# Geomechanical Basis for Assessing Open-Pit Slope Stability in High-Altitude Gold Mining
## 2 Materials and Methods  
The assessment of rock strength characteristics and slope stability at the Bozymchak open-pit mine was carried out using a comprehensive set of field tests, laboratory experiments, and analytical calculations based on modern geomechanical approaches [11]. To determine the strength parameters--namely, cohesion, internal friction angle, and density--shear tests were performed on prismatic rock specimens representing various lithological types, including grandoiorites and marbleized limestones. The geometric dimensions of the specimens (height, width, and length), their mass, and the area of the shear surface were measured directly on site (Table 1). The results of the shear tests on the rock prisms and the obtained parameters are presented in Table 1, including the calculated values of cohesion. Strength parameters were calculated from the results of the shear tests using the classical Coulomb-Mohr failure criterion [12]. The values of cohesion (c) and the internal friction angle (\(\phi\)) were derived from the relationship between the applied load and the resistance along the failure plane, taking into account the volume and mass of the tested prisms. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Rock Type**} & \multirow{2}{*}{\begin{tabular}{c} **Sheared Prism Parameters, m** \\ **Refinit.** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Shear Surface Area** \\ **After Shift, m\({}^{2}\)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Prism** \\ **Volume, m\({}^{3}\)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Manometer** \\ **Reading, kgf/cm\({}^{2}\)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Internal** \\ **Friction** \\ **Angle, Deg** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Cohesion,** \\ **MPa** \\ \end{tabular} } \\ \cline{2-2} \cline{6-8}  & **Height** & & & & & **Prism Weight, t** & **Shear Force, t** & **Angle, Deg** & **MPa** \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} **Marbleized** \\ **limestone** \\ \end{tabular} } & \multirow{2}{*}{0.412} & \multirow{2}{*}{0.50} & \multirow{2}{*}{0.66} & \multirow{2}{*}{0.330} & 0.136 & 250 & \multirow{2}{*}{25} & \multirow{2}{*}{1.17} \\ \cline{6-8}  & & & & & 0.3875 & 38.709 & & & \\ \hline \multirow{2}{*}{
\begin{tabular}{c} **Granodiorite** \\ \end{tabular} } & \multirow{2}{*}{0.425} & \multirow{2}{*}{0.55} & \multirow{2}{*}{0.900} & \multirow{2}{*}{0.504} & \multirow{2}{*}{0.214} & \multirow{2}{*}{122} & \multirow{2}{*}{25} & \multirow{2}{*}{0.36} \\ \cline{6-8}  & & & & & 0.6142 & 18.886 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Rock prism shear test results at the quarry. Rock density was determined by the weighing method, considering the geometrically measured volume. Shear tests were conducted using a hydraulic jack, rigid steel plates, and a protective steel casing, which ensured a uniform load distribution [13]. The slope stability analysis was conducted separately for different pit walls, both with and without consideration of seismic loading. Safety factors were calculated using the limit equilibrium method, incorporating engineering-geological parameters, slope geometry (height and inclination), and seismic loads in accordance with both national and international guidelines, including those provided in reference [14]. A comparative analysis of the calculated safety factors made it possible to identify areas with an increased risk of instability under dynamic loading conditions. These results were further validated by numerical modeling based on the geomechanical parameters obtained from field investigations [15]. The integration of field and laboratory data with numerical simulation results enabled the development of practical recommendations for optimizing slope geometry and applying slope reinforcement techniques. In particular, injection grouting was proposed for zones with structurally weakened rock mass, based on previously described methodologies [16].