the ELM deposit is certainly economically viable since it has $80/t opex verses $350+/t potash price, more like $400/t if sold to Brazil
$350/t revenue minus $80/t opex = economically viable =
$291M cash per annum or 6.3 year pay back for a mine that has decades of mine life
$400/t revenue minus $80/t opex = economically viable =
$375M cash per annum or 5 year pay back for a mine that has decades of mine life
thus the project is not uneconomic
the issue with the project is whether anyone wants to step up & fund it, due to a well-supplied potash market