The rapid growth of the Mardie salt and potash project

(Image source: BCI Minerals) Jetty where SOP and salt is exported from.
(Image source: BCI Minerals) Jetty where SOP and salt is exported from.

In April 2023, the Australian Mining Review spoke with BCI Minerals (ASX:BCI) managing director David Boshoff about the rapid growth and success of its Mardie salt and potash project on the West Pilbara coast in WA.

This month, we will look at the progress undertaken since then and what other developments are in the pipeline for the company.

Mardie Salt and Potash Project

100% owned by Mardie Minerals, a wholly owned subsidiary of BCI, the Mardie salt and potash project represents a rare and sustainable opportunity to develop a large-scale, multi-generational solar evaporation operation on the Pilbara coast.

Mardie has all the critical characteristics for establishing a large-scale solar evaporation operation, including optimum climate conditions, a large area, minimal environmental and heritage sensitivities and a coastal location for low-cost shipping.

The project is slated to become a tier one solar evaporative project that will supply high purity salt and sulphate of potash (SOP) for generations.

(Image source: BCI Minerals) Managing director David Boshoff.
(Image source: BCI Minerals) Managing director David Boshoff.

Mr Boshoff spoke about the history of Mardie and its future operations.

“When complete, Mardie will be the first major salt project developed in Australia in two decades, as well as the only Australian operation to produce commercially saleable salt and SOP,” he said.

“Salt is one of the most widely used substances on earth, and SOP is a crucial fertiliser containing essential macronutrients for plant growth, aligning the project with growing demand in the chemical and agricultural sectors, as well as the global demand for greater food security.”


Mardie was designed to produce around 5mtpa of high purity salt and 120-140ktpa of SOP with the first shipment of salt expected in the next few years.

“We are scheduled to have our first salt on ship in mid-2026 and this timeline will signal the completion of a large part of the initial construction project.” Mr Boshoff said.

“The first SOP on ship is expected 12-18 months later, and there will still be some construction works aligned with that milestone.”

At Mardie, an unlimited seawater resource will be concentrated through solar and wind evaporation to produce 5.35mtpa of high purity sodium chloride salt and 140ktpa of sulphate of potash fertiliser over an operating life of at least 60 years.

The project comprises of nine large evaporation ponds, salt and kainite-type mixed salts (KTMS) crystallisers, a salt wash plant, port facilities and a SOP plant.

Seawater is pumped from the ocean into the first evaporation pond before it is progressively concentrated via sun and wind evaporation energy over an 18-month period throughout the nine evaporation ponds.

When it reaches sodium chloride saturation point in the ninth pond, concentrated brine is transferred to the salt crystallisers where salt precipitates in solid form.

The remaining liquid is drained and the raw salt is harvested and purified in a two-stage counter-current wash plant to produce 5.35mtpa salt with sodium chloride content of more than 99.5%.

What sets Mardie apart from WA’s existing salt producers is that it will also produce SOP as a by-product.

The brine liquid is then pumped to the SOP crystallisers where KTMS forms with around 1.1mtpa of KTMS harvested and converted to 140ktpa of granular SOP product.

Final salt and SOP products will then be exported from a purpose-built port facility at Mardie with salt to be conveyed at a rate of 3ktpa.


Construction of Mardie began at the beginning of last year, with many major construction milestones achieved since then.

As of June 30, 2023, BCI had a total capital expenditure of $369m which was spent on the primary seawater intake station, the accommodation village, ponds one to four, the North West Coastal Highway Intersection and North South Road.

While this work has been completed, Mr Boshoff said there’s still more that needs to be done.

“We still have significant construction works to complete, including the completion of the marine package, ponds and wash plants,” he said.

“These works will continue as we start the process of growing salt in the completed ponds.

“As it takes about 18 to 24 months, depending on climatic conditions, to grow the salt to the quality levels required, we need to start this process as soon as possible to meet the strong demand we have for our product.

“As a result, we will be running our construction project and operations in parallel.”

To date, BCI has received credit approvals from all key debt providers for the full $981m of project finance needed for Mardie, while Export Development Canada has approved a $150m project finance facility.

Additionally, two leading commercial banks have increased their credit approvals to a combined $181m.

These approvals are in addition to a $490m 15-year facility from Northern Australian Infrastructure Fund and a $160m 11-year facility from Export Finance Australia.

Future Work

Due to the Pilbara’s proximity to Asia, Mr Boshoff says demand for product from Mardie is prominent from that country.

“The demand for the product is strong, particularly in Asia, which has BCI well placed, and as previously mentioned, we expect to be exporting salt by mid-2026,” he said.

“Our focus is very much on salt and potash in the short to medium term, and we believe the Mardie project will become a tier one operation to meet known and future demand.

“We also expect this project will become a strong contributor to the Pilbara, Western Australian and Australian economies through its exports and employment/ contract opportunities for decades to come.”

BCI has already executed an offtake term sheet with one of Japan’s largest trading and investment companies — Itochu Corporation.

Under the term sheet, Itochu is expected to purchase 500kt of salt in years one and two, 600kt in year three and 1mt in years four and five.

Subject to the executive of a formal offtake agreement, BCI intends to appoint Itochu as its preferred trading partner for Japan, Korea and Taiwan.

In FY24, BCI will focus on key areas of project development, including building mutually beneficial relationships with key offtake customers and completing the full funding package for project constriction.

BCI will also look at implementing an updated economic performance objective.