It does sound silly to open a new terminal that is not a unloading balloon loop but there are a number of grain terminals in use currently that are dead end sidings. The old SACBH terminal at Port Adelaide is still used as a secondary unloading site and I believe one of the unloading sites in Sydney is dead end sidings also.
So this would not prevent the dead end sidings being used especially if it is planned to be a smaller export location than the main outloader in Geelong.
Their all old setups from the days when hoppers wagons were first Introduced.
The roll rail plays In the grain transport has changed or Is continuing to change.
Grain trains are now only becoming to be used In the movement of grain between super Inland terminals to port terminals using fixed size wagon rakes/sets (like 40 wagons)
The change In grain marketing Is seeing a lot of on farm storage and deals done to sell small quantities of grain among growers, marketers and customers, all mostly NOT rail contestable (this new terminal would mostly be capitalising on this new trend of small volume deliveries)
At major Inland grain terminals, grain train operators would be looking at rapid turnarounds to maximise the utilisation of their trains, so they would be very reluctant to break up their trains Into short rakes to shunt Into loading and unloading sidings.
Geelong grain loop has the edge In Victoria, that the whole train does a U turn and stays In one.
Not sure how long the grain sidings are at Appleton Dock, as to If a full size train can be unloaded without splitting.
Portland on the other hand needs a lot of shunting to unload trains at It's terminal.