Ann: Pre-Feasibility Study Completed for Mackay SOP Project, page-18

the AMN ponds appear to be "un-lined". the PFS says:

* "The evaporation ponds are planned to be located in the south-western area of Lake Mackay where geotechnical testing has determined that the natural salt lake surface is suitable for un-lined evaporation ponds." ​

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KLL estimates:

* Lined ponds may achieve a SOP recovery of up to 87% (excluding purification plant recovery loses)​

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* Unlined ponds may achieve a SOP recovery of up to 69% (@0.5mm/day leakage, excluding PPRL)​

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RWD estimated around a 15% loss of recovery due to seepage from partially lined ponds:

* It is estimated that the will be a 15% loss of the potassium and magnesium values to seepage and entrainment in the halite ponds.​

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AMN has Brine Field & Pond System CAPEX of $107M

RWD has Production - Trenches and Ponds CAPEX of $57M

AMN has Process Plant CAPEX of $108M plus Utilities, Reagents & Vehicles of $57M

RWD has Process Plant CAPEX of $73M with 65% process plant recovery

AMN's 426,000tpa is exactly 80.3% recovery from 66.3Mm3 at grade of 8.0kg/m3.