PolyMet contends the project will actually reduce mercury and sulfate discharges into the St. Louis River watershed because it will clean up an old iron mining waste pond at the processing plant site.

First, in order to compensate for the diminishment of purchasing power that usually accompanies rising inflation, investors normally have demanded higher interest rates on their investment assets. This was particularly true in the 1977-81 era when inflation soared to almost 20% and interest rates rose to roughly the same level.

For the prospector, knowing what oxidized hydrothermal alteration looks like in the field is an important exploration tool.