Simple Rules of Gold Geology: Comparing Epithermal and Mesothermal Deposits

July 2017 by Chris Ralph

Geology is a science of general tendencies with frequent exceptions, not one of hard and fast rules that are always true and never vary. For almost every well-accepted rule of gold deposits, I can point you to a number of important exceptions.

Gangue Minerals - What Do They Tell Us?

January 2017
There are a large number of different kinds of gangue minerals, and each of them has its own tale to contribute to the story of the chemistry and geology of a deposit.

Why Haven't They Mined This Claim?

May 2011
Improvements in mining equipment and techniques, along with a higher gold price, make many mining properties profitable today that may not have been in the past.

Gold Deposition and Gradients of Placer Streams—Part I

June 2012
When placer miners from the gold rush era began experimenting with the slope of their sluices, they must have pondered the ideal slope for trapping gold in a creek bed too. Logic suggests the same is true for streams...

Las Médulas—The Gem of the Roman Gold Mines

July 2018

This mine was a real wonder of engineering, and the water supply and drifts had to be carefully managed to keep it in operation. In fact, it didn’t close due to lack of gold, but instead closed with the fall of the Roman Empire.

The Downieville Gold District

January 2011
Many locals are just waiting for California to allow dredging once more, especially with the current gold prices. There are still plenty of good opportunities for prospectors in this area, just as it has been for so many years.

The Wild Rush to Find More Cobalt—Part I

February 2018

While some future cobalt will come from recycling lithium batteries and other products, the coming huge need for cobalt is virtually a perfect storm of heavy demand and insufficient supply.

Critical Minerals: Gold

August 2011
A few quick calculations show that approximately 11 tons of gold are lost each year just in the manufacture of new cell phones.

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