Federal regulators also have become less certain that it is possible to clean up contamination from uranium mining. At Christensen Ranch and elsewhere, efforts to cleanse radioactive pollutants from drinking water aquifers near the surface have failed and uranium and its byproducts have sometimes migrated beyond containment zones, records show.
In 2007, when the Christensen Ranch mine operator proposed expanding its operations, bringing more injection wells online and more than tripling the amount of waste it was injecting into underground reservoirs, Wyoming officials eagerly gave their permission, but the EPA found itself at a crossroads.
If the agency did what Wyoming wanted, it could destroy water that someday could be necessary and undermine its ability to protect aquifers in other places. If it rejected the plan, the agency risked political and legal backlash from state officials and the energy industry.
The EPA declined interview requests from ProPublica for this story and did not respond to a lengthy set of questions submitted in writing. After learning that ProPublica contacted several EPA employees directly involved in the debate over Christensen Ranch, the agency instructed staffers not to discuss the matter without agency approval.
For the last five years, as regulators have vacillated over what to do, John Christensen has experienced a similar ambivalence.
His property is speckled with thousands of small, mysterious black boxes. From each dark cube, a mixture of chemicals is pumped into the ground to dissolve the ore and separate out the uranium so that it can be sucked back out and refined for nuclear fuel.
Horses graze behind a gate on a dirt road that winds across this 35,000-acre tract, 50 miles south of Gillette. Nearby, a small metal sign is strung to a cattle guard with chicken wire: "Caution. Radioactive Material."