Federal Government Approves Wyoming Clay Mine Project

Federal land officials approved the Black Hills Bentonite mine project in Wyoming on May 15, clearing the way for an open-pit operation to mine massive amounts of clay for industrial and consumer products.

Approval of the project, located in east-central Wyoming in Natrona County, will allow Casper-based Black Hills Bentonite to begin developing the site on 227 acres of public land. The mine is expected to operate for 20 years, and the clay produced will be sold to other industrial companies for use in cat litter, drilling fluids, binder in foundry molds, iron ore pelletizing, and other applications.

The company declined to comment on the approval May 19.

The project is expected to employ 12 full-time workers over the life of the mine, according to the Bureau of Land Management (BLM).

BLM reviewed Black Hills Bentonite’s environmental assessment and found the project presented no significant impact to the local environment. The plan calls for over 97 acres of open pits and will affect nearly 130 additional acres used for topsoil and stockpile placement, roads, and staging areas.

The substance, which was originally known as “mineral soap” or “soap clay,” was renamed “bentonite” at the turn of the 20th century for deposits in the Benton shale near Rock River, Wyoming.

As much as 70 percent of the world’s bentonite deposits can be found in the Cowboy State, according to the Wyoming Mining Association, a group representing 34 mining company members and over 100 associated companies.

The layer of bentonite at the Black Hills Mine is estimated to be about 108 inches thick, according to the company’s BLM application.

Mining for the clay has been conducted in the permitted area in the past, most likely during the 1960s by the Benton Clay Company, the permit states. Some of the areas were never reclaimed.

No mining activities for other minerals in the area have been attempted.

Several active oil wells are adjacent to the permit area, but because the permitting allows mining depths of less than 50 feet, the company is not expecting to reach oil or natural gas deposits, or groundwater.

The project will consist of mining a series of small pits arranged in multiple cuts, according to the company. The pits will be refilled in the future as part of the permit.

Once the bentonite is exposed, it is sun dried in the pit during the summer and early fall to reduce the moisture content of the clay, which reduces the amount of diesel fuel needed to transport it for processing about 40 miles away in Casper, Wyo.

The project is part of President Donald Trump’s executive order to Unleash American Energy. Trump’s nominee to lead the BLM, Steve Pearce, was confirmed by the Senate on May 18.

The BLM didn’t respond to requests for comment about the mine project or Pearce’s confirmation.