The ever changing demands of providing operating teams with grinding circuits that meet their needs has resulted in equipment suppliers offering a broader range of grinding equipment and operators and researchers investigating more efficient methods of reducing the size of ore. This paper presents Fluors learnings from grinding design and optimisation work carried out over the last decade, which includes the design and construction of the worlds largest High Pressure Grinding Rolls (HPGR) based grinding circuits and the optimisation of Semi-Autogenous Grinding (SAG) mill liner and grate design at a number of sites. In addition, this paper also presents emerging opportunities for reducing grinding operating costs by combining established size reduction technologies, such as HPGR, ball milling and stirred milling, to generate a superior processing outcome for the operator. CITATION:Sherman, M and Collins, A, 2019. Grinding circuit evolution, in Proceedings Iron Ore 2019, pp 786795 (The Australasian Institute of Mining and Metallurgy: Melbourne).