Can you explain this double standard on carbon tax and additional coal mining....?

Bite the hand that feeds you. Rob Peter to pay Paul. Steal from the rich and give to the poor, but skim a little off the top. Business as usual. Legalized crime. There's no duplicity, at least not in their minds. They allow something that they consider repugnant to continue as long as they get their cut. It's not extortion, it's government at its best.