Rock mass integrity assessment using a site specific discontinuity index: insights into fragmentation at Eureka Delta gold mine

Kanongovere, Makomborero Salachi; Suglo, Raymond S; Masialeti, Munyindei

doi:10.22059/ijmge.2025.396195.595264

Rock mass integrity assessment using a site specific discontinuity index: insights into fragmentation at Eureka Delta gold mine

Articles in Press

Document Type : Review Paper

Authors

¹ Mining Engineering, School of Earth Sciences, Botswana International University of Science and Technology.

² Mining Engineering, School of earth sciences, Botswana International University of Science and Technology.

10.22059/ijmge.2025.396195.595264

Abstract

This study introduces a Site-Specific Discontinuity Index (ssDI) to evaluate the influence of geological discontinuities on blast fragmentation efficiency at Eureka Delta Gold Mine. The ssDI integrates eight structural parameters: volumetric joint count, joint orientation, persistence, infill condition, alteration, water content, micro and macro-structural features. Validation was performed using Pearson correlation analysis, revealing a strong negative relationship between ssDI and fragmentation efficiency (r = -0.77) and a moderate positive relationship with Rock Mass Rating (r = 0.56). Additionally, fragmentation performance was evaluated across three ssDI categories (low, medium, high) using Welch’s one-way ANOVA (p = 2.26 × 10⁻¹⁶), confirming significant differences between structural domains. To further validate the ssDI, particle size distributions (D₅₀, D₈₀, D₉₉) from WipFrag image analyses of 20 representative blasts were assessed across ssDI groups. The results showed that high ssDI zones produced finer but more variable fragmentation with larger oversize extremes, medium ssDI zones achieved the most uniform fragmentation and low ssDI zones yielded coarser but more consistent fragment sizes near the target specification. These findings confirm that the ssDI offers a robust, site-adaptive tool for optimising blast design and enhancing fragmentation predictability in structurally complex rock masses.

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