Most people think of creeks and rivers when they are looking for a place to go gold prospecting. The fact is that many rich gold bearing areas do not have the water necessary for panning, sluicing, or suction dredging. Many areas in Arizona, New Mexico, Nevada, and Southern California have limited water, yet excellent gold can still be found there. There are two primary ways that the small-scale prospector can look for gold in these areas;
and dry washing. In this article we are going to discuss how to dry wash for gold.
Dry washers are devices that are used to separate gold from lighter material without the use of water. They do this by using a regulated air flow, which blows off lighter material and allows the gold to settle. It was actually invented by Thomas Edison in 1897, and the new tool provided miners with an invaluable way to prospect in the desert. Remember that prior to the invention of dry washers, miners needed water to process the
out of rich gravels. This was often done by physically moving tons of gold bearing material to other areas from processing, but in many remote areas this was not feasible, and very rich areas were abandoned. With dry washers, these areas could be mined profitably, and they have been used in many arid climates ever since.
The earliest models were hand operated, and used bellows to puff air across a series of riffles to catch the gold, while lighter material would go over the riffles and onto the ground. Many dry washers used today are powered by a small blower motor, which provide a constant flow of air that moves a counter weighted fan that shakes the whole apparatus, allowing gold to separate out of the lighter materials. Most have a two box setup; the upper hopper uses a grizzly to screen out the larger rocks, and the lower box has a series of riffles to capture gold. Both hand operated and motorized types are used today and each has its own benefits and drawbacks. Motor driven devices can process more material in a shorter amount of time, but the motor means that it will be louder to operate.
As with any type of prospecting, carefully searching for areas with high concentrations of gold will result in higher recoveries. Dry washers are less efficient than other methods such as a sluice box. Water will always work better than air for separation, and when possible it is always a good idea to process material by panning or sluicing rather than dry washing. However, since this is not possible in many areas, using a dry washer will often be the best option.
Dry washing works best during the summer months when the weather has been dry. Due to its design, it is critically important that the material that is fed into the machine be extremely dry so that the vibration will allow it to break apart and gold to be able to separate naturally out of the mix. Many operators prefer to dig their material and let it lie out in the sun for a day or two before running it through the machine, allowing the material to dry out as much as possible. The drier it is, the more efficiently the dry washer will operate.
Another thing to consider is the use of a
as a backup search tool. Despite anyone’s best efforts, the design of a dry washer means that there is going to be some gold lost, either over the riffles, or rejected by the grizzly on the upper box. Using a metal detector to scan the waste piles will help ensure that you are doing the best possible recovery. A good quality VLF metal detector that can detect small pieces of gold is highly recommended.