Google Street View captured this image of the Black Hills Bentonite plant in Worland. (Google Street View)

Wyoming environmental regulators will investigate complaints that a bentonite mining company regularly violated rules and escaped proper oversight, Gov. Mark Gordon’s spokesman confirmed.

The Wyoming Department of Environmental Quality will investigate complaints made by a former employee of Black Hills Bentonite, LLC., according to the governor’s chief energy policy advisor Randall Luthi. 

He made his commitment in an Oct. 22 email that responded to at least 14 complaint letters from former Black Hills employee Bruce Lawson, who retired in September. Lawson sent the letters to the DEQ, Gov. Gordon and the federal Bureau of Land Management. 

They allege the overseeing agencies and the company, which sells most of its dried-clay products for cat litter, are in a regulatory mess that needs to be cleaned up.

Lawson alleged recurring violations of mining rules and regulations by Black Hills Bentonite at several sites in the state. Lax and incompetent enforcement by DEQ and BLM regulators allowed infractions to continue, the letters say.

Black Hills Bentonite, which the Wyoming DEQ documents describe as having “a pattern of violations,” violated crucial big game winter range closures, worked improperly in core greater sage grouse habitat and mishandled topsoil that’s essential for reclamation of the open pit mines, Lawson claimed.

The BLM is guilty of “gross negligence … for failing to protect elk and mule deer on crucial big game winter range,” Lawson alleged in an Oct. 15 letter to the federal agency. He aimed similar charges against the Wyoming DEQ, saying inspectors there “are so poorly trained that they are incapable of recognizing these flagrant violations.”

Black Hills Bentonite president Tom Thorson rejected claims his firm was operating improperly.

“I don’t know what he’s talking about,” Thorson told WyoFile in a telephone interview. “I’m surprised he’s creating a lot of issues. We’ve always had a good relationship.” WyoFile did not receive a response to a request to the company Monday for a more detailed explanation of its operations.

A BLM spokeswoman said last week the agency had “not found any non-compliance” at a Black Hills mine near Ten Sleep in Washakie County. The agency will “take another look” at the company’s records, spokeswoman Courtney Whiteman said.

The state, too, will follow up on the complaint, Luthi wrote in his email to Lawson. “A copy of your letter was sent by me to the Director of DEQ,” Luthi’s email reads. “I understand that he will include it with other letters he has received from you and will investigate the matter.”

Alleged violations 

Black Hills Bentonite violations relate to seven permits, Lawson contends, including at a mine north of Ten Sleep in Washakie County. “BHB has ignored … seasonal big game winter stipulations,” Lawson wrote DEQ Director Todd Parfitt, “and has continued to conduct surface mining and hauling activities … on a year-round basis…

“Since 2014, the [Wyoming DEQ – Land Quality Division] Administrator has made no effort or taken any enforcements (sic) actions against BHB … despite the fact this matter has been addressed in several past annual inspection reports,” Lawson continued. Employees “never conducted follow-up inspections to insure wintering wildlife restrictions were being observed.”

Erosion from this roadbed at a bentonite mine, which Lawson asserts was constructed improperly, has led to destruction of vegetation and topsoil, among other things, he claims. (Bruce Lawson)

The agency and its employees, including Land Quality Division administrator Kyle Wendtland, failed their duties “for more than five years,” Lawson alleged.

DEQ employees and administrators also failed to enforce reclamation requirements, including rules requiring the preservation and proper stockpiling of topsoil and governing the construction of roads, Lawson wrote. At least one of those alleged infractions impacted greater sage grouse core area, Lawson said.

DEQ intends to “investigate each one” of the letters sent by Lawson, agency spokesman Keith Guille told WyoFile.  The probe will examine the work of agency employees as well as the alleged environmental infractions, he said. “We obviously take that very seriously,” Guille said of assertions that regulators didn’t do their jobs. “Our staff is highly capable and they’re great.”

Lawson also accused the BLM of “gross negligence” for failing to protect elk and mule deer crucial winter range.

Lawson charged that since 2014, “the BLM Worland Field Office has made no effort … to protect wintering big game….”

“I can personally attest to these facts,” he wrote, “as I was employed by BHB for the last thirty-five (35) years as BHB’s Mine Development and Reclamation Manager.”

The BLM rejected the charges against inspectors and others, spokeswoman Whiteman said Monday. “We don’t believe any BLM employees have been slacking on their jobs or have not been meeting the regulatory requirements,” she said.

Inspectors have made two visits a year to some mines in question, she said, where only one visit is required.  “We haven’t found any instances of the BLM not following the regulations,” she said.

The Paintrock mule deer herd

Black Hills Bentonite operates a total of six plants in Upton, Mills, Casper, Worland and Glenrock, according to its website. They are fed from a variety of open pit mine sites including the one near Ten Sleep.

Mule deer in the area north and east of Ten Sleep are part of the Paintrock Herd, for which the Wyoming Game and Fish Department has set a population objective of 11,000 animals. In its latest estimate from February, the herd numbered 7,673, 30.2% below the objective, according to a WGFD report.

