Barnaby Joyce, who is also the member for New England, says the Liverpool Plains mine is "absurd" but he wasn't able to stop it.
In a Facebook post, he spoke out against his own party, writing "I think it is ridiculous that you would have a major mine in the midst of Australia’s best agricultural land."
But former independent member for New England, Tony Windsor, says Joyce's public concern is rubbish.
"The Liverpool Plains and Namoi Valley has the largest groundwater system in the Murray Darling Catchment which will now be at risk. Days ago, Ag Min Joyce waxing on about need to ensure water resources are protected for food production. Does this guy read what he says?" " he tweeted on Wednesday.
In fact, Tony Windsor's so angry about the mine that he's considering a return to politics.