Metallurgically, the high cost of coking coal forces steel...

Metallurgically, the high cost of coking coal forces steel manufacturers to use higher grade iron ore, as lower grade ore needs to use more of the very expensive coal to remove crap and create high quality iron for the steelmaking phase of the process. Environmental factors play the usual part here, as higher grade iron ore also requires the removal of less rubbish and subsequent pollutants. BTW, for those who care, a WMT of iron ore does not mean the ore is saturated with water, it's the minerals contained with the iron ore aggregate that contains hydroxyl molecules in the minerals. I vaguely recall...