(Here's an old work horse for you.)
A number of you out there have asked me about using water-based mining gear to recover gold in desert or dry placers. It's a reasonable question but in this post I'm going to explain why the venerable old dry washer is still your best bet.
It should go without saying that mining equipment that uses water to concentrate gold-bearing material is the most efficient type of gear you can use. Gold is nearly twenty times heavier than water and you don't have to be an Isaac Newton or an Einstein to figure this premise out. Still, the last time I checked, desert or dry placers are pretty much devoid of water which is why they're called desert or dry placers. Yes, I'm being a bit of a smart ass here but therein lies the rub. Desert or dry placers don't lend themselves to sorting gold with water. After all, they are what they are.
Are there ways of getting around this lack of water issue? Absolutely. You can:
1) Work a desert or dry placer where substantial amounts of water are close by.
2) Haul water in from a nearby location.
3) Bring lots of water with you and use a recirculating gold recovery system.
Let's look at these three options one-by-one:
1) How many desert or dry gold locations have you come across in your prospecting and mining career where substantial amounts of water were close enough for you to use in your small-scale mining efforts? I suspect the answer is very few, if any. In fact, in my 35-plus years of gold prospecting and mining the only desert or dry placer location that even comes close to meeting this criterion is the "Potholes" Gold District near the Colorado River in extreme southeastern California. Even at the "Potholes" you'd be pumping water a fair distance or hauling it to your work location...which brings me to option number two.
("Hmmm...could'a sworn there was water close by somewhere.")
2) Sure, you can always haul water to the dry placer site you're working. But be prepared to do lots of hauling and burning decent amounts of gas doing so. It takes a lot of agua to run just about any water-based piece of mining gear and desert communities are typically few and far between. Here's the real kicker to this option though. Every minute and every hour you spend hauling water is another minute and hour you could've been mining and getting that desert gold. I don't know about you, but I don't have unlimited amounts of time to prospect and mine. So every minute I can spend doing one or both of those things is precious to me. If you can't grasp this subjective consideration then how about answering an objective question for me? Is it truly efficient and cost-effective from a gold recovery standpoint to be hauling water to your small-scale mining operation? If you can answer an honest "Yes" to this query then you're a much better miner than I am and my hat's off to you.
3) I've known a few small-scale gold miners in my day who used (or use) small-scale mining gear that runs off re-circulated water. The more experienced of these did pretty well at times and others simply tanked. Here's the deal as I see it (and you don't have to agree, of course). You better be running some pretty rich dirt through that gear. Otherwise, that water you brought along to recirculate and re-use is going to get very gummy and dirty very quickly. More quickly than you could imagine, as a matter of fact. Doubt what I'm saying here? Try this test sometime. Get your gold pan and a panning tub full of clean water and start working your gold pan using five-gallon buckets of dry placer or desert gravel. Next, time how long it takes for the water in that panning tub to become relatively useless because it's been turned into a sludgy muck. "Just haul in more fresh water" you say? OK, and where does that leave us? Right back at option number two.
Best Tool for the Job
I'm trying my best to be objective in all this and not prejudicial. After, all...if one of the three (or all three) of the options listed above works for you then go for it. More power to you my friend. I'm simply trying to present my case that a "puffer" or electrostatic dry washer is still your best bet in desert or dry placer gold ground. Just as you may be solidly sold on your recirculating water get up, so am I rock solid on my choice of a good dry washer on desert gold ground. I understand your choice and your rationale, but I'll opt for my approach each and every time. Like they say, "Never the twain shall meet."
(Look at that little beast go!)
All this said, are dry washers the ultimate answer to working dry placer ground? No, they're not. Dry washers can be temperamental and balky at times, there's an art to configuring and setting them up properly, they're less efficient (in an overall sense) in trapping gold than their water-based counterparts, and you'll end up eating a lot of dust, dirt, and grit running one for any length of time. So no, dry washers aren't perfect by any stretch of the imagination. But it's my opinion that they represent the best tool for the job at hand.
Been There Already...
Let me put things another way. I wouldn't EVEN dream of heading out to work a dry or desert placer location without my trusty dry washer snuggled up next to me in my vehicle. Sounds a bit strange perhaps, but it's a love affair of sorts for me. I cut my mining teeth using a hand-made "puffer" dry washer on dry, desert ground. That little machine got the gold for me despite my initial mining ignorance and no matter how hard I ran it. That "puffer" had heart. It would run DRY (yes, gold-bearing dirt can sometimes be damp in dry placer areas) gravel all day, day-after-day. I only had to feed it gas and periodically replace a pulley belt or tighten a few screws along the way.
Try to find a dry or desert placer with plenty of water next to where I'm working? I'd be more effective pissing into a strong westerly wind. Spend my valuable mining time hauling water around the desert? I'll respectfully decline, if you don't mind. Recycle the same dirty water over and over again until it gums up the works? No thanks. Been there and done that.
Trust me...a dry washer is still your best bet.
(c) Jim Rocha (J.R.) 2014
Questions? E-mail me at firstname.lastname@example.org