A trail camera captured this image of mule deer in the Wyoming Game and Fish Department’s Cody Region. The region is home to the Paintrock Mule Deer Herd, which lives southeast of where the camera took this photograph. (Wyoming Game and Fish Department)

The wildlife agency lowered the herd’s objective in 2013 to match a trend of declining numbers, according to a 2019 Game and Fish report.  

The report acknowledges “[b]entonite mining and oil/gas development [that] occur in marginal mule deer habitat on the west side of the herd unit.” But it discounts human land uses as a significant influence on populations, saying those modifications “rarely” affect survival and productivity.

The report shows the estimated population has been below the plus-or-minus 20% objective range for the last three years and below the 11,000 figure for at least six years. The population hasn’t met the specific objective figure for 19 years, according to the report.

‘I loved my job’

Lawson found good work At Black Hill Bentonite for decades. “I loved my job,” Lawson said. His title was mine development and reclamation manager, he said.

But his complaints to company management fell on deaf ears, Lawson said. He warned president Thorson repeatedly against bad practices, he said, but the president “just blew it off.”

The DEQ has issued 14 citations, or notice of violation, at five large-scale BHB mining operations, Lawson wrote. Those citations sought $142,000 in penalties, a figure the agency reduced to $68,000 through negotiations with the company, Lawson wrote.

The Wyoming Mining Association published this photograph of bentonite mining at an unnamed location in Wyoming. (Wyoming Mining Association)

The DEQ website lists numerous notices of violation, or NOVs, with BHB, as well as settlement agreements that resolve the infractions through payment of monetary penalties.

The compounding citations against Black Hills Bentonite began to deeply bother Lawson, he said. “Now that I can speak freely, I am doing just that,” he wrote WyoFile in an email.

The latest NOVs in November 2018 related to two mines, one near Ten Sleep, the other in northeast Wyoming between Moorcroft and Upton. In those NOVs, the DEQ referred to several previous citations to BHB and alleged “a pattern of violations.”  

DEQ can impose enhanced penalties on a company with a pattern of violations, Lawson said. Thorson signed a settlement agreement for the 2018 NOVs that the DEQ received on March 18, 2019, according to DEQ documents made public following a records request by WyoFile.

The agreement detailed a series of reforms the company must make and set a $60,000 fine.

If Black Hills Bentonite adheres to the agreement for 18 months, the DEQ will “consider the pattern of violations no longer exists,” the settlement reads.

The settlement mandated that Black Hills establish a “regulatory compliance group” to meet the conditions. The group is required to create a monthly timetable of “continuous self-inspections,” and mine supervisors will scrutinize operations daily, according to the agreement.

The settlement also required the company to write a handbook for employees that outlines proper operations, put employees through additional training and meet other conditions.

Bentonite, the cat’s meow

Thousands of years ago, Yellowstone volcanic eruptions spewed ash across what is now the Bighorn Basin triggering a geologic process that created bentonite. Today, miners find Wyoming bentonite, a clay, in seams as thick as 10 feet, according to the company. 

Bentonite’ can absorb notable amounts of water, which make it slick and slippery. Also known as gumbo, the mud plagues off-road motorists and cyclists but has a wide variety of industrial and consumer applications.

Kitty litter is a $2 billion-a-year industry in the U.S. that uses bentonite as a key ingredient. (Matthew Copeland/WyoFile)

Among those are bentonite’s use as a drilling mud in oil and gas operations, where it carries bore-hole cuttings to the surface and seals and lubricates well holes. However, bentonite may be most widely used as a key ingredient in cat litter. 

Thorson told CBS in 2017 that Black Hills Bentonite gets 80% to 90% of its business from Clorox and other companies that make cat litter. Clorox is an investor in Black Hills, according to AMCOL International’s website.

Clorox is serious about its environmental responsibility, according to its website.

“Our commitment to environmental sustainability shows up in all parts of our business every day,” the website reads. “Since 2008, we’ve made it a top priority to go beyond environmental compliance and begin a long-term journey to reduce the footprint of our operations, improve the sustainability of our products and enhance the transparency and sustainability progress in our upstream supply chain, which involves ingredients and other materials that go into products and packaging.”

WyoFile did not receive a response to a request for comment from Clorox.

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Angus M. Thuermer Jr.

Angus M. Thuermer Jr. is the natural resources reporter for WyoFile. He is a veteran Wyoming reporter and editor with more than 35 years experience in Wyoming. Contact him at or (307)...

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  1. I had the pleasure to meet Bruce Lawson at the When Coal Is No Longer King panel discussion in Sheridan last weekend. He is a passionate defender of Wyoming, and a patriot. I hope now that he’s retired, he chooses to run for office.

  2. Take a drive south of Ten Sleep and see all the erosion and sediment that has accumulated on a state ground parcel….hopefully someone will now pay attention.