Mines

Of the 1.52 billion metric tons of copper discovered t
Of the 1,740,000 metric tons of silver discovered to d
Fool's Gold can be one of three minerals. The most common mineral mistaken for gold is pyrite.
The fineness of jewelry gold is stated as the number of parts in twenty-four that are gold. Thus, 24 karat gold is pure gold; 12 K would be an alloy that is half gold and half copper or other metals. 
White gold was originally developed to imitate platinum, and is usually an alloy containing 25% nickel and zinc. If stamped 18 karat, it would be 75% pure gold. 
A rock is an aggregate of one or more minerals; or a body of undifferentiated mineral matter. 
Mine drainage is formed when pyrite, an iron sul
After 85 years of service, the U.S. Bureau of Mines closed effective January 1996. Certain functions, such as the collection, analysis, and dissemination of minerals information, have been returned to the U.S.
When sulfurous, sulfuric, and nitric acids in po