Saltworks

All along the West Coast one can see the salt works. At the Oranje River's mouth we saw the white deposits of salt in the marshland, but further down south salt mining is a serious business at the Sout- en Olifant's river mouths. I also know of salt mining near Yzerfontein. For most of us living in the Cape, the salt mines near Velddrif are probably best-known, when going north from Cape Town one cannot miss the snow-white salt mounts iof the Cerebos salt plant sparkling in the sun.

We cannot imagine a life without salt. Sodium chloride, generally known as common salt, is not only important to us in bringing out our food's flavours, it is also essential to the health of our bodies.  Sodium and chloride, together with potassium, are the ions necessary for nerve conduction.  Workers and athletes exposed to the high temperatures of the outdoors, lose a lot of salt through sweating and are prone to muscle cramps because of that. One can prevent and cure this by adding salt tablets or energy drinks with high levels of salt to the diet. A diet rich on meat and milk will probably not need much more added salt, but if the diet is mostly limited to grains, fruit and vegetables, it will need a supplement of salt.  Wild and domestic animals use salt licks to obtain essential salts.  Other uses of salt include the preservation of meat and fish and for curing hides.  Salt is an ingredient for the manufacture of washing soda (sodium carbonate), baking soda (sodium bicarbonate), caustic soda (sodium hydroxide), bleaching powder and chlorine.  It is also used in the manufacture of glass, soap and glasses.

To ensure that table salt remains free flowing, small quantities of sodium carbonate or trisodium phosphate are added.  In South Africa a small quantity of potassium iodide is also added, to overcome iodine deficiency.

Many substances make up the salt in seawater, but sodium chloride is by far the dominant compound.  The proportions of salts in the sea are relatively constant – sodium chloride (77,8%), magnesium chloride (9,4%), magnesium sulfate (6,6%), calcium sulfate (3,4%) and potassium chloride (2,1%).  The salt content of seawater is similar to the body fluids of most animals.

In other countries salt is mined out of rock-salt deposits, but along our western shores salt is extracted from the saltwater by evaporation.  Preliminary concentration of the seawater is achieved by channeling seawater into a series of shallow ponds.  As the water evaporates the brine becomes more concentrated and the different salts separate out as each reaches its point of saturation in the solution.  The order of deposition is calcium carbonate, calcium sulfate, sodium chloride, magnesium sulfate, carnallite and magnesium chloride.  Sand, clay and less soluble salts are then removed.  The remaining clear concentrated brine is run into a succession of crystallising pans, usually three, where the salt is deposited.  In the first pan the best grade “table salt” is produced.  In the second pan second grade salt for the chemical industry is produced and the brine from the third pan is used for pickling fish.

Hand harvesting for the general sea salt is usually done twice a week.  Staff use long handled rakes and stainless steel mesh skimmers, bending over the shallow rectangular pools of seawater, dense with salt, drawing the crystals to the sides of the pans.

The salt in each crystallising pan is raked into rows and then heaps and drained for several days, before being lifted from the pans and dried in hot-air rotary driers.

In 1972 Cerebos erected a factory to produce salt, to the south of Velddrif, where the Berg River runs into the sea. The Velddrif Salt Works consist of 400 year old brine that is pumped from an underground seawater lake on the shores of St. Helena Bay near Velddrif. Due to siphoning through shell beds, the salt here is higher in calcium content and lower in sodium.  The dry summers and low rainfall of the West Coast make this region ideal for extracting salt from sea water. High evaporation rate by wind and heat produces high quality salt. In addition, the many drying and canning fish factories provide a ready market for considerable quantities of salt.

Cerebos Salt Works have guided tours on Thursday to enlighten anyone interested in where our salt comes from. One can also visit the KhoiSan Salt Factory in town.

The history of salt is not the only reason to visit these salt works. The salt works offer aquiet resting place for thousands of local sea birds and migrating and wader species.  Especially when the water levels in the salt pans are low, when they can reach the macro fauna easily. With high tide when the muddy banks of the river are flooded, the waders will also find refuge here till the river's water level drops.

The read coloured water of the salt pans are caused by the microscopic algae called cyanobacteria, these are the bait for filter feeders like the Greater and Lesser Flamingos who are present here in large numbers at certain times of the year.

Thousands of birds breed here. Apart from the large number of Caspian Terns, Greater Flamingo and Lesser Flamingo started breeding here in the last few years and one should not be surprised to see Chestnut-banded Plovers on their nests.

It is an amazing sight to be here next to the snow-white salt mounts and reddish water and watch the different birds feeding, each in its own unique way.

Flamingos are slowly pacing to and fro, heads bowed while filter feeding. On the banks a swarm of stints chase the small insects flying around, a bit to the side a yellow-billed egret is ready to pounce on its prey. Every now and then the Caspian terns fly up as if in a large cloud above your head. From the sea a dark line of bank cormorants are flying in to roost.

The setting is spectacular. Photogenic. Peaceful.