There are many methods of prospecting for gold in the 1990's. The search for this precious metal includes panning, sluicing, dredging, dry washing and electronic metal detection.

Sluice boxes were once built at the location of the mining site from the material that were on hand such as heavy wood planks and logs. Often the river current was diverted through the sluices so that gold-bearing gravel could be processed far quicker than using the laborious "hand panning" method. The old sluice boxes were lined with raised obstructions that were placed in a vertical position to the flow of the current. (These obstructions were later referred to as riffles)

When the gold-laden gavels were dumped into the upper end of the sluice, the flow of water carried the material down the length of the box. The lighter gavels (tailings) would be carried in suspension down the entire length of the sluice and then discharged. The heavier material (such as gold, platinum metals and black sands), would quickly drop to the bottom of the box, where they became entrapped by the riffles. Once the riffles collected a large quantity of concentrated black sand, a "cleanup" was implemented. The flow of water through the sluice would be diminished by a type of water gate. Then the riffles would be removed, allowing access to the heavier materials, which had collected during the "run." This remaining material or concentrate often contained all the values amounting to many tons of gravel which had to be tediously panned.

Among the more popular sluice boxes in use today are these two lightweight aluminum models from Keene Engineering. The A51 Mini Sluice (right) weighs in at seven pounds, while the larger A52 Hand Sluice tips the scales at eleven pounds.
The sluice boxes in the days of the 49'ers were very similar to the ones of today. The primary difference is the construction and materials. Sluice boxes were built of heavy wood planks, because lumber was cheap and easily obtainable. Today's sluice boxes are constructed of light weight aluminum and steel.

Any miner or prospector will tell you that portability is the key to success. Most of the gold deposits that easily accessible have long since been depleted of their gold. Today you will have to "get off the beaten path" to find any virgin areas.

During the Gold Rush sluices were first used to work the extremely rich bench deposits "terrace" gavels" which lined the banks of many Mother Lode Rivers. As time passed it became clear that sluice boxes could be used for working other types of gold-bearing material, to include ancient river channel deposits located hundreds of feet above the existing stream beds.

Modern prospectors use sluice boxes to work literally any type of gold-bearing gravel which can not be worked with a suction dredge. Sluice box's have been successfully used to process gold bearing gavels located in dry desert areas, by utilizing transported in water and recirculation systems.

In many cases today's prospectors use their sluice boxes to work areas located adjacent to flowing streams. Frequently, people who own suction dredges will carry in a lightweight sluice box to sample gravel bars they may wish to dredge at later date. If it turns out a gravel bar is not as rich as originally believed, all the labor of carrying in a large equipment may be avoided. For the benefit of those who are not familiar with the proper use of a sluice box, I will explain the basic principles involved. As you will learn shortly, they are not the least bit complicated. Anyone can be come a qualified "sluice operator" after just a few hours time spent in the field!


How to Sluice

Step 1: Getting Setting Up


Once you have located a good deposit of gold-bearing gravel set up your sluice box at any nearby place where the stream current Is flowing quite swiftly. The water depth should be nearly to the top of the sluice trough.

Transporting material to hand sluice in buckets.

Feed the gold-bearing gravel Into the upper end of the sluice box in carefully regulated amounts. Do not dump the entire bucket into the sluice box all at once. The proper Introduction of gravel will ensure maximum riffle efficiency and optimal fine gold recovery.


Step 2: Feeding the Sluice

Feed your gold-bearing gravel into the upper portion of the sluice box in carefully regulated amounts. Do not, under any circumstances, dump a large amount of gravel into the sluice box all at once! The gravel must be fed at a pace that will not overload the riffles. How can you tell when the riffles are overloading? It is simple. If you cannot see the uppermost "crest" of each riffle bar at all times, you are feeding the gravel too fast. Back off a bit. The use of a 1/4 inch classifier screen to prescreen material before dumping into the sluice box can save much time and effort. The penalty for overloading your riffles often results in lost gold! Each time a new load of gravel is dumped into a sluice box with overloaded riffles, any gold in that gravel will wash right over the material that is clogging your riffles and out the discharge end of the box.

Classifier screens are available in many sizes to fit both gold pans and various size buckets

Check the black rubber matting for the occurrence of values


Step 3: Check the Sluice for Values



Step 4: Tending the Sluice

After dumping each load of gravel into the sluice box, check the riffle section for large waste rocks that may be lodged in the sluice. Flick these rocks out of the riffles with your fingers. When large rocks are allowed to rest in the riffle section they will cause the current to wash out all the concentrates from the immediate area of the rock. If a rock is lodged in the uppermost portion of the trough, the washed out concentrates will merely settle in the next few riffles down. But if the washout occurs at the lower end of the trough, the concentrate may flow out of the sluice box altogether. As one can see, it pays to keep an eye on those waste rocks! And one more thing, don't forget to shovel away the tailings which will periodically build up at the discharge end of the sluice box. If you don't the tailings will back up into the lower end of the sluice trough, burying some of your riffles.

Remove large rocks that may cause values to wash away.

Shovel the material that has built up at the end of the sluice to prevent any obstruction that may prevent the flow of material.

Remove the sluice's riffle section, screen, carpet and wash into a pan or bucket carefully.


Step 5: Performing the Cleanup


Gold has a tendency to work its way beneath the matting which often lies at the bottom of the trough. You may be surprised at the amount of "color" that can accumulate there. Check to see if there is any fine silt clinging to the bottom, rinse all of it into your concentrate bucket.


After the riffle section has been removed, roll up the matting which lines the bottom of the sluice box trough and thoroughly rinse it off in a pan or bucket. The concentrate rinsed from the matting will contain most of the gold accumulated during the run.

Once the sluice's bottom matting has been rinsed, check the empty trough for fine silt which may have worked its way beneath the matting. If silt is present, rinse all of it into the concentrate bucket. Also rinse off the riffle section and screen and black matting. You may be surprised at the amount of color that can accumulate!

The final step of the sluicing is the panning of the concentrates, to get the gold out. Do this very carefully, since the material in your pan contains all the gold once spread throughout the many hundreds of pounds of gravel you have processed through your sluice.


Step 6: Getting the Gold Out



Summing Up

By the time you get to Step Six, you will have processed several hundred pounds of gravel, far more than the average person could ever hope to hand-pan during a daily outing. Using a sluice box of the type shown, you can also work this much gravel. All you need is a sturdy shovel, a couple of good buckets to carry gravel to the creek, and if your fortunate, a mining partner to feed the sluice box while you dig gravel, and a solid desire to get that gold.

Happy sluicing!