For hydrogeologists, the main challenge in underground works is to carry out estimation based on observed and inferred hydrogeological information with numerical expressions to calculate the seepage flow during excavation. Initially, analytical techniques were a basic and fast solution widely used. However, underground mining projects restrict their use due to complex geometric and geological conditions. Given this, current computational advances allow the integration of geological and hydrogeological knowledge; the use of specific software with flexible meshes is an example to estimate inflows, pressures and hydraulic heads variations in steady and transient conditions in underground works. Parallel calculation and continued innovations of the cloud platform gives us the tools with which to model more complex problems and faster estimations.
An application of current innovations in meshing and tools for groundwater modeling was applied in an underground mining project in South America with infiltration records > 400 L/s located in an area of high deformation with karstic and fractured conditions. A geological model was constructed in 3D Geomodeller to represent the complex geology in the Andes mountain range and generate the unstructured geometry with CGAL. Numerical modeling was implemented in FEFLOW with the TetGen algorithm to merge both complex geometries (i.e., geology and underground mine with galleries and tunnels > 150 km) and represent the current and future conditions in the mining project. Inverse modeling was done with FePEST to calibrate the current infiltration rates and several sensitivity analyses scenarios were done to identify the potential inflows and drawdown impacts according to the future construction plan of galleries and tunnels.
Keywords: FEFLOW, 3D Geomodeller, unstructured meshes, groundwater, inverse modeling.