The Weld Range greenstone belt, in the Murchison Domain of the Yilgarn Craton, hosts two Archean, high-grade magnetite±hematite±goethite deposits, Madoonga (68 Mt resource at 57.7 wt.% Fe) and Beebyn (62 Mt resource at 59.6 wt.% Fe, ASX announcement 2008). Five main styles of high-grade Fe mineralisation at Weld Range were recognised and each display characteristic grades, tonnage, and contaminant levels, which affect exploration
strategies and beneficiation methods.
In addition to mapping and detailed examination of diamond drill core, ASTER data was acquired for the Weld Range district as a pilot project to test the usefulness of ASTER geoscience products for the identification of iron oxide minerals and hypogene alteration mineral assemblages in neighbouring mafic igneous country rocks. The results were positive in that the ASTER products proved useful for the delineation of outcrop, high-grade iron ore bodies, and hypogene alteration minerals in mafic rocks (e.g. Fe-rich chlorite and Fe-rich talc).
The Weld Range study provides insights into multiple processes of iron enrichment in BIF, leading towards the formation of hybrid deposits that host more than one style of mineralisation. These deposits are heterogeneous in terms of their physical and chemical characteristics (ore grades, contamination minerals, density, magnetic susceptibility), A district-wide exploration strategy needs to first evaluate the types of Fe ore present in the district, rank these types in order of economic importance, and to then systematically explore for the ore type of greatest interest."