Black Hills Bentonite celebrates 75 years

Hannah Gross

Submitted photo

Siblings Tom Thorson, Mary Gullikson and Don Thorson have long been involved with the Black Hills Bentonite Company, which their father Harry started 75 years ago. The business has grown through the years and still operates under the family.

Hannah Gross

NLJ Correspondent


The Black Hills Bentonite Company LLC has been in the Thorson family for three quarters of a century, and as the “elder statesman,” Don Thorson has a lot of knowledge about the history and workings of the company. So, in celebration of the 75-year-old business, he retold the story of how his father, Harry Thorson, started it. 

Harry grew up on a farm in North Dakota, where he attended high school. He went to a business college when he was 16 and then began teaching at age 18. Because of his asthma, Harry had to leave the frigid North Dakota temperatures, which is what brought him to Wyoming, where he landed his first job in Casper collecting money for the local newspaper. 

In 1923, Harry moved to the Clay Spur area 5 miles north of Osage, where he loaded oil trucks. This opened the doors for him to become the superintendent of an oil company in Osage, and he started producing his own oil. Additionally, Harry had a truck he wasn’t using, so he hauled bentonite every summer to last through the winter months. 

Harry agreed to haul bentonite for Barreled Edge Sales, which was a bentonite company at the time, Thorson said. He acquired leases to sell bentonite, but because he couldn’t use them, Harry decided to start his own company in 1946. That’s when he partnered with an engineer from the Colorado School of Mines
to form Black Hills Bentonite — whose name was created by his wife, Inga Thorson. 

Construction on the company’s building began in Moorcroft shortly after Don finished eighth grade. Because the cement for the building was not available in the ready-mix concrete packages like it is today, they had to make it themselves. Because he was old enough to drive, Don began hauling water and shoveling sand and cement. 

In the fall of 1947, Black Hills Bentonite officially opened its doors. During that time, the Belle Fourche bentonite company was burned down, increasing business for the Thorsons. The company continued mining and processing bentonite, and when Don’s brother, Tom, graduated from the University of Wyoming in 1961 with a degree in geology, he “actively” joined the family company. 

In the late 1950s, it was discovered that “bentonite is a very good glue for foundry,” according to Don, so Bethlehem Steel bought bentonite from the company, forming a partnership in 1965. 

“They (Bethlehem Steel) decided they needed to have a dependable source of bentonite,” Don said, adding that they owned 49% of the company while Black Hills Bentonite maintained the other 51%. 

However, when the steel company went out of business, Black Hills Bentonite no longer had a place to store the clay. Additionally, Halliburton bought Bethlehem
Steel and merged with MI Drilling Fluids, which was the rival to Thorson’s company. 

“We were on the wrong side of that,” Don said. So, the Thorsons bought out MI Drilling Fluids. 

Business continued to grow when two men from Houston, Texas, realized that bentonite was a good substance for cat litter, so Black Hills Bentonite began doing business with First Brands. The Clorox Co., “which is always looking for more products,” Don said, also hopped on the bandwagon and bought First Brands interest in the company. The Clorox Co. continues to receive 500,000 tons of bentonite every year from Thorson’s company.

Today, Black Hills Bentonite has three plants in Casper, where its headquarters is located, one in Worland and one in Upton, Don said. The company has 100 employees and 50 pieces of “big machinery” to mine and haul the bentonite in various places across the state from Osage, where the company originally began, all the way to Ten Sleep. 

“We ship an equivalent of a full trainload (of bentonite) a week,”
Don said, enough to fill 120 to 140 train cars.

Tom was president of the company until he passed away last December, and so his daughter Cynthia stepped in to fill his shoes. Don, his sister Mary and Tom’s son Peter maintain their interests in the company. To this day it remains a family business. With all the children and grandchildren coming up the pipe, Don said it’s scheduled to stay that way.

When Harry first started, he knew nothing about oil, but Don admires the way his father pursued the business opportunity when it became available. 

“He never had a goal to do this, but he had the ability to see business ideas and make them work,” Don said. “I learned a lot about business and how to build on it.” 

Don said his father led a life of honesty and always kept his word, teaching his son “how to live an honorable life.” This helped Don when he branched off to operate his own oil company for 35 years, the Thorson Oil Co., also known as TOCO. 

Even though Harry passed away in 1976 at age 74 and Inga in 1994 at age 92, the legacy he set for his children continues through the company’s success. Although unsure of how they will celebrate the 75th anniversary, the Thorsons are planning and hoping for more years to come. 


News Letter Journal

News Letter Journal
14 W. Main St.
P.O. Box 40
Newcastle, WY 82701
Ph: (307) 746-2777
Fax: (307) 746-2660

Email Us


Please Login for Premium Content