History & Geology
PGMs in the United States
August 1999 by Edgar B. Heylmun, PhD
Until just recently, platinum-group metals (PGMs), especially palladium, had been holding their own on the market. But, Russia has now resumed shipments and it has brought prices down.
Exploring Iron Oxide Copper Gold Deposits
The excitement over IOCG deposits began with the discovery of a monster deposit at Olympic Dam in Australia in 1976. The discovery was accidental as the operator was searching for strata-bound copper deposits.
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.
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.
The Miner’s Switchback
Common thought is the switchback slows the velocity of the rushing water and gold drops out from the cut bank to a fill gravel bar within or below the switchback. I am not going to disregard that model; however, I hope to improve upon it.
The Goldfield Mining District, Nevada—Part II
The majority of the gold produced in Goldfield has come from ores that are close enough to the surface to be oxidized by the air. This oxidized ore is normally a soft, shattered, earthy material usually stained yellow to brown by oxides of iron.
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.
Gold, Quartz & Chalcedony—Part II
The specific gravity of chalcedony is 2.58 to 2.64. This is slightly lower than coarsely crystalline quartz because of slight porosity in chalcedony. Being so light, it will easily wash out of a gold pan.
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