Actually salt mines have caused sinkholes in Missouri right in the city I live in so I imagine they can in Michigan too. I was hoping it was real large and Detroit would fall into it and money wouldn't have to be poured into the city anymore since it is just a waste of it. It is a stink hole in most area's of that once beautiful city anyway only the river front newer buildings are worth more than a dime in that city. I will never figure out why they kept on building some of them there it also was a waste of effort trying to save that dying city and we all knew it for the last 30 years. I left Michigan about that time and couldn't go alone driving in that city or over the city on the freeway even then.