Our ore bodies were formed during the Midcontinent Rift tectonic event 1.1 billion years ago. This rifting, or breaking apart, separating, and thinning of the Earth’s crust allowed magma deep within the Earth to rise up through the crust and cool as igneous bodies.
Our ore deposits were the result of at least three different intrusions of magma rich in metals. As the magma cooled, nickel and copper minerals crystallized into a solid ore body. The bottom of the ore body sits roughly 3,000 feet deep and measures to be roughly 6 acres in size.
We have two ore types; massive and semi-massive sulfide. Massive sulfide is about 6.5 percent nickel and 3.8 percent copper. Semi-massive contains about 1 percent nickel and 1 percent copper. The Eagle deposit is high-grade nickel and copper, but also contains trace amounts of cobalt, platinum, palladium, silver, and gold.
producing nickel & copper
THE Mining journey
Eagle Mine in Michigan's Upper Peninsula will produce approximately 360 million pounds of nickel and 295 million pounds of copper. That's roughly the same weight as the Empire State Building. In fact, now in production, Eagle Mine is the only primary nickel mine in the United States and produces 1.5 percent of the world's nickel.
So how do we get our ore out from 3,000 feet below the surface?
First, we make a tunnel underground that's one mile long declining at a 13% grade and 18 feet in diameter. This tunnel serves as our main route for trucks, equipment, and miners to get safely in and around the mine.
The mining process is done in three stages, first, holes are drilled and loaded with explosives that are set off and the ore breaks apart. Second, the loosened ore is now mucked or scooped and put into special underground haul trucks. Each truck delivers roughly 100,000 pounds of ore to the surface. Third, we mine from the bottom up and once an area is mined, we fill it with a special mix of rock and concrete. This helps the ground stay nice and solid so we can continue to mine the other areas.