Potash Decommissioning Project Wins APEGS Award

Saskatchewan has a robust potash industry, with deposits that have maintained mine lives of more than 100 years. The Mosaic K1 and K2 potash mines opened nearly 60 years ago and are situated within complex hydrogeology conditions. These mines have been coping with mine inflow challenges since late 1985. As a result, Mosaic decided to close the mine shaft on June 4, 2021, because of accelerated brine inflows.

RESPEC was part of the team selected to work on the abandonment of the shaft. The complex hydrogeology that surrounds the shaft resulted in unique conditions that needed to be accounted for in the decommissioning project. RESPEC conducted geomechanical and hydrogeological modeling to aid in the design. RESPEC also consulted with subcontractors on the concrete mixture design for the shaft plug system, interface grouting between the existing liner and plug system, grouting of the surrounding geological formation, and backfill design from shaft plug to surface. The design included developing the QA/QC programs, preconstruction activities, site inspections, and the shaft plug implementation with the mining construction contractor.

In conjunction with Mosaic, RESPEC has developed long-term monitoring plans for tracking and assessing the implemented design functions as expected.

In late 2022, Jay Nopola, Senior Vice President of RESPEC, was informed that RESPEC’s engineering team was receiving the Exceptional Engineering/Geoscience Project Award by the Association of Professional Engineers and Geoscientists of Saskatchewan (APEGS). On March 2, 2023, Jay accompanied several members of RESPEC’s Saskatchewan office to the APEGS Awards Gala in Saskatoon, Saskatchewan, to accept this award.

Jay comments, “This project has been exciting on several levels and is a true accomplishment in engineering and geoscience work. To put it briefly, this is the first fully designed and engineering decommissioning of a potash mine in the province and was performed on the first successful potash shaft constructed in the province roughly 60 years ago. A significant factor that was driving many of the design requirements in this project was the complex hydrogeology of the mine system. Our team had to adapt quickly to changing circumstances but, ultimately, our efforts paid off. The long-term safety of the public and the environment was of paramount importance in designing the shaft decommissioning, as we needed to ensure isolation of mine waters from nearby surface waters. While this was the first project of its kind in Saskatchewan, the robust design approach will set the benchmark for all future similar salt and potash shaft decommissioning projects.”

Jay further states, “I would also like to thank our team that spent numerous hours, including weekends, to get this project finished. This project required our staff to be on call 24 hours a day for the duration of the project to ensure strict QA/QC protocols were met and to minimize the financial impacts to the budget and schedule.”