a nationwide mining depression beginning in the 1920s, a new mine opened
east of Sunnyside and the Gordon Creek district also entered production.
However, the depression deepened as railroads switched to diesel fuel
and homeowners changed to natural gas. A few new owners acquired mines
in the thirties to power industries still run on coal. Two decades of
depression were relieved only when World War II demands caused Utah
coal production to reach its zenith.
another economic setback struck Utah coal in the 1950s and 1960s. It
was relieved only when the combination of the Arab oil embargo and the
original Clean Air Act in the seventies resulted in coal mine acquisition
by energy companies which use coal to generate electricity. Utah coal
production reached an all-time high in the early 1980s, a trend that
has again been reversed.