This method is much less common, and produces, for example, 15% of minerals in the United States
This method generates more risks to workers than the other
It causes a serious impact on the environment.
With this method, big machines can be used.
This method is more expensive than the other
This method gained popularity throughout the 20th century
This method requires horizontal, diagonal or vertical accesses
It consists of digging tunnels or shafts into the earth to reach buried ore deposits
The majority of this method (type of minerals extraction) occurs in North America
It requires a wide area
