to realize that a very large flash flood had come through the previous fall. The flood that came through completely filled the wash. By examining the water lines on the sides of the canyon, we estimated that this flood was about six feet deep and at places, greater than fifty feet wide. And, in addition to scouring the wash, this flood also left gold.

     We went back and worked the same stretch of river that we had worked out the previous spring and found about ½ oz of gold over about three weekends.

     Most of this gold has come in the form of coarse grains, about the size of granulated sugar. We have also found some very large flakes and an occasional rice-grain size nugget. Several guests (3) to our claims have even found pea size nuggets, be we (the owners) have not yet been that lucky.

What the future will hold is uncertain. We believe that there is a lot more gold there. The gold is in pockets and almost all of it is on bedrock. The trouble is, except where the bedrock is shallow or exposed, we can’t get to it without heavy equipment. The area is too wet to dig—all the holes fill with water—but too dry to dredge. I tried working it with a small 3” dredge, but had to dig a hole just to hold the dredge, and I then had to re-circulate the water. I was dredging in mud and couldn’t see anything. Rock jams were common, and it was difficult to tell where I wanted to work. The clay also made it very slow, as it was stuck in place and didn’t want to come up the dredge hose. After a day of dredging (with poor results) I realized that I probably could have gotten more gold (maybe twice as much) by working by hand with a pan and shovel. A highbanker does work well if you are there early enough in the spring to catch the runoff.

     The public panning area is upstream from our claims and has much better water flow. If you go in late summer or fall, you might find water in the morning and evening—but a relatively dry riverbed in the heat of the afternoon when evaporation is going strong. And yes, it does get hot. In the summers expect 100°+. The Public Panning Area fortunately does have shade from several large trees and is a nice place to camp. There is even an old cabin at the public area. It is in fairly good shape if you need to get out of the weather. In this area, you can pan, sluice, highbank or dredge. Sluicing, highbanking and dredging all require a state permit, but they are free—just contact the Utah State Division of Water Resources. If you like, dry washers can be used on all of the gravel found above the creek. And I know of a prospector that found a pe sized nugget with a metal detector.

     This is a great area to explore. There are good opportunities for photography, hiking, four wheeling, and riding motorcycles or ATV’s. Small uranium and vanadium prospects also litter the lower margins of Crescent Creek—they are interesting, but you should probably stay out of them as they are in soft rock and are especially prone to cave-ins—and also full of radon gas.

As a general rule, take what you are going to need if you are going to explore the area. Hanksville is a small town with a few basic supplies like gas, ice and groceries. If you need anything else, you are probably out of luck—and it is 25 or 30 miles just to Hanksville from the panning area; it will take hours to get anywhere else. This area is remote but well worth the trip.

Over 1/3rd ounce placer gold from Crescent Creek. Several small nuggets were also found.

     This article was originally printed in the October 2009 ICMJ and references the Crescent Creek chapter of A Guide to Gold Panning in Utah, also by Alan J. Chenworth. The maps and many of the photos are also taken from this book.

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