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 Nuggets of News Blog 

Friday, April 27 2018

A good rule of thumb that most prospectors agree on is to look for placer gold on bedrock and within crevices in the bedrock. This simple principle makes sense— placer gold is heavy and dense and therefore settles at the lowest point as it is pushed around by flowing water. However, gold isn’t always going to make it all the way down to true solid bedrock at the bottom of all gravels. Instead, in certain conditions, it will be found ABOVE bedrock. When these conditions exist, gold will collect on “false bedrock.” For example, a clay layer in streams can act like bedrock and yield more gold than the true bedrock below it. 

bedrock goldAnother situation where gold cannot make it to bedrock is where the streams and gullies have “caliche.” Caliche is a form of cemented gravel often found in desert areas. The gravel is deposited by water flows, just as it would be in any other stream. The difference is that the water contains dissolved calcium salts, and as the water dries up in the streambed, the calcium salts turn into calcium carbonate or calcite. This material gets deposited on the gravel a little at a time and eventually the calcite glues it all together into a solid mass. The solid mass then acts like false bedrock and any new gold flowing across it is stopped in its downward movement by the caliche.

Residual placer gold is formed near the source of the gold and doesn’t really have a chance to work its way downward. Hillside placers are residual placers that are sliding and making their way down the side of a hill into a stream drainage. Gold generally is distributed all through these types of gravels and is not concentrated in any one place. A hillside placer often will be located up above a stream, making it difficult to determine it from a bench placer. Old benches of river gravel can be good places to prospect because they are virgin ground, but because the river used to flow at this location, it’s highly likely that the best gold will be right on bedrock or in crevices of the bedrock. The best way to tell the difference between hillside and bench placers is the shape of the rocks in the gravel. If the gravels and rocks are well-rounded and smoothed, then it’s probably an old river bench. If the gravel is angular, pointy, and sharp, it’s probably a hillside placer that hasn’t yet made its way into a stream.

Another type of placer—the windblown placer— concentrates on the surface, just exactly the opposite of what you would find in a river or stream. The lightest materials such as sand and silt are blown away by the wind. Heavy materials like gold remain behind on the surface. These types of placers are marked by desert pavement, which is a concentration of small to medium-sized rocks that cover the surface and prevent continuing wind erosion. They occur in dry regions with flat terrain, and are often favorite locations of metal detectorists who find nice nuggets at shallow depths.

The next time you find yourself in an environment with well-washed river gravels, you know that the gold will most likely be on the bedrock. But if you find yourself in other types of environments, especially in the desert, consider the possibility that the best gold may actually collect ABOVE it.  Good luck!

Posted by: Denise AT 06:43 pm   |  Permalink   |  Email
Friday, December 29 2017

Given a choice, most miners prefer using water to wash and run material, but in some dry, remote areas that  drwasheris just not feasible. If you focus on the natural conditions that exist in desert regions and work with them, you can maximize fine gold recovery. The number one rule is that the drier the soil, the better. Damp soil conditions are very much a hindrance for drywashers. Beyond that, learning the different soil types you may encounter in the desert and how to deal with them can increase your gold recovery.

Clay is generally known as a great gold robber, making clay-bound gravels the biggest difficulty to overcome. In most of the placers directly derived from weathering lode deposits, the placers are in ravines, gullies and hillsides with sometimes very little gravels and mostly decomposed fragment of rock and fine silt from the decomposing host rock. Host rock containing a lot of feldspars are most problematic. As feldspar breaks down, it creates some difficult clays and silts that bind fine gold to small rocks and sand with the clay and silt particles forming larger clods.

Loamy or sandy conditions are much easier to process with a drywasher than clay-bound material due to the absence of clods and clumps. But if dirt clods are giving you grief, break them down with a large hammer on a canvas tarp, or use a mortar and pestle (dolly pot).

Once you are set up to run material, process in short runs before cleaning out the riffle tray (perhaps after every three 5-gallon buckets). Frequent clean ups minimize the amount of fine gold that may creep or walk down the riffle tray with the tailings. This method uses your dry washer as a form of a classifier to screen off larger material while getting rid of much of the fine silt and lighter weight material.

Re-running tailings can aid in the recovery of lost gold— especially small gold dust and flakes. The second pass through is usually much quicker than the first time because the material has already been classified. With some placers, especially flat, fine gold, rerunning material can be very lucrative. In places where gold is more coarse and angular, very little gold will like be recovered by running the tailings a second time.

You may want to experiment with adding a second layer of cloth to a portion of the riffle tray. Doing so reduces airflow by almost half in that section. In addition to the riffle tray, the void under the riffle tray can collect a sizable amount of really fine gold mixed in with fine silt.

No doubt there are going to be losses of gold when using a drywasher to recover fine gold (20 minus mesh down into the 200 minus gold), but the end goal should be to limit those losses as much as possible and these tips should help.  Good luck!   Learn more about Gold Buddy drywashers here.

Nugget of News Blog

Posted by: Denise AT 02:47 pm   |  Permalink   |  Email
Sunday, December 01 2013

Dry washers are like highbankers except they do not use water to recover gold. While wet processing is nearly always faster and more efficient, especially for fine gold, dry washers are the best tool for recovering gold nuggets, pickers, and flakes from dry materials in the desert or other areas where water is not plentiful.

dry washerDrywashers are operated by shoveling gold-bearing gravels into an upper box which is covered with a screen. The larger rocks that are too big to pass through the screen slide off. Gravel small enough to go through is fed down into the lower gold recovery box, which is an inclined trough with cross riffles much like a sluice. The bottom of the recovery box consists of a thin, light-weight porous cloth. Beneath the riffle box is a blower that pulses air up through the cloth. The vibrations and air flow, combined with the shaking and classifying action of the dry washer allows the gold to settle to the bottom where it is captured in the riffles.

Keep these tips and tricks in mind when using a dry washer:

• Moist soils and clay cause problems, so be sure to crush lumps of clay and dry your dirt in the sun (plastic tarps are ideal) before running through your dry washer. Surface soils might seem dry, but if you dig down a few inches, you may find moisture in the soil that will cause your sand, gravel, and gold to stick together.

• Double-check all the "throw away" rocks. Scanning them with a metal detector is a great way to ensure you're not tossing aside gold-laden rocks. Also, don't assume old tailings piles have been totally worked out. This is  another time to use a metal detector because ordinary rocks could be  laced with gold and completely over-looked by earlier prospectors.


• Consider using a dry gold vacuum to clean out crevices in bedrock. Feed the material that you sucked up into your vacuum bucket into your dry washer.


• Drywashing can be a very dusty process, so try to stay upwind as much as possible and wear a dust mask.
• Do a clean up every couple of hours, or after processing roughly one to two yards of material.

Looking for a drywasher? The Gold Buddy brand is available in 4 sizes and also check out the new heavy duty
Gold Storm dry washer. Whichever you choose, SAVE $10 with coupon code TAKETEN at check out. Offer expires Dec. 31, 2103.

Posted by: Denise AT 06:14 pm   |  Permalink   |  0 Comments  |  Email
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