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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.
Additional articles that might interest you...
Battle Heats Up Over California Suction Dredging
March 2010
The State of California is seeking dismissal of the federal lawsuit filed by Public Lands for the People (PLP) on grounds that they are immune from such lawsuits under the 11th Amendment to the US Constitution. However, there is plenty of prior case precedence suggesting that state officials and agencies are open to such lawsuits when they assume responsibility for regulatory authority from the federal government.
The State of California is seeking dismissal of the federal lawsuit filed by Public Lands for the People (PLP) on grounds that they are immune from such lawsuits under the 11th Amendment to the US Constitution. However, there is plenty of prior case precedence suggesting that state officials and agencies are open to such lawsuits when they assume responsibility for regulatory authority from the federal government.
Picks & Pans: The Gold of "Eldorado Canyon"—Mariposa County, California
June 2002
First, let me say that Eldorado Canyon is what we call this area, but it’s not the real name. It’s a piece of private property where we have permission to metal detect; I do not want to start another gold rush! The property is located in Mariposa County...
First, let me say that Eldorado Canyon is what we call this area, but it’s not the real name. It’s a piece of private property where we have permission to metal detect; I do not want to start another gold rush! The property is located in Mariposa County...
Melman on Gold & Silver
January 2006
The focus of attention by the financial media during past month has shifted considerably away from the international political and terrorist outlook and turned clearly toward important developments as they appear likely to affect the outlook for the US and worldwide economies in the coming year.
The focus of attention by the financial media during past month has shifted considerably away from the international political and terrorist outlook and turned clearly toward important developments as they appear likely to affect the outlook for the US and worldwide economies in the coming year.
Legislative and Regulatory Update
October 2014
• California dredging update
• Study: Sage grouse does not need protection
• Tennessee enacts harsh new gold prospecting regulations
• California dredging update
• Study: Sage grouse does not need protection
• Tennessee enacts harsh new gold prospecting regulations
Mining Stock Quotes
September 2008
The Basics of Small-Scale Heap Leaching with Cyanide
August 2007
In last month’s article I talked a bit about opportunities for heap leaching small hardrock deposits. This month I’m going to talk about the basics of putting together a heap leach project, including building the pad and leaching the ore.
In last month’s article I talked a bit about opportunities for heap leaching small hardrock deposits. This month I’m going to talk about the basics of putting together a heap leach project, including building the pad and leaching the ore.
Gem Theft in Tucson
March 2001
Police are investigating the theft of five stones, valued by their owner at $128,000, from an exhibit at a Tucson gem show.The largest of the stones taken from the show was a 7-inch-tall pink tourmaline worth $85,000.
Police are investigating the theft of five stones, valued by their owner at $128,000, from an exhibit at a Tucson gem show.The largest of the stones taken from the show was a 7-inch-tall pink tourmaline worth $85,000.
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