On Again, Off Again

Climax Mine, Colorado

The molybdenum ore-bearing rock is fractured by blasting to form horizontal “benches,” and hauled out of the pit up the ramp at lower right by giant trucks to a mill for processing into ore concentrate. Large, low-grade “porphyry” ore deposits like this are capped by layers of barren rock that is removed and disposed to reach mineable ore, resulting in deep open pits. The Climax Mine is the largest, richest molybdenum mine in the world. Molybdenum is used to make steel tougher and to raise its melting point and is used in weapons and jet aircraft engines as well as industrial lubricants. The Climax Mine has opened and shut in cycles based on price and demand, with major bursts of activity during World War I and World War II. At one time 75 percent of the world’s molybdenum came from this one mine, which most recently reopened in 2012.

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