Fire Assay Reliability

KJJ

Newbie
Nov 24, 2022
2
1
Oregon
I had ore samples tested from seven different veins on one property. The first results from a small assay lab in May's Landing, NJ provided results that showed the veins to range from a low of 0.109 gold oz/T (0.81 silver oz/T) to a high of 0.328 gold oz/T (0.167 silver oz/T). I then sent the same seven samples to a large lab in Sparks Nevada that does testing for the largest mines in the US. This lab showed "non detect" for both gold and silver (results were <0.01 Au ppm and <0.1 Ag ppm). Both labs performed a fire assay using 29.16 grams of ore and both tested the same seven ore sample materials. The ore samples were from two historic quartz lode mines and from an unmined greenstone (non asbestos I had a test done) serpentinite vein system discovered during logging. With such widely varying results do I now get a 3rd test done and if so, from whom? Could the first assay be a false high positive?
 

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southfork

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Jun 15, 2014
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Seems odd the seven samples from seven different areas sent back east all have trace amounts of precious metals. But same samples sent to a well-known lab in Nevada precious metals were absent
 

HeavyMetalThunder

Jr. Member
Aug 5, 2015
40
30
Colorado
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...If I had a Million dollars I could almost become a gold miner...

I think your optioned out and a 3rd is a must, and likely a 4th...then some core sampling then some more assay's ...and another million dollars...and such is the life of a mine owner/operator.

A "MUST READ" regarding Assayers is a 34 page 785.45 KB pdf that was produced in the mid 1980's by the Bureau of Land Management (back in the days when tax payers dollars meant and went to something.) in your search engine type in "BLM assay lab survey-2002" it should then take you to BLM's Knowledge resource center and the pdf...
 

HardRockNM

Jr. Member
Nov 8, 2020
32
65
New Mexico/Arizona
Primary Interest:
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Definitely time for a third (and possibly fourth) split of that sample to be sent off for a check assay. How large are the initial samples and what kind of prep/splitting was done before shipment?

Skyline Labs in Tucson is decent enough, if I remember correctly they'll also do whole-rock and base metal work.
 
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KJJ

Newbie
Nov 24, 2022
2
1
Oregon
  • Thread Starter
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  • #5
...If I had a Million dollars I could almost become a gold miner...

I think your optioned out and a 3rd is a must, and likely a 4th...then some core sampling then some more assay's ...and another million dollars...and such is the life of a mine owner/operator.

A "MUST READ" regarding Assayers is a 34 page 785.45 KB pdf that was produced in the mid 1980's by the Bureau of Land Management (back in the days when tax payers dollars meant and went to something.) in your search engine type in "BLM assay lab survey-2002" it should then take you to BLM's Knowledge resource center and the pdf...
The BLM assay report shows a very wide range of assay results for the same sample. Unless you know how many ounces per ton you have before getting an assay done it's hard to tell if you are getting good information back. Guess I can see if any of the labs that tested close to the true BLM baseline are still in operation and have them run a third test for me.
 

HeavyMetalThunder

Jr. Member
Aug 5, 2015
40
30
Colorado
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...make up a known blank /sterile sample like the BLM did and send that along with your other samples for assay...and hope a report of anything other then "non detectable" doesn't comes back for that particular sample, a N.D. baseline for accuracy has at least some slight merit...
 

red hardrock

Tenderfoot
Dec 3, 2017
9
19
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The BLM assay report shows a very wide range of assay results for the same sample. Unless you know how many ounces per ton you have before getting an assay done it's hard to tell if you are getting good information back. Guess I can see if any of the labs that tested close to the true BLM baseline are still in operation and have them run a third test for me.
I have had good luck with Ray Grimmer labs. I think they did a good roasting job on my ore before they fired it from all other assays i have had done on the same ore.
 

Mountaineer2020

Jr. Member
Jul 5, 2020
76
198
Oregon
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Minelab gs3000
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If you're not in a rush on the results i would take that "black seam" sample .32 opt and send it to a 3rd assayer. The first assayer said they ran that twice. If the numbers on that one check with the 3rd assayer then I would go with the large assumption that the first set of assays was correct. If not then sadly it's time to rerun the whole batch. I have run some samples of known values by Reed Laboratories and they came up identical to the known values with the exception that they parted the silver and gold which I didn't do. They also do spectometry if you think there is other metals in your samples. Expensive but I have been pleased with the results. I'd put my gold on that first assay being correct.
 

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