Lake Mackay’s hydrogeological setting and favourable brine chemistry provide important attributes that support the development of a globally significant SOP operation. Lake Mackay hosts the largest SOP deposit in Australia and covers an area of approximately 3,500km2.
Lake Mackay is a brine-hosted potash deposit in a closed basin, salt lake setting. The Mineral Resource is based on the dimensions of the lakebed sediments, the variations in porosity (void space) and the potassium grade within the groundwater.
The drainable porosity (or specific yield) Mineral Resource contains 123Mt of SOP to a maximum depth of 211m. This drainable porosity Mineral Resource represents the static free-draining portion of the total porosity Mineral Resource prior to extraction.
There is a high level of confidence in the geological model for the project. The geology is simple, with brine-hosted in flat lying, relatively uniform, lakebed sediments.
Geology has been used to separate the deposit into different layers for the resource estimate. The upper sandy layer is more porous, beneath which there is a less porous unit overlying the lower clays that are again less porous, prior to reaching the coarser LZ3 sediments.
Within the upper zone (UZ) the lakebed sediments are further separated into top and bottom sub- horizons labelled as UZT and UZB.
The lower zone (LZ) sediments are separated into three sub-horizons labelled as LZ1, LZ2 ........
