Western Australia’s Pilbara Coast is one of the world’s premier regions for solar salt production, with five existing solar evaporation salt projects having been operating successfully in this region for up to 50 years. These projects produce a quality, reliable salt product which is consistently in high demand in chemical and other industries.
BCI Mineral’s Mardie Salt and Potash Project represents a rare, sustainable opportunity to develop a large-scale, multi-generational solar evaporation operation in the area. As part of the project, a 100km2 evaporation pond and crystalliser system, seawater intake pump structure, two processing plants and a new export facility will be constructed.
Mardie’s site has all the critical characteristics for establishing a large-scale solar evaporation operation, including: optimum climate conditions (high temperatures, low rainfall, low humidity, and high wind speeds); a large area (~100km2) of impermeable mudflats as an ideal floor for evaporation ponds; minimal environmental and heritage sensitivities; and a coastal location for low cost shipping to Asian markets.
It will be the first major salt project developed in Australia in two decades and the only Australian operation to produce commercially saleable salt and sulphate of potash (SOP). It will be the largest salt operation in Australia, and with the potential expansion into newly acquired tenements (not included in the optimisation), it could become one of the largest evaporative operations globally.
Production of a high value by-product from waste seawater adds downstream processing credentials to the project, which aligns with the Western Australian Government’s long-standing objective for the resources industry to include secondary processing in project planning.
At Mardie, an inexhaustible seawater resource will be concentrated through solar and wind evaporation to sustainably produce 5.35 million tonnes per annum (Mtpa) of high purity sodium chloride (NaCl) salt and 140,000 tonnes per annum (ktpa) of SOP (or K2SO4) fertiliser, and supply the growing chemical and agricultural industries over an operating life of at least 60 years.
The production concept involves a time-proven and low-risk process where seawater is pumped from the ocean into the first evaporation pond and progressively concentrated via natural sun and wind evaporation energy through a series of nine evaporation ponds over an 18-month period. Upon reaching NaCl saturation point in Pond 9, concentrated brine is transferred to the salt crystallisers where salt precipitates in solid form.
The remaining brine liquid (bitterns) is drained from the salt crystallisers and raw salt is then harvested and purified in a two-stage counter current wash plant to produce 5.35Mtpa salt with >99.5 per cent NaCl content.
Construction begins
The main construction works began in February 2022, following approvals being granted, including a mining proposal, Part V Works approval and two Section 18 approvals. The start of construction signalled the beginning of a four-year journey to first salt sales and the culmination of four years’ work.
BCI Minerals aims to complete construction of Pond 1 and fill it with seawater by Q4 2022. It is expected to take three weeks to fill Pond 1, during the fourth quarter of 2022, with Pond 2 to follow closely after.
The seawater pump structure
A $16 million contract was awarded to Ertech’s Geomarine business to maintain the inflow of seawater to Ponds 1 and 2 from the seawater pump structure. The main pump structure will be represented by six 3,000L-per-second pumps, with the aim for the primary seawater pump station to pump 160GL of water into BCI’s evaporation ponds each year – equivalent to approximately 70,000 Olympic swimming pools.
While the pumps were procured outside of Ertech’s contract, Ertech is handling the design, procurement, construction and commissioning of all the earthworks, piling, structural steel, concrete, mechanical and electrical installations required to accommodate and operate the pumps.
Ertech Group’s 40-year track record in safely delivering mine-site, transport and marine infrastructure was a key consideration in the contract.
Ertech also has a long-term commitment to developing local industry and Indigenous capability. Mardie is forecast to contribute approximately $4 billion of Gross Regional Product to northern Australia over a minimum 60-year operating life. Mardie has received Federal Government loan facilities of $600 million through the Northern Australia Infrastructure Facility (NAIF) and Export Finance Australia (EFA).