What were some major empires that were involved in salt mining after the fall of the Roman Empire?

Question

What were some major empires that were involved in salt mining after the fall of the Roman Empire?

Answer 1

I'm not 100% sure about empires,  but all I can say now,  is that some of the biggest places that have salt mines are, 

 : - Rheinberg, Germany,

 : - Khewra, Pakistan,

: - Avery island, Louisiana, and  Detroit, America,

: - Chesire, and Worcester, England,  

     But the biggest one of them all is in,  

: - Gooderich Ontario,  Canada...

Sorry I couldn't help you any more then that...