Groundwater within the backfilled mine pit at the Flambeau Mine site is highly contaminated, as compared to baseline, with heavy metals and sulfate. Case in point: Flambeau Mining Company (FMC) promised the people of Wisconsin in its 1989 Mine Permit Application (see page L-30 of linked document) that:

  1. Manganese levels in the groundwater within the backfilled pit would top off at about 550 mcg/l (0.550 mg/l), as compared to a pre-mine baseline that ranged from 90 mcg/l to 360 mcg/l, depending on well depth; and
  2. It would take over 4,000 years for the manganese levels to drop from 550 mcg/l to baseline.

But here’s what really happened: There is a monitoring well within the backfilled pit (MW-1013B; 600 feet from the Flambeau River) that has registered manganese levels as high as 42,000 mcg/l. In other words, FMC underestimated the manganese levels by a factor of 75.

All of this information, and much more,  is documented and discussed in: Report on Groundwater and Surface Water Contamination at the Flambeau Mine, David M. Chambers, Ph.D. and Kendra Zamzow, Ph.D., Center for Science in Public Participation, June 5, 2009. The report also includes a diagram showing the locations of the monitoring wells at the mine site and the direction of groundwater flow.

To see graphs showing the levels of various pollutants in select monitoring wells at the Flambeau Mine site, click on the following links:

  • Manganese (MW-1013B in backfilled mine pit)
  • Iron (MW-1013C in backfilled mine pit)
  • Copper (MW-1014B in backfilled mine pit)
  • Sulfate (MW-1013B in backfilled mine pit)
  • Manganese (MW-1000PR, between backfilled mine pit and Flambeau River)
  • Manganese (MW-1000R, between backfilled mine pit and Flambeau River)