I'm thinking of making a new type of dry washer. Want your comments.
I've seen lots of vids of dry washers and seen several in person. There seems to be two types out there right now. The first is the puffer type that puffs air up through a tightly woven cloth to puff up the dirt to let the gold settle. The second is basically the same puffer type with some vibration added. The one problem they all seem to have is that they do not liquefy the dirt adequately enough. The air puffs seem to break through the dirt in a small area leaving the rest undisturbed and the vibrations are not vigorous enough to liquefy the dirt. The one I remember the most had the feed dirt flowing down the sluice over top a layer of undisturbed dirt trapped between the riffles. Basically the top layer of dirt was just flowing over the lower layer not allowing the gold to drop into the riffles.
I have also watched several vids of dry panning, which is basically panning without water. You shake the pan vigorously to liquefy the dirt, thus allowing the gold to settle.
So, what I am thinking is a regular metal sluice box with reverse riffles and V-matting, with a vibrator that will shake the sluice side to side, maybe a slight vertical vibration too. The sluice would hang from chains to allow the side to side motion, with light springs to hold it in the middle of the supports. It would be at a steep enough angle so that the vibration would cause the dirt to flow down the sluice, over the riffles and out the bottom. As the dirt flows down the sluice the heavies would work their way to the bottom and get trapped in the riffles.
I would have to watch my feed rate so I don't overload the sluice causing the feed material to flow over a trapped layer of undisturbed layer like I have seen on too may puffer type dry washers.
Please give me your ideas, suggestions and comments. If anyone knows of anything like what I am suggesting let me know too. A web page or picture would be helpful if any exist.
Thanks, Keith
Comments
this is a idea I got from a youtube video in some dry areas they use a small cement mixer to break down the dirt and then run it through their dry washer, some old dry stream beds are cemented material but hold a lot of gold.you can get one from Harbor Freight tools and run it with a inverter of your pickup.
I built something like you are talking about just a little different. I had a classifier screen on top like high banker, but I also add a spray bar when near water. then under that i had a 4ft sluice help with bungy cords your chain idea would work too. then I found an old grinding wheel at an antique store (getting hard to find except on ebay) and too the wheel off. It had a ration of 1 to 10 and had the hand crank. I drill a hole just offset from center (not much) and put me a large bent rod in it and attached to bottom of sluice. Held rod in place with large rubber band. All of this was attached to an old ladder. When you cranked the shaft a lot of vibrating action of the sluice box. I never did get to prospect with it cause soon after I got a divorce and before I could get it wife's brother sold it for scrap. I hope this helps out your idea. Marvi
I have been working in desert placers where there is no water available. If you have water and use of a sluice, then separating values should not be a concern. It may be helpful to wet down your materiel from your buckets prior to running threw the sluice.
Hadn't thought about the need to break up clods prior to feeding them. I do plan to classify everything down to 1/4" before feeding. My plan is to classify stuff during the day into a buckets. Then process through the sluice at camp in the evening. I'll have to watch for clods.
I have a Keene 140 dry-washer using a (leaf) 2-stroke motor blower for air flow; and have some observations and opinions to share.
Electrostatic benefit (outside of what mentioned in your post) is present only when the field conditions are bone-dry. I wrapped the metal legs of my dry-washer with foam (for winter pipe insulation) to isolate it from (earth) ground. Definitely sparks leap from dry-washer to shovel in use in field. If this realizes an increase in gold recovery I have yet to asses.
Best gold recovery I have realized is when blower is running at near low idle and material is fed slowly. Much slower than the 2/3 cu yd rate stated in the Keene literature. Even here, there is a sudden drop of in gold recovery at/below #70 screen size.
Because of this I think a puffer style dry-washer may be a better choice in placer's where you anticipate small gold available. This as a motor driven blower system disgorges fine gold with all the dust. But if your'e interested only in course gold and pickers... then Rock On.
Mr. Purplebike has recommended running the recovery tray at a steep angle (like 38 degrees),
which I have not done yet but suspect intuitively is the way to go.
Air based systems do not break up and separate dirt (values) as like can be realized with the relative ease in a water based system (dirt clods just melt in water). Breaking down materials prior to running threw dry-washer is something which should not be ignored. Davy Dude has posted numerous videos which may demonstrate a practical solution to this issue.
Vibration (shaking) of recovery tray is very good, think your going in the right direction.