Out of many worries about this world and its future, running out of salt is really at the bottom of the list.

You can always extract it form the sea by mere evaporation like our ancestors did. Plus salt deposits in the ground all over the world are massive, we had salty seas for billions of years.

Not sure why you're getting downvoted. People shouldn't get punished for asking questions.

Salt mines in particular are of the safest kind in the whole world, they are super stable. It's a self supporting rock with enough plasticity that the whole thing doesn't crumble down.

If you ever have privileged info of a huge earthquake happening, going into a salt mine is probably not the worst idea.

Plus it rehabilitates your lungs to be in a salt mine for a long time.