Blast-induced ground vibration management in deep open pit mines using GIS: A case study

摘要

Blasting is considered to be one of the significant unit operations in the open pit mines for achieving higher production and productivity. As the blasting operation has been carried out frequently in deep open pit mines, the disturbance in the form of structural damages or psychological issues are also gradually exaggerated with increasing depth and change in the rock characteristics. Safety in terms of environmental effects is one of the significant aspects of a good blasting which can be accomplished possibly through advanced blasting practices and innovative approaches. Generally, the ground vibrations arising from the blasting operation is one of the fundamental reasons for creating unpleasant environmental issues for the mines situated near the population area or any sensitive structures. Similarly, the control of vibration is much helpful to deep open pit operators to achieve their operational objectives closer to the final limits such as wall control and sensitive infrastructure like crusher plant, shaft, buildings, pump house, pipelines and haul roads. Hence, prediction of the ground vibration components is very crucial for designing the safe blast. The intensity of the blast-induced ground vibration is affected by the parameters such as the physical and mechanical properties of the rock mass, characteristics of explosives and the blast design. Based on the plethora of research activity on the subject, different criteria have been designed to specify limits of blast-induced ground vibrations. In spite of the significant research, the criteria vary from one place to another and are not foolproof. This is primarily because of varied rock and blasting conditions. The rock characteristics can vary greatly from one part of a bench to another part, and also can have the directional variability according to discontinuities in the geological formation and structure. In this study, field measurements were carried out at the different benches of a deep open pit copper mine where dissimilar structural lithological characteristics exists and their results were analysed to evaluate blast-induced vibrations according to the type of rock formation. Finally, a thematic mapping indicating the blast-induced vibration level (ppv) for the different rock formations incorporating the structural geological features are prepared using Geographical Information System (GIS) technique. This thematic mapping can be used as effective tool in providing an interesting insight into the influence of rock characteristics on blast-induced vibration level while designing a blast in order to protect the pit slopes and surrounding structures in future.