Ann: Trading Halt-GPH.AX, page-35

This was tucked away in today's announcement as well:

In addition to confirming the high-grade potash grades at depth, this recent aircore campaign again intersected significant widths of the upper sand unit, previously not considered in the Exploration Target the Company published in March. Returning grades consistent with the brine chemistry in all samples, this upper aquifer has the very strong potential to improve the potential yield of the palaeochannel, as these upper sands have a greater specific yield than the intermediate clays (as utilised in the Exploration Target assessment).