The statement made was that "halite has very low permeability". ...

The statement made was that "halite has very low permeability".  The statement on p109 of the LPI DFS says that the halite is highly permeable, so much so that production from trenching is a feasible alternative to production wells.

How this is the evidence I should have submitted:

LPI's long run brine flow testing in the Maricunga salar's halite zone down to 40 metres produced an outstanding flow rate of 45 litres per second whereas the flow rate from its deeper volcaniclistic sediments was 25 litres per second.  The halite zone at Maricunga is highly permeable.