OF-02-19 Evaluation of Mineral and Mineral Fuel Potential of Eagle and Routt Counties State Mineral Lands Administered by the Colorado State Land Board


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Citation: Widmann, Beth L., and Harry Terbest. “OF-02-19 Evaluation of Mineral and Mineral Fuel Potential of Eagle and Routt Counties State Mineral Lands Administered by the Colorado State Land Board.” Mineral and Mineral Fuel. Open File Report. Denver, CO: Colorado Geological Survey, Division of Minerals and Geology, Department of Natural Resources, October 2002.


This open-file report for Eagle and Routt Counties includes an introduction to the geology and mineral resources of the counties along with an index map of tract locations, maps of oil and gas test wells with oil field locations, coal resources, metallic mineral prospects, and industrial mineral prospects. The main body of the report is an evaluation of each individual tract, which includes text as well as a topographic map and a geologic map. Digital ZIP download. OF-02-19D

Four general categories of resources are included in this inventory:

  • oil and gas
  • coal
  • metallic minerals
  • industrial minerals and construction materials

Each individual tract evaluation includes:

  • A bar graph which ranks each tract’s resource potential for each of the four mineral categories. An explanation of the categories may be found at the end of this introduction
  • Tract identifier number, county name, and county location map
  • Tract location on a 7-1/2-minute United States Geologic Survey topographic map
  • Tract location on a United States Geologic Survey surface outcrop map
  • Location as to section, township, and range and approximate acreage
  • Overview of tract geology
  • Specific assessment of the resource potential for the four resource categories
  • References used in assessing tract potential

From the Introduction:

Eagle and Routt Counties occupy the northwestern portion of Colorado. This evaluation of the mineral and mineral fuel resource potential was conducted for the nearly 128,670 acres of state mineral lands within these two counties. It was conducted as part of its long-term evaluation of approximately 4 million acres of state lands administered by the State Land Board. For evaluation purposes, the counties were divided into 96 individual tracts that range from approximately 40 to 15,000 acres.

There are numerous oil and gas fields and wells in Routt County, but only a few wells in Eagle County. The Green River Coal Region encompasses most of the western half of Routt County, with four active mines as of 2001. There is no active metallic mining in either Routt or Eagle counties. However, the historic Gilman and Red Cliff districts in Eagle County produced significant amounts of lead, zinc, copper, silver, and gold into the late 1980s. The Hahn’s Peak district produced similar metals in Routt County, but to a much lesser extent. Locally, uranium minerals may be present in certain sedimentary rocks, but there has been almost no production in either county. Sand and gravel resources, clay deposits (used generally for bricks) primarily in the Cretaceous Mancos Shale, gypsum (used in wallboard) of the Pennsylvanian Eagle Valley Evaporite, and Tertiary or younger volcanic rocks are the most widespread and readily accessible industrial mineral resources in Eagle and Routt counties.