Ore sorters, concentrators and iron grade discussion, page-5

Among the projects with the worst iron ore conditions to manage is Mineral Resources Wodgina project in the Pilbara region.

The 2016 flow chart below for Wodgina was using LIMS and WHIMS to manage iron issues. The secondary method used from one previous TG6 posters comments was mining into the pegmatite to avoid any mafic contamination. They have the resource size and the iron problem that they lose part of the resource to ensure less iron issues.


So how big is the iron ore issue at Wodgina?
Its a big issue. This project has open pit Fe grades of 1.85% (multiplying by 69.9% gets Fe₂O₃ grades so the pit's at 1.29%). In trying to remove iron, they have created a tailings storage facility that now has 22Mt at 0.96% Li₂O. While the tailings is well above normal lithium cut-off's grades, the material has an iron grade of 5.14% Fe (3.59% Fe₂O₃). Presumably because the Wodgina operation is so concerned about Mafic adding to the already high iron grades at the project, they have assumed a minimum 10m mining width. If those seams were say 20m wide on average - 1m of pegmatite loss on each side of the pegmatite is accepted in avoiding even more Mafic iron issues.