I know we've had some side discussions about salt in other threads, so I went looking...
The following threads have some mention of either, usefulness of salt, salt production or salt mines etc. etc.
(Note that I have started adding the 'salt' tag to some of these threads as well, including this one.)
https://forum.juhlin.com/showthread....highlight=salt
https://forum.juhlin.com/showthread....highlight=salt
https://forum.juhlin.com/showthread....highlight=salt
https://forum.juhlin.com/showthread....ht=salt&page=2
https://forum.juhlin.com/showthread....highlight=salt