Minerals and Geology


Geologic Overview

The Kootenai National Forest is underlain by the Belt Supergroup. Rock in these formations is over 800 million years old, and was created when sedimentary layers deposited by a large inland sea lithified, or hardened, into rock. Exposures of the Prichard formation of the Belt Supergroup are found throughout the KNF.  Stone from this formation, composed primarily of metamorphosed silts and muds, is sought after for use as building and landscaping stone.  The Montanore ore body is located in the Revett formation of the Belt Supergroup.

KNF Rocks and Minerals

Mining Projects

Montanore Project

Draft Supplemental Environmental Impact Statement

The Kootenai National Forest has released a Draft Supplemental Environmental Impact Statement for the Montanore Evaluation Project.

The Notice of Availability has been published in the Federal Register on June 21, 2019, beginning a 45-day comment period. Comments may be submitted in writing or electronically. Written comments can be hand delivered or mailed to the Forest Supervisor’s office at 31374 US Highway 2, Libby, Montana 59923. Electronic comments may be emailed to SM.FS.r1monteval@usda.gov.

A public meeting on the project is scheduled for July 23, 2019 from 6 to 8:00 pm at the Kootenai National Forest Supervisor’s Office in Libby, Montana.

View the News Release for more information.

Federal Register Notice of Intent to Prepare a Supplemental EIS

The Federal Register has published a Notice of Intent to prepare a Supplemental Environmental Impact Statement (EIS) for the evaluation phase of the Montanore project.

Kootenai National Forest Montanore Project Record of Decision - February 2016

Montanore Project Joint Final Environmental Impact Statement - December 2015

  • Federal Register Notice of Availability -  12/18/15 (pdf)
  • Cover Letter (pdf)
  • Volume 1 - Summary through Section 3.6 of Chapter 3 (pdf)
  • Volume 2 - Sections 3.7 through 3.24 of Chapter 3 (contains the missing page, page 944) - (pdf)
    • Correction Note: Volume 2 of the Joint Final EIS was missing page 944 on the CD version and the electronic download version available on the agencies’ websites prior to January 4, 2016. The missing page included sections and and primarily discussed the cumulative effects of the Montanore Project on Sound, Electrical and Magnetic Fields, Radio and TV. This missing page can be downloaded here or from the corrected Volume 2 document link above this note.  If you requested a hard copy it will be sent to you within approximately two weeks. The hard copy version includes a complete Volume 2. You can also request a new CD from one of the Project Coordinators, Lynn Hagarty, KNF, 31374 US 2, Libby, MT 59923-3022, 406-293-6211, or Craig Jones, DEQ, 1520 East Sixth Avenue, Helena, MT 59620-0901, 406-444-0514.
  • Volume 3 - Section 3.25 of Chapter 3 through Chapter 8 - (pdf)
  • Volume 4 - Figures and Appendices A through L - (pdf)
  • Volume 5 - Appendix M Response to Comments - (pdf)

Supporting Documents

Kootenai NF Final Environmental Impact Statement for Objection Process - March 2015


The following documents are in pdf format.

Response to Objections

Rock Creek Project

View Project Information

Troy Mine Reclamation Project

The Final Environmental Impact Statement (EIS) for the Troy Mine Revised Reclamation Plan describes the land, people, and resources potentially affected by the proposed revised reclamation activities.  The purpose of the proposed revision is to return lands disturbed by mining to a condition appropriate for subsequent use of the area.