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Steel Dumpster placer wash plant


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Had a load of odds & ends trash that need hauled to the local dump. The dump recycles certain things & had several different style steel dumpsters for cardboard, plastic, glass, etc. Unloading some recyclable stuff into a dumpster. I could not help but notice how ruggedly built they were.

A light comes on in the old noodle, with well thought out modification, the right style top load 4,5 or 6 yard steel dumpster tilted slightly (trailer or skid mounted) could be made into one hell of a large yardage (50-100 YPD) capacity grizzly / placer wash plant. Picture below gives you an idea what I am thinking. Just use your imagination, a bit.


Once home, I called around to get sale prices on used 4,5 & 6 yard dumpsters. I was pleasantly surprised to find out, many were available to purchase & priced cheaply ($300 to 500 bucks). In fact far cheaper than the cost of new steel to build the same thing, which surprised me. So, I have to make a few short trips to eye-ball a few for sale. Plan is if I can find the right style, size & priced used steel dumpster, to buy it, haul it to the shop & go from there. I have a considerable stack of salvaged steel mine rail to build a grizzly out of, for it. Spray bars from steel pipe are no big deal. Looks like a prospective winter project coming on.

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elder-miner, There is a guy in Centerville,Id who uses old 5 yard dump truck beds for highbankers. he is working material that is high in clay with big rocks takes a lot of washing to free up the gold.

He sets them with a slight slope to one side and toward the dumpgate which is removed, a 2'x4' is set at an angle flat inside the old gate with an 18" gap left to feed the sluice. He stock piles the material nearby and dumps it in the bed with the front bucket of his backhoe dumping it toward the back of the bed and on the uphill side and can run about 2 yards at a time.

He has water rights so he has a large setteling pond and a diesel pump suppling water to 3 dump beds, using an 1 1/2 inch hose he blasts the material toward the back of the bed and has to stop often to use a rock fork to remove bigger rocks.

Continually washing from the bottom of the pile from front to back you can soon see the black sand flowing through the gap into the sluice.

The gold there is small but plentyfull, he opens to the public some weekends and its bring your own highbanker and buy the material by the yard.

On the truck beds the minium is 5 yards, You will know you have did a days work because 2 yards will be rocks that have to be forked out.

I think your ideal is a good one!

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Repurpose is a miners right and seen a couple before as trommel holders and a classifier plant,so many doodads and sooo little time. To get one fabbed would cost mucho casha and just think of it as your green tribute to recycling--go get some gold-John-John

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Over the last 40 years, I have bought, built, leased, and/or used about every kind of large capacity placer wash plant around. That experience has taught me…… keep the plant as toilet flush simple as possible. The fewer moving parts, the better. Power driven moving, turning, spinning or gyrating parts create friction wear and pressure stress points. Usually if anything goes wrong, it is at those moving parts stress points. If a trommel stops spinning, or a vibrating screen stops vibrating, your plant is essentially down, until you fix, repair or replace whatever part, or parts went wrong.

Lots of wash plant designs look good theoretically on paper. On paper is one thing, actual rough and tumble operation in the field is another. Wet coarse mixed river or bank run gravel weighs just about 3000 lbs per yard. If you are designing a 50 YPD plant. That means in full blast maximum load operation you intend to run about 150,000 lbs of bank run material through it a day. Assuming 6 days of operation per week, that means you will theoretically run about 3.6 million lbs of mixed course gravel material through it, a month.

In effect you are going to drop 3.6 million lbs of river rock into it and tumble that rock out of it in at least 2, possibly 3 directions, one way or another. So, it had better be built tough, durable and sturdy enough to stand up to that kind of abusive wear. Greatly reinforcing all rock drop impact points when you initially build a wash plant, adds significant longevity to it. Initial & secondary grizzlies will reduce the size & weight of the raw feed material significantly, sizing the feed material down to what you run through the sluice box.

It is also prudent to build a wash plant with about twice the yardage capacity you plan to run daily. Bigger capacity is better, as there is far less chance of overloading your plant. How you feed the plant is also a critical factor. As dropping to much raw oversized material at once on a grizzly tends to plug it, and dumping to much material into a trammel tube at once tends to surge the whole load through the barrel, resulting in some gold exiting the tube, without dropping into the sluice header box.

The finer the sluice feed material is, the better gold recovery you will have. Simply because the water volume and velocity & box grade required to wash larger rock through a sluice box, also generally washes out finer gold. My experience is that reducing your sluice box feed material to below ¾ or 5/8ths inch minus is generally optimal for most gold recovery purposes. You also want to calculate the daily amount of water required by the plant, to operate at maximum efficiency. Obviously, without enough water to run the plant at optimal efficiently, you will have significant problems.

Then there is the question of sluice box design, width, side wall height and what sort of riffles to use in it. If your feed material contains mostly course gold, about any sluice box design will work, as big gold is relatively easy to catch. On the other hand very fine & ultra fine placer gold is not so easy to catch. My experience is where you have feed material that contains every type of gold ranging from course nuggets, down to ultra fine gold. You should start with a bare header-crash box, then a length of course expanded metal (catches course nuggets), then a length of ¾ or 1 inch angle iron riffles (catches small nuggets & flakes), then a length of smaller expanded metal with matting underneath it to catch the fine & ultra fine gold.

The following link is a good read on sluice box design.


So, there are a lot of factors to balance, getting any large capacity wash plant to work efficiently, all day every day, all working season. Assuming a site contains recoverable placer gold. Most large volume placer operations “fail” because the owners/operators don’t look at the whole operation from a material handling prospective.

1. Machinery (cost)

2. Labor to operate machinery.

3. Stripping, hauling, oversize material removal, washing, gold recovery, fine washed material removal, effulant settling ponds.

4. Fuel, maintenance, repair, insurance & incidental costs.

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  • 4 weeks later...

Some great thoughts there E-M. I followed that Clarkson study as the basis for the CC690 power sluice that my company, Advanced Mining Equipment, manufactures. I scaled down the stationary wash plant sized design into a hand portable version that a couple guys with #2 shovels could feed. It works great at catching the fines and the same general design could be scaled up to a portable wash plant size to partner with the grizzly design you mentioned. Best of all, no moving parts... just add water.

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Another way to do it.

But, I dislike the moving parts.

How would you keep it from clogging up without a vibrator or shaker motor???


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