This open-file report for Custer and Huerfano counties includes an introduction to the geology and mineral resources of the county along with an index map of tract locations, map of metallic mineral prospects, industrial mineral locations, and oil and gas test wells and oil field locations. 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/PDF download. OF-01-10D
Four general categories of resources are included in this inventory:
- oil and gas
- 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:
Huerfano and Custer Counties lie just east of the Continental Divide in south-central Colorado. This evaluation of the mineral and mineral fuel resource potential was conducted for the nearly 68,000 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 108 individual tracts that range from approximately 120 acres to 2,880 acres.
Huerfano County produces coalbed methane gas and carbon dioxide (CO2). Only one oil field ever produced in Huerfano County, and that field was abandoned in 1991. No productive oil, gas, or CO2 fields have ever been developed in Custer County. Coal has been mined in the past from areas in Huerfano County. The Raton Mesa coal region extends into the south-central part of the county, within the Raton Basin.
Most of the precious and base metal production (gold, silver, lead, and zinc) of this region has come from vein and breccia deposits of the Rosita Hills and Silver Cliff (Hardscrabble) districts in Custer County. Uranium has been produced in very small quantities from scattered deposits, most notably from the Farisita Conglomerate (Tertiary age) in northern Huerfano County.
Several varieties of industrial minerals and construction materials are present in Custer and Huerfano Counties, including sand and gravel, perlite, vermiculite, clay and stone.