If you have wondered why most WA Pilbara iron ores are not suitable for making green steel, I just read this good explanation - which was actually on BHPs website.
"For ore from deposits that have higher Fe content in situ, those of sufficient grade to be marketable with minimal processing (referred to as direct shipping ore, or DSO), intensive beneficiation methods can also be applied to further improve the quality of mined ore. However, many of these ore deposits, including those in our WAIO operations, exhibit weaker magnetism and density differentials between the iron and impurities contained in the ore and consequently they are less responsive to beneficiation, which relies on these properties for its effectiveness. As the grade target of the beneficiation plant is pushed upward, iron is lost in the rejected waste at an accelerating rate, reducing mine production and eroding the yield of iron that is recovered from the deposit. For most mines, this creates a practical ceiling to the achievable product grade that is below current DR standards, even with best available technology for beneficiation applied. In some cases, selective beneficiation of the most responsive parts of an orebody can deliver DR quality product but only for a fraction of the mine output.
BHP has an on-going beneficiation technology development program to improve grade recovery performance and we are currently considering the construction of a beneficiation plant at our Jimblebar mining operation, however reaching current DR quality thresholds for all mine output is unrealistic for Jimblebar and most other Pilbara mines and deposits in the foreseeable future. " [emphasis added]
