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Anyone have experience/opinions on drywashers?


#1

Just found out they exist. I’m curious if they are good?


#2

Won’t work many (if any) places in New Zealand, our ground is way too wet … it’s my belief they aren’t as efficient at catching the range of gold that a highbanker will, and a highbanker will process a lot more material in an hour.

If you are too far away from water I would look at building a pond and lining it with polythene and recirculating water before considering dry washing, we don’t live in a desert.


#3

Used a lot in W.A, mostly on a much bigger scale, this is just a smaller Keene dryblower.
80% return is about the norm, some plants are processing over 200 tonnes a day running fast.

Yep, much higher returns on a wet plant, however no water where most of the gold here is and the w.a gov or epa (environmental protection agency) has pretty tight control over bores etc due to salinity/ground water reserves.

I have a small sluice which recycles about 200L of water running off a car battery/12v bilge pump and that water lasts about 2 hours before it sludges up too much.


#4

Thanks.
Just curious about the concept. Figured they might be for drier areas.
I can’t find any details, having trouble working out where the air flow circulates in them?


#5

Basically there are bellows underneath the riffles in the larger models, these smaller ones rely on your smaller ‘leaf blower’ to lift the lights up. The main part about a dryblower is getting the dirt to ‘dance’ through vibration and lift from air. Gold doesn’t like to dance too much, most heavies are found like in a wet sluice trapped in the first few riffles, however the very fine gold can more easily be lost with dryblowers, hence the 80% as a guide for recovery rates.
The only place i can think of using this system in nz is in central otago or canterbury in a very dry summer, working old pig sty’s etc…


#6

I experimented many years ago with a dry blower system because I had decided to do a smart arse two fold thing. I had bags and bags of Arrow River blacksand and fine sand plus gold and decided to use the dry blower principle to get rid of the sand and blacksand so made up my arrangement and waited until it was blowing. I had two boards each with extremely powerful magnets down them on opposite sides and the other two sides were open for the wind to blow through.

Yes it did work to a large degree of success BUT the sand and spoil has to be completely dry. The wind did blow the fine sand and smaller stoney bits away and the magnets did get a good deal of the blacksand though had to be cleaned off every minute or two - no hard task.

In New Zealand there is not really any need for a dry blower and it is not the most efficient means of recovering golod. I only did it to ‘try it out’ and also to experiment for a means to get rid of blacksand.


#7

I’m quite interested in the process for sifting non-gold bearing ore dust. Better to not add water as it may change the ore makeup.
Nice that you got the wind to do the work for you.
I’m currently in a very windy west coast location.