In open-pit mining operations, the stability of deep excavation slopes is directly dependent on groundwater conditions within the site. An increase in pore water pressures can reduce effective stress, leading to a decrease in shear strength and potentially causing sudden slope failures. To enable early detection and mitigation of these risks, a comprehensive subsurface instrumentation program was implemented by the GeoAnts engineering team. Within this framework, piezometer sensors were installed at different elevations and locations along the slope mass to continuously monitor the pore water pressure distribution. The piezometers were configured as multi-point systems (up to five sensors) within the same borehole, allowing the determination of vertical pressure gradients. In addition, multi-point piezometer systems were integrated with TDR (time domain reflectometer) cables installed in inclined boreholes to identify potential slip surfaces. Through these demanding installations, displacement zones developing within the slope and the relationship between pore water pressure and displacement were evaluated in real time. The data obtained enabled both early warning of potential ground movements and optimization of slope design. This integrated approach significantly enhances the effectiveness of safety-oriented design, continuous monitoring, and risk management processes in mining sites.