How to Interpret Assay Values
January 2018 by Don Robinson
This assay system of ounces per ton sounds simple enough, but the use of the metric system and the additional measuring terms of “grams per ton” and “parts per million” (ppm) has created some misunderstanding of ore value.
I thought it might be worthwhile to take a look at the basics of this important mineral separation technique and how a miner can use it to recover the values out of an ore.
In processing gold, silver and other valuable ores, the minerals containing the values, such as metallic gold, silver-bearing sulfides or other minerals, must be freed from the surrounding host rock before those valuable minerals can be captured.
Digging in the right spots will produce excellent results, like this group of nuggets taken by the author while metal detecting during the last few months. The biggest nugget is over an ounce.
Even though they have put down thousands of dollars, the buyers often stop paying on their claims part way through the process after they realize they’ve been duped, but the company just sells it again to another buyer.
Prospectors have many reasons why they might want to break rocks. These include dividing up a specimen too large to carry.
• How small should I crush my hard rock ore?
If there is misleading wording anywhere, it will be in the sample data and in reserve/resource estimates.
The Bawl Mill • Legislative and Regulatory Update • California: The Land of Big Nuggets—Part II • Bedrock Nugget Hunting: Tools of the Trade • A Primer on Bitcoin and Other Cryptocurrencies • Gold Hunting on Libby Creek • PLP and MMAC Update • Man's Best Friend • An Interview with Minelab Engineer Mark Lawrie • Third Largest Nugget in Existence Returns to Dallas • Melman on Gold & Silver • Mining Stock Quotes and Mineral & Metal Prices