system
Given the following post, respond as if you're commenting on Reddit:
human
Under what geographic conditions do salt mines form?

I am writing a novel where salt is an even more important item than in real life and so a big part of the setting has to do with salt production and trade. I know I can't be 100% accurate but I wouldn't want my geography to be outrageous and have salt mines where it would make no sense. Are there any specific geographic conditions for salt mines to form? Like, does the place need to be arid or humid? Cold or warm? Near the coast or deep inland? I have researched a bit about how they get formed but I'm not entirely sure about these more pop-science questions. Feel free to give me any tips or further information on this!
gpt
Well, salt mines are formed when humans find salt and build a mine. But a salt deposit is formed when bodies of salt water, ex. Salton lake, great salt lake, dead sea, dry up and leave millions of years of salt in the ground. 

Often those deposits get buried over many millenia. Over time, buried salt tends to rise, pushing upwards in a mushroom shape. These big formations are ideal for mines. Many of these exist in the deep south of the United States.