3-D displacement comparison between modeling field data for an open pit mine in USA

The intact rock properties and discontinuity properties for both Devonian Rodeo Creek (DRC) and Devonian Popovich (DP) rock formations that exist in the selected open-pit mine were determined from laboratory mechanical property tests conducted on rock samples. Special survey equipment was used to perform remote fracture mapping in the research area. From remote fracture mapping data, the fracture orientation, spacing, size and density were calculated using more refined procedures compared to what exist in the literature. Discontinuity orientation distributions obtained through remote fracture mapping agreed very well with the results of manual fracture mapping conducted by the mining company. The GSI system and Hoek-Brown rock mass failure criterion were used to estimate the rock mass properties combining the aforementioned fracture geometry parameter results with laboratory test results of intact rock samples. Fault properties and the DRC-DP contact properties were estimated based on the laboratory discontinuity test results and field discontinuity information. The built major discontinuity system of 44 faults in 3DEC with their real orientations, locations and three-dimensional extensions were validated successfully using the fault geometry data provided by the mining company using seven cross-sections. The displacements occurred between July 2011 and July 2012 due to the nearby rock mass excavation that took place during the same period were compared between the field monitoring results and the predicted numerical modeling results; the best agreement was obtained for κ₀ = 0.4. Therefore, κ₀ = 0.4 can be considered as the most probable k₀ value for the studied mine site. Overall, the successful simulation of the rock excavation indicated the possibility of using the procedure developed in this study to investigate rock slope stability with respect to expected future rock excavations in mine planning.