In seeking to extend its Dendrobium coal operation, the miner may have miscalculated how far it could push before finally being told "no".

Times have changed since this mine began and it appears it's no longer acceptable to cause such damage to the catchment, backed by doomsday threats of the steelworks closing. "Public interest" seems broader now.

This shocked many, given Peabody recently won permission to drive two longwalls underneath the Woronora Reservoir.

South32's longwall panels were to be up to 305m wide and up to 4km long, with the potential to cause cracking from the surface to the seam.

The Planning Department should face questions here. Its expert told the IPC that reducing the longwalls' width might reduce surface damage, but this could make it harder to calculate the amount of money South32 would pay to the Government in "offsets".

This, he said, meant the less damaging option was not preferable.

The IPC also cast doubt on South32's doomsday scenario, saying the Wongawilli Seam coal said to be essential for Port Kembla steelmaking would be offline for 19 years under this plan, as the Bulli Seam was to be mined first.

BlueScope has said only that local coal was "very important" to its supply chain. Dendrobium will continue to supply it until 2025, and South32 more broadly until 2032, under existing contracts.

Time will tell. If Dendrobium closes, yet the steelworks adapts and continues operating, South32 leadership will have questions to answer about a strategy that threatened doom for the region's economy, but overreached under a water catchment which is now being valued.

Watch this space. With the finances at stake, and the investment South32 has poured into its application process, one certainty here is that this is not finished.