History & Geology
The Ups and Downs of Geologic Faults
May 2011 by Chris Ralph
Faults are fractures, breaks and broken zones in the Earth’s crust where one side of the break has moved relative to the other, and they come in many different varieties.
Copper Deposits of Alaska
Only the famous Kennecott copper mine was able to continue operating through the Depression owing to the exceptional richness of its ore.
Critical Metals: Antimony
I’ve been taking a look at the mining and uses of a number of critical metals in series of articles, and it’s time to take a look at antimony.
Gold in Quartz
Because quartz and gold may be deposited together across a considerable range of temperatures, not all quartz veins are the same, and there are several different types of gold-quartz deposits.
The Giant King Mine
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.
Gold in Tertiary Gravels
In some places, semi-continuous sections of riverbed can easily be linked in many places to identify the path of the ancient rivers.
Critical Minerals: Titanium—Part II
There are both hard rock and beach sand types of titanium deposits, but the hard rock deposits need to be at least 10 percent titanium while the beach sands often are economic with only two or three percent titanium.
The Strange History of the Utica Mine
In the summer of 1854, John Selkirk, a discouraged placer miner who was down on his luck and ready to go back to Massachusetts, tied his mule up in a gulch north of what is now downtown Angel's Camp.
Subscription Required:
The Bawl Mill
• Why Haven't They Mined This Claim?
• Ask The Experts—Where can I find information on the Abby mine?
• Ask The Experts—Is it possible for a mountain range to have good lode gold deposits and yet the area streams not carrying like deposits of gold?
• Ask The Experts—How do you amend a placer claim?
• Ask The Experts—What happened to the BLM web site geocommunicator.gov?
• Fountain of Youth Gold
• Legislative and Regulatory Update
• Suction Dredging Update for California & Idaho
• The Disappearance of State Mining Departments
• The Golden Streams of Butte County, California
• Melman on Gold & Silver
• Mining Stock Quotes & Mineral and Metal Prices
Free:
One Question, Forever Unanswered—Did He Really Find the Gold?
