History & Geology
Enrichment of Mineral Deposits by Weathering—Part II
April 2016 by Chris Ralph
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.
Critical Minerals: Gold
A few quick calculations show that approximately 11 tons of gold are lost each year just in the manufacture of new cell phones.
The Seven Troughs Mining District
The favorable geology of the northeastern and central parts of the Seven Troughs Range are the parts most interesting to prospectors. They are underlain by a thick sequence of Tertiary volcanic rocks, mostly rhyolites and andesites.
Rare Silver Nuggets And Their Origins
Silver nuggets have been described as “ultra-rare,” “prized” and “unique.” Naturally occurring silver nuggets are rare enough to suggest caution when purchasing. Fakes have reportedly been produced and misrepresented for sale as genuine specimens.
Diary of a Diamond Prospector
I couldn’t wait to get started. With no field budget, an assay budget of $100/year, a 1975-Ford Bronco that was a road hazard, a gas card, a topo map and full support of the director, I headed to the State Line district near Tie Siding along US Highway 287 to begin mapping kimberlite.
The Basics of Geophysical Exploration
In developing a mineral property or mining claims, one of the first goals is to identify and quantify valuable deposits. The classic method of doing this is by drilling holes into the ground to sample what is below the surface. The problem is that one or two holes usually are not going to tell you a whole lot...
Critical Minerals: Tungsten
Because tungsten minerals are heavy, exploration can be done using stream sediment samples. Prospectors looking for gold have found scheelite or wolframite in their placer concentrates, and in some cases this has led them to make important tungsten finds.
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.
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