Answer:
Seafloor spreading at the mid-ocean ridge provides the mechanism for tectonic plate movement. The Earth's mantle moves through convection, showing that tectonic plates are able to glide. The location of the plates was determined by locating their boundaries, using data on the Earth's magnetic field.
The rock erodes over time and creates soft, supple material which we refer to as soil
Coal seams are far deep underground to be considered for opencast minings. These coal seams require underground mining. Since it is too deep underground, it can be used for mapping and correlation of sedimentary rocks or as a key bed.
Just look it up on the internet
