SALT EXTRACTION: from Flats to Containment Ponds to Underground Tunnels

Salt – sodium chloride – is a mineral everyone is familiar with, it is essential for human life and is one of basic human tastes. Before our travel to South America, we knew salt came from various places (think Black Hawaiian Sea Salt, Pink Himalayan Salt, etc.); however, we had very little understanding of the different methods used to extract it from the earth. As it turns out, mining salt is a huge industry with sodium chloride being one of the largest inorganic raw materials used in the world by volume (and its manufacture is one of the oldest). Today, we use almost 70% of the salt extracted from the earth for manufacturing and industrial processes while only 6% is used in food (the remainder being used for water conditioning, de-icing highways and agriculture).

We have visited three salt mines in South America – one each in Bolivia, Peru and Colombia – and all were very different. As is evident from the fact that all three of these countries have turned their salt mining industries to double as tourist attractions, salt mining can produce beautiful landscapes worthy of professional photography and high-priced tours.

1. BOLIVIA:  Salar de Uyuni

DSC05104 (1024x683)Approximately 40,000 years ago prehistoric lake Minchin dried up leaving behind two smaller lakes and two salt flats. Salar de Uyuni is estimated to contain over 10 billion tons of salt making it the world’s largest salt flat (as well as the highest at 3700m above sea level). The mining which takes place on the salt flat is very small in proportion to its size – less than 25,000 tonnes of salt are extracted annually by the Colchani’s cooperative. That said, indigenous people in the area have been mining the salt there for centuries.

Mining in the salt flats consists of a worker scraping the surface salt just underneath the thin layer of saturated water that covers the salt flats into piles with hand shovels. Once the salt has dried out, it is shoveled into the back of pickup trucks and milled with a hand-operated device before it is shipped off.

2. PERU: Salinas de Maras

DSC05788 (1024x683)The Salinas de Maras were constructed by pre-Incan civilizations on the slope of a mountain in the Sacred Valley, Peru. They currently contain over 3000 small ponds less than four square meters in area and less than 30 centimeters deep.

Salty water from a local subterranean stream emerges at a spring and is redirected to the pools through an intricate system of small channels constructed to gradually run down the slope and fill all of ancient terraced ponds. Each pond is owned by a different keeper (who must be a member of the community) and as a result there is a necessity for close cooperation between the community of users. The “mine” is only operational during the summer months as it requires the heat of the sun to evaporate the water in the ponds. Once the water is supersaturated with salt, the water-feeder notch in the pond is closed; therefore, allowing the pond to dry up. Then, the ponds keeper scrapes the dry salt from the sides and bottom on the pond and re-opens the notch to repeat the process. Depending on the skill of the worker the salt varies from white to light reddish to brownish tan.

3. COLOMBIA: Minas de Sal – Nemocón and Zipaquirá

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The Salt Mines of Nemocón and the Salt Cathedral (in an abandoned Salt Mine) of Zipaquirá are Colombia’s two largest salt mines. Both mines have immaculately preserved collections of tunnels and chambers filled with stalagmites and stalactites which have become major tourist attractions.

The salt deposit was formed 250 million years ago when an inland sea that covered the region dried out leaving an enormous deposit of salt buried below the earth and mud. Over time, it solidified and became rock salt.

DSC06856 (683x1024)The ore (rock and rock salt) is removed from the mine in a checkboard pattern, in which large square caverns alternate with square pillars of ore that serve as support for the rocks above and provide ventilated air for the workers. The rock salt is then blasted into smaller pieces which are then dissolved into water in processing ponds. From there the water is evaporated and the remaining salt is collected.

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