1. Milanka Negovanović, University of Belgrade, Faculty of Mining and Geology, Serbia
2. Lazar Kričak, University of Belgrade, Faculty of Mining and Geology, Serbia
3. Dražana Tošić, Univerzitet u Banjoj Luci::Vojvode Petra Bojovića 1A, Republic of Srpska, Bosnia and Herzegovina
4. Snežana Ignjatović, University of Belgrade, Faculty of Mining and Geology, Serbia
The paper deals with the issue relating to the deviation of drill holes during the rock blast operations in surface mines.Accurate drilling is of primary importancein every rock drilling process. It results in improved rock fragmentation and lower overall cost. Each hole should be drilled in the correct direction to the proper depth according to the designed drill pattern grid. However, during the drilling process, theactual drill hole path often deviates from the planned one, more or less. Many factors influence the drill hole deviation such asthe rock mass characteristics, the technical parameters of drilling equipment, the experience of drill operator, the angle drilled, geological conditions etc.Drill hole deviationcan be measured. Nowadays, there are many precise deviation measurement systems. Many problems may occure if blast operators proceed to charge blast holes on the basis of the designed drill pattern gridon the assumption that holes are straight, rather than the actual drilling results. Drill hole deviation may cause bad blasting results and increase blast and operating costs. Deviation in drilling has also an impact on flyrockaccidents, injury to workers and property damage.The factors that lead to deviation during drilling, the consequences of deviation and measures to be taken to minimize drill hole deviation will be presented in this paper.