Abstract
In March 2024, Nutrien Rocanville Potash Mine lost access to two of its continuous borers because of deteriorating ground in the two remaining access drifts of a mining zone. A coordinated effort between a cross-functional team was required to first retrieve the two borers, and then design and cut new development drifts in the remaining pillars to sustain the 5-10 year life of the mining area.
With limited room left to cut new access drifts, discrete element modelling was used to estimate the optimal placement of the rooms within the stress-relieved zone of the existing drifts. Then, load cells and ground movement monitors were used to test the theory by recording the ground reaction. Additionally, the decision was made to cut the new development drifts in stronger material below the ore zone, sacrificing profit for long-term stability. As the rooms were being cut, ground penetrating radar at varying frequencies was used to ensure the borer was at the proper mining horizon, and a combination of test holes, sag flags, and ground movement monitors were used to assess roof stability.