History & Geology
Greenstone and Gold
September 2013 by Chris Ralph
Contacts, faults and zones of weak rock are all places that can act as a pipeline to convey gold-bearing fluids, leading to valuable deposits.
Mining Pegmatite Deposits
With successively lower temperatures as the water mixture cools, new sets of minerals are formed and many of those stable at a higher degree of heat became subject to alteration as the temperature progressively moved lower.
Greenstone and Gold
Contacts, faults and zones of weak rock are all places that can act as a pipeline to convey gold-bearing fluids, leading to valuable deposits.
Testing Ores for Free Gold
I get a number of questions from people about testing and treating hard rock ores. The simplest way, but also an expensive one, is to just have an assay test done by an independent assay firm. As an alternative...
Heavy Sands Mining
Lately my mind has been involved with group 4 of the transition elements, namely titanium, zirconium, and hafnium. They all have similar chemical properties. Of greatest interest to economic geologists and miners is that these valuable elements often occur together in sands.
Bedrock Gold: When It’s There and When It Isn’t
Has your experience ever led you to wonder why some gold is deposited on bedrock and in crevices, while other gold is not? We’re going take a deeper look at this and see what we can figure it out.
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.
Las Médulas—The Gem of the Roman Gold Mines
This mine was a real wonder of engineering, and the water supply and drifts had to be carefully managed to keep it in operation. In fact, it didn’t close due to lack of gold, but instead closed with the fall of the Roman Empire.
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