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...
Enrichment of Mineral Deposits by Weathering—Part II
While both zinc and lead deposits also are enriched by the surface weathering process, in part two we will look at the enrichment process for copper and also gold deposits, and at the interpretation of leached outcrops to figure how rich the concentrated deposits below them may be.
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.
Refractory Gold Processing
After your excitement peaks when you first receive the high gold assay from the vein you just exposed, you ponder how you will extract and sell your gold. You will need to develop a flow sheet for your process to optimize your recovery and minimize your costs and permit requirements.
Calcite and Limestone
The other distinguishing feature of calcite has to do with its chemistry. Geologists sometimes take a small bottle of dilute hydrochloric acid out into the field with them because calcite reacts with acids to make a bubbly foam.
Electrum: Gold and Silver Together
...if you are out prospecting and find something that looks very much like a nugget but has an odd greenish-gray cast to it, don’t be too quick to simply toss it aside as junk.
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.
Weathering, Erosion and Placers
The big interest to prospectors thinking about the effect of erosion is not what might happen long into the future, but what they might find in the rivers later this summer when the water levels go down.
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