Posted on December 10, 2020
A PROSPECTIVE Western Australian Sulphate of Potash (SoP) fertiliser producer has engaged a Dutch specialist ship builder to design an automated wet harvest salts dredge.
Agrimin Ltd plans to produce SoP fertiliser from solar-evaporated potassium-rich brine collected from beneath remote Lake Mackay – WA’s largest salt lake – on the border with the Northern Territory.
Rather than harvesting sun-dried salts from end ponds of long evaporation trains and trucking the salts to nearby processing plants – as two of Agrimin’s more advanced competitors are preparing to do – it plans to harvest wet salts from ponds using an automated dredge.
Harvest salts will be pumped as a slurry from the dredge, working two on-lake pre-concentration ponds, to an off-lake processing plant where heating – part of the normal processing into SoP fertiliser – will evaporate the remaining moisture.
According to Agrimin’s statement to the Australian Securities Exchange (ASX) recently, pumping a slurry will use less energy than loading and trucking dry harvest salts.
The automatic wet harvest dredge will reduce labour costs and increase overall potassium recovery, Agrimin claimed.
It also claimed the harvest dredge will enable evaporation pond sizes to be reduced because it will remove potassium salts earlier in the evaporation train and will not require the ponds to be taken “off line” for harvesting.
Agrimin has engaged Royal IHC to design the dredge, including cutting tools, propulsion, electronics and hydraulics, as well as the slurry pipeline pumping system, over the next eight months.
It has asked for both detailed design drawings and a fixed-price quote for supply of the dredge and slurry pipeline.
Based in The Netherlands, Royal IHC has a maritime design and construction history dating back to mid-17th century shipyards.
It builds specialist vessels for dredging operators, oil and gas corporations, offshore contractors, mining companies and government authorities.
A feasibility study completed in July for the Mackay SoP project considered wet harvest techniques based on field data from Agrimin’s pilot evaporation pond trials conducted between October 2018 and June this year.
The Mackay project was granted major project status earlier this year by the Federal government.
Earlier this month Agrimin announced it had agreed on a protocol with Parna Ngururrpa Aboriginal Corporation, representing the Ngururrpa Native Title holders, to negotiate approval to construct and operate a haul road from Lake Mackay to Halls Creek.
Agrimin plans to truck 450,000 tonnes per annum of SoP fertiliser 940 kilometres to Wyndham for export using a dedicated fleet of roadtrains.
It is scheduled to begin commercial production in the first half of 2024, with a projected 40-year production life for the project.
Chairman Richard Seville told the Agrimin annual general meeting last week it was the company’s objective to become “the lowest cost seaborne supplier” to a global SoP fertiliser market.
Also last week, another prospective SoP fertiliser producer, Kalium Lakes Ltd (KLL), said it has started harvesting and stockpiling potassium salts from its evaporation ponds, ready for when its processing plant is completed.
KLL’s Beyondie SoP fertiliser project is based on a chain of salt lakes in the Little Sandy Desert 180 kilometres south-east of Newman.
It said all production bores, surface trenches and pump stations were installed on two lakes and the primary evaporation ponds needed for production plant commissioning were 99 per cent complete.
So far more than 44,500t of SoP in brine has been pumped into the ponds, it said.
KLL said the German designed and manufactured processing plant was being installed, with 80pc of key components already delivered on site.
Commercial production is scheduled to begin in July next year.
Initially KLL is looking to produce 90,000tpa of SoP fertiliser, ramping up within three to five years to 180,000tpa.
It has a 10-year offtake agreement with German fertiliser distributor K+S for its total first stage production volume.
Australia currently imports all of its SoP fertiliser and K+S provides more than 60pc of it, KLL claims.
As previously reported in Farm Weekly, Salt Lake Potash (SO4) is likely to become the first Australian SoP fertiliser producer and exporter from March next year.
It has fast-tracked its project at Lake Way near Wiluna by using hypersaline brine, pumped from a former gold mine open pit on the salt lake, as initial feedstock for its evaporation ponds.
At its recent annual meeting shareholders voted to change the company’s name officially from Salt Lake Potash to its ASX abbreviation of SO4.
