(Home-made wooden sluice box under construction.)
The venerable sluice box has been around a while now. Most, if not all, placer gold miners will employ a box at one time or another during their small-scale mining careers.So let's take a look see at this little gem.
The Rocker and the Golden Fleece
Historical accounts of sluicing for placer gold go back at least as far as the Greek and Roman empire days and it's probable some form of sluicing was done much earlier than that. The legend of Jason's golden fleece is no myth. Gold miners in Greece were known to use the wool from sheep hides to trap particles of placer gold in streams in ancient times. To the best of my knowledge the precursor of modern-day sluice boxes had its roots in American mining. Early gold strikes in the states of Virginia, North and South Carolina, and Georgia produced the rocker box or miner's cradle which employed a riffle tray, something that every sluice box has. The rocker was more efficient than a gold pan for processing gold-bearing gravels but it had its limitations. Although the rocker could could double or perhaps even triple the amount of material a gold panner could handle in the same amount of time, the rocker box had its limitations as well. It was unwieldy and depended on "hand-dipped" water to run material as opposed to the sluice box which uses the hydraulic action of a stream's flowing water to clear material from the riffles.
(Schematic of a rocker box or "miner's cradle.")
Early Sluices and Variations
With the advent of the California Gold rush in 1849, small-scale gold miners needed a piece of gold mining equipment that could handle greater amounts of gold-bearing gravels. This led to the construction of long boxes or chutes constructed of wood with perpendicular "cleats" (riffles) running the greater part of their length underlain at times with a "carpet" of rough material like burlap to trap finer particles of gold. At the top end of these sluice boxes was a removable header box with a metal "grizzly" or heavy perforated screen at the bottom that prevented larger rocks from passing down and into the box. An improved variation of the header employed a grizzly screen sloped at an angle that allowed larger rocks to slide off without the laborious process of removing a header box again and again for emptying. Some sluice boxes during this period used no header box or grizzly screen at all, however. Any material that could fit into a shovel blade was simply tossed into the upper end of the box. However, this required someone to stand by and remove larger rocks or move them on their way with a wooden paddle or shovel. An early sluice box like this could double or at times even triple the amount of material a rocker box could handle, especially if the miner or miners working the sluice were adept. Still, these early sluice boxes lost gold at times, especially the finer stuff. To help solve this issue, California miners began employing a variation of the sluice box called a "Long Tom." This was simply a series of ever narrowing wooden sluice boxes combined together to form one very long box. Long Toms proved very successful at trapping the finer gold that regular boxes tended to lose.
(A "down-'n-outer" from the Depression Era tending his sluice box.)
(Miners using a Long Tom during the California Gold Rush.)
Each and every sluice box employed today whether do-it-yourself or manufactured is a variation of these early boxes. Sluices remain the main gold trapping component of all sorts of mechanized mining equipment these days as well, including suction dredges, highbankers, and even those large gold mining wash plants seen on TV gold reality shows. Although not sluices per se, even dry washers used for desert or dry placer mining employ riffle trays. I constructed my very first sluice box out of wood and used it to good effect early on in my placer mining career. On occasion I still use the manufactured sluice my wife gave me for my birthday 35 years ago. In my book every small-scale gold miner out there should have a sluice box in his or her mining arsenal. You can't beat a box.
Here are some reasons why:
Portability: Manufactured sluice boxes are very portable these days due to the materials used for their construction (aluminum and other light-weight metals, high-impact plastics, etc.). There are small sluices and even fold-up versions that will fit into a 5-gallon bucket or in your backpack. The only issue that crops up in my mind with some of these store-bought sluice boxes is that some of them are very short in length...refer to my description of sluices in the California Gold Rush if you're still unsure why I say this. However, no matter how long a sluice box is, the operator's skill in setting it up and using it has a lot to do with its overall efficiency. We'll talk more about this in a later post.
(Keene Engineering mini-sluice box.)
Ease of set up: Compared to other pieces of mining equipment (especially those that are motorized) sluices are pretty easy to set up once you get the hang of the correct slope and water flow necessary for running gold-bearing material efficiently. I will say this though. On occasion your patience can be tested in setting up a box! However, the more you use one the easier the set up factor gets.
Greater processing capacity: An average-sized sluice box correctly set up and running with peak hydraulic action can process much more gold-bearing material than the old-time rocker and you may, at times, find yourself hard-pressed to feed an adequate amount of gravel into it once things are running at peak efficiency. Granted, using a box can be labor-intensive but there's very little in small-scale gold mining that isn't.
I'll continue in this vein (pun intended) in my next post.
(A bare-bones, high-impact portable box.)
You newbies out there listen up. One thing you need to remember in this small-scale mining gig is that your gold pan is a prospecting and clean-up tool, NOT a piece of mining equipment. On the other hand, a sluice box IS a piece of mining equipment (albeit rudimentary). Use your gold pan to test, sample, prospect, and to pan out concentrates. Don't try and process gold-bearing material with it unless you're pulling a troy ounce per pan...and that ain't likely to happen in this lifetime! Get my drift?
Good luck out there.
(c) Jim Rocha 2017
Questions? E-mail me at firstname.lastname@example.org