Purple dots indicate nonferrous (non-iron) mineral exploration sites.   Generally, these are sulfide mineral deposits.

Drill core samples are stored in a huge, overflowing DNR warehouse in Hibbing.  After a period to allow the leasing company propietary rights to the information, they are available to the public (other companies) for further evaluation of the mineralization.

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MINING FOOTPRINT map

See a recent map of mining activity in northern Minnesota produced by the Minnesota Center for Environmental Advocacy (MCEA), who says:

"To help legislators and the public better understand the Safe Mines to Protect Our Water legislation [2009] under consideration at the state capitol, we've worked with our partners to produce several informational pieces, including a brief introduction to the bill, a reality check, a few examples of sulfide mines gone wrong, and a detailed map showing mining activity in northern Minnesota."