The theory for Alligator Energy's uranium discovery was...

The theory for Alligator Energy's uranium discovery was this.

Hiltaba Granite which makes up the Gawler Ranges and surrounding area is very rich in Uranium.
As the Granite wears, uranium is released and is quickly dissolved and carried through rivers and streams to the ocean..

Uranium however comes out of solution when it hits Carbon/Graphite.

So we have Uranium Rich Granite (Source Rock), Graphite (Redox Boundary)

Go drill on the edges of the Graphite and you might find uranium!

Apparently when Jungle Dam was discovered they were looking for Unconformity Style of Uranium.
With Alligator Energy finding it in Paleo Channels, this changes the exploration technique.

They will now be looking for gravity lows, ancient subtle faults in the graphite, and pools of ground water.