glot
Gold Digger
Posts: 75
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Post by glot on Dec 29, 2016 17:55:31 GMT 10
I have a source of very fine gold but a lot of it is attached to the sand grains. I am talking minus 50 mesh. Some minus 70 mesh. Does anyone have any realistic suggestions for recovering the gold? I am talking small quantities.
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Post by shivan on Dec 29, 2016 19:34:03 GMT 10
If it is substantial enough to worry about look at going up to 100 mesh classifier and blue bowel or miller table. An alternative would be to look into chemical processing such as mercury, but you need to have the gold there to worry about.
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glot
Gold Digger
Posts: 75
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Post by glot on Dec 30, 2016 10:58:14 GMT 10
Blue bowl works great but the secret is multiple classification. Also, in Qld, unless you are on a mining lease, they are not legal to use. My issue is the gold is attached to the sand grains like paint gold I guess.
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Post by shivan on Dec 30, 2016 12:11:53 GMT 10
You cant use a blue bowl in the field i guess, but not sure i would want to. I have not seen anywhere that you cant use one as home to process your concentrates from panning or sluicing though, which is what i thought you were talking about.
I do not really know of any other method in the field besides sluicing or panning unless you are on a lease. Again if it was consentrates you could try heating them and quenching in water to try and release the gold, but if your not catching it in the first place then not sure what you could try sorry.
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glot
Gold Digger
Posts: 75
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Post by glot on Dec 30, 2016 15:27:14 GMT 10
The Qld fossicking Act and Regs says clearly no machinery unless on a mining lease. A blue bowl and a miller table require a pump which is machinery. At home is still with in the state of Qld. Same laws apply. I am catching the gold in a pan but am trying to separate it at a later date. I have considered chemical or smelting. It is simply a challenge and fun as with all hobbies. First time I have come across material like this. It has some loose gold plus a heap of iron pyrites and chalco pyrites in it. I can see under a microscope gold attached to the sand particles like paint gold. I think pyrites would have broken away. Also, Pyrites shines like gold in the sun but not in the shade. Gold shines in the sun and shade. Also, when looking at pyrites through a double lens loupe, it looses all sparkle and just looks dull, in my experience anyway. Pyrites tends to maintain it's crystal shape even at microscopic sizes. Gold looks like gold in shape and texture. I am thinking of soaking it all in some sulfuric acid to see if the pyrites gets dissolved away. If it does, this would also reinforce my opinion that it is gold stuck to the sand.
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golddiggerart
Super Sluicer
I was born for a reason...
Posts: 381
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Post by golddiggerart on Dec 30, 2016 15:29:26 GMT 10
Acid would do the trick mate....
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Post by shivan on Dec 30, 2016 16:03:25 GMT 10
The "No machinery is permitted" is while you are out digging and fossicking, once you bring concentrates home you are no longer fossicking and can process them however you want. I will not get into an arguement over regulations however, at the end of the day do what you are comfortable with.
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Post by mushmouse on Dec 31, 2016 0:16:47 GMT 10
I recall some discussion we had about this that Shivan mentions.? A method where you can heat the gold on quartzite up on to a very hot temperature on a hotplate or whatever then dunk it in icy water. The sudden contraction should crack the sand and release it from the flake without damaging the gold in theory. I have a few pieces like this that are around 50 - 60 mesh but haven't got around to trying it myself yet. Or Acid like Art says could sizzle it off with micro stuff.
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Post by marked on Jan 1, 2017 20:53:46 GMT 10
Shivan points out the very relevant difference between "fossicking" in the field and subsequent "processing concentrates" back at home as regards to regulations ... as long as you are only bringing concentrates home and not bulk unprocessed material you are fine ... a Blue Bowl in the back yard is not against any regulations, yet the problem remains of the gold being bonded to other material.Acid or quenching, as suggested, are both methods you could try.
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