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Righting a wrong at Riley Pass: After 51 years, mine cleanup finally begins

  • 5 min to read

RILEY PASS | Up on the scenic tablelands of the North Cave Hills in northwestern South Dakota, the 16 people doing the digging, hauling and grading on a major land clean-up project this summer form a veritable cavalry that has arrived mounted on trucks, excavators and bulldozers.

They’re reclaiming the land, 51 years after a uranium mining company used it, abandoned it, and then left contaminants to blow in the wind and wash into streams.

“It’s really rewarding work,” said Mary Beth Marks, “because you get to make a difference on the ground.”

Marks is the on-scene coordinator for the U.S. Forest Service, which manages the site as part of the Sioux Ranger District of the Custer Gallatin National Forest located about 135 miles almost due north of Rapid City.

She visits every few weeks to monitor the work of private contractors, including the main one, North Wind Construction Services, of Kellogg, Idaho. The company has a $2.27 million contract, funded by a massive settlement agreement, to reclaim parts of three buttes.

That work began June 6 and is scheduled to finish Sept. 30, but it’s only a fraction of the overall job that needs to be done. In the coming years, more multimillion-dollar contracts will be awarded to reclaim six more buttes, all to undo the damage done five decades ago by uranium mining. Right now, there is no firm total cost for the cleanup, which will be done in stages and be paid for from a larger $194 million settlement received by the federal government.

Riley Pass map

Butte-tops scraped away

The site’s contamination dates to the 1950s and '60s, when the U.S. government subsidized mining across the West to amass a stockpile of uranium, the primary ingredient in Cold War nuclear weapons.

Among the 20 square miles of flat-topped buttes, pine-forested slopes and sandstone outcrops that comprise the North Cave Hills, the worst mining damage was done by the Kermac Nuclear Fuels Corporation in a 250-acre concentration of buttes that is accessible via Riley Pass. The pass is part of an old wagon route about 25 miles northwest of the small town of Buffalo and eight miles west of the hamlet of Ludlow.

During the mining era, scrapers were used to peel off the tops of buttes and uncover seams of uranium-bearing lignite coal. The earth that was scraped away — the “spoils” in mining terminology — was pushed over the sides of the buttes, and the ore that was unearthed atop the buttes was left exposed after the uranium was extracted.

The mining unearthed a toxic and radioactive mix of chemical elements, including arsenic, molybdenum, selenium, uranium, radium and thorium. But the mining permits that were issued by the federal government did not require any cleanup, and no significant reclamation efforts were undertaken when mining ended in 1964. Streams in the area were left vulnerable to sediment in runoff that spilled over the butte tops and channeled through the spoils.


Mary Beth Marks, of the U.S. Forest Service, points out levels of arsenic on a bluff in the North Cave Hills west of Ludlow.

Cattle and people exposed

Out on the surrounding plains, according to Ludlow-area rancher Tom Kalisiak, cattle drank from the polluted streams and suffered weakened immune systems. Routine illnesses became fatal, and cow fertility declined.

Ranchers tried for years to counteract the pollutants by administering mineral supplements to their cattle, with limited success. Finally, Kalisiak and others got help from state government to drill deep wells and build pipelines, so cattle could drink clean well water instead of polluted stream water.

Kalisiak said he now has about 36,000 feet of pipelines under his pastures. He’s gotten some funding from state government but has also spent his own money.

He and some other ranchers once hired a lawyer to press for compensation from mining companies, but nothing came of it. Kalisiak recalled $850,000 as the figure his lawyer determined he was probably owed for the pipeline costs and other damages.

Besides the effects on their cattle, ranching families have been exposed to elevated cancer risks from breathing windblown contaminants and eating the meat of cattle that consumed contaminated water.

A 2006 risk assessment commissioned by the Forest Service determined that the lifetime cancer risk to some people in the North Cave Hills area could be as high as 3 in 1,000, which is 30 times higher than the threshold of 1 in 10,000 that the Environmental Protection Agency considers concerning.

