From all accounts an alternative power supply for the major...

From all accounts an alternative power supply for the major power station to the north of Perth is not viable. The transmission lines from the south of Perth lose too much due to the distance involved and gas from the northern ends of WA are far too far away (thousands of kilometres). The Coalition Government in WA seems pro-business and development so I would expect approvals to be made...hopefully, sooner than later. AVA has the coal deposite; they own the land and it has previously been used (it's close to other major infrastructure (rail, roads, labour, transmissions lines and lots of industry and mining activity needs the electricity); whilst the carbon emissions may be successfully sequenced in the dis-used mines only 50km away from the site.
Alternatively, in South Africa/Botswanna, should SA not approve their mining and building their own power station, AWA and its partner have stated they will go it alone.
This is looking better by the day...DYOR and you will confirm my comments, Bernie.