Surface mining

Surface mining is a method which operates on the surface of the land. Machines remove the overburden to get at material, such as coal, below it. 
Surface mining includes strip mining, open-pit mining (UK: open cast mining) and mountaintop removal mining. It is mining in which soil and rock overlying the mineral deposit are removed. It is the opposite of underground mining, in which the overlying rock is left in place, and the mineral removed through shafts or tunnels. 
Surface mining gained popularity throughout the 20th century, and became the main way of coal mining in places such as Appalachia and America's Midwest.
In most forms of surface mining, heavy equipment, such as earthmovers, first remove the overburden. Next, huge machines, such as dragline excavators or Bucket-wheel excavators, extract the mineral.