Mining of Salt in Namibia – Transport and Stockpiling

Walvis Bay Salt Holdings (WBSH) is producing the largest volumes of solar sea salt in sub-Saharan Africa. They process 93 million cubic metres of salt water each year to produce over 900 000 tons of quality salt, also known as ‘white gold’. Unitrans Namibia has the contract to partner with WBSH for the transportation of salt from the strategically located, massive 5,000 ha site to the port-side holdings at the docks, just 10km away.

The Namibian location is prime for high evaporation rates owing to the usual hot weather, so neighbouring countries, Europe and North America benefit from this country’s high production levels. Most of the exported product is used commercially for de-icing in cold climates, industrially to produce hydrochloric acid, caustic soda and other chemicals and in many manufacturing processes (producing pulp and paper, dye setting in textiles and fabrics, and making soaps and detergents). Consumer sale requirements only account for about 8% to 10% of production in various countries worldwide.

The crude solar salt produced at sites such as WBSH undergoes a washing process to remove impurities such as calcium, magnesium and insolubles and to reduce the moisture content, in order to grade the salt that meets a wide range of clients’ technical specifications. A common misconception is that all salt is the same.

Sea salt mining is environmentally more cautious

The sun and wind method of extracting salt from the sea means that this is an ecologically sustainable process. As the sea is an almost inexhaustible source of salt, there are lower CO2 emissions compared with other salts. One sea vessel which transports salt is equivalent to about 2,500 trucks on the road, so exporters deliberately make use of this mode of delivery rather than by its cheaper road alternative to prevent the carbon emissions from a comparable 10,000 truck journeys per year.

By optimising the equipment, Unitrans Africa Namibia reduces not only the number of trucks on the road, but also the noise levels. The company actively searches for new technology to help mitigate and reduce any negative impact of operations on the environment. Among other things, they constantly focus on reducing fuel consumption across the entire project.

Storage or stockpiling of salt

One of the most efficient methods of stockpiling or storing bulk salt is in stainless steel silos to prevent exposure to humidity or heat. Steel silos can store thousands of tons of salt without deterioration. Sensors can gauge volume, even though dust may form on the exterior and controllers can access the easily transmitted data. When the time comes to moving stock from shipping terminals or warehouses, logistics companies draw the salt from the containers into side tipper trucks and move the load to the shipping vessel.

How is salt transported?

Salt first has to be moved around and from the salt plant. Owners use heavy equipment such as front-end loaders, bulldozers and side-tipper trucks with large loading bins to do the job. The processing factory uses barrels or specially modified bags to pack the salt, or else transport it in bulk to the port. To avoid contamination, controllers move the salt destined for bulk exports from the bulk storage facility at the harbour by a conveyor belt and spout-trimmed into the ship’s hold at the dockside.

Freight managers then transport salt as bulk cargo all over the world by sea. They have to refashion the containers or the ship’s hold carefully to prevent water vapour exchange between the salt and the hold or container air. When stowed in containers, pre-preparation ensures the interior of the container is absolutely dry and clean. Bagged product (1,000kg) must be of top quality and not stowed with goods that may release moisture. Further protection by freighting includes fitting an addition inner liner.

Salt corrodes steelwork, so transporters using breakbulk shipments with steel structures in the holds, apply multiple coats of whitewash to prevent oxidisation, as well as filling cracks in ceilings and planking. They also seal spaces between packages or pallets to prevent slipping or tipping and load the pallets flush with their edges, to prevent protruding package damage.

During the voyage, salt may lose 5% in weight by evaporation. A bulk liner bag is fitted inside the container and heavy equipment shovels bring in the salt cargo. Additional safe conveyance methods include creating a door bulkhead, either by fitting bars into the doorway recess or by bagging a portion of the cargo to hold the liner in position across the doorway.

Unlike other mining operations, sea salt mining is not a ‘diminishing supply’ commodity. Andre Snyman from WBSH is upbeat about the opportunities to generate revenue from this low-priced commodity. “To be successful, there are a few key points – you must have volume, you must be in control of your logistics and have high economy of scale benefits in terms of your volumes,” he explains.

Unitrans Africa is a leader in the transportation industry in Africa, with a strong footprint in countries like Namibia and Botswana. Customers can be assured of the Group’s commitment to drive innovation in their service delivery, save on costs wherever possible and maintain high safety standards in all their operations.

Find out more about bulk handling and Unitrans Africa’s logistics solutions by contacting them via email.