Agrimin Ltd, says Lake Mackay project at Lake Mackay gets closer to starting

By Mal Gill
May 11 2022 - 4:00am
A drawing of the wet harvester dredge Agrimin Ltd plans to use to pump a concentrated potassium and sulphur slurry onshore from solar evaporation ponds proposed on Lake Mackay, a salt lake on the Western Australian-Northern Territory border, to be processed into Sulphate of Potash fertiliser. An environmental impact assessment for the project is on public exhibition for comment until the end of the month.

PROSPECTIVE Western Australian Sulphate of Potash (SoP) fertiliser producer, Agrimin Ltd, is a step closer to having its remote Lake Mackay project "shovel ready" by the end of the year.

An environmental review document (ERD) six years in the making for the SoP project, located on the WA East Pilbara and Northern Territory border, has been accepted by the Environment Protection Authority (EPA) WA and is on display for public comment until Monday, May 30.



Agrimin has exploration licences covering more than 3000 square kilometres of WA and 1200km2 in the Northern Territory - claimed as the largest undeveloped potash-bearing salt lake in the world, Lake Mackay straddles the border.

It intends to use a network of shallow trenches constructed across the lake's salt crust to collect hypersaline brine containing dissolved potassium and sulphur and to evaporate off excess moisture in onlake solar evaporation ponds.

Wet harvesters will pump the concentrated slurry to a processing plant proposed to be built beside the salt lake and powered by a hybrid gas, solar, wind and battery system, with renewables generating up to 58 per cent of its average power load of 16 megawatts.

The plant will refine harvested salts into high quality finished SoP fertiliser which is proposed to be trucked by a fleet of road trains 940 kilometres north to a purpose-built storage facility at Wyndham Port via a haul road proposed to be constructed through the eastern Great Sandy Desert to join the public road system at the Tanami Road near Balgo.


The ERD reveals Agrimin is seeking EPA approval allowing it to cause "disturbance" of up to 15,000 hectares within a 217,261ha on-lake development envelope for its trenches and evaporation ponds.

It is also seeking approval to clear up to 200ha of native vegetation off-lake for the processing plant and accommodation village and up to 300ha south of Lake Mackay for a fresh water bore field and a wind farm.

The ERD also seeks approval to clear up to 1000ha of native vegetation along a northern infrastructure development corridor for the proposed haul road out to Balgo.

It proposes abstraction of up to 100 gigalitres per annum of hypersaline brine for SoP processing, up to 3.5Gl/a of groundwater through a reverse osmosis plant for drinking water and SoP processing and disposal of up to 18 million tonnes per annum of waste salt - a SoP production byproduct - to be retained on the lake surface.

Documents submitted to the EPA indicate Agrimin has been working with the local indigenous community at Kiwirrkurra, 60 kilometres south west of the project site and considered the most remote indigenous community in Australia, on the exact location of the proposed haul road to avoid an environmentally significant colony of Great Desert skink listed as vulnerable and on the location of the borefield and wind farm to avoid cultural sites.

It has also been discussing training and employment opportunities with the community and is particularly looking at training interested locals as road train drivers for the project.

In a statement to the Australian Securities Exchange, Agrimin pointed out the EPA's assessment of the project is being undertaken as an accredited process which means a separate assessment by the Commonwealth Department of Agriculture, Water and the Environment will not be required.

Agrimin chief executive officer Mark Savich described the ERD exhibition for comment as an "important milestone".

"The ERD is a comprehensive document detailing the environmental and social impacts relating to the Mackay Potash Project," Mr Savich said.



"We are extremely proud of the many years of high-quality, industry-leading environmental work that has been completed to produce this document.

"We believe the rigour and effort that has gone into the ERD strongly demonstrates Agrimin's commitment to managing the Mackay Potash Project in a socially acceptable and environmentally responsible manner.

"With the EIA (Environmental Impact Assessment) process well-advanced, Agrimin is in an excellent position with record high potash prices and a tier one potash project that remains on track to be shovel ready this year."

As previously reported in Farm Weekly, SoP has the lowest salt index of any potassium fertiliser making it particularly suitable for use on salt-affected areas.

Australia imports all of its SoP requirements which have grown from about 40,000 tonnes per annum five years ago to about 63,000tpa currently, but the price of imported SoP means it is generally only used on higher value crops like fruit and vegetables.

Agrimin has said it aims to become the world's lowest cost source of seaborne SoP and to do that with one of the lowest carbon footprints associated with any macro-nutrient fertiliser product.



Last month it announced a 50,000t per annum seven-year binding SoP fertiliser offtake agreement signed with Gavilon Fertilizer, a leading wholesale distributor of crop nutrients in the United States of America.

It has now secured offtake agreements for a total of 315,000tpa of SoP, representing 70 per cent of the Mackay Potash Project's planned production capacity of 450,000tpa.

But the salt-lake-brine, solar-evaporation path to producing SoP fertiliser for domestic use and export in remote WA has been fraught with financial and technical problems.

Salt Lake Potash, once the front-running WA SoP company expected to be first to produce and export a shipment of fertiliser from its almost completed project at Lake Way near Wiluna, was placed in administration last year.

Receivers and managers KordaMentha have undertaken a process to sell the project and to draw up a revised operational plan for the network of trenches, evaporation ponds and processing plant to overcome consistency problems previously experienced.

Another front-runner, Kalium Lakes Ltd, is scheduled to restart its purification plant next month after "rectification works" at it Beyondie SoP project, 160 kilometres south east of Newman in the Little Sandy Desert.



It expects to begin SoP sales in July, more than 12 months later than originally anticipated.

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