Mines in the Strait of Hormuz: How dangerous are they?

Iran says it has placed mines in the Straight of Hormuz to discourage independent traffic. How dangerous are naval mines, and what can be done to clear them?

source https://www.dw.com/en/mines-in-the-strait-of-hormuz-how-dangerous-are-they/a-76847658?maca=en-rss-en-ger-1023-rdf