Bonded block modelling (BBM) is a relatively new numerical modelling technique that attempts to capture rock mass damage through the interaction and breakage of contacts between “blocks” (volumes) of rock. Its suitability for modelling spalling cases in Scandinavia is evaluated in this report. The intended outcome of this work is to provide up-to-date information, guidance, and insights on how BBM can be applied and used by practitioners. While steadily increasing in quantity, the small number of published works on BBM show promising qualities for modelling rock mass damage. A gap in the literature exists, however, concerning many choices those modelling BBM must make. Additionally, the examples found in the literature typically use block sizes which are significantly larger than those that would be required to represent the spalling phenomenon, as spalling occurs at the inter- and intra-grain level. A well-documented spalling case was selected for analysis: Malmberget Mine’s Öde E8 ventilation shaft. The depth of spalling was approximately 10 cm. A BBM material with very small blocks (near grain size) was created. The rock in the shaft was represented by this BBM material through a careful calibration process. This process included models of UCS and Brazilian tests. It was demonstrated that the configuration of the blocks effects the results. In situ quasi-3D models were created with a BBM region in the expected area of spalling. Results were obtained for the calibrated BBM material calibrated to the laboratory test results, as well as a BBM material where the UCS was reduced to that of the laboratory crack initiation value. Spalling was present in both models; however, the position and form did not match that of the actual case. The reduced strength models had more spalling, but still did not achieve the spalling depth of the actual case. Signs exist that the stiffnesses between and in the continuum portion of the model and the discontinuum portion of the model are resulting in some boundary effects. It is one of the challenges of these models. The research presented in this report, both the literature review and practical application, is one of many steps towards the regular use of BBM techniques by practitioners. While BBM is a promising step forward towards a better understanding and modelling capability of rock mass damage, the application of BBM for spalling behaviour in 3DEC is currently challenging due to the requirement of small block sizes and the limitations of current computing power. Modelling depth of spalling damage is possible with BBM, provided one does not need to capture the entirety of the underlying mechanism. Specific recommendations to practitioners concerning modelling of spalling using BBM include: • Suitable spalling cases to be modelled using BBM techniques are those which have good data concerning laboratory testing and can be run in quasi-2D. • Attempting to model the exact process of spalling using BBM is currently difficult due to computational limitations restricting minimum block size. It is suggested that for practical cases block size should currently be selected to achieve at least six blocks across the damage (notch) depth and width, similarly to common practice in continuum modelling. Care should be taken to check that this block resolution is appropriate for each specific modelling case, by examining the results from a critical perspective. • Adequate time for the calibration process is important, as it is not always straightforward. • Block configuration during the calibration process is important. • Contact shear and normal stiffnesses are less significant than the other properties, such as cohesion and tension in models of laboratory tests. • The use of a ratio between tension and cohesion is appropriate until proven otherwise. • A distribution of the tensile strength (and therefore cohesion) across all contacts may help better represent the variance of UCS tests. Correlated random fields should be considered. • Start in situ modelling with simplistic models (continuum) to check model behaviour and identify exactly where in the model the BBM region should be built. • Contact stiffnesses in in situ modelling between the BBM region and the continuum should likely be based on zone size, not the values from calibration. These stiffnesses may result in problems with the stresses in the model, and time and effort may be required to find values that work. • It is inconclusive if a reduction of the BBM material strength is required when the block sizes are near grain size. However, it is still postulated that this strength reduction is required for larger blocks. It is proposed that this is due to a combination of 1) rock mass strength being less than intact strength, 2) the lack of strength heterogeneity of the material, and 3) the lack of damage build-up possibly caused by the stress path. Keywords: numerical modelling, BBM, spalling, damage