The present case study pertains to the analysis of the use of stemming plug and its effect on fragmentation and muckpile shape parameters in a solid bench of a limestone quarry located in the Philippines. The quarry had major problems of improper fragmentation, back break and poor heave characteristics of the muckpile. The presence of fractures and fissures particularly in the top portion of the blast holes, a major portion of explosive energy was vented off. Excavators were over assisted by dozer because of coarse fragment size and tight muckpile, which, in turn, unnecessarily increased the dozing costs and irregular final wall profile after excavation of the blast. State-of-the-art digital image analysis of the blasted muck in conjunction with excavator cycle time observation, boulder count and measurement of throw were deployed. Use of stemming plug in the blast hole below the stemming column produced favourable results.
Keywords: stemming plug, blast hole plugging, progressive relief, throw, drop, muckpile shape