MINERAL MATERIALS, ABANDONED MINES INVENTORY AND ASSESSMENT OF LEWIS AND CLARK NATIONAL FOREST, MONTANA

The U.S. Forest Service in conjunction with the GeoCorps America program sponsored by the Geological Society of America conducted a forest-wide mineral materials inventory and assessment of the Lewis and Clark National Forest, Montana. The Lewis and Clark National Forest encompasses 1.8 million acres of forest ranging from the eastern front of the Rocky Mountains to the isolated mountain ranges of central Montana including the Little Belt Mountains, Highwood Mountains, Castle Mountains, Little Snowy and Big Snowy Mountains and portions of the Crazy Mountains. The goal of the project was to describe and catalog known and new mineral material sites in order to provide thorough data on the availability and quality of material present on the Forest and thus more efficiently facilitate engineering and road maintenance projects. Data pertaining to the geology of each site, classification of material according the Universal Rock Classification System, potential for mineral material use and site development was collected. Results were presented in a final report and map allowing information to be readily distributed to appropriated parties within the Lewis and Clark Forest. The Lewis and Clark National Forest was mined with vigor in the 1800s. Previous mining operations have left a trail of pits, mine shafts, abandoned buildings and tailings piles. In addition to inventorying mineral materials on the Forest, abandoned mines were cataloged and reviewed in order to assess environmental impact, safety issues and potential remediation.