The stability of high rock slopes is becoming an increasingly important concern in the fields of mining and civil engineering. The need for mineral resources due to the exponential world population growth is driving the excavation of deeper and steeper open pit mines. Today, large open pit mines can reach depths in excess of 1 km. Maintaining and monitoring the stability of the excavation is of paramount importance to ensure the safety of miners, equipment, and mining operations, as well as the profitability of the mine. Despite safe, state-of-the-art mining practices being followed, pit slope deformations occur, usually controlled by geological factors and driven by the progressive accumulation of stress within the pit walls. The deformation of high engineered rock slopes is inevitably associated with the formation of slope damage features, such as rock mass dilation and bulging, brittle fracture and rockfalls. The progressive accumulation of slope damage can reduce the slope rock mass and discontinuity strength causing a decrease in stability, potentially resulting in slope failure. Blast damage, localised at the pit wall surface, may also promote rockfalls and increase the risk of slope instability.In this paper, we present the results of recent slope damage research undertaken in the Engineering Geology and Resource Geotechnics Group at Simon Fraser University. The focus of this ongoing research program includes the definition and characterisation of slope damage, modelling, monitoring and visualisation of slope damage. The factors and mechanisms that can promote and/or induce the accumulation of slope damage within engineered slopes are discussed. The role of engineering geological factors, including geological structures, rock mass quality, lithology, intact rock strength, stress magnitude and groundwater, are addressed and a preliminary rock slope damage interaction matrix approach is presented. Examples of the characterisation of damage using field mapping and remote sensing are presented. New methods of quantifying slope damage are also described.The range of numerical modelling techniques we have used in the investigation of rock slopes is outlined, with a focus on the explicit simulation of rock slope damage accumulation. The critical inter-relationship between slope damage and fracture connectivity is discussed with implications for pit slope design. The importance of continuous monitoring of slope deformation (damage) is highlighted both for the purposes of early warning systems, and as a means to constrain numerical simulations. Finally, a brief discussion on the potential applications of innovative, immersive geo-visualisation methods, such as mixed and virtual reality, in the interpretation of slope damage mechanisms in engineered slopes is provided.

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.

Over the past two decades, advances in remote sensing methods and technology have enabled larger and more sophisticated datasets to be collected. Due to these advances, the need to effectively and efficiently communicate and visualize data is becoming increasingly important. We demonstrate that the use of mixed- (MR) and virtual reality (VR) systems has provided very promising results, allowing the visualization of complex datasets with unprecedented levels of detail and user experience. However, as of today, such visualization techniques have been largely used for communication purposes, and limited applications have been developed to allow for data processing and collection, particularly within the engineering–geology field. In this paper, we demonstrate the potential use of MR and VR not only for the visualization of multi-sensor remote sensing data but also for the collection and analysis of geological data. In this paper, we present a conceptual workflow showing the approach used for the processing of remote sensing datasets and the subsequent visualization using MR and VR headsets. We demonstrate the use of computer applications built in-house to visualize datasets and numerical modelling results, and to perform rock core logging (XRCoreShack) and rock mass characterization (EasyMineXR). While important limitations still exist in terms of hardware capabilities, portability, and accessibility, the expected technological advances and cost reduction will ensure this technology forms a standard mapping and data analysis tool for future engineers and geoscientists.