Rio Tinto Energy America (RTEA) was a wholly owned American subsidiary of the England and Australia-based mining giant, the Rio Tinto Group, headquartered in Gillette, Wyoming, United States. The company, previously known as Kennecott Energy after another of Rio Tinto's American subsidiaries, was formed in 1993 when Rio Tinto purchased NERCO and placed that company's and under the RTEA umbrella. Subsequent acquisitions included the Cordero Mining Company, the , and the Jacobs Ranch coal mine. RTEA operated four mines in Wyoming and Montana, supplying fuel for the generation of approximately 6% of the United States' electricity consumption. The RTEA mines were spun off to Cloud Peak Energy in 2010.