WITH potential commercial production of Sulphate of Potash (SoP) fertiliser in WA now little more than 12 months away, local companies are moving quickly to prove up their technologies.
One of the leading potential SoP producers, Australian Potash Ltd - known as APC on Australian Security Exchange (ASX) listings - last week announced a successful trial of solar evaporation pond vertical barriers had confirmed expected low seepage rates.
APC is proposing to build "pre-concentration" ponds for its Lake Wells SoP project 500 kilometres north east of Kalgoorlie, covering about 10 square kilometres of the salt lake surface, with almost three square kilometres of plastic-lined 'harvest ponds' to be built just off the salt lake surface.
Using the flat surface of the salt lake will minimise earth works costs that APC has maintained and the geology at Lake Wells enables this with an impervious clay layer just below the salt lake.
APC told the ASX it had created a trial "pre-concentration" pond at Lake Wells in May by using local materials to build a causeway across an inlet to assess earthworks "constructability".
It then installed three types of vertical barrier designs to test their efficiency in stopping sideways seepage and filled the trial pond with hypersaline brine pumped from paleochannels - ancient underground waterways - using a nearby production bore, APC said.
"Filling of the trial pond with approximately 16,000 cubic metres of brine commenced in early July and the trial has shown approximately two per cent seepage loss through the lateral barriers, which is in-line with our definitive feasibility study (DFS) calculations," said APC managing director and chief executive officer Matt Shackleton.
"The trial has shown that the seepage barrier designs, including sheet piles, bentonite mix and geopolymer, were easily and quickly installed.
Mr Shackleton said the trial also proved the clay layer identified in APC's DFS geotechnical program sealed the bottom of the pond adequately and that adjoining consolidated dunes could provide suitable construction materials for evaporation pond perimeter walls and internal bunding.
It also proved specialised wide-tracked low-pressure construction and salt harvest equipment would not be needed on the lake surface, significantly reducing costs.
The trial pond was built using a normal 20-tonne excavator, articulated dump truck and front-end loader.
"We can now confirm the most economically and technically optimal construction method for the pond perimeter walls and internal bunding, which is central to the efficacy and speed of future development plans," he said.
A week earlier, Salt Lake Potash (SO4 on ASX listings) announced pilot plant test work at its Lake Way SoP project just south of Wiluna had produced some of the best SoP specifications obtained so far by potential WA producers.
Two separate trials using five tonnes of harvest salts from the Lake Way project had confirmed a premium SoP product with a greater than 53pc potassium content, SO4 told the ASX.
The tests also confirmed the addition of Potassium Chloride (KCl) to the production process to make use of excess sulphate naturally present in the Lake Way brine, further increased the SoP output for "no material additional capital expenditure", it said.
Its SoP product would be highly water soluble with tests showing a dissolution rate of 95pc within a minute, making it suitable for use in "drip irrigation" and other fertigation systems, SO4 said.
The tests were conducted by the Saskatchewan Research Council in Canada, recognised as a global SoP authority.
SO4 is aiming to attract a premium price for its SoP by targeting top-end markets world wide.
It plans to complete a bankable feasibility study (BFS) on its Lake Way project this month.
"This is a significant outcome for the company and will strengthen the already compelling economics for the Lake Way project," said SO4's chief executive officer Tony Swiericzuk of the test results.
"We are focussed on finalising the BFS which will reflect the pilot plant results and confirm the excellent potential of Lake Way," he said.
As previously reported, SO4 was APC's neighbour at Lake Wells, but transferred its attention to Lake Way as a means of fast-tracking its SoP project.
Under an arrangement with gold miner Blackham, SO4 has bought its Lake Way tenements and will pump hypersaline brine from the Williamson Pit former open-cut gold mine on the salt lake into evaporation ponds built on the tenements.
Blackham retains the rights to any gold found.
At least seven Perth-based companies are proposing to produce SoP fertiliser from remote salt lake brine, with the opportunity to replace up to 40,000 tonnes of SoP imported into Australia each year with local product.
But the real prize will be creation of a new value-added export product for Australia and capturing a potential significant share of the multi-billion and growing global SoP market.
The WA company most likely to begin commercial production of SoP fertiliser first, Kalium Lakes Ltd (KLL) will this week formally open its completed workers' accommodation village at its Beyondie SoP project 160 kilometres south east of Newman.
On Wednesday guests were flown from Perth into the recently completed Beyondie air strip to inspect the project.
KLL expects to begin production of a granular SoP product in the fourth quarter next year, quickly followed in the following year by premium granular and liquid SoP products.
