Underground sulphur is mined by using a special technique known as “Frasch process”. This process is based on the fact that sulphur has comparatively lower melting point. In the Frasch process, a hole is bored into the sulphur beds. Through this hole three concentric pipes are pushed. Through the outermost tube, superheatd water is forced down. Because of this superheated water, the sulphur in the bed gets melted. Through the innermost pipe, air at high pressure is forced which pushes the molten sulphur through the middle pipe which can be taken in the pots. In the same way sulphur is extracted from mines.