The Seven Troughs Mining District
September 2016 by Chris RalphThe favorable geology of the northeastern and central parts of the Seven Troughs Range are the parts most interesting to prospectors. They are underlain by a thick sequence of Tertiary volcanic rocks, mostly rhyolites and andesites.
It’s not easy to figure out what is best without testing, and so a certain level of confusion has developed about how small the ore ought to be crushed.
Most gold-bearing veins in this region are controlled by fractures associated with the Melones Fault, a late Cretaceous structure that is 108 to 127 million years old.
The whole purpose of sampling mineralized ground is to measure the values in a small volume of material that would be representative of a much larger volume of similar material. The key word is representative. Chemical and fire assaying will not accurately represent placer deposits by themselves.
So let’s dive in and see what I can do to convince you that this is the year you should be out staking your own claims.
Improper sampling techniques lead to more avoidable heartache than almost anything else in micro mining.
So you think you have an ore deposit? The work has been long and hard, but there are a few drill holes, lots of samples and assays. The data is in a reliable computer and there may be a mine at the end of the tunnel. What is the likelihood of a profitable operation? Can you raise capital for development or exploration?
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