18th-century salt mines

HISTORY

“ Prior to the 20th century, salt mining was an incredibly difficult and hazardous undertaking”

How was salt mined?

Learn how this valuable mineral was harvested before the Industrial Age

Salt is one of the earliest resources mining was used for, with the industry dating back thousands of years. Salt, as we know it, comes from halite in evaporated deposits (see ‘Salt of the Earth’ for more detail), which are usually – though not always – located underground. As a result it requires an extensive mining operation to both retrieve and process it for use in cooking and beyond.

While today we have advanced mining machines, electrical lighting systems, air fi ltration networks and super-effi cient processing facilities worldwide, prior to the 20th century, salt mining was an incredibly diffi cult and hazardous undertaking, with conditions, tools and techniques requiring expert knowledge and a good deal of luck!

Lighting was delivered by tallow candles or fl aming torches, for example, while halite extraction relied on a mix of manual pickaxe labour and the use of black powder explosives – the latter often resulting in cave-ins.

One of the biggest killers in salt mines prior to the 20th century, however, was dehydration. Due to the miners’ constant contact with salt, both physically while digging for it and also via inhalation, rapid dehydration and excess sodium intake were common, with many miners passing out through exhaustion. This dehydration was heightened by the intensity of the labour, with long cave networks to navigate, colossal deposits to be broken down with just pickaxes, towering wooden scaffolds to be climbed and heav y barrels to haul.

Indeed, in many countries, salt mining was used as a form of punishment or slave labour until the 1900s, with the life expectancy of those sentenced to this work very low.

Inside the Wieliczka Salt Mine

Check out what went on within one of Europe’s oldest salt mines

Salt of the Earth

Salt – or to be precise, rock salt – is the common name for the mineral halite (pictured), which has the chemical formula NaCl. Halite is formed by the evaporation of salty water – like that found in the Earth’s seas, which contains large quantities of dissolved Na+ and Cl– ions – over long geological time frames. Due to epic changes in our planet’s structure and atmosphere over time, today halite deposits can be found underground, with the lighter salt deposits driven upwards by movements in the denser rocky crust below.

Scaffolding

Often miners carved ladders out of the halite, but for elevated deposits, wooden scaffolding was erected.

Animals

Various animals – though most often horses – were used to pull carts of tools and excavated halite around the mine.

Tools of the trade

A variety of pickaxes, hammers and cutting blades were used for mining halite, as well as powder explosives.

Barrels

Halite was put into wooden barrels for transportation to the surface and on to the processing factory.

Miners

At its peak, hundreds of miners descended each day into the mine from the town of Wieliczka in southern Poland.

Lighting

There was no electrical lighting network in the Wieliczka mine, with workers relying on torches for illumination.