Blacksand concentrate values as reported in USGS Bulletin No.280

specksandflecks

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Nov 13, 2009
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Thought I would put this out there. I'm sure it's been posted many times before, although a quick site search returned no results. Begins on Page #150.

Bulletin - Google Books

It's my understanding that 95-98% of the values were recovered as free gold/platinum down to 200 mesh using Wilfley type tables, although other means were also apparently used in the assay process.

What I was trying to find when I found this was what amount of gold could potentially be bound to the black/heavy sand concentrates from various areas. Since I have several hundred pounds from several areas I have been thinking more about grinding/roasting,etc to see what values they might hold.

What are the preferred methods for reducing my heavy cons from say #8, down to 2-#300? Ball Mill Vs Roller Vs Impact for example? I have been considering re purposing a used cement mixer into a makeshift mill of some type but was doubtful the values would be worth the time/trouble, Bulletin 280 almost has me re-considering the experiment, almost. :dontknow:
 

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russau

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May 29, 2005
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youll never know untill you do it! already haveing a cement mixer is a plus for grinding large amount of BS. add some vinigar or something to help wash off any lingering mercury or oils to help in your recovery.
 

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specksandflecks

specksandflecks

Full Member
Nov 13, 2009
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Eugene Oregon
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Primary Interest:
Prospecting
Thanks Russau, about how much vinegar for a 5 gallon batch?

Thats great Oakview2, I seldom read the hardrock section of the forums, figure I would probably end up down an old mineshaft somewhere. Maybe an occasional looksee wouldn't hurt though!
 

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