Sluice Box: How It Works and How to Use One

A gold pan is great for testing a spot, but it is slow. When you want to work more gravel, the next step for most prospectors is a sluice box. This guide explains what a sluice is, how it catches gold, what riffles and mats do, how to use one at a creek, where you are allowed to, and how to clean it up at the end of the day. Randy has run sluices and built his own.

What is a sluice box?

A sluice box is a channel that you run water through, with ridges called riffles across its floor to catch gold. California's state report on placer gold recovery methods calls the sluice and its riffles one of the oldest ways of separating gold by gravity that is still in use. Sluices come in every size, from small portable prospecting models you can carry to a creek, up to commercial runs hundreds of feet long, and they are made of wood, aluminum, plastic or steel.

The idea is old. In the gold rush days, the Forest Service and BLM explain, miners shoveled gravel into long, narrow wooden boxes with water running through them. Slats across the bottom caught the gold, and the waste gravel, called tailings, washed out the end.

How does a sluice box work?

It uses water to move the light material and gravity to keep the heavy material. Gold is far heavier than sand and gravel, so as the mix flows down the box, the gold sinks fastest.

The riffles do the catching. The California report explains that they slow the flow along the bottom, so a bed of sand builds up behind each one. The water swirling over the riffles keeps that bed churning, which lets heavy grains tumble down into it while lighter ones get lifted and carried away. Some riffles have an overhanging lip that adds extra swirl behind them.

The balance matters. The report says you need enough water to build that sand bed and keep it churning, but not so much that it washes the bed away.

What are riffles and sluice mats?

Riffles are the cross bars in the bottom of the box. The California report describes them as made of wood, rubber, iron or steel, and even rocks, usually set in a removable rack so you can lift them out for cleanup.

Under the riffles there is usually a lining or mat to catch the gold that slips past. In the old days miners used carpet, corduroy, burlap or denim. Today it is more often artificial turf with long strands, screens or ribbed rubber mats. The report explains that these act like many tiny riffles packed close together, which helps hold fine gold. Some prospectors call this kind of lining miner's moss.

Does a sluice box catch fine gold?

Not as well as it catches bigger gold. The California report lists fine gold losses as one of a sluice's main weaknesses, along with needing plenty of clean water and having to stop for cleanups. On the plus side, it says sluices are portable, cheap, need little watching and cope with uneven loads. Mats, screened gravel and frequent cleanups all help with fine gold. Our guide to fine gold recovery covers more ways to keep it.

How do you set up and use a sluice box?

There is no official setup guide for small hobby sluices, so the steps below stick to the general principles in the California report and the public land rules. The report's own numbers for slope and flow were written for large commercial sluices, so we do not repeat them as advice for a small one.

1. Check the rules first. Make sure the land is open, unclaimed and that sluicing is allowed there. See the section below.
2. Find moving water. A sluice needs a steady flow of clean water, so look for a spot in the active stream where the current is strong enough to run through the box.
3. Set the box in the current. Water should run through with enough swirl to keep the bed behind the riffles moving, but not so hard that it scours the box clean. Adjust the angle until the gravel moves through and the riffles hold.
4. Screen your gravel. Sift out the big rocks with a classifier before feeding the box. Smaller, more even material is easier on the riffles and helps with fine gold.
5. Feed it steadily. Shovel gravel in at the top a little at a time rather than in big loads.
6. Clean up often. A sluice that sits too long between cleanups starts to lose gold.
7. Leave the creek as you found it. Dig only in the loose gravel of the active stream, not the banks. Fill your holes, put rocks back and keep muddy water to a minimum.

Where can you use a sluice box?

It depends on where you are, more than for a gold pan. A sluice is fine in some places and banned in others, so check with the land manager and your state wildlife agency before you go, and check the current rules, since some of the sources below are years old.

On Bureau of Land Management land, the BLM counts non-motorized sluicing as casual use, the low-impact activity that normally needs no special permit, unless the area is closed or claimed.

National forests differ from place to place. On Alaska's Chugach National Forest, the Forest Service's 2010 guide allows gold pans and hand-fed sluices year round in its set-aside panning streams. In Montana, the Forest Service's Northern Region asks for a Notice of Intent to the district ranger before you use even a small sluice or rocker box. At Arizona's Lynx Creek panning area, mechanical mining aids are not allowed at all.

States set their own rules too. Washington needs no formal Hydraulic Project Approval for a small, non-motorized sluice box, but you should follow the state's Gold and Fish rules. Oregon's general mining permit covers non-motorized equipment in the water without registering, as long as you follow its conditions, while high bankers need an individual permit. Utah closes its stretches of the Green, Colorado and San Juan rivers to dredging and sluicing. Some parks allow no sluices at all: South Yuba River State Park in California allows hands and pans only, and Whiskeytown in California bans sluices and rockers.

In California, the Department of Fish and Wildlife has banned suction dredging, but in a July 2026 news release it said that gold panning and non-motorized sluice boxes remain legal. Land managers can still ban sluices on their own ground: California's state recreation areas allow no tool but a gold pan, and South Yuba River State Park and Whiskeytown ban sluices, as noted above. Check with the land manager before you set one up.

Never set up on someone else's claim or on private land without permission. Our guide on where to pan for gold explains how to check land and claims.

How do you clean out a sluice box?

Wash it down, collect what the riffles and mat caught, and pan it out. The California report's cleanup steps come down to this:

1. Run clear water. Stop adding gravel and let clean water run until the riffles are free of loose gravel.
2. Catch the outflow. Set a pan or bucket at the outlet end.
3. Lift the riffles. Starting at the top, take out the riffle rack and rinse it back into the box.
4. Wash the mat. Rinse the mat or lining into its own bucket or tub, since much of the gold sits there.
5. Pick out the big pieces. Any gold you can see can come out by hand.
6. Pan the concentrate. Wash everything left into a container and pan it down. The report notes that sluice concentrate is usually finished by panning.

What is left in your pan will be mostly black sand. A black sand magnet lifts out the magnetite, and in a normal pan it pulls up all the black sand we see. A magnet does not pull gold, but a tiny flake can ride along stuck to a grain of magnetite, so check what you lift before you toss it. Then a quick final pan leaves your gold. Read our magnet safety warnings before you use one, especially around steel sluice parts and tools. Our gold cleanup page walks through the whole process.

Never use mercury in a sluice or on your concentrate. It is a serious health hazard.

What about rockers, long toms and high bankers?

They are all relatives of the sluice. The California report describes each:

A rocker is a short box you rock by hand while pouring in water and gravel. It was one of the first tools used after the pan and is rarely used today. A long tom is a sluice that uses less water, with a screen over a riffle box at its lower end. A dip box is a short, lined sluice that you feed by the bucket where water is scarce, though it is poor at catching fine gold. A dry washer is basically a short sluice that uses air instead of water, for the desert. A high banker is a sluice with a small pump, so you can work gravel away from the stream. Randy has worked a high banker and dry washed for gold.

Because high bankers have a pump, they fall under different rules from a hand sluice in places such as Oregon and Alaska, so check before you bring one.

Can you build your own sluice box?

Yes. The California report notes that most sluices in use were made for a specific job, often by local shops or by the miners themselves. Randy has built his own sluice. We do not publish plans or measurements, but if you build one, a removable riffle rack makes cleanup much easier.