Assay and Analytical Services

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Do you have need for an assayer?

  • Yes

    Votes: 32 76.2%
  • No

    Votes: 2 4.8%
  • Possibly, I have future plans that may require assay services.

    Votes: 8 19.0%

  • Total voters
    42

Lou

Moderator
Staff member
Moderator
Joined
Nov 4, 2007
Messages
5,203
Location
Rhodia Drive
There has been significant interest in assaying on this forum. I am conducting a poll to find out just how many people need quantitative (how much) and qualitative (what is it) assays.

Let's say the following assay services can be offered:


AA analysis
SEM/EDX and other x-ray technologies (semi-quantitative) analysis
ICP metals analysis
traditional fire assay

Assaying for:

gold
silver
platinum
palladium
rhodium
rhenium
osmium
iridium
ruthenium

other metals on request.

Other pertinent questions:

What seems reasonable in terms of price per assay?

What is a reasonable processing time?

Is ACS, IPMI, AOAC and other relevant organization membership/accreditation important to you or your company?

Is compliance/accreditation with ISO, ASTM, and other trade specific regulatory entities important to you or your company?


Any feedback will be greatly appreciated--I am keen to hear what people need and what exactly they want.
 
If you're running a production lab and produce enough volume to justify the expense, ICP is the way to go but the assays are expensive when PGM,s are involved because the fusions usually involve adding fine gold to get a good dissolve for the dilutions. I guess they want you to believe they don't recover the gold. Between the cost of the digestion, the instrument cost, and the instrument annual service contract costs, break even pricing is high to start. If you're talking large lots, a good lab with a track record of winning alot of umpire assays, is well worth it. For my money, a good gravimetric fire assay supplemented with an AA can produce excellent results. I've won many an umpire because I've had the time to run enough duplicates to reproduce results until I was happy. I feel a lab with a good track record concerning umpire assays is more valuable than affiliations with professional organizations. Two weeks is a reasonable turn around time for a gold, PGM assay. Gold and silver usually 2 days. Cost for gold is usually $25 for bullion another 15 for silver, and PGM's can top the $100 price tag. A good lab is hard to find and will do well. Of course as an analytical chemist I'm prejudiced! :D
 
ETA is a breeze but it's slower, about 10X less elements can be analyzed at a given time, and offers usually less precision (on par with ICP OES). Thankfully it's also somewhat cheaper than ICP MS. Flame ionization is the least expensive and most rapid throughput if you're doing one or a few analytes, but you know its limitations if you're any kind of analytical chemist.

ICP is expensive chiefly because of 1.) the high quality acids used are very expensive, 2.) the internal standards are expensive, 3.) the argon is expensive.


Theoretically, an ICP analysis should be about 1.50 per sample, I've heard as low as $0.78. Reality is different.

2 weeks turn around time is excessive in my opinion, especially if it is on sample that is coming from an easily prepped matrix (i.e. drill shavings). When you're working with ores and have to do fusions, it's a different story.

For me, I'd much rather analyze bulk metal than do ores just because of the hassle factor and the added expense of reagents. Nonetheless, I was hoping for much more interest to make it worthwhile.
 
Lou said:
For me, I'd much rather analyze bulk metal than do ores just because of the hassle factor and the added expense of reagents. Nonetheless, I was hoping for much more interest to make it worthwhile.

Lou, I have used several assayers such as Reed, Southern Spectro, Acme and others and here is my take on the situation from a prospector's viewpoint... Most assayers just don't get it. That is to say they have an entirely different viewpoint than the prospector. Every assayer out there who's worth his salt is shooting for high precision and high accuracy, which of course takes time and money. So, the cost per assay is waaay too high and it takes waaay too long in most cases. What the prospector really needs is relatively good accuracy and modest precision. It doesn't matter to me if the result shows 10ppm or 12ppm, just as long as it's not a false positive. Worst of all is a tight cluster of results that are falsely high or low (inaccurate) but with high precision. Just give us a ballpark number but make damn sure there's no cross-contamination and the aliquot is thoroughly homogenized and digested. The BIG item is speed. I hate sitting on my hands for 2-3 weeks waiting for results. If I send an assay in by FedEx on Monday I would like a result by Thursday. This is why even small companies like mine are seriously considering forking over $30,000 or more for a hand held XRF. Sure, the LOD for gold is maybe only 5-10 ppm but who cares if one can within minutes do a multiple element scan to determine qualitatively the values of the PM's and indicator minerals. Of course, if you are focusing on assays for fellow refiners, then disregard my rant :wink:
 
Would the analysis be able to indicate which gold plated computer material has a higher PPM.If I were able to find out which material had a thicker plating it would be worth it to me,then I would concentrate on accumulating more of that material,and of course the opposite....If I knew that certain material had virtually no plating then I would waste my time finding it.Of course this could also be beneficial on a morketing scale,you could have the upper hand in bidding on items,because you would have more knowledge of the ppm of PMs in the material you were bidding on.And if you had a handheld,you could even take it to a lot of the auctions that I go to,where its a silent auction and you have a week to go through the material before you place your final bid,then you could actually test the material right then and there.
 
The problem with that Johnny is assuring you have a homogeneous sample. Sampling is very, very, very important--mess it up, and you've messed up the rest. Reality says that one can't really obtain a nice and comparatively easy sample out of electronics. How do you ensure that what you have is representative of the whole lot? Let's say you're after fingers. What gurantees that the plated surfaces were deposited evenly amongst many different boards, let alone, what guarantees that they all wore evenly...etc.


