Production, which began in 1899 at the Sunrise Mine in Wyoming was initially by open-pit mining at a cost of 15 cents a ton.
In 1903 CF&I was the largest producer of coal in the Rocky Mountain west with 23 mines in Las Animas, Huerfano, Fremont, Gunnison, Garfield, and Pitkin County, Colorado producing 53% of the coal mined in Colorado and its 9 coking plants producing 89% of its coke [REF].