Frimpong, Mensah.2018-07-032018-07-031994https://hdl.handle.net/10539/24713A project report submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master ofil science in Engineering.Given the high capital intensity of the dragline operation, the mine can not afford to" tolerate fragmentation problems with its concomitant low dragline productivities. At Syferfontein colliery very large boulders and completely unfraqmented sections resulting in Low digging efficiency of the dragline were encountered in the interburden blast, This project, investigates the causes of the blasting related problems with an intent of improving dragline productivity at the minimum possible cost. This is achieved through blast monitoring, evaluation of the existing practice (blast design) using empirical relations, fragmentation assessment using a model, analysis of operators performance and dragline availabilities. Dragline productivity is evaluated in the light of the various productivity indices , viz, fill factor, fill time and BCM/H. The results indicated explosive incompatibility with the blasting environment and. questionable practices regarding blast design and Delay performance. Engineering field controls such as reduction in drill pattern, reduction of VODof explosive and improvement in draqline utilisation are found necessary. Contributing 61% to the total cost I concentrating on reducing draqline cost must receive preference over drilling and blasting cost as it would produce the most tangible advantage in any cost reduction effort. Regression equations relating cbst and productivity are established.enBlasting -- South Africa.Coal mines and mining -- South Africa.Thesis