Critical minerals are products that the government has designated as critical to our national interest because of both their potential military and industrial applications.

Silver refining has been used from ancient times to change the characteristics of the metal. Early metallurgists refined silver by heating it a couple hundred degrees above its melting point and holding the metal at an elevated temperature for a period of time.

According to some experts, after the peak is reached, the production rate will slowly decline until it reaches near zero while the price shoots upward. At that point, we will have pretty much mined all the economic ore deposits that are present on the planet.

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.