Radioactive Legacy, Part 2: Danger in the mines via Rapid City Journal


The mining industry temporarily boosted the local economy, lined the pockets of faraway executives and helped keep the federal government stocked with uranium, the key ingredient in the country’s Cold War buildup of nuclear weapons.

But throughout Edgemont’s mining era, there was little to no government regulation. After the industry’s collapse, Edgemont and its economy were left to shrivel in the shadow of the defunct mill and its giant radioactive waste piles, while open-pit mines remain abandoned north of town.

Now, as regulatory agencies consider approving a proposed new method known as “in situ” to mine uranium near Edgemont, there aren’t many people left to tell the story of the first boom. But the tales that do get told reveal the serious risks, and sometimes real consequences, faced by many.


Life in the mill

When haulers like Spencer brought ore into Edgemont, they dumped it at the mill for processing.

On the mill’s fifth anniversary in 1961, mill workers numbered 76 and the mill’s total annual payroll was $338,000. That equates to average pay of $4,448 annually, which would be about $35,500 in inflation-adjusted 2015 dollars.

Many of the mill workers were ranchers who viewed the extra income as a way to stay on the land.

John McKnight, who suffered a chemical inhalation incident at the mill in the 1960s, was blunt about his reason for taking a mill job.

“Starvation out here on the ranch,” he said.

The mill was alongside a north-south set of railroad tracks on the east side of Edgemont, next to Cottonwood Creek less than a mile south of its confluence with the Cheyenne River. The 213-acre campus included a collection of high, steel-covered, industrial-looking buildings, plus ever-growing waste piles and ponds.


Up to 400 tons of ore per day was processed. The ore was crushed and ground into sand and mixed with water to make a slurry, and then treated with sulfuric acid to dissolve the uranium.

Next, the slurry underwent a separation process to remove the waste sand, called “sand tailings,” which was discharged to outdoor piles that continued to grow to 40 or 50 feet in height throughout the life of the mill. There was apparently no plan to bury or otherwise dispose of the tailings, and a lack of regulation relieved the company from what would turn out to be — years later for the federal government and for a different company — a significant expense.

After the sandy tailings were separated, the remaining slime was sent through a “resin-in-pulp” process which, as described in a late 1950s newspaper article, contained chemical resin beads with “an affinity for uranium ions.” The beads attracted the uranium, and also vanadium, like water softener beads attract minerals. The remaining waste slime after the uranium extraction was called “slime tailings” and was sent to holding ponds.

Finally, the uranium was stripped from the resin beads, precipitated, filtered and dried to form triuranium octoxide (U3O8). Before the drying, the yellowish product came out of a press in cake form and was called yellowcake. Before packaging, the yellowcake was broken down into a fine powder.


By the late 1960s and early ’70s, the U.S. government had more uranium than it needed and ended its guaranteed purchases. After that decision, uranium demand from the private nuclear-power industry was not enough to sustain the mines and mills that dotted the West. Meanwhile, environmentalism was flowering among the social movements of the ’60s and ’70s, and Americans were growing concerned about the piles of radioactive sand tailings at mill sites.

Concern for the health of mine workers and mill workers was slower to coalesce. It wasn’t until 1990 that Congress passed and President George H.W. Bush signed legislation — the Radiation Exposure Compensation Act — that created a fund to reimburse uranium-industry workers who suffered increased cancer risks from long-term radiation exposure, or other problems including respiratory ailments associated with mining and milling dust.

That fund still exists, and individual applicants can receive up to $100,000. About $2 billion has been awarded nationwide, including $5.175 million to 59 people with South Dakota addresses.

During a debate over amendments to the law in the late 1990s that expanded eligibility to states including South Dakota, a Sturgis woman, Sharon Kane, wrote a letter to then-U.S. Sen. Tom Daschle, D-S.D., which was entered into the Congressional Record. Kane said her late husband, Joe, worked at the Edgemont uranium mill from 1959 to 1970. He suffered upper respiratory problems that the Kanes blamed on his mill job before he died of bone-marrow cancer at age 53 in 1990.

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