220 increase in m&i, page-20

Au and Tungstan have similarities as both can have similar metalurgy regarding processing with grinding then heavy media /gravity seperation.
Taconite and limestone are bulk commodities where transport losgistics prevent them from being converted to logicly be Au equivalents.
Also why the relevance of taconite anyway as it needs to be ground and palleted a rather complex process considering the amount of hematite available in Oz
Diamonds well they are normally processed using a trommel with no milling needed so a pour comparison unless compared to alluvial tin/gold

You are probably just pulling my chain anyway.