A half mile under the vast prairie soils of Saskatchewan, Canada, miners employed by Nutrien Ag Solutions work 12-hour shifts, 24/7, digging into a 350-million-year-old dry seabed to deliver potash, a necessary macronutrient to grow high-yielding corn and soybeans. “When you’re underground, you’ll see rock that predates the dinosaurs,” say Les Frehlich, general manager at Nutrien's Allan potash mine.