Specifically, he’s referring to the fact that Milestone is capable of yielding up to 2.8 million tonnes of potash per annum at pre-tax mining costs of around $62 per tonne for at least 40 years. This would generate approximately $1 billion a year in revenues, based on current potash prices (which are in the range of $400-$450 per tonne). This also computes to a projected payback within six years on the mine’s anticipated $3.3 billion in commissioning costs.

Wpx capex is correct and cheaper as Potash One's Legacy!