its very simple, if the coke produced is not good enough for steel, it will not be viable to mine and they'll stop. they wont dig it up anyway and attempt to compete with cheaper coal from Russia, Australia, South Africa etc, because they'd go bust. so let them mine. the net amount used will...
good start to question "How do we ensure our economy grows?" is treat it as an economic question, not a political question. government should do no more than set a tone and framework for growth. instead we get superficial promises of growth which usually amount to spending more day to day...