Development of a 3D structural model of a mine by consolidating different data sources

Abstract

Joints and faults are inherent part of the rock mass. In the vast majority of mining slopes, discontinuity structures play an important role in slope stability and may trigger a slope failure. The most important step in understanding the slope failure mechanism is to have a reliable model, which shows how all the discontinuity sets are constituted in the rock mass and how they interact with each other. However, building a fracture model is not a straightforward process, since it needs to combine discontinuity information from a variety of sources, such as detailed slope mapping, borehole logging data and remote sensing technologies. Hence, this manuscript attempts to develop a comprehensive structural model of the complete mine area in an open pit, which is the biggest in Norway with respect to its depth and area of coverage. The manuscript demonstrates on how it is possible to consolidate information from different sources in order to identify typical orientation of the detailed fractures that are associated with the main structural lineaments. The process involves analysis of different sources of data in order to correlate this information into useful evidence about the orientation of the fracture systems in terms of dip and dip direction. Further, the mine is divided in different structural domain and a 3D structural model is developed. As an end result, the domains are kinematically tested with respect to different types of failure modes in both overall slope and bench slope scale of the mine for both hanging wall and foot wall. It is highlighted here that the results presented in this manuscript are the part of the research project called "Decisive Parameters for Open Pit Slopes (DePOPS)".

Assessment on the hydrogeological condition of an open pit mine based on piezometric measurements

“…In terms of joint persistence, zone 2 is believed to be enclosed by two clay filled water barriers related to FS3. Average spacing between the main fractures of lineament FS3 is around 400-500 meters (Morales et al, 2017a), which is the widest spacing of all the fracture systems at this mine. Radar monitoring of the area confirms small displacements of a well monitored wedge during rainfall events.…”

“…Discontinuities like faults, joints or cracks developed generally due to tectonic activities provide important clue on surface features and are responsible for infiltration of surface run off into sub-surface and also for movement and storage of groundwater (Subbu Rao et al, 2001). Morales et al (2017a) have shown that there are six different main discontinuities orientations in the mine area, which are correlated with the regional pattern of lineaments. In this manner it was also possible to distinguish six different fracture systems (FS) in the site, as shown in Figure 1.…”

“…The assessment of hydraulic conditions in the study area is based on many sources of information: jointing distribution from the structural model of the mine (Morales et. al, 2017a), groundwater level measurements from boreholes, piezometric data, rainfall data, joints roughness profile measurements in the mine area, and results from hydraulic testing.…”

“…According to Morales et al (2017a) the fracture system at 40-70/060 is considered to be present in two area of the mine, both in the hanging wall (zones 1 and zone 3 in Figure 8). This is in line with the values of SMR calculated in the pit as indicated in Figure 13.…”

The Arsenic Fault-Pathfinder: A Complementary Tool to Improve Structural Models in Mining

“…In mining operations, the precise determinations of relevant fault geometries oriented to geotechnical design are a major concern for structural geologists and geotechnical engineers [1][2][3][4][5]. The principal uncertainties in structural and geomechanical models are mainly controlled by both limited data collection resolution [6] as well as the spatial distribution of data.…”