This open file report for Weld County includes an introduction to the geology and mineral resources of the county along with an index map of tract locations, maps of oil and gas test wells with oil field locations, coal regions and mines, metallic mineral resources, and industrial mineral resources. The main body of the report is an evaluation of each individual tract, which includes text as well as corresponding topographic and geologic maps. Digital ZIP download. OF-02-23D
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:
Weld County located in northern Colorado, has common borders with the state of Wyoming and Nebraska to the north. It is in the northern Denver-Julesburg Basin, which is asymmetrical in shape and consists of two sub-basins, the Cheyenne and Denver basins. This evaluation of the mineral and mineral fuel resource potential was conducted for the nearly 224,672 acres of state mineral lands within the county. 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 county was divided into 276 individual tracts that range from approximately 40 to over 11,725 acres in size.
In 2000, Weld County ranked first among Colorado’s counties in annual oil production and second in annual natural gas production from a total of 120 producing fields and eight producing horizons. Weld County contains two great coal basins, the Denver Basin and the Cheyenne Basin. The Boulder Weld coal field is the most productive coal mining area in the two basins. Production for this field began around 1863 and continued until the Lincoln Mine closed in 1979. Additional small fields are discussed in the report.
There are no significant metal mining districts or industrial mineral opportunities in Weld County. Construction materials consist of sand and gravel in various alluvial formations and clay from the Fox Hills Sandstone.