aMES® TECHNOLOGY

The Karinga Lakes Potash Project (KLPP)

• An extensive brine lake system that covers approximately 1,109 km² over pastoral land in the Northern Territory, Australia.
• Consists of a chain of dry salt lakes and is located within the Central Australian Groundwater Discharge Zone.
• Extensive resource appraisal studies have been performed by JV partner Verdant Minerals since 2010.
• Ideally located, with major road and rail infrastructure located in close proximity to the project, with regional gas options also available. 

Extensive Resource Appraisal Status

The potash brine investigations including those utilised for the purposes of resource appraisal and reporting were based on data acquired over several years, including:

• 93 brine samples from hand dug pits
• 4 small backhoe trenches which were pump tested
• 8 vibracore drill holes, 73 sonic drill holes & 200 aircore drill holes
• 42 installed 50mm piezometers around drill holes & 48 piezometers around trenches
• 47 installed 100 mm wells
• 10 pumping tests from 100 mm wells
• 4 long term pump tests from 3 trenches and a well
• 142 porosity samples.

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The KLPP development concept involves the processing of naturally occurring hypersaline brines from a series of salt lakes at the KLPP, in order to produce 40,000 tonnes per annum (tpa) of high-purity sulphate of potash (SOP), over an initial mine life of 20 years. The development concept is divided into two broad areas of operation, upstream and downstream operations.

The upstream operations at the KLPP consist of the following key stages:

1 - Brine Harvest – extraction of raw brine from trenches and pumping to evaporation ponds.

2 - Brine Concentration – the raw brine is concentrated, through a i) pre-concentration pond, then pumped to, ii) a Halite crystallisation pond, where waste sodium salts are precipitated, and then pumped to the, iii) final potassium salts crystallisation pond, where the potassium enriched mixed salts are harvested.

3 - Salt Stockpile - the harvested potassium enriched mixed salts, are then transported a short distance to a stockpile, near the processing plant, ready for processing in the SOP processing plant.

4 - Process Plant – the aMES® based process plant, then processes the potassium enriched mixed salts, to produce SOP, which is then packaged on-site.

5 - Site Logistics – packaged SOP is then transported to key domestic markets, via the proposed access road leading to the Lasseter Highway to the north of the project area.

The downstream operations at the KLPP consist of the following key stages:

 1 - Salt Stockpile – the downstream operations in the processing plant, commence with the potassium enriched mixed salts, harvested from the evaporation ponds, during upstream operations.

2 - Salt Preparation – the potassium enriched mixed salts are screened and milled, to ensure adequate dissolution of potassium minerals.

3 - Salt Extraction – the milled salts are dissolved in warm water, ensuring the transfer of potassium and sulphates from the mixed salts, into the warm leach solution, to form a concentrated brine.

4 - Core aMES® Plant – the concentrated brine from the salt extraction step, is processed through a proprietary aMES® based flowsheet, in order to:

• Remove impurities (mostly sodium and magnesium chlorides).
• Recover pure water.

5 - Produce intermediate products:

• Sylvite (KCl).
• Leonite (K2SO4.MgSO4.4H2O).

6 - SOP Synthesis - as a result of reacting the Sylvite and Leonite intermediate products, with the addition of recovered process water.

7 - SOP Logistics – the drying, packaging, storage and dispatch of the produced SOP product.

A number of significant advantages of the proposed KLPP-PFS development concept have been established through the KLPP-PFS, including:

• ​Strong Financial Performance - Despite the relatively small-scale of the project which would ordinarily be considered sub-economic, the development concept outlined in the KLPP-PFS appears to be financially attractive.
• High Potassium Recoveries & Grade - The unconventional processing route based on the aMES® technology is capable of achieving high potassium recoveries.
• Efficient Water Use - As the aMES® technology recovers freshwater during the processing of brines, the development concept outlined in this study, is highly efficient, in terms of water use. In comparison to other major SOP projects, the KLPP-PFS envisages a water use intensity of approximately half that of the peer group, with a realistic pathway to potentially reducing the intensity of water use, by approximately half again.

Additional Information regarding the KLPP-PFS is outlined in the following documents:

 Sulphate of Potash Resource and Production Plan (KLPP-SOPRPP) 

Karinga Lakes Potash Project - Pre-Feasibility Study (KLPP-PFS) 

Parkway ASX Announcement (5 Nov 2020), incorporating the KLPP-SORPP and the KLPP-PFS.