Ann: Strong Maiden Cassini Mineral Resource, page-14

Hi momark
Not only is this ore Class 1 more importantly in BHPs eyes for Kalgoorlie smelter longivity this ore is the sweet blend high in FeMgo that the smelter requires for a good pour tap at blast furnace without spitting and small explosions. Currently leinster ore is blended with the low grade mt keith ore to raise FeMgo then it was blended with Kambalda ore to get the right mix, when all the Kambalda ores stopped production due to low prices the WSA and IGO ores were/ are used.
But these are concentrates are not so much a premium for BHP and WSA not as high in FeMgo.