The last of 34 maintenance workers who were trapped underground at Nutrien’s Corey potash mine near Saskatoon was brought back to the surface about 6:00 last night. They were stuck underground Tuesday, after the service shaft, which moves employees and equipment up and down, stopped working. They were brought up through a production shaft, which would normally be used to transport potash. A Nutrien spokesman says while the workers were underground they were safe and had air, food, water and WiFi service.