This report summarizes the economic consequences of drillhole deviation in relation to the quarries’ production chain. The report is divided in three parts where: •The main drilling methods are described and discussed •The drillhole deviation is expressed and the major problems associated with deviations are presented, as well as the management strategies to prevent those problems •A drill rig manufacturer’s (Sandvik) offering to reduce drillhole deviation is presented. •Further two case studies about the economic potential of reducing of drillhole deviations are done and the economic potential of reducing drillhole deviations is discussed •Summary of the main results, based on the literature and the case study finding is finally given and comments and recommendations are done The conclusions from this study are that there is a strong correlation between drillhole deviation and extra costs in all steps of the production chain (drilling and blasting, secondary breakage, loading and hauling, crushing). However, the state of the research on the subject with a small population of figures, together with a lack of global data on the case studies are preventing to give extensive values of these extra costs associated with drillhole deviations. The result of the case study in the quarry show that the extra costs, associated with control means and measures, are paid back by the savings on drilling and blasting operations. The literature data collection and case studies tend to show that extra costs associated with drillhole deviations are only a small portion of overall operations costs. Consequently, the main advantage of reducing drillhole deviation seem to be related to the decreased risk of flyrock, hence increased safety for people around the blast zones, which must be the top priority of any quarry manager. Further investigations on a global scale and focused on drillhole deviation control would be necessary to get a better picture of the extra costs associated with drillhole deviation. The results of this research will hopefully enable more efficient drilling and blasting programs to be developed, leading to better efficiency in blasting operations.