would an airlift work as a dredge / sluice combo ?

[lobsterman]

hi all,
i posted this question on a mining forum and i thought that someone on here might know if this has been tried as a prospecting method ? or if it sounds at all feasable ?

i was thinking of an airlift set up, that uses 4" corregated drainage pipe, with a 5'-10' semi-level section at the bottom (suction end), leading up at a low angle, to a 5'-10' level section at the surface (outlet end) that dumps across a riffled tray that the sediments spill across.

now i was thinking that the heavier sediments may stay lodged in the riffles of the pipe, and any of the heavy sediments that made it up thru the pipe may be caught in the spillway tray riffles.

now i realize that any of the sediments trapped in the pipe would be difficult to get at, but not impossible, as i am sure there could be a way to flush it out without losing the (hopefully) gold rich sediments, that could then be panned.

so do you think this type of set up might work ?

obviously depth for the airlift, and being in the right location, are going to have alot to do with the success of it.

 

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[Jeffro]

First let me say that I have personally never used an airlift- but I have done some research on them and it seems that while they work great for sand and silt, not so much for river gravel from what I have read.

I have, however used the corrugated drainage pipe you are talking about and it works great, even without a sluice. In fact, it is my main dredge for remote access areas- sans motor, pump, etc. Gravity dredging. Love the stuff! Just pat the sides down working all the stuff inside down to one end, then set your tub or pan beneath that end and carefully pat it all out. Some goodies and fines will stick in the ridges as its still wet, but just wait til tomorrow (if its hot weather) and tap it out in the morning before you get back to work.

 

[Hoser John]

Air assist to a preexisting suction nozzle/pj works great BUT due to the expotential expansion as it moves up from the deep leaves you a frothing mess that is extremely hard to deaireate. What you have then(air only) is a floatation cell type of unit that won't move rocks effectively and floats away your gold too. tons a au 2 u 2-John

 

[lobsterman]

Hi jeffro and john,

sorry it took a while to get back, my computers been acting up, and i can't get the email notifications.

i was thinking that the airlift would be used in conjunction with a hookah set up and an underwater MD., at a couple of specific locations in a couple of lakes and ponds in central Alaska area, where my research has suggested a high probability of nature made gold traps with rich sedimentary deposits of gold ( i hope ), i know i'm going to have to remove a fair amount of sediment / overburden to get to the deposits. (thus the airlift and MD). i expect to be fanning the silt also and the airlift will help to keep good visibility in the hole's i'll be working in, but i think the naturally made gold traps that i will be working will be worth the effort, hopefully i can get the permissions to search these sites. i hope to make a go of it for next summer. i do expect it's going to be a logistical nightmare getting everything set up for when i get up there, but most of the gear i will need is available for rent in Anchorage and i have some family up there that may be able to help as well.

jeffro, i think you are right, i do believe that the pea gravel may be a problem, there will be a an alum. grate type device ( a screw on vapor lamp, shield/cage )on the suction end to keep out any larger gravel and to keep it from sucking up anyting i don't want it to. but on thinking about it perhaps having some gravel in the bottom of the tube might not be such a bad thing as it may help to stop any of the flake gold from shooting up the pipe.

Hoser John, i guess i didn't understand your post, are you suggesting injecting air into a suction hose that is going to a pump of some sort ? wouldn't that cause extreme cavitation and air locks at the pump ? i guess i just dont understand.

although i was planning on putting a Y splitter and a modified blow gun wand at the bottom of the air line for use as an air assisted waterjet / blower.

 

[Hoser John]

Turbidity is your worst problem,seeing what the LL your doing requires a good flow of water. Thats why a dredge works wonders--your are 12-20' upstream and the flow is behind you so you can still see. I'd just get a tiny p90 hooked up to a t-80 compressor and use the pump flow to blast the junk out of your way, clean out cracks and cut through clays and impacted gravels like butter. Air is not a decent medium for sand removal.Look at sea borne treasure hunters-they use blast from water pumps,and dredges as allowed, to remove the sands too. tons a au 2 u 2 -John