what would stop bhp from making a ta bid now?

Please feel free to shoot me down in flames as I'm not a close follower of this stock... I sold most of my holdings at much higher prices before potash prices tanked.

But what would stop BHP from using this as an opportunity to make a superior TA bid?

At the recent EGM there was open discussion about potash being BHP's next business pillar. There was also a failed TA of Potash Corp a couple of years back. And as it's well established, ELM have a world class resource.

Am I missing a trick here?