Canada is well known as a potash producer, being the biggest source globally of the crop nutrient with a market share of about 33%.

The little known, but widely used, mineral made international headlines last year, when BHP Billiton made a $40-billion hostile bid for Potash Corp, the world’s biggest producer.

Now the fertiliser ingredient is cropping up with potential multi-billion dollar investments in Saskatchewan from the two old rivals – BHP Billiton and Rio Tinto – in the works. Martin Zhuwakinyu talks to Matthew Hill about the latest developments.