It’s easier to distinguish between high- and low-quality coal.
Explanation:
Coal mining is the extraction of coal from the depth of the soil around the area where such coal is found. <em>This extraction shows that, there are various grades of coal ranging from low quality which is very dangerous for use to high-quality which is better for use. The use of the surface coal mining technique will help to distinguish it based on their various colours.</em>
<span>The
process that takes place at convergent boundaries by which one tectonic
plate moves under another tectonic plate and sinks into the mantle as
the plates converge is called SUBDUCTION</span>
