The Mardie Salt and Potash Project (Mardie or the Project) is 100% owned by Mardie Minerals Pty Ltd, a wholly-owned subsidiary of BCI Minerals Limited (BCI).  The Project presents a rare and attractive opportunity to develop a large-scale, multi-generational solar evaporation operation on the Pilbara coast of Western Australia (WA).

The Pilbara coast is one of the world’s premier regions for solar salt production.  Five existing solar evaporation salt projects owned by Rio Tinto and major Japanese companies have been operating successfully in this region for up to fifty years, producing a high quality and reliable salt product which is consistently in high demand in the chemical and other industries.

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 windspeeds); 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.

At Mardie, an inexhaustible seawater resource will be concentrated through solar and wind evaporation to sustainably produce 4.4 million tonnes per annum (Mtpa) of high purity sodium chloride (NaCl) salt and 120 thousand tonnes per annum (ktpa) of sulphate of potash (SOP or K2SO4) fertiliser for supply to the growing chemical and agricultural industries in Asia over an operating life of at least 60 years.

Figure 1:  Mardie Project Layout

Salt is one of the most widely used substances on earth, with over 10,000 direct and indirect uses. It has a large and mature market with 350Mtpa consumed globally in 2019. SOP is a premium fertiliser containing essential macro-nutrients (potassium and sulphur) for plant growth.  It accounts for approximately 10% of the global potash market of 70Mtpa, with the majority supplied as the chloride containing muriate of potash (MOP or KCl).

A Definitive Feasibility Study (DFS) commenced in early 2019 and was completed in June 2020 at a cost of $20M. The DFS was managed by BCI with support from GR Engineering Services Limited (GRES) as lead DFS engineer, and with additional support from Worley, CMW Geosciences, Preston Consulting, RPS, Roskill, Argus Consulting, Braemar ACM Shipbroking, KPMG and others. Key Project parameters and highlights of the DFS are shown in Table 1 below.

Table 1 :  Key Project Parameters

Key Project Parameters

Production Rate

4.4Mtpa Salt (>99.5% NaCl)
120ktpa SOP (>52% K2O)
(with optimisation and expansion potential)

Operating Life Minimum 60 years1
Site Conditions

Coastal location with ready access to seawater
High temperature, low rainfall, low humidity and high wind – 2,895mm annual net evaporation
Extensive mudflats (100km2) hosting clay soils ideal to retain water in ponds
Availability of construction materials

Environmental Approvals >3 years surveys and studies; Public review process underway
Ministerial approval targeted by early 2021
Production Processes

9 evaporation ponds
34 salt crystallisers and 18 SOP crystallisers
Salt plant and SOP plant

Port Facility

Multi-user port with third party access capability
2.3km trestle jetty
3,000tph shiploader


Transhipping using 12,000dwt self-propelled, self-unloading transhipment vessel
Supramax, Panamax and Capesize vessels loaded 28km offshore


Construction: peak workforce (onsite and offsite) of 470
Operations: steady-state workforce of 190

Economics (real, 2020 $)

Capital costs - $779M2
Salt all-in sustaining costs (AISC) - $20.3/t FOB
SOP AISC - $310/t FOB
Pre-tax NPV7 - $1,197M (ungeared)
Pre-tax IRR – 15.3% (ungeared)
Annual EBITDA - $197M
Significant value upside via optimisation and expansion options

1 – Input resource is an infinite supply of natural seawater which could continue for 100+ years.
2 – Excludes working capital and funding costs.

Mardie will be the first new major salt project developed in Australia in two decades and the only Australian operation producing commercially saleable salt and SOP.  It will be one of the largest single salt operations in Australia, and with the potential expansion into newly acquired tenements (not included in the DFS), it can 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 WA Government’s long-standing objective for the resources industry to include secondary processing in project planning.

In addition, the Project has strong “green” credentials given 99.9% of the energy requirement is derived from natural sun and wind to evaporate seawater, as defined by an independent KPMG study.

Project Description

The primary project components are listed below:

  • Seawater intake pumping station and evaporation ponds
  • Salt crystallisers and salt wash plant
  • KTMS crystallisers and SOP plant
  • Port facilities
  • Supporting infrastructure

The production concept involves a time-proven and low risk process.  Seawater is pumped from the ocean into the first evaporation pond (Pond 1) and progressively concentrated via natural sun and wind evaporation energy through a series of nine evaporation ponds over an eighteen-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 4.4Mtpa salt with >99.5% NaCl content.

Figure 2:  Salt Wash Plant

A unique attribute of Mardie compared to WA’s five existing salt producers is that it will also produce SOP as a by-product.  Bitterns from the salt crystallisers, which is deficient in sodium but rich in potassium and magnesium, is pumped to the SOP crystallisers where kainite-type mixed salts (KTMS) precipitate. Approximately 770ktpa of KTMS is harvested and converted to 120ktpa of granular SOP product with >52% K2O in a chemical flotation processing plant.

Figure 2:  SOP Processing Plant


Final salt and SOP products will be exported from a purpose-built port facility at the Mardie site.  A range of port options have been studied and a transhipment facility best satisfies the marine environment and product volumes to be exported by BCI.  DFS studies confirmed the optimum port solution is a 2.3km jetty and a 4.5km dredged navigation channel into open waters. The jetty has been designed to withstand a 1-in-500 year extreme weather event.  A navigation channel will accommodate a 12,000 deadweight tonnes (dwt) self-propelled and self-unloading transhipment vessel (TSV).

Salt product will be conveyed from salt stockpiles to the jetty head and loaded onto the TSV at a rate of 3,000 tonnes per hour (tph).  SOP will be transported by truck from a SOP storage shed to a receival hopper, conveyed to the jetty head and loaded onto the TSV at a 700tph rate.  The TSV will transport product 15 nautical miles (28km) offshore to ocean-going vessels (OGVs) at anchor.

Figure 3: Port and Transhipper


BCI is planning to ship salt to customers in OGVs ranging from Supramax (50,000dwt) to Capesize (160,000 dwt).  The use of larger average OGVs will reduce overall freight costs materially compared to other WA salt operations with berth constraints. SOP can be shipped by either small vessels or together with salt shipments, where the products have customers with a common or nearby port.


The Mardie DFS outcomes indicate that the production of 4.4Mtpa of high purity salt and 120ktpa of premium SOP fertiliser is technically and financially viable. DFS results confirm a compelling value proposition with a pre-tax NPV7 or more than $1B, supported by an attractive market opportunity and no insurmountable obstacles to development.

Mardie can become a potential Tier 1 asset categorised by its long life (minimum 60 years), top quartile scale, lowest quartile salt operating costs (after SOP by-product credits) and high-quality salt and SOP products.

With attractive financial returns over many decades and expansion potential from the new tenements, development of the Mardie Project should result in considerable long-term value and dividends being created for shareholders.

Next Steps

BCI has a strong cash position at June 2020 and ongoing royalties from its iron ore interests, making it well placed to complete this next phase of work at Mardie.

An FID by the BCI Board is targeted in early 2021, which will be followed by completion of the funding task.  Construction can commence in Q2 2021, which will allow for first salt sales by mid-2024 and first SOP sales by mid-2025.

Please refer to our DFS report here for more details