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Mineralized Calderas in Colorado
May 2002 by Edgar B. Heylmun, PhD
A caldera is a large circular volcanic depression caused by collapse due to the removal of molten magma from an underlying magma chamber. The removal of magma is due to explosive venting of lava and pyroclastic material.
Guest Editorial—Globalizing Mining in America, Part I
Is it environmental concern that's driving mining out of the United States or rather politics on the grandest scale?
Surviving The Boom and Bust Cycle
Back when I was in college, when I first started classes, the demand for new engineers was so strong that every graduate had multiple job offers without even trying.
Placers Directly Associated with Lode Deposits
Placers that are directly associated with lode deposits are sometimes overlooked and may have good potential for those who are willing to search for them.
Successful Mineral Property Promotion
Before you invite anyone to look at your mining claims, whether it's to find yourself a partner, to secure operating capital, or to interest a mining company, there are rock-bottom, basic requirements to consider.
Commercial Placer Mining With Jigs
During the upward stroke, water is pushed up through the shot layer causing it to open up and lifting the gravel particles above. The heavier particles settle faster based on Stokes law, and move down into the shot bed layer, while the lighter...
A Working Arrastra
If everything you see, the men, the animals, the crude mechanism that grinds gold from rock, everything around you, looks to be from centuries ago, if the mysterious sound you hear is pure history and the smell around you is primitive, if the earth beneath your feet quivers with untold strangeness; and, the taste in your mouth sweeps time out of mind then, if all of this happens at once, if every one of your five senses has taken you into the past, then you’ve traveled back in time.
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The Bawl Mill
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• Looking Back
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