Q: I read your articles about gold in quartz with great interest. We have a hard rock mine in Montana that produces gold in small pockets of high grade ore along a contact zone. Much of it is in quartz. The attached photo is representative of how the gold is deposited.
I used the formulas that were included in your article to evaluate several specimens and the results were extremely interesting. I had tried previously to estimate how much gold was in the rock but they were uneducated guesses at best. With these formulas I can now get a reasonable estimate based on science. It’s not perfect, because not all of the rock is either gold or quartz, but pretty close. I really enjoy the magazine and usually read it cover to cover the day it comes. Kudos. I am planning to attend the Prospecting and Mining Summit and am enrolled in the hard rock field training on April 18th. Maybe I’ll get a chance to meet you there? Looking forward to it.
Bill Stiles
A: I will certainly be at the show in Placerville, and I am always happy to chat with our readers and other folks who are there. That said, during the show I am constantly running around trying to cover all the bases I need to take care of and giving talks on mining related topics. Please be sure to stop me and say hello when you get the chance. I will not be at the hard rock field training as I will be assisting at the placer training event a few miles away on that day.
When there is a significant amount of other minerals in your specimen, the gold estimate is not very accurate because the formula allows only for gold and quartz, not other minerals. Significant amounts of other minerals will result in an over-estimate of the amount of gold in the specimen.
Q: Could you write more about the last two methods that you mentioned—the expanding chemical mixtures and the micro blasters, how and when to use them, and when not to use them?
