Considered by many to be one of the most prolific characters of the 19th century, Thomas Edison is responsible for a number of familiar inventions that helped revolutionize the modern world. With an amazing 1걁 U.S. patents to his name, one can only imagine he led an incredibly active life. We hear his name and think famed inventor, entrepreneur, even patriot, but how many of us would have ever thought gold prospector? Believe it or not, the father of the electric light may have been touched by a slight case of gold fever. According to Straight, In 1897, Thomas Edison designed a dry-process machine for recovering gold in New Mexico He may not have been a full-fledged miner, but there is little doubt Mr. Edison was at least intrigued by the yellow metal. His early prototype may have given rise to one of the most popular pieces of placer mining equipment ever created - the dry-washer.
In its simplest form, a dry-washer consists of a grizzly and an adjustable riffle tray which is supported by a frame. Although the appearance of these machines has changed in the past 110 years, the principal of their operation hasnt. Hand operated models typically use a system of bellows to vibrate the gold-bearing material across the riffles, while the more common blower motor powered models are equipped with a fan offset by a spinning counter-weight. Air is pushed through a hose by the blower, which then causes the unequally weighted fan to spin, effectively shaking the riffle tray. As dirt is shoveled into a dry-washer, the larger overburden is screened off while the smaller material passes through and enters the riffle tray. This process leaves two distinct piles which are referred to as the coarse and fine piles. The fine pile is composed of all material that was passed over the riffles; the coarse pile is composed of the larger rocks that were screened off the grizzly.
I was fortunate enough to make the acquaintance of Randy Wilson and his wife, Lela, at the historic mining camp of Stanton, Arizona. The Lost Dutchman Mining Association (LDMA), the current property owners, were hosting one of the yearly outings where members gather from across the nation to work the gold-bearing gravels of nearby Antelope Creek. These gatherings are not only a lot of fun, but also a great opportunity to meet new friends and peruse a wide selection of the latest, greatest prospecting equipment.
While strolling through camp, Mr. Wilsons display caught my eye. Having been an avid dry-washer myself, I couldnt help but wander over for a closer look at his products. Marketed under the name of Gold Duster, these were some of the finest machines I had seen in a long while. The finish was clean, the integrity seemed sound, and more importantly, these dry-washers were incredibly easy to set up and disassemble. I can only imagine how big the grin on my face must have been when I was asked to field test one of these units for Lost Treasure.
The 28-pound dry-washer I tested uses a 185 to 205 mph leaf blower (not included) to process up to 2 yards of dirt per hour. The hopper measures 12 x 23, and the riffle box measures 10 x 23, both of which are constructed of aluminum. The Gold Duster boasts a unique axis shake, along with an improved airflow control in the riffle box to help retain fine gold. Plus, with the ability to be folded down as small as 17 x 15 x 23, this dry-washer is compact and fairly easy to carry into the backcountry.
I had no trouble at all choosing an area to try out the Gold Duster. The test site was actually a narrow gully situated in the mountains north of Phoenix. This was an ideal place to run a dry-washer for two reasons. The first being that I knew it carried gold. Prior to this trip I had already found several ounces of tiny nuggets in it with my metal detector. The second reason was both the size and depth of the gully. The width and depth of the overburden varied, but on average the gully ran 8 feet wide with a bedrock depth ranging from exposed on the surface to 3 feet deep. With a relatively confined space such as this, I knew it would be easy to move a substantial amount of material in a short period of time.
Those of you who have dry-washed before know it can be hard, dusty work. The equipment must be assembled, the ground broken up with a pick or pry bar, then shoveled into the dry-washer, and finally the concentrates must be panned down by hand. Hard work indeed, but an exhilarating experience when you see lovely pieces of butter-colored metal stacked behind the riffles! A dry-washer can be manned by a single person; however a second set of hands can really lighten the load. I wanted a partner, but I needed someone who was willing to help me pack in the equipment, then spend several hours shoveling under a hot Arizona sun. I dialed the phone, when a voice answered I said, Hey dad, whataya doing this weekend?
Being an avid prospector as well, my father, Steve, was only too happy to help me put the Gold Duster through its paces. The two of us got an early start and arrived at the gully just in time to see the sun creeping over the horizon. I dug a small sample hole and was pleased to see that the gravels were almost bone dry. The lack of moisture would really help with fine gold recovery. Dry dirt as opposed to wet, always runs more efficiently through a dry-washer.
Within 10 minutes we had the Gold Duster assembled and connected to our leaf blower, and had a decent area of the gully already broken up and ready for processing. As with any dry-washer, it is a good idea to run a few test shovels of dirt through while watching the material pass over the riffles. If the material races quickly over the riffles the angle should be pulled up. If the material is sluggish and clogs the riffles, it is a good idea to drop the angle.
Once we had achieved the proper angle, I began shoveling in the dirt while my father stood beside the hopper and helped clear away any oversized rocks that became stuck on the grizzly. A few hours later we had managed to open up a respectable hole down to bedrock. The bedrock itself was a variety called schist and was full of cracks and crevices, all ideal for trapping gold. Using a nylon whiskbroom, we carefully swept out any material remaining in the cracks and placed it in a bucket. This was the high-grade dirt and would most likely contain high gold values. Once full, the bucket was dumped into the dry-washer for final processing. When all the material had been run, I switched off the motor and unhooked the riffle tray. This was the fun part; any decent sized nuggets would stand out against the black cloth. My father and I were as excited as a couple of children on Christmas morning when we spotted several bright pieces of gold - it appeared our labors would be rewarded!
The last step before packing up our gear was to scan the newly exposed bedrock with a metal detector. This is an extra step that many dry-washer owners often neglect. It does take a little extra time, but it is time well spent. I cannot count how often I have detected nuggets out of abandoned dry-wash holes, and the hole my father and I created was no exception. A quick sweep of our excavation produced several signals, one was a bullet; the other three were shiny nuggets! Each of them had been concealed in a layer of red clay wedged down between the folds of the bedrock. They were small, weighing less than a quarter gram each, but at least we could walk away from our diggings knowing that we hadnt left anything larger behind. Later that evening we panned out our concentrates in the backyard. Our final clean up wasnt anything to write home about, but a few hours of enjoyable work had netted us roughly 2.5-grams of desert gold.
Dry-washing has always held a special fascination for me, and even though a majority of my time is now spent swinging a metal detector, I still consider the dry-washer to be one of the most important tools a placer miner can have in their arsenal. I have owned several of them over the years and each time I go to purchase a new one I always look for the same qualities. These include: portability, ease of use, and price. Portability encompasses weight and overall size of the unit. I like my dry-washers to be small and light enough to be carried by a single person or stowed on the back of a quad; yet large enough to process a decent amount of material. Ease of use also tops my list. I like things that are simple; the less fussing and assembly the better. My equipment has to be quick and easy to use; otherwise I waste more time setting up instead of prospecting.
I have taken this dry-washer out on several other expeditions and all of them left me feeling impressed. Any dry-washer can trap small nuggets and pickers, these heavier particles are easy prey; it is the lighter fine gold that proves problematic. I can tell you that the Gold Duster excels in its ability to catch and retain the elusive fines. This excellent recovery coupled with heavy-duty construction, a limited lifetime warranty, and a price tag of just over $400, makes the Gold Duster one of the most attractive dry-washers on the market.
For more information on the Gold Duster, contact the manufacturer at 1-877-527-8402, or visit them online at www.golduster.com. Dont forget to mention you read about it in Lost Treasure!