Chilala, GC, de Assuncao, J, Harris, R & Stephenson, RM 2015, 'Initial effects of improved drill and blast practices on stope stability at Acacia’s Bulyanhulu Mine', in Y Potvin (ed.), Design Methods 2015: Proceedings of the International Seminar on Design Methods in Underground Mining, Australian Centre for Geomechanics, Perth, pp. 241-254, https://doi.org/10.36487/ACG_rep/1511_12_Chilala (https://papers.acg.uwa.edu.au/p/1511_12_Chilala/) Abstract: High levels of stope dilution were experienced in the deeper longhole open stoping mining areas at Bulyanhulu Gold Mine, a narrow vein underground mining operation in Tanzania. Production losses and equipment damage were often associated with large slabs becoming dislodged from stope walls. One of the major contributing factors causing high dilution was considered to be drill and blast practices applied in different rock types. A preliminary quality assurance and quality control (QA/QC) study was undertaken in order to decrease dilution and improve productivity from stopes, with many of the introduced measures being integrated into standard procedures. The QA/QC study was a collaborative effort between geotechnical engineering, survey, and drill and blast engineering. This paper discusses the QA/QC process, implementation, preliminary outcomes of the study and ongoing improvement.