Fine Gold Recovery

Big flakes take care of themselves. It is the fine gold that slips over the lip of the pan or washes out the end of a sluice. This guide is about the methods that help you keep it, from the pan to the sluice to the magnet step at cleanup.

Why is fine gold so easy to lose?

Because every gravity method catches gold by its weight, and fine gold has very little weight to work with. Water that is gentle enough to leave a flake behind can still carry off a speck.

It has always been this way. California's state guide to placer gold recovery notes that early miners recovered no more than about 60 percent of the gold in their gravel, and that even in 1945 the average was only about 70 to 75 percent. Most of what got away was the very fine gold. The same guide expects most of the placer ground still left to work to hold a bigger share of fine gold than the gold rush ground did.

Panning alone can miss a lot of it. In one study of very fine gold from the Snake River, cited in a USGS report, experienced panners recovered only about 18 percent of the free gold in the samples. That was unusually fine gold, but it shows how much careful method matters.

What counts as fine gold?

The Forest Service and BLM panning guide calls gold between 0.4 and 0.9 mm "fine" and anything smaller "flour". To learn what the smallest gold looks like and why some of it floats, read our guide to flour gold. This page is about the methods that keep both.

How do you recover fine gold in a pan?

Screen to an even size

Run your material through a classifier before you pan it. California's state guide says material of an even size gives the best recovery in a pan, and the USGS screens its own samples to a narrow size range before separating fine gold for the same reason. When everything in the pan is about the same size, weight is the only thing left to sort it.

Wet every grain

Fine gold that stays dry on top can float off. Let your material soak fully before you start washing, and if you see specks floating, add one drop of dish soap to the pan. The USGS uses a single drop of detergent the same way in its lab method, to help water wet the grains so they sink.

Slow down and pan in calm water

Swirl gently once you are close to the black sand. Calm water helps, and California's state guide suggests a tub or pool of clear, still water for panning. Do the final panning over a second pan or tub so anything that slips over the edge can be panned again. The USGS report also notes that cold water separates grains slightly better than warm water, as long as no air bubbles form on the grains.

Mind your pan's surface

A little rust in an old steel pan actually helps hold fine gold, according to the Forest Service and BLM. Plastic pans are different: they scratch easily, and the USGS found that small grains can lodge in the scratches. If your plastic pan is badly worn, fine gold may be hiding in it.

Clear the black sand with a magnet, then check it

Black sand is where fine gold hides, so taking the magnetite out leaves far less material to pan and makes small specks much easier to see. Pass the magnet over the wet black sand in your pan. In a normal pan, our magnet pulls up all the black sand we see.

Then check what it lifted. Gold is not magnetic, but a tiny speck can be stuck to a magnetite grain and ride along with it. The USGS lab method moves the magnetic grains through several containers in a row so no gold leaves with them. At home, the easy version is to release the magnetic sand into a pan of water and pan it once more before you dump it. Our magnets let you slide the sand off with your thumb, so it drops wherever you want it. Keep the magnet away from steel tools, phones and cards, and read our magnet safety warnings. A black sand magnet makes this step quick, and our separation guide walks through it in full.

How do you set up a sluice for fine gold?

California's state guide gives a few clear points. Clean up the sluice more often, slow the flow of water and gravel to about 2 to 3 feet per second, and screen your material so you feed it smaller pieces. Some operators add a liner to trap fine gold, or make the sluice longer. A long, narrow sluice works better than a short, wide one, and the guide gives slopes of about 4 to 18 inches over every 12 feet. Run well, a sluice can come close to catching 90 percent of the gold.

A rocker follows the same idea. With coarse gold the head of the rocker sits 2 to 4 inches above the tail, but where fine gold is present the guide suggests lowering that to about an inch. Too much water carries gold straight through, and too little turns the material to mud that carries fine gold away.

Do dry methods work for fine gold?

Not well. California's state guide notes that every dry placer method, including dry washers, loses a large share of the very fine gold. Where you have water, use it.

What about blue bowls and other fine gold machines?

Larger operations use shaking tables and spiral concentrators. California's state guide describes shaking tables that catch heavy grains from about 100 microns down to 5 microns, and spirals that handle material from about 3 mm down to 75 microns. These are cleanup machines for a lot of concentrate, not tools most panners need.

Some panners use smaller tools at home, such as a blue bowl. In a blue bowl, water swirls around a bowl, the fine gold settles, and the lighter sand washes over the rim. We found no official testing of blue bowls or similar hobby tools, so we give no recovery figures for them.

How much fine gold can careful work save?

A lot more than rushed work. Using a shaking table followed by careful panning, the USGS lab method recovered at least 95 percent of the gold particles in its Snake River samples. That was a lab with lab equipment, not a creek, so do not expect the same number in the field. It does show that patience and the right steps pay off.

Should you use mercury or chemicals for fine gold?

No. California's state guide names the health hazard of mercury as its biggest drawback, and the USGS estimates that about 10,000,000 pounds of mercury were lost to the environment from placer mining in California. Home chemical methods have no official support. Stick with the pan, the magnet and a careful final pan.