I think t64p has a point ... coal, coking coal and the derived steel is quite expensive to transport - i.e. local producers can command a premium. It certainly looks like the New Zealand coking coal market returns much better prices than currently international markets.
Still don't get my head around how Carbon scape (https://www.snowballeffect.co.nz/carbonscape) can get through with a business case assuming long term $450 / ton of coking coal (and claiming that they get even at todays depressed prices $350 from NZ Steel) - but even if BRL manages to get just half of that price, than they would be rocking all the way to the bank.
So - who knows what the future brings, but in my view BRL is at current prices a worthwhile risk to take - but hey, no doubt - it is a risk!