What are the ways of coal mining?

Mining coastal coal mines generally starts from the shore and extends to the seabed. There are also natural islands and artificial islands to open the wellhead. People's mining methods are different, mainly chamber method, pillar method, longwall mining method and bench longwall mining method. These sand mining methods are similar to land mining, and the equipment used is roughly the same. However, at present, some countries are studying the exploitation of submarine coalfields by vaporization.