The grades at MacKay are less than 2/3 that at LD. Convince me...

The grades at MacKay are less than 2/3 that at LD. Convince me otherwise that MacKay won't need 50% larger ponds and be pumping 50% more brine to match final output, assuming equivalent rates of recovery.
Furthermore without using deep bores, the necessary recharge from surface water will dilute the grade further.
This is all about solute concentration, simple, dissolved salt in a bucket job, left in the sun to evaporate. Think about it.
Grade is important, as is trench flows, as is the ability to maintain pond concentrations using deeper pumped brines.
I'm not convinced that the K to Na ratio and waste is as important as KLL claim as the NaCl will ultimately end up back in the lake, it comes down to the pile size.
Of course none of this means that MacKay can't be a successful operation but don't kid yourself that K grade and trench flows have zero impact on capex and opex costs.

PS RWD did access the MacKay tenements, how do you think it acquired the data that they sold to AMN. The on site work done by AMN has been minimal. Most of their stuff is desktop. They have dug minimal trenches.