History & Geology
Eastern Arizona: Gold and Base Metal Deposits—Part I
February 2011 by W. Dan Hausel
Arizona is well-known for its copper-gold porphyries and massive base metal-gold sulfide deposits such that primary gold deposits in the state are often overshadowed.
Gold Circle (Midas) Gold District
Many prospectors thought that Nevada was all prospected out following all the rich discoveries of the 1860s and 1870s, and what was there to be found had already been found.
ICMJ Visits Grass Valley, California
March 2023
How Rich Must My Ore Be?
How rich does a hard rock ore have to be for it to be worthwhile to process and extract the gold?
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.
One of the Richest Beaches Ever Mined
Everyone has heard of the golden beach at Nome, but Nome did not have the richest beach.
The Goldfield Mining District -- Then and Now
In 1983, some of the ore yielded more than 2,500 ounces of gold within 30 feet of the surface. The shoot pinched to a narrow vein.
Prospecting for Diamonds in Kimberlite
Kimberlite is very difficult for geologists to find, let alone prospectors and rock hounds. This is because kimberlite is rarely exposed on the surface and few people know how to identify the rock.
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