Laboratory assays shall be as accurate as possible. And inexpensive.

Yet, in the field, we are not using laboratory assays. Rather practical field assays. Most important is to obtain the sample to be representative, and that is hardest task. Grab samples are simply not samples of ores.

Then we are using gravitational patented method to obtain even the finest gold particles of 5 micron in size. The method we are using is recovering continuously about the same percentage of gold. Now, when gold particles are counted, one may get pretty good feeling if the ore contains just 0.20  grams per tonne or 0.50 or is it maybe 2-4 grams in a tonne. With written reports of such assays, one may obtain a table where number of particles found is referring to certain range of gold grade, for example 200 particles found may indicate 0.50 - 1 gram of gold. And I speak of particles of all sizes, one need to use the magnifier of 30x to count it.

I may direct you to the patent owner and manufacturer who may deliver to you this inexpensive technology with methods explained, that may spare you immense amounts of money and give your company or group a mean to know, within 30 minutes, if the ore is workable, and what expectations you may have. There are no chemicals involved and no expenses but work.

Jean Louis

There are a few titration methods but most people don't use them - AAS is very cheap and accurate and is the preferred choice for wet chemistry.  ICP has also been utilized.  Here are a couple of links to papers with several wet methods.  You may have to search around for full texts of these for free on other sites.

https://www.ncbi.nlm.nih.gov/pubmed/18961634

http://pubs.rsc.org/en/content/articlelanding/1962/an/an9628700349#!divAbstract

https://link.springer.com/article/10.1007/BF00325623

If you have any luck with these let me know.  It would be nice to know if they are accurate.

Todd