This primary source comes from the Records of the Environmental Protection Agency.
National Archives Identifier:
543717Full Citation: Colorado Fuel and Iron Company Feldspar Mine On Monarch Pass. (Infared Film); 5/1972; Records of the Environmental Protection Agency, Record Group 412. [Online Version, https://www.docsteach.org/documents/document/colorado-fuel-and-iron-company-feldspar-mine-on-monarch-pass-infared-film, May 9, 2024]