Rio Tintos Iron Ore group has sustained significant growth over 50 years. The complex operational system has grown from a single site to 16 mine operations delivering over 338 million tonnes of shipped products during the 2018 calendar year. Throughout the expansion, organisational design changes have impacted the capacity and capability of the resulting Mine Geology team and their ability to deliver orebody knowledge and value. The current structure is lean and centred on productivity; which is essential to meet the complexity and production volume. Our Mine Geology teams strive to ensure grade control practices and mining take into account the unique geological features of the orebodies. The current best practice uses geological domains as a key input to drive grade control models known as Dynamic Integrated Geology (DIG) models. The process ensures that up-to-date mapping, material-type logging, sampling, and localised product predictions are used in the estimation process; directly informing the mine block ore delineation. Building DIG models develops practitioners skills and enables orebody knowledge transfer across teams as an auditable and transparent process. The models also drive increased orebody knowledge by ensuring consistent capture of essential data. Immediate value benefits are dig-block outlines that align more appropriately with the unique features of the orebody as well as improved product quality predictions for blending and processing plant throughput. This is of increasing importance with the recent shift from a tonnes driven, to a quality/ grade focussed market. Additional value benefits include blast outline planning and future bench planning. DIG models capture and summarise the interpretations of the definitive geometry and grade for reconciliation. The role of Mine Geology in Rio Tintos Iron Ore group will continue to evolve with teams engaged to assess and share options to meet the future of mining; including incremental improvements, advancements in technology, automation and data science. CITATION: Robinson, D, Crystal, A, Mackenzie, P and Tabrett, D, 2019. Evolution of mine geology in Rio Tinto Iron Ore including the use of geological domains to drive improvements in orebody knowledge and value, in Proceedings Mining Geology 2019, pp 328338 (The Australasian Institute of Mining and Metallurgy: Melbourne).