Ann: Hammer Executes Earn-in with South32 at Isa Valley Project, page-20

Aka , like in the VMM podcast interview yesterday—ideally about pH 4 solution , to easily and readily lifts out ~75% level of REEs, and notably ~60% from memory (superb recoveries) of the heavy rare earths that are most valuable and needed in significant magnets.
(Not so much like the AR3 report yesterday for Koppamurra, with pH ~2s acids solutions utilised and even lower, to lift out the valuable elements to gain possibly economic enough REEs recoveries)

This field, ionic deposits, is being re-written through the next few years.

There will be likely economic deposits identified up in North Queensland, inc especially related to where known bauxite resources are found.
Excellent recoveries are what is ultimately needed if an ionic deposit resource is to be defined as an economic resource.
Often associated with uranium, & other nuclear elements also.

Best is if heavily weathered resources area I gather.
And the REEs that you want are all that is more left, the heavier rare earths, and they have hopefully sunk and are concentrated to above wherever the basement rock is.
Or simply deeper somewhat beneath the weathered topsoils- that you have to simply remove topsoil layers, set aside until later in rehabilitation phase ,to mine out the REEs, hopefully if you have a shallow enough resource deposit.

You can see my knowledge is too rudimentary.

But interesting that in a study, investigations for ionic resources deposits, which must be in HMX area with Mary Kathleen and other deposits near.