Lode gold question for the geologist's on line

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This ore shows visible gold mixed in with the Chalcopyrite, Quartz and Tourmoline... But what I find weird is the gold also often mixed in with the Mica. I've just never seen that before so it seemed strange. Is it more common than I thought?

The picture is of a 2 pound dump rock showing the visible gold. The areas circled are just full of small gold best seen under 100 power magnification. The top center gray spots are Mica inclusions with gold mixed throughout them. Not a lot of visible gold in this piece but thousands of powder you need at least a 50 power to see.

Thanks... :blink:


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Sericite (I think I misspelled that, but I am on the road in Vegas and have no books that I could look it up in) is a common mica mineral found in both gold and silver veins. I have seen it in California mother lode material and is very common in some places in Nevada, like the Comstock Lode. In some parts of California, especially Mariposa Co. down in Grubstakes neighborhood, there is an emerald green mica that occurs in the quartz veins - the mineral is called Mariposite. Grubstake I am sure you have seen that stuff, there are fences in Mariposa Co. made of that stuff.


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Thanks Chris, I owe you a trip when you get this way again... Call when you do...

While on the subject though... We have found the gold on the dumps (1.2 million conservative cu ft) associated with all of the aforementioned minerals. We recently found the point of discovery and the sort pile from it that exactly matches the DUMP refuse ore. Can you offer any thoughts as to what we should be looking for when we go underground that they were spending so much time and energy chasing? What doesn't compute to me is why they would leave all this good ore on the tailing dump?

I also agree with your earlier thoughts that we should find some rather large stopes down below. The amount of tailings is staggering for its location.

Thanks again...

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First place I would be looking is around the margins of stopes in the mine underground. I'd bring in some bright lights and look for visible gold.

Why is it still there?

Two possible reasons:

1. For stuff in sorted piles: many small mines shipped ore and sometimes ores were sorted out but never run or shipped - perhaps the owner died or the War board closed the mine, or something.

2. If its just in the dump: miners hand sorted the ore when it was dirty - often underground. Sometimes they just missed good gold.

I will be in AZ. in mid February again.


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