Ann: US Potash Presentation May 2011 , page-6

Rexsh - We can do it very simply (Though very crude) using a weighted average... Exclude Potash Corp because it's a freak.

0.73c is the weighted average EV per tonne for that list. This of course doesn't represent and time/risk factors that are present.

STB looks way over priced, but I think its price has factored in many more tonnes, which looks to be the case based on recent reports.