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.
Coal strip mine in Wyoming. Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit (the overburden) are removed.t gained popularity throughout the 20th century, and is now the predominant form of mining in coal beds such as those in Appalachia and America's Midwest. In most forms of surface mining, heavy equipment, such as earthmovers, first remove the overburden.