Pre- and Post-Blast Rock Block Size Analysis Using UAV-Lidar Based Data and Discrete Fracture Network

Drilling and blasting is one of the key processes in open pit mining, required to reduce in-situ rock block size to rock fragments that can be handled by mine equipment. It is a significant cost driver of any mining operation which can influence the downstream mining processes. In-situ rock block size influences the muck pile size distribution after blast, and the amount of drilling and explosive required to achieve a desired distribution. Thus, continuous measurement of pre- and post-blast rock block size distribution is essential for the optimization of the rock fragmentation process. This paper presents the results of a case study in an open pit mine where an Unmanned Aerial Vehicle (UAV) was used for mapping of the pit walls before blast. Pit wall mapping and aerial data was used as input to generate a 3D Discrete Fracture Network (DFN) model of the rock mass and to estimate the in-situ block size distribution. Data collected by the UAV was also used to estimate the post-blast rock fragment size distribution. The knowledge of in-situ and blasted rock size distributions can be related to assess blast performance. This knowledge will provide feedback to production engineers to adjust the blast design.