Salt can be extracted from the sea or underground mines in the following methods:

1) Evaporating the water from seawater to leave salt, used for food
Positives: produces lots of salt, easy and cheap
Negatives: long process, better in warm climates
2) Rock salt mining*, used on roads
Positives: produces lots of salt
Negatives: difficult and expensive, requires large machinery
3) Solution mining**, used for chemical industry and food preservation
Positives: easy to do, produces brine to preserve food
Negatives: expensive, requires large machinery, lengthy process