1937 - 1969: The Monolith Portland Midwest Coal Company at Hanna and Elmo, Wyoming
Notes from Bob Leathers with contributions from Gary Milliken
The Monolith Portland Midwest Coal Company's Monolith open pit mine near Elmo opened coal production in 1937 and closed production in 1969. The mine produced, over 32 consecutive years of coal production, a total of 1,694,398 tons of coal with a peak work force of 60 workers in 1966. The mine produced coal for the Portland Cement Company in Laramie. No miners were killed in the Monolith mine.