ECONOMIC EFFICIENCY OF DRILLING AND BLASTING IN UNDERGROUND MINING: A COMPARATIVE ANALYSIS UNDER REAL OPERATING CONDITIONS

As underground mines have small cross-section faces, drilling and blasting have a direct impact on operating costs and efficiency, where small design changes can be associated with measurable economic effects. This study will determine the economic effect of optimizing drilling and blasting design for one underground mining face (2.1×2.4 m) through direct cost and performance comparison with conventional vs optimized design. Methodology: Both case direct drilling and blasting costs were measured at the blast level, adjusted for effective advance (US$/m) and excavated volume (US$/m³). Field data were utilized to determine operational blasting KPIs for integrated comparison (blasting efficiency, powder factor and total explosive charge). Results: The optimized design reduced the overall total cost per blast, which was predominantly due to blasting related costs but the drilling costs were virtually unchanged. It leads to lower costs per meter advanced and per volume excavated. The optimized design obtained better blasting efficiency and better harmony of explosive energy and effective advance, indicating more effective usage of resources. Therefore, optimization of the drill and blast design is an economically viable and operationally efficient solution for underground mining operations and development. Standardization of these economic indicators provides a practical and replicable basis for decision making in underground excavation planning and control.