History & Geology
The Golden Days of Julian, California
October 2011 by Frank Lorey III
Some scattered reports say that gold may have been washed from streams here as early as the 1840s, but the undisputed major discovery came in 1870.The Rochester Mining District of Nevada
Only the richest ores could be worked and shipped off for processing at a profit. As a result, early mining in the southern part of the Humboldt Range was short-lived. In the 1880s, placers were discovered in Spring Valley and American Valley on the east side of the range...
Gold Deposition and Gradients of Placer Streams—Part I
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...
Enrichment of Mineral Deposits by Weathering—Part I
The exact minerals formed in the concentrated supergene deposits depends much on the type of country rock around the deposit and the chemistry of the deposit itself, but if conditions are right, this process will form some rich patches of bonanza ore, in some places valued at thousands of dollars to the ton.The Verde Copper-Gold-Silver-Zinc District, Jerome, Arizona
When I was a student in the College of Mines at the University of Utah, the Verde district was used as an exploration model for “submarine volcanogenic massive sulfide deposits.” So I looked forward to visiting this district and the town of Jerome in central Arizona in the spring of 2012.
Reno's 1872 Time Capsule Includes Gold Rush Lore
The Reno Masonic Lodge was built along the railroad tracks back when Ulysses S. Grant was president and shortly after the Comstock Lode of gold and silver was struck in Virginia City.
Confluence Placers
Confluences of placer streams are well known as concentration sites for heavy minerals. The basic reason is that...
The Ups and Downs of Geologic Faults
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.
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The Bawl Mill
• Legislative And Regulatory Update
• Ask The Experts—Separating platinum from sands using bubbles
• Ask The Experts—Extraction of micro gold from black sands
• Ask The Experts—Difference between a Geiger counter and scintillator
• Then and Now: Is Gold Really Money?
• Gold, Quartz & Chalcedony—Part I
• Prospecting Australia—Part I
• Oregon Dredge Permit Litigation Update
• Gold From Black Sand Tailings
• The Fine Art of Panning Heavy Sands
• California State Gold Panning Championships
• An Expensive Lesson
• Judge Denies Request To Delay Michigan Mine
• Melman on Gold & Silver