@jsargent,

I understand your feelings. My counter to that is: what if the financial feasibility of a project depends on a 3 ppm swing? I suppose having a rough idea is good for prospecting purposes, but how could one ever build a mine on anything less than the best information?
 
Lou said:
@jsargent,

I understand your feelings. My counter to that is: what if the financial feasibility of a project depends on a 3 ppm swing? I suppose having a rough idea is good for prospecting purposes, but how could one ever build a mine on anything less than the best information?

Lou, I would say that in a perfect world where a prospector has unlimited time and money, settling for only the most accurate and precise assay is the way to go. In the real world though it's always a balance between perfection and efficent use of time and money. I would say that 90% or more of all samples sent for assay are simply grab samples collected at a potential prospect where the prospector is simply trying to establish whether or not there is zone of mineralization worthy or further pursuit. If a potential zone is marginal to the point where 3ppm would make or break it either way, then it's already at the point of being discarded for greener pastures. Unless of course it's a damn big area. I know you get my meaning so I won't put a finer point on it, except to say this... I just watched another prospector inspect an old mine where I had carefully collected a dozen samples a couple years ago and found nothing. He had the good fortune to have an XRF in hand and by quickly shooting multiple sites along the mine shaft and walls, he was able to establish pay zones in excess of 10ppm gold. It was just by chance I had missed these areas with my careful and methodical samplings. If I'd had an XRF back then, it would have made all the difference. Arrrrrgh!
 
jsargent said:
This is why even small companies like mine are seriously considering forking over $30,000 or more for a hand held XRF. Sure, the LOD for gold is maybe only 5-10 ppm but who cares if one can within minutes do a multiple element scan to determine qualitatively the values of the PM's and indicator minerals. Of course, if you are focusing on assays for fellow refiners, then disregard my rant :wink:

Hi jsargent

I am interested in the "handheld XRF. I am new to all this assaying but it seems like just what the doctor ordered for me. I want to start buying raw gold from the bush, but I will only pay for that which has been "scrubbed" of all mud and other impurities, and assayed. I am hoping the handheld XRF, whatever it is, may be able to help me in the bush. :shock:
 
About the only way I know to get a decent samples from a large pile of assorted circuit boards is to chop them up and then sample them using something like a sample splitter.


There is commercial equipment that will measure plating thickness quite accurately. Two of these, Betascope and Microderm use very small quantities of several different radioactive isotopes. The beta particles penetrate the plating and are scattered back (backscattering) to a detector. The less entering the detector, the thicker the gold deposit. However, they require standards in the range that you are working in. I don't think they make these anymore, but would imagine that they are still available somewhere in a used equipment list.

Another type is made by Kocour. It dissolves the plating, in a very small circular area, using current and usually a cyanide solution. When the plating is gone and the solution hits the underlying nickel or copper, the voltage changes, the machine shuts off, and a reading is taken. Here again, standards are needed and the equipment may possibly be found used.

There is another machine that measures thickness using eddy current (I think).

I haven't kept track of the newer technology and I would imagine that there are lots of newer types of thickness measuring equipment out there.
 
Hi All-

Thought I would provide a link to Niton"s XRF gun, for those of you with lavish tastes in field testing equipment.

Spendy pup, but difficult to match in portable and fast determinations...

http://www.niton.com/mining.aspx?sflang=en

Enjoy!
 
ANALYSIS BY ICP
Hello, we already have FRX, I would like to know if somebody handles here the technique of analysis by ICP for PGM, if they know where the patterns are obtained, the analysis by this method is expensive, but I want to learn how to do it, if someone can teach me, and We can agree a price.

On the other hand, refineries, do not make good trials and try to lose the seller, time, up to a month to issue a platinum result, I find a lack of professionalism.
 
ICP works for some and not others.

There are pros and cons for ICP over AAS depending on the type of material you are processing.
 
zachy said:
ANALYSIS BY ICP
Hello, we already have FRX, I would like to know if somebody handles here the technique of analysis by ICP for PGM, if they know where the patterns are obtained, the analysis by this method is expensive, but I want to learn how to do it, if someone can teach me, and We can agree a price.

On the other hand, refineries, do not make good trials and try to lose the seller, time, up to a month to issue a platinum result, I find a lack of professionalism.


Analyze PGMs with my Agilent 5100 ICP-OES every single day.
 
Hi Lou, thank you very much for responding, you can help me please, to have the method for analysis of platinum with ICP-EOS, I can pay you money, I do not have much, but we can get to do business. I reward you because I know that your knowledge has been obtained through work.

Thank you very much.
 
I believe that better results can be obtained in PGM analysis by combining the technique of ISO 11210, JEWELERY-DETERMINATION OF PLATINUM IN PLATINUM JEWELLERY ALLOYS-GRAVIMETRIC METHOD AFTER PRECIPITATION OF DIAMONOMIC HEXACHLOROPLATINATE, is much less toxic than mercury chloride precipitation , This is very poisonous to health. It is also better to precipitate than to make dilutions to read alluvial minerals with contents of 84% of platinum.

But here is the dilemma this rule is used for jewelry. I do not know if it can be standardized for minerals. It is my question. Or is it just representative for jewelry?

Thank you.
 
Back
Top