I am not a chemical engineer, metallurgist or uranium expert but...

I am not a chemical engineer, metallurgist or uranium expert but at a guess I would say that the ion exchange extraction process does not work effectively without a specified chemical composition in the fluid.coming from the wells.
They adjust the chemical levels and reinject the fluid so that the dissolved uranium is retained in solution and so potentially,able to be extracted on a subsequent cycle. That should increase the concentration of uranium as the fluid passes through more ore.

What this is telling us is that there is still a way to go before commercial extraction can be achieved. They are still testing/trialling with limited circulation and do not have their processes sorted out yet..

Whether they can meet their target date for commercialiisation is an open question.