Welcome to A People's Atlas of Nuclear Colorado

To experience the full richness of the Atlas, please view on desktop.
Department of Energy, Posting a location notice for uranium claims in Colorado Plateau, 1957, Flickr
2/6

Issue Brief

Mining Techniques

Uranium resources can be extracted from the ground in three ways: open pit, underground, and in-situ leach.

Open pit mining refers to the removal of surficial soils and rock to reach the ore below, which is only possible if the ore is near the surface. While this process has better ventilation, it has a huge environmental footprint as waste rock piles can be enormous and can become hazardous to the environment and nearby populations.

Underground mining is a technique used when the ore is too deep to access using open-pit mining. The ore is drilled, then blasted to create debris, which are carried to the surface. For both open pit and underground mining, the uranium is removed from the rock and concentrated—a process called milling. Milling is the only effective method to extract uranium from conventionally mined ores. However, tailings are exposed to the environment, which can lead to the release of remaining uranium or metals, potentially harming local groundwaters.

In-situ leach mining, if applicable, is the preferred method to extract uranium since it is cheaper and considered more environmentally friendly and safer for workers than the two traditional mining techniques. In-situ leach mining involves pumping water and adding an oxidant, which moves through the rock and dissolves the uranium. Wells pump this uranium-enriched water to the surface. World Nuclear Association, "In Situ Leach Mining of Uranium," May 2020 [last updated], https://www.world-nuclear.org/information-library/nuclear-fuel-cycle/mining-of-uranium/in-situ-leach-mining-of-uranium.aspx.At the surface, the uranium is recovered in much the same way as in any other mill. The waters are treated and filtered to remove the uranium and recycled back into this process. Concerns associated with this technique include concerns about waste water disposal.

Specifically, Azarga Uranium's (formerly Powertech) 6,880-acre Centennial Project in northern Colorado's Weld County would use open-pit and in-situ leach uranium mining. Individuals have expressed concern over possible groundwater contamination: the project would be within and use water from the Laramie-Fox Hills aquifer, which covers most of the Denver Basin. Residents worry that the project could also affect the Dakota-Cheyenne aquifer, which is Colorado's largest aquifer east of the Rockies. The residents of this area highly depend on groundwater sources to sustain their agricultural economy. Legislation has attempted to protect these important sources: Eryn Gable / Colorado Foundation for Water Education, "Uranium's Popularity, Residents' Concern Both on the Rise," Headwaters (Summer 2008): 18.in May 2008, Governor Bill Ritter signed into law a measure that requires uranium companies to prove that they can return groundwater to pre-mining conditions or levels in line with current state standards.

Sources

Azarga Uranium. "Powertech Uranium (Azarga Uranium) Updated Investor Presentation." September 18, 2014. Accessed July 31, 2020.

Gable, Eryn / Colorado Foundation for Water Education. "Uranium's Popularity, Residents' Concern Both on the Rise." Headwaters (Summer 2008): 18.

Ulmer-Scholle, Dana S. "Uranium–How is it Mined?" New Mexico Bureau of Geology and Mineral Resources. Accessed July 31, 2020.

World Nuclear Association. "In Situ Leach Mining of Uranium." May 2020 [last updated]. Accessed July 31, 2020.
 

Last Updated:

01/14/2023

Continue on "Extraction"