Date of Award
Master of Science (MS)
Digital photogrammetry is becoming a more common method used for mapping geological and structural rock mass features in underground mining. The issue of capturing geological and structural data in inaccessible, unsupported areas of mines remains even when utilizing terrestrial photogrammetric methods; thus, geotechnical models of mines are left with incomplete datasets. Large unsupported underground voids, like stopes, have the potential to cause major failures, but by filling in the geotechnical data gaps in inaccessible areas, potential failures can be predicted through kinematic analysis of the area’s mapped discontinuities. Implementation of Unmanned Aerial Vehicles (UAVs) in underground mines and recent advances in obstacle detection systems have allowed for greater experimentation with photogrammetry conducted from a UAV platform in mines.
For this study, a UAV-based underground photogrammetry system was developed to manually capture imagery in an inaccessible stope at Barrick Gold Corporation’s Golden Sunlight Mine (GSM) in Whitehall, Montana, to see whether or not the approach is a viable remote sensing technique for gathering georeferenced geotechnical data. Development of the system involved selecting an appropriate UAV platform, identifying a lighting system capable of providing adequate illumination, acquiring a sensor system that consistently avoids obstacles, and choosing the appropriate UAV camera (and its respective settings) for underground UAV-based imaging. In order to georeference the data collected in the inaccessible stope, paintballs were shot into the stope to create ground control points that were then surveyed in laser range detection. These paintball marks had to be in visual line-of-sight and visible in the imagery captured via UAV camera in order to georeferenced them.
Using the imagery collected in the stope at GSM, models were constructed and structural features were mapped on those models. Bentley ContextCapture software was able to successfully construct a stope model from the video frame imagery collected via UAV in the stope, while ADAM Technology was not. Split-Engineering’s Split-FX and ADAM Technology were used separately to map the discontinuity planes present within the model. A comparison of underground discontinuity mapping was performed using the UAV-based photogrammetry captured in the stope and hand mapping data collected around the entrance to the stope. It was found that northeasterly striking discontinuity planes were identified using the digital mapping, but not in hand mapping. Using UAV-based photogrammetry for geotechnical data collection creates a quick and thorough mapping process with time-stamped imagery that can potentially create a safer mine. The lessons learned during this study may help guide future efforts using UAVs to capture geologic data and to help monitor stability in areas that are inaccessible.
Russell, Elizabeth Anne, "UAV-BASED GEOTECHNICAL MODELING AND MAPPING OF AN INACCESSIBLE UNDERGROUND SITE" (2018). Graduate Theses & Non-Theses. 177.