By now, we are familiar with the sparkling minerals mined in western Montana, but here, in Big Horn County, another resource is being extracted: coal. While oil was discovered seeping to the surface in the Powder River Basin in 1887, strip mining coal didn’t take off until roughly 1924, when the Northern Pacific Railway needed to fire the engines in their steam locomotives. Though the story actually begins millions of years ago.

Southern Montana was once the bottom of a shallow sea. Layers of plants began forming in the rich, subtropical swampland 60 million years ago and were later buried and compressed into coal strata. When vegetation is compressed between rock for that long, coal veins form. As the Missouri River and its tributaries began cutting through the landscape, their erosion left coal seams just below the surface, in an area we now call the Powder River Basin.

The Powder River Basin coal boom started in earnest in the 1970s. Twenty years later, another boom happened when energy developers discovered how to extract, transport, and market coalbed methane, a form of natural gas in underground coal seams. The Powder River Basin has become one of the largest coal producing regions in the United States, its massive deposits enough to light the entire country almost into the 23rd century. But where there’s coal, there’s also conflict.

Coal is known as being the dirtiest fossil fuel, creating concern over the role it plays in not only global warming, but health-related impacts as well. While the future of coal extraction is uncertain, a future that depends on political backing, it has undeniably had an impact on Big Horn County, as one of the principal industries in the county.