An accurate slope stability assessment of fractured rock masses remains a major challenge because conventional limit equilibrium methods generally assume a constant shear strength along the failure surface and may therefore overestimate stability in structurally degraded rock. This study presents a fractal-enhanced Mohr–Coulomb (FEMC) model coupled with the classical Fellenius method of slices to explicitly incorporate fracture complexity into slope stability analysis using rock quality designation (RQD) data. In the proposed framework, RQD is transformed into an effective fractal dimension, which is then used to modify the cohesion and friction angle, allowing the factor of safety (Fs) to vary according to rock mass conditions. In simple terms, poor rock quality corresponds to greater fracture complexity, lower effective shear resistance, and reduced slope stability. To illustrate the framework, representative RQD values of 30 per cent, 70 per cent, and 95 per cent, derived from the rock mass quality conditions reported for the Mashamba West deposit in the Democratic Republic of the Congo, were used to generate the corresponding fractal dimensions (Ds) and evaluate their influence on slope stability. The analytical results show that the classical Fellenius solution yields a baseline Fs of 1.55, whereas the FEMC-corrected values are 1.23, 1.46, and 1.57 for RQD values of 30 per cent, 70 per cent, and 95 per cent, respectively. These results indicate a reduction of approximately 21 per cent under poor rock mass conditions and convergence toward the classical solution for competent rocks. Numerical validation using Slide2D produced the same overall trend, with Fs values decreasing from 1.103 to 0.899 for RQD = 30 per cent and increasing slightly to 1.119 for RQD = 95 per cent. Additional finite element verification using PLAXIS further confirmed the sensitivity of slope stability to fractal-dependent strength properties. The results demonstrate that the FEMC–Fellenius framework provides a practical and mechanically meaningful way to link routine rock mass characterisation with slope stability analysis while preserving the simplicity of classical limit equilibrium methods.