It's too bad Regina missed out on the K+S Potash head office. It just opened in Saskatoon, even though the mine site is just NW of Regina. This is a historical thing as the original developer, Potash One always had an office in Saskatoon, although its head office was Vancouver.
Regina is developing a bit of a potash office node to rival Saskatoon, though. Mosaic, Vale, and Rio Tinto all have their Potash HQ's here. Western also has an office in the RBC Blg.