Toward sustainable mining: Experiment-based comparative investigation of energy absorption techniques for reducing air overpressure and enhancing rock fragmentation

Air overpressure (AOP) is recognized as one of the most disruptive environmental hazards of blasting. Existing research has focused on identification of AOP generated by the drilling and blasting parameters, often neglecting the contribution of blasting accessories (BAs) to AOP generation, as well as the mitigation of AOP induced by BAs. Moreover, the effectiveness of mostly AOP mitigation approaches is dependent on geological conditions and often neglects their influence on rock fragmentation (RF). Consequently, these approaches are inadequate in addressing the dual challenge of mitigating blasting-induced environmental hazards while simultaneously achieving optimal RF, thereby limiting progress toward sustainable mining. To bridge these gaps, the present study quantifies the contribution of various BAs to AOP generation and comparatively evaluates two practical energy attenuation techniques (EATs) that simultaneously mitigate AOP and enhance RF. An expert-based survey of 10 industry-professionals using a structured ranking-scale questionnaire identified detonating cord as the accessory contributing most to AOP generation. Subsequently, seven experimental blasts were conducted in a limestone quarry employing two EATs: (i) mud capping and (ii) clay-filled jute-sacking-bags (JSBs), applied over surface-exposed detonating cords. AOP was measured using a Micro-Mate, and RF was analyzed using Split-Desktop®. Both EATs reduced AOP and enhanced RF; however, JSBs outperformed mud capping, as 30 kg/m mud capping achieved 9% AOP reduction and 5% RF improvement, whereas equivalent mass of JSBs achieved 14% AOP reduction and 8% RF improvement. These findings offer a practical, geology-independent solution to BA induced AOP, improving safety, operational efficiency, and sustainability in mining operations.