I lost hope for something better at the 2 minute mark.
I don't doubt that there is more to the North Korean thing than we are being told but his coal hypothesis sounds far fetched.
A more probable explanation is rail than coal. Both Koreas recently agreed to rail links which tie into Trans-Asian Railway. South Korea is world's 11th economy by GDP. Just below Canada and just above Russia in the ranking. A rail access way to Eurasian markets gives them additional options and bargaining power versus a dependent on maritime trade at present.Some links on Trans-Asian Railwayhttps://www.rt.com/business/russia-north-korea-railway-241/https://www.youtube.com/watch?v=EhtcYFZiAFAhttps://www.csmonitor.com/2000/0919/p7s1.htmlhttps://en.wikipedia.org/wiki/Japan%E2%80%93Korea_Undersea_Tunnelhttps://en.wikipedia.org/wiki/Trans-Asian_Railway