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Derrick screens have been used in iron ore since the 1950’s processing all types of iron ore. From removing fine impurities in Direct Shipping Ore sinter products to scalping relatively coarse (+53 to 75 µm) middlings and size control in pellet concentrates. Some of the greatest benefits of fine screening have been achieved by replacing hydrocyclones in grinding circuits. The improved classification of fine screens results in a shift in the grind/grade relationship. In other words, a similar grade can be achieved at a coarser grind size or a higher grade at the same grind size compared to cyclone classification. Screen classification also allows for increase mill throughput that results in a lower power and steel consumption per ton. Fine screening can allow for lower grade ores to be processed more economically and can be used to produce higher grade and more valuable products. Typical operating cost is 1 to 2 US cents per ton and Returns On Investments for the capital costs are often measured in weeks.