The Keene Model 151S with Hot Air Induction

 (This desert rat ain't screwing around.)

After reading my two previous posts on Keene Engineering dry washers, you no doubt fully understand that I still maintain my love affair with dry washing in general. As I already mentioned, I've not slung high desert dirt into a dry washer for some time now, but in my early and journeyman small-scale mining days dry washing was my main gold mining approach.

Bait on the Hook

There's very little, if anything, I don't like about small-scale gold mining and prospecting. I've had the gold Jones (i.e., fever) from the outset and I'll readily admit that fact to one and all. Color has been running through my veins for over 35 years now and I still love to see that lovely gold in a sample or clean-up pan, although I must admit I've been around the mining block long enough now that it takes much more color to get me excited than it did when I was still green behind the years. Have I grown cynical about it all? Perhaps a tiny bit. But don't think for an instant I'm not ready to shoulder a pick and shovel if there's decent gold to be found, anytime and anywhere. This willingness to hump the boonies and work harder than a Third World coolie includes all those desolate dry placer areas I used to dry wash regularly as a younger (and somewhat fitter) man. Hell, I'm still game on that issue and not liable to bow out any time soon unless the Universal Source decides otherwise. Dry washing? You bet pard. Just give the word and I'll load up my puffer, my tent and sleeping bag, grab a few cans of beans and jugs of water, and I'll damn sure give you younger mining studs something to think about. After all, I'm a legend in my own mind! Anyhoo, this sort of digression is simply bait on the hook for those of you out there who've never had the opportunity to dry wash for desert gold. Like I said before, you're missing out on a special aspect of small-scale mining that's comparable to anything you're now experiencing on those streams, rivers, and creeks. Sure, it's a different ball game in many respects, but gold is gold and getting it is the medium...if not the message. Somewhere along the line you should shut down that dredge or highbanker and learn how to dry wash for gold, even if it's only for the experience and knowledge gained. You can be one hell of a miner with that dredge or highbanker I just mentioned and if so, my hat's off to you. Just as it is to anyone who knows the ropes and does this thing of ours well. But here's the deal. You'll never be a well-rounded miner in my book. This is not a value judgement on my part so don't get your hackles up. I fully understand that geographic locations are a big factor in your overall ability to dry wash for gold and it ain't easy to travel hundreds or thousands of miles to eat desert grit. I'm just saying, you know?

(Here's an interesting home-made job.)
Electrostatics and Gold Recovery

So this brings us to the heart of the matter, the Cadillac of the Keene series of dry washers, the Model 151S with hot air induction. Doesn't that make your little dry washer's heart pitter-patter a little faster? Well it should since the Model 151S is an electrostatic machine. Actually, Keene uses the term "vibrostatic" and I'll explain what that means in a second. First things first though. Electrostatic dry washers are a relatively recent phenomenon (in terms of decades, not years) and are based on the principle that electrical charges exert certain forces on one another, especially when those charges are coming off the surfaces of certain dry materials. This is my somewhat inept description of Coulomb's Law. Static electrical charges and more importantly, their discharges, are a good example of what I'm talking about here. All of us have experienced static electrical shocks at some time in our lives. Ever wonder why certain thin plastic wrapping or cling wrap sticks to your hand or fingers when first removed from some sort of packaging or product? That's because there's an electrostatic charge involved and that cling wrap is attracted to it. This is the basic principle behind electrostatic dry washers, with small particles of gold being attracted to the charge generated by the electrostatic machine itself. This gold recovery principle is nothing new, by the way. In the early 1900s, inventor and wealthy businessman Thomas Edison came here to northern New Mexico to try and use an electrostatic process to recover placer gold from the arroyos and washes of the Old Placer District near Santa Fe. Ultimately his attempt at getting the gold failed and I know why, having prospected and worked the Old Placers for many years. Edison encountered damp dirt once the dry top layer or two of wash gravel was removed. Again, for any dry washer to work effectively the material being run through it must be completely dry. This is especially true for electrostatic machines where static charges are part and parcel of their gold recovery ability. In case you didn't already know, dry washers are (overall, anyway) not as effective gold getters as machines or gear using water to concentrate heavy minerals and gold. Often, very fine particles of placer gold will spill over the tail end of a dry washer's riffle tray and end up mixed in with your fine tailings. Electrostatic machines like the Keene Model 151S are designed to help solve this problem.

The Keene Model 151S with Hot Air Induction

OK, I said I'd explain Keene's use of the descriptive term "vibrostatic" to describe the Model 151S, so here goes. The Model 151S not only uses the electrostatic charge principle for recovering gold, but also suspends the riffle box in a way that uses the vibration of the machine itself to shake or vibrate the material flowing through the riffle tray for enhanced separation of heavies and gold from lighter materials. It's a "one-two punch" sort of deal. Now you know what the term "vibrostatic" means when Keene applies it to one of their electrostatic machines. According to Keene, the Model 152S incorporates a soft-bed technology that creates a greater electrostatic charge beneath the riffle tray and employs what they term "scrubbing pins" for earlier gold separation. These scrubbing pins are also supposed to help create a more even flow of material before it enters the riffle tray. Since even the slightest dampness contained in potential gold-bearing dirt or gravels is the bane of all dry washer operators, the Model 151S ducts pre-heated air into the radial blower at nearly 50 degrees fahrenheit above the ambient temperature. This is the hot air induction factor and it's a great asset in ensuring the material being run through the Model 151S is dry enough to ensure maximum gold recovery, even with the very fine stuff. The Model 151S comes with a Briggs and Stratton 5 horsepower motor, a 4" x 2000 cubic feet per minute radial blower, and 10 feet of four-inch ducting hose. Set up and operating properly, Keene claims that the Model 15S can process over two tons of material per hour. That's a shitload of dirt, ladies and gents. I suspect that if you shoveled two tons onto that puppy every hour your dry washing activities would be put on hold for a bit while you recuperated and tried to straighten your back out! Still, that's an impressive capacity for gold-bearing dirt. The bad news? The Model 151S weighs in at 100 pounds (give or take a pound or two) so you probably won't be humping that puppy on your back into some remote desert wilderness. Additionally, the Model 151S ain't cheap since it runs around $1600.00-1800.00 dollars (USD) retail. Like they say get what you pay for.

 (Keene's cheaper, pack-in version "vibrostatic" dry washer.)

That's it for this round. You desert rats out there take good care and throw a shovelful of dry dirt onto that hopper screen for me, OK?

(c) Jim Rocha (J.R.) 2015

Questions? E-mail me at


  1. Good morning JR, The thing I have against a dry washer or suction dredge is the noise......I like the peace and quite of lonely places far from other people. The other thing I have against them, and more importantly,is the added expense of gasoline. Before you can make any money, you have to pay for that, as well as the gas your truck used to get there.......something I have not yet ever been able to do. If you look at this as more of a hobby (I do) it is still cheap entertainment, but it would be nice to come out ahead once in awhile. At least with a dry washer the Forest Nazis can't say you are hurting the fish! This may become the only legal way to enjoy this hobby of ours before long. Until they find some sort of endangered microbe in the sand.......
    They say it is already illegal to dig pits on "Federal property"....fill 'em in as you go I guess........ getting so a guy can't have any sort of fun without breaking a law somehow.


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