Salinera

1776
Philip Kelley
Salinera
A woman working in a salt mine

What is a salinera?

A salinera o salina is an operation established in the open air to obtain common salt from its saturated water. This is achieved by evaporating water from sea or salt lakes, as well as extracting groundwater from deposits rich in said salt..

The salt mines are located in coastal marine areas, on the shore of salty lakes or in areas of springs rich in salt. On the other hand, the salt extraction process is carried out by evaporating the salty water under the action of solar radiation and winds..

These structures require high solar radiation environments, with high temperatures, constant winds and flat and impermeable floors. In these areas the salinera is established, which consists of an area where the salty water is deposited.

Then, it passes to another area where it is subjected to solar radiation and wind so that the evaporation of the water occurs. Finally, the resulting brine is deposited in a third zone where the crystallization of the salt occurs..

The salt mines can be of two types depending on the geographical region where they are established. So there are coastal salt mines, on the marine coasts, and inland salt mines, in lakes or salty springs inland..

What are the salt mines for?

Excavator in salinera de Huelva, Spain

Common salt or sodium chloride can only be obtained by extracting it from salt-saturated bodies of water, such as the seas and some lakes. As well as salt mines, which are salt deposits in the interior of the Earth, formed from ancient seas or salty lakes..

In addition, in some deserts, salt is obtained directly from the surface of the ground, where in the past there was a sea or lake. Therefore, the salineras or salinas are exploitations that serve to obtain common sea salt, which is a product that has various purposes.

The main one of them is the use as a condiment in the preparation of meals. This is due to the ability of salt to enhance the flavor of food products. Additionally, salt prevents iodine and fluoride deficiency, as well as helping to eliminate lactic acid and uric acid..

On the other hand, salt is a very effective preservative, which is why it has been used to preserve food since the earliest days of mankind. Especially in the preservation of fish and meat, when these are covered with thick layers of salt.

The cause of this preservative power is the ability of salt to absorb water, thus dehydrating food. The less water there is in the tissues, the less conducive to the development of bacteria and fungi that cause decomposition..

In addition, salt has many other uses in various industries, such as chemical, textile, metallurgical and in leather tanning..

Characteristics of the salt mines

Piles of salt in salinera de Bonaire

Location

Salt mines are located near bodies of salty water, either in coastal areas or near salty lakes. On the other hand, they can also be established in areas of the interior of the territory on land with deposits of underground water rich in salts..

Atmosphere

The ideal environment for the establishment of a salt works is one where there is high solar radiation and little rainfall. This is due to the fact that the rains dilute the salt deposits, dragging it back to the bodies of water..

On the other hand, the evaporation process required to separate the salt from the water requires high temperatures. Additionally, the occurrence of frequent winds contributes to the process of evaporation of water and drying of salt..

Soil and relief

Salt mines require soils with a compact clay layer that prevents water infiltration. On the other hand, the ideal is flat terrain that allows to maintain shallow water sheets and control runoff..

Waste and environmental impact

Although salt mines are not a highly polluting activity, they do produce some problematic waste. Mainly the so-called bitters, which are the deposits that remain after extracting the salt.

These substances have a high concentration of salts and other minerals, so they must be properly disposed of to prevent negative impacts on the environment..

Parts of a salinera

The parts of a salinera can vary depending on the type of salinera and their names change from one country to another. However, every salt works consists of some basic parts to guarantee its operation..

Marine water catchment and storage area

In this area, salt water from the sea, lake or salty spring is taken and stored. In the case of lakes and springs, pumping is generally used to move the water.

While in the salt mines of the marine coast, it is obtained from the so-called take-offs, overflows or saltaderos, taking advantage of the rising tide. Then the water is transported through channels to the estuary, a large lagoon where sea water is received.

Evaporation zone

Salt evaporation ponds in Secovlje, Slovenia

From the estuary, the salty water is carried through channels and gates to rectangular pools of great extension and little depth, called eras. These ponds must have a compact, clayey, impermeable bottom and are separated from each other by low elevation earth or stone walls..

These initial rafts are somewhat deeper than those used in later stages. Then, the water is transferred to other shallow ponds called heating or heaters..

Here the action of solar heat and the wind evaporates the water and concentrates the salt. In some systems, the water passes into a complex of increasingly shallower serpentine or labyrinth channels, where the salt is concentrated by evaporation.

In the salt flats of Cádiz these areas are called pike, made up of turns that are deep and wide followed by narrower and shallower ones. At the end of the whole process, a dense residue with a high concentration of salt is obtained..

Crystallization zone

Subsequently, the residue is passed to other so-called crystallization or crystallizer ponds, where salt crystals are formed and go to the bottom of a layer of water that does not exceed 10 cm. These crystallizers are called tajos in the salt flats of Cádiz and maretas or crystallizers elsewhere..

This area has the so-called balaches or drains, which are the dividers between crystallizers. There, the piles of the extracted salt are placed to drain and dry, being subjected to a washing process.

Salt shaker and warehouse area

From the crystallizers or pits, the salt is transported to an area where it accumulates in large mounds, ending its drying process there. In some systems, the salt is deposited in closed warehouses while waiting for its transfer to the processing plant..

Loading Zone

In this area, the salt is loaded depending on the means of transport used, be it boat or trucks..

Types of salt mines

There are basically two types of salt mines, depending on the geographical area where the source of the salt is located. These are the coastal salt mines and the interior salt mines.

Coastal salt mines

The coastal salt mines, as their name indicates, are located on the sea coasts, since they extract salt from sea water. These salt mines obtain sea water by channeling it from the rise of the tides or by pumping.

In many cases, they combine their salt production activity with the fish farming of saltwater species. The coastal regions where the salt mines are located are in tropical and subtropical areas, where solar radiation and temperatures help the process..

On the other hand, they take advantage of flat terrain to avoid uncontrolled water runoff or the invasion of fresh water from nearby rivers..

Indoor salt mines

The inland salt mines are dedicated to obtaining salt from springs and salty lakes located far from the coasts, inland. As well as underground salt deposits in areas with a high water table.

In the latter case, they use drilling and pumping processes of the salt water, to then evaporate it and obtain the salt crystals..

There are also cases where salt is collected directly from the surface of the ground, in areas of old seas or already dry lakes. Such is the case of Salinas del Rey in the desert areas of Coahuila, Mexico.

Indoor salt mines do not always have flat terrain, so evaporation ponds are established on terraces. In such a way that the water is pumped from the main tank and then passes from one basin to another by gravity..

References

  1. Albaladejo-García, J.A. and Gómez-Espín, J.M. (2016). Inland saline spaces: the Sangonera la Seca and Librilla salt flats in the Murcia region. Geography Papers. University of Murcia.
  2. Hueso, K. and Tejedo, P. (2008). Reflections on the future of traditional salt flats. Presentation of the Technical Conference The Cultural Heritage of Las Salinas.
  3. Moreno-Pulido, J. and collaborators (2018). La Sal de Cádiz, from the coast to the interior. Geolodía Collection. Edited in Salamanca by the Geological Society of Spain.
  4. Ruiz-Lozano, C. (2015). The landscape of the Mediterranean littoral salt farms: The case of the salt flats of Ibiza. Final degree project. Department of Geography, Faculty of Geography and History.

Yet No Comments