Image analysis as a technique for fragmentation measurement of rock piles has been the subject of research since the 1980s, and to date, run of mine (ROM) fragmentation optimisation studies have primarily relied on particle size measurement using photographic-based 2D imaging systems. Disadvantages of 2D imaging systems include particle delineation errors because of variable lighting and material colour and texture variation; no direct measure of scale and perspective distortion; and inability to distinguish overlapped particles, non-overlapped particles, and areas of fines. With the development of 3D imaging technologies, there is an opportunity to develop techniques that could improve data collection and overcome the limitations of existing 2D image-based systems. This paper describes the first attempt to use 3D high-resolution laser scanning techniques to quantify 'whole of muckpile' fragmentation from full-scale production blasting. During two monitoring campaigns in 2013, high-resolution laser scanning data were collected from production blasts at Esperanza mine (Antofagasta Minerals Group). Fully automated analysis of the 3D data was possible in all cases where the data were of sufficiently high resolution. Manual pre-processing was required when the data were of low resolution to specify the region of fines. Overall results indicated that ROM fragmentation requirements were meeting specified targets, despite the marked differences in powder factors. This was particularly the case for those blasts conducted in similar geological domains. This work has demonstrated that high-resolution laser scanning can be used as an alternative technique to measure 'whole of muckpile' fragmentation in production blasting.

In order to gain better insights into the complex mechanisms at play under fully confined blasting conditions in mining applications, several models were constructed and analysed using the hybrid stress blasting model (HSBM). A disturbed zone or microdamage criterion was proposed and used in the modelling analysis. It combined a lattice bond contact tensile failure criteria and a simple peak particle velocity based approach. Estimates were made of the extent of fracturing, disturbed and interaction zones from fully confined blastholes spaced at distances of up to 18 m, simultaneously initiated with primers positioned every 8 m. Continuous interaction was evident along the explosive column at spacings of ,15 m. When blastholes were spaced at 18 m, the attenuation of the stress wave showed only partial or limited interaction along the column. With regards to the influence of in situ stress magnitudes in the range of 500-1500 m, modelling results appeared to capture the impact of stress intensity on the final extension of the macrofracturing zone. At depths of 1200 m and above, the degree of continuous interaction was diminished at the level of the initiating primers. For the simulated geotechnical conditions, the orientation of radial fractures with respect to the principal stress direction is more evident at anisotropy ratios greater than two. However, the extent and shape of the disturbed zone does not appear to be influenced by anisotropy, which showed a deficiency in the implementation of in situ stresses in the current modelling framework and further work is being conducted to address this limitation.

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