While differentiating between Area strip mining and Contour mining with respect to coal extraction, discuss which of them is more dangerous to environment and why.

Area Strip mining and Contour mining are two types of surface coal mining techniques.
Area strip mining is a type of mining used on a flat terrain. In this, an earthmover strips away the overburden, and a power shovel digs a cut to remove the mineral deposit. The trench is then filed with overburden and a new cut is made parallel to the previous one.
On the other hand, Contour mining is also a kind of surface mining but it is practiced on hilly or mountainous terrain. In this, a power shovel cuts a series of terraces into the side of a hill. Then, an earthmover removes the overburden and a power shovel extracts the coal. Thereafter, an overburden from each new terrace is dumped onto the one below.
With respect to the mining technique being more harmful to environment, it’s a thin line to distinguish, because all the mining operations have a disruptive impact on environment.
However, in my opinion, area strip mining appears to be more disastrous. It can erode the soil or reduce its fertility. Further, it can also pollute waters or drain underground water reserves, damage roads, homes, and other structures and also destroy wildlife.