Explorers William Clark and Meriwether Lewis noticed burning coal seams along the Missouri River during their journey west in the early 1800s. These could have been ignited by wildfires.
Burning coal mines or coal seams are pretty common today. The Slagle-Bright Diamond coal mine in Colorado has been burning since the 1930s. It’s one of 34 active burning mines in that state alone.
Marshall Trimble is Arizona’s official historian. His latest book is Wyatt Earp: Showdown at Tombstone. If you have a question, write: Ask the Marshall, P.O. Box 8008, Cave Creek, AZ 85327 or e-mail him at firstname.lastname@example.org