Mines_de_sel_exterieur_02-Ete-Bex-Salines_Suisses_SA © Saline de Bex

Bex Salt Mines: history and how salt is mined

Alain Fiaux has been employed by the salt mines since 1995 and guides visitors through the mine while also taking part in servicing the mining machinery. He tells us the history of the mines and the current methods used to mine salt.

The salt mines are a key element in the life of Bex and are strongly rooted in both the territory and the hearts of the inhabitants.
Indeed, they were the first industry in Bex and have employed hundreds of “Bellerins” (local inhabitants) throughout their history. They have been worked unceasingly since 1680 and today employ ten people, including three miners, who work full time on mining, exploration and maintenance. The presence of salt implies major issues with corrosion and important maintenance work is required to keep the machines operating.

35 000 tons of salt are mined annually, thanks to 110 000 tons of spring water from the neighbouring Muveran mountain. The electricity required to keep the salt mine going is generated in the neighbouring Peuffeyre hydro-electric factory. This method of exploitation enables the Bex Salt Mine to have the best eco-balance in a 250km circumference, and has also resulted in the salt mines being awarded the eco-business label, thereby minimising their environmental impact.
80% of the salt manufactured is used as de-icing salt for the roads in winter, 10% is sold as cooking salt, and 10% is transformed into by-products such as herb salt or cosmetic products, amongst other things.

The discovery of considerable salt deposits near the Rhine (in Switzerland’s German region) in the 1830s and the creation of the Rhine Salt Mines resulted in a major decrease in the exploitation of the Bex salt mines. However, while the Rhine Salt Mines produce 20 times more salt than their Bex counterpart, they have no tourist use and no by-products are manufactured.
History of the salt mines

History of the salt mines

The first signs of salt in the region were discovered by goats around 1640. But according to the legend, when Jean du Bouillet, a poor peasant poacher was hunting in the Fondement region (above Bex), he saw a herd of chamois deer licking the rock. As these animals usually collect around water, a large number of them far from any river attracted his curiosity. He tasted the damp rock and noticed a slightly salty taste.

For more than 50 years, the location entrapped water, sent it down to the valley from the Fondement located at an altitude of 1000 m and heated it to extract the salt. Later, they dug into the mountain and discovered slightly salted new springs that they made flow through graduation works made of thorny branches in order to increase the salinity. By flowing slowly, part of the water would evaporate in the wind, and by repeating the operation several times, the water became increasingly salty.
Towards 1680, the springs dried up and the first two galleries were dug at the exact time that a new spring was found. For centuries, kilometres of galleries were dug, in the hope of finding a large collection of salt. As the first traces of salty water were found at an altitude of 1000m, miners dug stairs, creating new galleries deeper. The vast
maze of wells, staircases and tunnels today enable air to circulate in the galleries (through a system using a chimney flue).

Later, a large well was dug from the Fondement, the remains of which can still be seen today. The salt rock from the Triassic Period was then discovered which held large quantities of salt. (The Triassic Period: the era in which the oceans evaporated 180 to 220 million years ago). It is the presence of gypsum in the salt that has kept these
quantities of salt intact.

The Bernese who exploited the mines up to around 1780 wanted to stop working the mines, considering it too complicated. The Revolution in 1798 convinced the people of Vaud to continue working the mines. They decided to wash the rock in situ instead of extracting the salt filled rock and washing it outside. Jean de Charpentier then dug a huge hall, into which the salt rock was piled up to the roof. The hall was then hermetically sealed and the rock literally drowned in the desalination room. From this time forth, it was no longer salt rock which came out of the mine but salt water which was recovered at the bottom of the mine.

In 1840, the people of Vaud abandoned the mines because it was considered too complicated to work them. At this point people from the region, subsequently nicknamed “the founders” refused to abandon them and invested their own money to find concessions, absolutely against losing the years of work and abandoning the many existing galleries. They thus continued to “drown” the halls, the water dissolved the salt stuck in the rock, and given the impermeable nature of the rock, the saline water was recuperated and pumped. This method of exploitation was used until about 1920. At this point rock drilling began with the aim of piercing the rock as deep as possible to find a spring. The core sampling on the other hand began in about 1960, when a French oil engineer moved to Bex and experimented with various drilling techniques.

How is mining done today?

Currently, the salt is mined using a system of double tubes inserted into the rock. Fresh water from the neighbouring mountain is injected using high pressure in the first tube. The water pressure allows the saturated water to remount into the second tube. The water that remounts that is not sufficiently saline is reinjected several times until its salt content is adequate. The current drilling is done from Le Bouillet at an altitude of 600 metres, while some go up to 840 metres deep. However, the ideal depth is from 300 to 600 metres as the saline areas are found at an altitude of between 0 and 300 metres.

The Bex Salt Mines currently contain 50km of galleries and drilling holes. The longest gallery is 3km and connects Le Bouillet with the Grand Chamossaire 1000 metres below the ground.

Bex-les-Bains and the benefits of saline water

From the 1880s onwards, Bex diversified the exploitation of its saline springs by specialising in wellness. While part of the spring water feeds the salt mines, the other part is used by the wellness centre at the Bex-les-Bains hotel which was in operation until the 70s. It was at this time that Bex acquired great notoriety in the realm of health.
Indeed, the saline water from Bex had great qualities and many guests visited regularly to enjoy wellness cures, including characters such as Tolstoy, Nietsche, Victor Hugo, Alexandre Dumas and the Empress Marie-Louise.

In the 1900s, a doctor from Geneva advocated the virtues of the saline springs in Bex in the following manner: “Those of you who suffer, come to Bex. The sickly, the impotent, the ill and the dying will leave cured.” The water from Bex was reputed to cure 53 diseases, including sterility. Amongst the many treatments offered is a treatment for rheumatism, which involved immersing the patient in a bath of saline water in which a low voltage electric current was conducted. All women wishing to found a family were also strongly advised to have a saline water cure. By the same token, certain doctors recommended a spring wedding to all young girls having undergone a cure at Bex-les-Bains the previous year. 

The hotel at Bex-les-Bains closed down during the 70s, following a fire which destroyed almost the entire building.