Congenital anomalies are also known as birth defects, congenital disorders or congenital malformations. Congenital anomalies can be defined as structural or functional anomalies (e.g. metabolic disorders) that occur during intrauterine life and can be identified prenatally, at birth or later in life.
But unlike in 2012 when Wyoming was home to nine of the US' ten biggest coal mines, the Cowboy State had a bit more competition last year. North Dakota's Freedom mine has taken the spot of the US' tenth biggest coal producer, as Wyoming's Caballo slid off the top-ten chart. All production figures are in metric tonnes.
The coal comes from the Cretaceous Laramie Formation. Mining began in the late 1850s and stopped in 1979. Large lignite deposits are present in the Paleocene Denver Formation in the central part of the basin, in a north-south belt east of Denver and Colorado Springs, in Adams, Arapahoe, Elbert, and El Paso counties. Some mining was done from about 1886 to 1940, but was reportedly minor.