The Oyu Tolgoi copper and gold mine in Southern Mongolia contains Mineral Resources that make it one of the worlds largest known copper and gold deposits. The project is a significant contributor to regional development and is jointly owned by the Government of Mongolia. There are several deposits that make up the Oyu Tolgoi project, which is planned to be mined by open-pit and underground methods. Oyu Tolgoi has been mining the open pit since 2011 and the underground mine, Hugo North, is currently under construction and will be mined as a block cave. In mid-2016, Oyu Toglois geologists implemented implicit modelling techniques for open pit geological models and adopted a centralised data sharing platform which allows tracking changes in models. Prior to using implicit modeling, the geologists used to have a manual and paper based section-by-section system to record and understand surface mapping, which they would then digitise to build an explicit model. Today, all geological models are built using implicit modelling software and every new model is published onto a platform where geologists can discuss, hypothesise and add annotations to areas which need focus and reinterpretation. The platform that has been implemented is also allowing the geologists to produce different versions, facilitating even more flexible modelling and fostering discussions. Publishing and storing models in this platform enables the team to work on models and conduct peer review from different locations. Using an integrated version control platform as a control point not only makes the team more efficient, but it also allows geologists to easily interact and collaborate as a wider team. Following successful application in the open pit, implicit modelling will be introduced to the Hugo North underground project and potentially Oyu Tolgoi-wide exploration projects. CITATION: Otgonbayar, T, Erdenebayar, T, Dorjbat, L, Otgonbayar, O and Crook, G, 2019. Application of implicit modelling tools, Oyu Tolgoi Copper and Gold Mine, Southern Mongolia, in Proceedings Mining Geology 2019, pp 6571 (The Australasian Institute of Mining and Metallurgy: Melbourne).