Day 11, Highbanking


A power sluice, sometimes called a highbanker or hibanker, is a piece of gold prospecting equipment that uses a pump to force water through a sluice box to mimic the natural flow of a stream. Sometimes a hopper box with spray bars and a classifier screen (or grizzly) is employed. The gravel is added slowly by shovel into the hopper box and washed over a classifier screen to remove pieces of rock that are too large to go through the sluice.


Our Highbankers, ready to work at the Motagua River

The water pump can be either electric or gas powered. If the unit is designed to catch and recirculate the water it is called a recirculating power sluice, or recirculating hibanker.

Benefits of highbankers:

Rather than haul material to the water, you can bring a lightweight, efficient power sluice to the source. The power sluice can work remote placer deposits hundreds of feet away from the water source. In the case of recirculating units they can be operated in desert areas with very little water.

The typical hopper design washes clay and debris with a high pressure washing spray bar and all washed material becomes classified to less than 1/2 inch for impoved recovery of smaller gold. The spray bar may be equipped with a water valve for ease of controlling the flow in the sluice.

The sluice box itself is constructed like a normal stream sluice except it is equipped with an adjustable independent leg support system that enables the power sluice to be assembled on any type of terrain in a matter of minutes.

Consider a sluice box, mounted on a 4-legged stand that gives the sluice box the correct slope. Then, mount a box (called a Hopper) at the top end of the sluice box that gravels are shoveled into. In the hopper, put a “grizzly” which is a series of rods sloping in the box that will filter out larger rocks. Also in the hopper, put one or two “spray bars” that shoot a spray of water onto the gravels that you have just shoveled in. Add a gas engine with a water pump and some hoses to get the water from the pump to the spray bars and you have a High Banker.

When you shovel in gravels into the hopper, water sprays onto the gravels. Anything that is small enough to drop through the Grizzly enters the top end of the sluice box. Anything to large to fall through the grizzly falls, or is scraped off with a shovel, into a pile directly behind the rig.

When the smaller gravels fall into the top of the sluice box, the water from the spray bars begins washing out the gravels just like in a regular sluice box. The sluice box has riffles, carpet or miner’s moss just like a sluice box. In fact, High Banking is often called “Power Sluicing.”

Just like pans and just like sluice boxes, High Bankers come in a large variety of styles and sizes. The small High Bankers often come with a pack frame so the high banker can be backpacked to remote locations. The largest high bankers often are a combination of dredge and high banker, giving the recreational prospector the option of high banking or dredging.

Differences in riffles, spray bars, carpets, miner’s moss, engine-pump combinations, hose and frames all contribute to a seemingly infinite selection of high bankers. I suggest getting the largest High Banker-Dredge combination you can easily handle and can afford.

High bankers give you the ability to bring the water to you work site. Sometimes, gold bearing gravels are located some distance away from a water source, or the water source is not conducive to using a typical sluice box. The high banker pumps water from the water source to the worksite, so you don’t have to carry buckets of gravel back to the creek.

High bankers are moderately priced, come in pieces for easy transport, and are very efficient.

Highbanking Tips:

Tip #1

Do not run your high banker water pump without an air filter. Even though it may not look dusty, microscopic dust will score the intake valve and the combustion chamber, greatly reducing the life of the engine. Change the air filter a minimum of once per year.

Tip # 2

Change the engine oil after the first 5 hours on a new motor. This is “break-in oil.” After that, change the oil every 20-25 hours running time. Typical high banker engines do not have an oil filter, and the oil must be changed more often than your car. Use ONLY grades and weights of oil recommended by the manufacturer. For Briggs & Stratton engines, ONLY 30W detergent oil (do not use 10W-30 or non-detergent oil).

Tip #3

Do not leave the water pump’s gas tank empty, even overnight. When done for the day, top off the tank with fuel to prevent condensation from forming in the tank.

Tip #4

To store the water pump at the end of season, hook a water supply to the pump (do not run dry). Fill the tank with fuel treated with a fuel stabilizer, such as STABIL. Run the engine for 5-10 minutes. Cover and store in an area not susceptible to gas fumes buildup.

Tip #5

Use only the amount of hose necessary to bring the water from the water source to the work site. It is better to have 2 or 3 section of 25 feet each than a single 75 foot length of hose. The longer the hose, the more the pump has to work to get the water there.

Tip #6

Keep the speed of the water in the sluice box only fast enough to get a good “bubble” over the riffles. The water needs to be fast enough to wash out the light gravels, but too fast will also wash out the fine gold.

Tip #7

Feed the high banker slowly. Packing the hopper full will only cause the fine gold to ride the gravels farther down the sluice box, and possibly out of the sluice box all together. Feed it slow to keep the fine gold.

Tip #8

Watch the tailings coming off the grizzly. Large nuggets or specimens will fall off the grizzly into the pile of rocks and be lost. When the high banker is moved, check the tailing pile with a metal detector.

Tip #9

Use ribbed carpet under miner’s moss in the sluice box. This will do a better job of catching fine gold better than miner’s moss or ribbed carpet by themselves.

Tip #10

Attach a garden hose with a garden sprayer nozzle at the hopper. If necessary, you may have to modify and attach a connection for it. This hose will be used to spray down those areas of the hopper that don’t get enough water to properly wash the gravels shoveled into the hopper.


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