Assessment of underground alternatives at Engebø rutile deposit using the Mineable Shape Optimizer

Abstract

Computer software is nowadays commonly being utilised for mine planning purposes, MSO is such a software and is used to find the optimal stope shapes and dimensions for a given block model, representing an orebody, in terms of ore recovery or material value. This study aims to use MSO to find the optimal stope shapes for the Engeb{\o}fjellet deposit, and to demonstrate how it can be used for placement of these stopes, horizontal and vertical pillars.

Based on previous work as that of \cite{mork}, and the results and discussion related to choosing mining method presented in this master's thesis, sublevel stoping was found to be the most cost efficient mining method, and the one which allows the highest ore recovery. The block model was provided by Nordic Rutile AS, and was the most important input to this master's thesis, it was configured based on previously performed drilling campaigns by NGU/DuPont.

Finding the optimised stope dimensions for a given orebody depends on more than trying to make the largest possible stopes that are not unstable, smaller stope dimensions will also necessitate narrower vertical pillars relative to larger stope dimensions,furthermore, smaller stope dimensions increases the selectivity of the mining method. The simulations performed in MSO indicate that smaller dimension with length between 70m- 90m might be more economically beneficial than 100m long stopes, especially if instability surveys shows that for stope lengths between 70m- 90m the vertical pillar thickness can be kept at 15m. The work also demonstrates the use of MSO to place horizontal and vertical pillars, and placing the stopes.