Dry Washing for Gold: How to Find Gold Without Water
In the desert there is no creek to run a sluice. A dry washer uses air and vibration instead. Learn how it works, what ground suits it and how to clean up the concentrates.
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Much of the world's placer gold sits in places with no running water: the deserts of Arizona and Nevada, southern California and the vast goldfields of Western Australia. Prospectors there developed a way to separate gold from gravel using air instead of water. In North America it is called dry washing. In Australia it is known as dry blowing.
How a dry washer works
A dry washer is basically a sluice box that uses air. It usually has three parts:
- A hopper with a screen on top. You shovel material in, and the screen removes larger rocks.
- A sloped riffle tray below, with a cloth or fine screen underneath.
- A source of air, either a hand-cranked bellows or a small motor-driven blower.
Fine, dry material drops through the screen onto the riffle tray. Pulses of air come up through the cloth under the riffles, lifting light particles and blowing them along. Gold and other heavy minerals are too dense to be lifted easily. They settle behind the riffles while the rest flows off the end of the tray.
The result is a concentrate that you can pan or blow down further later.
Bellows vs blower
| Type | How it works | Pros | Cons |
|---|---|---|---|
| Bellows (puffer) | A crank or motor drives bellows that push pulses of air | Pulsing action separates well; classic design | Heavier; hand-cranked models are hard work |
| Blower | A leaf-blower style fan pushes continuous air through | Simple and light | Constant flow can be less effective on fine gold |
Many experienced dry washers prefer the pulsing action of a bellows machine, but both designs catch gold when set up properly.
The golden rule: material must be dry
Dry washing only works on completely dry material. Even slightly damp soil clumps together, sticks to the cloth and carries gold off the end of the tray. If the ground is damp after rain, wait a few days or spread the material out to dry in the sun.
Clay is the other enemy. Clay-rich material forms lumps that roll through the machine. Break it down by hand or skip it.
Choosing where to dig
The same logic used in creeks applies to dry washes, because desert channels were shaped by flash floods:
- Inside bends of dry washes, where floods slowed.
- Bedrock exposed in the channel and the material sitting right on it.
- Cracks and low spots in bedrock, cleaned out with a crevice tool.
- Old dry-washer tailings near shallow pits. Old-timers often missed fine gold or did not reach bedrock.
- Benches and older gravels above the current wash.
Look for black sand and rusty quartz in the gravel, and test before committing to one spot.
Setting up and running
- Set the angle. Most machines have adjustable legs. A typical starting point is a moderate slope where material moves steadily down the tray without racing. Watch the riffles and adjust.
- Feed slowly. Shovel small amounts into the hopper. Overloading pushes gold over the riffles.
- Keep the air pulsing. Turn the crank or keep the blower running steadily.
- Check the tailings. Occasionally take a pan of material from the end of the tray and test it with water at home. If you find gold, adjust the angle or slow your feed.
Cleaning up
Every few buckets or at the end of a session:
- Stop the machine and lift the riffle tray carefully, keeping it level.
- Dump the concentrate into a bucket or a large pan.
- Brush or tap the cloth to release fine material.
- Process the concentrate. If you have water, pan it. If not, you can blow it down further by gently winnowing it in a pan, then take it home.
Many desert prospectors carry a few litres of water just for a final pan, or collect concentrates over several days and process them at camp.
Dry washing and metal detecting
The two methods work well together. Detectors find larger nuggets in shallow ground, while dry washers recover the fine gold and small pickers that detectors miss. Many prospectors detect an area first, then dry wash the best spots. Read our guide to metal detecting for gold for more.
Safety and rules
- Dust. Dry washing raises a lot of fine dust. Work with the wind at your back and consider a dust mask.
- Heat. Desert work is for the cooler months. Carry plenty of water.
- Land status. Much desert gold ground is covered by mining claims. Check claim records before you dig, and fill your holes when you leave.
Our state guides to Arizona and Nevada, as well as our Australia guide, cover some of the best dry washing regions.