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LKAB's Kiirunavaara Mine, located in northern Sweden, has exhibited seismic behaviour since the mining production extended below 700 m depth. Iron ore is mined from the 4.5 km long orebody via sublevel caving at a production rate of 28 m t per annum. The deepest current production level is at approximately 800 m depth, and current mining plans call for mining to about 1,200 m depth. It is thus of critical importance for LKAB to gain a deeper understanding of the stress and rock mass behaviour at the mine. The Kiirunavaara orebody has complex geometry and geology, which is represented using the discontinuum distinct element code 3DEC. As part of a larger series of models investigating the influence of strength and structural geology on rock mass behaviour, the results of multiple continuum models are presented. The goals of these continuum models included: (i) obtain a better understanding of the virgin stress field and redistribution of stresses caused by mining, (ii) further define the extent of mining induced plastic failure; and (iii) increase the understanding of existing failure mechanisms at the mine. The elastic and plastic continuum models accurately produced principal stresses similar to measurements recently conducted at two sites in the mine, confirming the previously estimated virgin stress state. Spatial correlations between plastic failure in the model and seismicity in the hanging wall and footwall were found. However, these correlations were not consistent throughout either material for any evaluated set of material properties; either the plastic failure in the footwall or hanging wall corresponded well with seismicity. This may be because a set of rock mass properties which represent rock mass failure at this scale have not been evaluated or that some underlying failure mechanisms causing seismicity are not represented in the models, for example, failure along discontinuities. Some events larger than moment magnitude of 1.2 in the hanging wall, in particular shear source mechanisms events, do not correspond well with plastic failure from the model. These results potentially indicate that geological structures, which are not represented in these models, influence mine behaviour. The improved understanding of input data, rock mass behaviour, and failure mechanisms as a result of these models has a direct impact upon mine excavation design and future rock behaviour investigations, and will be used in the continued research, as well as in mine planning. https://papers.acg.uwa.edu.au/p/1410_24_Vatcher/ Mine-scale numerical modelling, seismicity and stresses at Kiirunavaara Mine, Sweden

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When it comes to deep mining, the geomechanical risks of production planning decisions are amplified due to the high-loading environment and typical deep rock mass behaviour such as seismic activity, ground falls, spalling, strainbursting, and rockbursting. Assessing how production decisions influence hazards is an important aspect of risk assessment. A preliminary analysis of the historic production at the Luossavaara-Kiirunavaara Aktiebolag (LKAB) Kiirunavaara mine indicated a significant likelihood of ore/host rock remnants after production blasting in some volumes of the mine. These remnants are caused by a combination of drill fan geometry, orebody geometry, safety regulations minimising the likelihood for drill breakthrough, and typical limitations of blasting practices. Numerical stress analysis modelling was used for a selected volume of the mine critical to production to evaluate the effect of possible geometric realisations of the production remnants. A qualitative risk assessment of the production remnants was completed, with focus on results that indicated seismically active volumes. The understanding gained from this work is important to the mine's future production planning, as it gives insight into factors that increase the risk of seismicity.