I don't have any experience in this type of matter, so you may...

I don't have any experience in this type of matter, so you may want to wait for a better answer but I would assume that all of the options would have been explored and for some reason (which I also assume we will find out in time ) the mgmt decided that going into va was the best option (we also dont know who it was the best option for. Asteroiders scenario, which appears to be playing out finished with the mgmt team deploying golden parachutes, just before impact).
The only commitment bnd had was the port/rail charges. I often wondered, why bnd couldn't use their cash to buy up some brownfield coal mine that could be ramped up much quicker to springsure to meet the wicet start dates. This would have potentially allowed for the mothballing of springsure. It must have also been decided by the mgmt team that va was a better option (for who, I wonder).
I also wonder what was the reason Samsung became involved to help secure funding and then only a few months later bnd goes into va. The afr article implied that the land compensation costs were much higher than originally anticipated. CS must have also been looking for more money up front and also potentially higher repayment rates.