History & Geology
The Rochester Mining District of Nevada
August 2017 by Chris Ralph
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...
The Golden Days of Julian, California
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.
Green Valley Gold District, Payson, Arizona
Most gold-bearing quartz veins found in the district were fracture fillings in faults enclosed by crushed quartz zones along their margins. Since the host rocks were often extensively weathered, portions of the veins stood out as positive, resistant outcrops. The gold-bearing veins ranged from a few inches wide to the vein at the Gowan mine that was as much as 12 feet wide. The Pearce Mineralized Area, Dragoon Mountains, Arizona—Part II
There are many prospects within the known mineralized area and along the margins of the mineralized area that should be examined for gold and silver.
Why Haven't They Mined This Claim?
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.
Conrey Dredge No. 4
The large buckets were favorable for the type of ground worked. The gravel was tenacious and compact, due to the existence of irregular pockets of clay.
Understanding and Prospecting Benches
The most obvious benches are usually near the valley floor, but they can be thousands of feet above the valley floor. Since benches were made by streams, they can contain placer deposits.
How Mesothermal/Orogenic Gold Deposits Form
These deposits are very widespread across the planet. In fact, they are so extensive that something around 75% of all the gold ever mined comes from these types of deposits (if one includes the placer deposits that also formed from them).
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