Onsel, EI, Stead, D, Barnett, W, Zorzi, L & Shaban, A 2020, 'Innovative mixed reality approach to rock mass mapping in underground mining ', in R Castro, F Báez & K Suzuki (eds), MassMin 2020: Proceedings of the Eighth International Conference & Exhibition on Mass Mining, University of Chile, Santiago, pp. 1375-1383, https://doi.org/10.36487/ACG_repo/2063_103 (https://papers.acg.uwa.edu.au/p/2063_103_Onsel/) Abstract: Traditional methods of mapping in mines use a geological compass for orientation measurements, a tape measure for length measurements and pen/paper for sketching and taking notes. This has been improved in recent years with a change from compass to smart phones/tablets and the use of tablets for sketching photographic images. A significant improvement is the use of remote sensing e.g. LiDAR and photogrammetry to collect data with subsequent office-based data processing. However, the collected 3D data is usually displayed on 2D monitors which is a very different experience in comparison to fieldwork. The perception of 3D geometry and scale are lost, which may result in biased and limited interpretations. The Microsoft HoloLens is an augmented reality headset comprising a computer with a transparent screen and a 3D scanner. This device allows the creation of a 3D map of the real-world almost in real-time. Using this map, it becomes possible to place virtual objects within the real-world and to know the location of the HoloLens user. As the screen is transparent HoloLens users can see the real-world along with virtual objects, such as previous mapping and drilling completed anywhere within the underground mining operation. Advantage of state-of-the-art new VR/MR technology was taken and a Microsoft HoloLens application which can be used to annotate/draw directly on a rock face was developed and the necessary spatial data in the field for use during mapping is made available. After field work has been undertaken, the collected data can be easily exported to other software without further post-processing. Holographic mapping procedures for virtual rock outcrops constructed from remote sensing data, e.g. ground and UAV based LiDAR and photogrammetry was also developed. This allows office-based mapping of virtual outcrops. The developed software will improve direct outcrop mapping and office-based mapping using remote sensing data.