Despite Trump's statements this doesn't make much sense right now barring more information. Iran can already block the strait without mines while freely selecting which vessels (e.g. their own, Chinese) transit. They have the option in their pocket but I can't see why they would do it now.

Also, according to Zero Hedge but seems logically sound, Saudi Arabia is relying on the Red Sea and the UAE on Fujairah (port south of the peninsula where Khasab lies) to enable some exports. Meanwhile the U.S. navy refuses numerous daily escort requests due to risk despite public wording implying otherwise.