Yes, that's correct. I don't see salty water being...

Yes, that's correct.
I don't see salty water being appropriate for beneficiation & processing.

The only thing salty water would be of any use for is earthworks construction, dust suppression on haul roads, in and around the mine, mining activities, etc.

THE USE OF "BRACKISH" water from the Murray River system salinity scheme is just pie in the sky and highlights how desperate they are.
There's no way even if the brackish water was found appropriate for use (beneficiation) the sheer volume required for the processing alone in phase 1 (5Mtpa) would not be able to be 100% guaranteed and to risky.

The wording in the announcement doesn't fill me with confidence "The schemes CAN produce up to to1 12Gl/a of water for disposal. That word can, hmmmm ok probably not then i would say!
Then, the massive task of connecting all these schemes to harness the entire amount produced. Aside from all the negotiations and approvals, acetra, there is huge cost associated with this option.
To be a low cost producer, this pie in the sky desperate attempt to keep share holders hopes alive is simply not a feasible option.
To become the low cost producer MGT want to become, they will need to develop all 3 stages requiring more water than this River scheme can produce.

SEA WATER OPTION (assuming it's appropriate for use)
The CAPEX alone would scare potential partners/lenders running from the Virtual Data room.
Pumping sea water of these volumes over 250km to the processing facility will not allow MGT to be a competitive low cost Magnetite producer.
The cost of the pipeline, the cost associated with running the pumps and ongoing maintenance simply makes OPEX figures sky rocket and and suddenly AISC are at the point of not being feasible.

SEA WATER OPTION (study deems NOT appropriate for processing purposes)
There's no point going into option as it speaks for itself.
Again, the added costs associated with running a desalination plant (that's even if there is one able to process these mega volumes of water)
Just not a feasible option folks!

None of the above is proven factually correct information. This is simply my own opinion based on my experience & knowledge only and should be taken as such.

Please do your own research