New Hope Price Target Raised 23% to A$2.40/Share, page-125

My guess is that the NSW govt wants to extend the mine life but wants a more reasonable bonding process be put up by any new operator.
Agreed that they cannot change past rehab & bonding agreements, but an extension brings about a new landscape for them that allows for renegotiation.

Note this ....
SMH - May 2021
"A report to be released by the Australia Institute on Thursday has found filling in the region’s 23 mine voids would cost between $11.5 billion and $25.3 billion, based on the stated costs per hectare of four mines in the Upper Hunter. By comparison, the NSW government holds just $3.3 billion in bonds to meet the rehabilitation costs of all mines across the state."

The Mt Arthur rehab cost has been estimated at the moment at $1billion. I don't know how much of the above $3.3b was for Mt Arthur, but let's assume that 10% might be. So say $330m bonded at present. That's a hefty shortfall, and easy to see that BHP would be forced to pay the $200m (above) to the NSW govt as a bond topup to get out with a permit extension condition.

If Mt Arthur produces 20mtpa into the future (and little rehab is done) then the "bond" increases by $240m pa (less whatever rehab works is done each year).

Easy to see that a permit extension of (say) 10 years could get the bond up to cover the full cost of rehab, and hope like hell that the coal selling price remains strong for that time.
I guess that's the logic of the NSW gov't, as they are on a hiding to nothing at the moment.
The alternative would be a series of long and protracted legal tussles with BHP (and also with other mines including Idemitsu) based on the current Mt Arthur closure date.

So NHC could get the mine for $1 with a 10 year lifespan and with a production cost of $92pt ($80pt current cost +$12pt rehab royalty).

What are the chances of the coal selling price being north of $92pt averaged for the next 10 years ?