Estimation of cutting feasibility on the example of Põhja-Kiviõli II mine [MSc thesis. Supervisors: B. Grafe, S. Kanter]

This thesis evaluates the applicability of a computational cutting model developed by Dr. Andreas Lemm for predicting surface miner productivity in Estonian limestones. The study stems from the need for more sustainable excavation methods, with a lower environmental and social impact. Surface miners offer an alternative to drilling and blasting, but their performance is strongly influenced by rock mechanical properties, rock mass structure, and operational conditions. Field measurements were carried out at the Põhja-Kiviõli II mine on a Wirtgen 280 SMi surface miner, complemented by laboratory testing of UCS, BTS, elastic modulus, Poisson’s ratio, and CERCHAR abrasivity. Mineralogical composition and equivalent quartz content were also determined using XRD/XRF. The rock showed significant variability between layers, with UCS ranging from 30 to over 100 MPa and generally low abrasivity (average CAI 0,42). Strong heterogeneity and anisotropy were observed. Measured production rates ranged from 125 to 252 m³/h. Initial model results overestimated specific energy consumption, but the modelling results improved after applying corrections for rock mass conditions and pick wear. However, deviations remained in certain layers due to heterogeneity and operational influences. The study concludes that while the Lemm model shows promise, additional research needs to be conducted. The model can be improved by implementing rock mass factor in the calculations.