Navajo Transitional Energy Company has signed a 15-year deal for North American Coal subsidiary Bisti Fuels to be the contract miner at the Navajo Mine in New Mexico.
BHP Billiton New Mexico Coal currently operates the mine will and exit operations when its contract expires at the end of 2016.
Navajo is a surface coal mine located within the Navajo Nation near Fruitland, San Juan County.
Production from the mine is expected to be around 5.9 million tonnes of coal per annum.
NTEC has also signed a separate agreement to sell the coal produced from Navajo to the third-party owners of the nearby Four Corners Generating Station.
NTEC CEO Clark Moseley said: "We are proud to bring in an experienced coal mining company to Navajo Mine. Given the unique structure of Navajo Mine, we believe that North American Coal is the best fit to meet our contractual duties with Four Corners Power Plant.
"This ensures the Navajo Nation will continue to receive coal royalties and revenues for the coming years."
Earlier this year, NTEC began the process of seeking a new contractor for the Navajo Mine and received proposals from various companies in May.
Moseley added: "With each proposing company, we weighed our needs at Navajo Mine against the strengths of each company. North American Coal submitted a compelling proposal, which illustrated they could clearly meet our needs."
The Navajo Nation created NTEC in 2013 to purchase Navajo Mine from BHP Billiton.
Following the acquisition, more than 700 jobs at Navajo Mine and Four Corners Power Plant were secured, in addition to more than $120m of annual revenue for the Navajo.
Image: An aerial view of the Navajo Mine in north-west New Mexico, with Four Corners Power Plant in the background. Photo: courtesy of Ecoflight.