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Kalisiak said he suspects a link between the mining pollution and some health problems suffered by residents in the sparsely populated area. But he acknowledged the difficulty of proving a connection, given the hereditary and behavioral factors that can also contribute to the development of diseases.

As Kalisiak looked across the plains toward the reclamation project on a recent summer day, he viewed the work with a mix of appreciation and aggravation.

“It’s a good deal,” he said. “It’s just 50 years too late.”

Huge settlement enables work

Though Kalisiak and other ranching families who live near the North Cave Hills have gotten no compensation from mining companies, the federal government won a huge settlement for itself and some states and a tribe in 2014.

The settlement resulted from litigation against the Kerr-McGee Corporation and its historical components, including the Kermac Nuclear Fuels Corporation that operated in the North Cave Hills.

According to the U.S. Department of Justice, Kerr-McGee and its numerous mining, processing and manufacturing businesses left environmental contaminants across the nation. Kerr-McGee executives viewed the contamination as a potential liability, so in 2002 and 2005, they transferred the assets of their main oil-and-gas business to a new corporate entity and left the environmental liabilities behind in the old company, which then declared bankruptcy in 2009.

The bankruptcy proceedings produced an initial settlement that included $7.3 million for cleanup at the Riley Pass site, and some limited reclamation work began.

Meanwhile, a bankruptcy judge found that Kerr-McGee’s actions constituted a fraudulent effort to avoid liability. The federal government sued the company as a result of that finding, and the case was settled in 2014 when Kerr-McGee agreed to pay $5.15 billion, most of which was earmarked for environmental cleanup.

Three sites managed by the U.S. Forest Service were allocated a combined $194 million from the settlement, and the largest of those three is the Riley Pass site. In 2015, money from the settlement was used to improve roads at the site; install a temporary office trailer, storage building and outhouse; and complete engineering designs for the reclamation of three buttes.

'As natural as possible'

This summer, the reclamation work has begun in a big way.

Heavy machinery is crawling up and down steep grades as operators scoop up contaminated dirt and soil, dump it atop one of the shaved-off buttes, and cover it with clean soil scraped from the nearby plains. By the time the initial three buttes are reclaimed, a total of 65,000 cubic yards of dirt will have been moved, an amount equivalent to about 5,000 standard dump-truck loads.

As the spoils are scraped away from the sides of the buttes, their crowning rimrock is re-emerging for the first time since being covered by spoils in the 1960s. The sides of the buttes are being re-graded to a natural-looking condition, while displaced boulders and large rocks are being replaced in what seem like natural locations, and native grasses are being planted. In a couple of years, after vegetation has thoroughly sprouted, the captivating buttes could look like their old, natural selves again.


Heavy machinery crawls across a reclamation project at a former uranium mine in the North Cave Hills west of Ludlow. The reclamation work could continue for 15 years.

Beyond the three buttes receiving work this year, the six additional buttes that need reclamation vary widely in their size and the extent of their contamination. The Forest Service estimates it could take 15 to 20 years to completely reclaim the area.

Parts of the North Cave Hills are closed to the public while the work progresses, cutting off access to some beautiful spots. 

The area's pine-and-grass-covered slopes are rimmed by rocky cliffs that stand as high as 150 feet. Erosion has worked innumerable holes and small caves into abundant sandstone formations, and generations of people have made carvings on the rocks. The flat tops of the steep-sided buttes afford breathtakingly panoramic views of the surrounding plains, which are populated mostly by cattle and antelope.

The view is enjoyed every weekday by members of the reclamation crew. Some are locals, and some are transplants living for the summer in Bowman, N.D., about 30 miles north of Riley Pass.

Marks, whose Forest Service office is nearly 450 miles away in Bozeman, Mont., also stays in Bowman during her visits. Although the reclamation has been a long time coming, she’s excited about having the funding and the opportunity to do the job and do it well.

“It’s the right thing to do,” she said. “My goal is to return this site to as natural as possible.”

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