250 million years: Ancient and from the primordial sea

Salt is essentially a simple compound made up of two elements: sodium and chlorine, which combine to form sodium chloride. Both elements are among the most common substances found in nature.

Salt is water-soluble, with its main component being dissolved in the world's oceans: oceans are the largest salt reservoirs on Earth. If the oceans were to completely dry up, the entire ocean floor (which covers 70 percent of the Earth's surface!) would be covered with a crust of dried substances, almost 50 meters of which would consist of salt.

Over 90% of all salt deposits originate from the sea – even if they are now far inland. The distribution of land and water has changed repeatedly, as has the climate and the location of continents. Therefore, there were times when Central Europe was a tropical sea – and we owe Austrian salt to this primordial sea. Thus, our salt is approximately 250 million years old and originates from the Triassic/Permian period.

The salt cycle in nature

The components of salt were bound in other minerals and rocks long ago: through weathering, they were dissolved and carried away by water. Since sodium chloride, in particular, is very soluble, it remains in the water of streams and rivers. Therefore, all bodies of water constantly contribute new salt to the large lakes, seas, and oceans.

Salt deposits only form under certain conditions: in smaller enclosed bodies of water where inflows bring in a lot of salt (such as the Dead Sea or salt lakes), or in shallow ocean basins at the edges of the oceans. Massive salt deposits typically form in warm climates with strong evaporation.

The oldest salt production in the world: Hallstatt

For over 7,000 years, salt has been mined in Hallstatt in the Salzkammergut region. This makes the Salzkammergut the oldest region globally where salt has been continuously mined and produced to this day. Historically, salt extraction is among the earliest technological achievements of humanity.

Initially, salt was accessible to people where it naturally surfaced: presumably, in ancient times, they observed animals drinking from brine springs. Soon, they developed techniques for salt extraction: besides skimming salt crusts on salt lakes, salt evaporation played a crucial role. Seawater or brine from salty springs was heated in pans until the water evaporated, leaving behind the dried salt.

The salt mine – from the Hallstatt period to the present day

Salt mining in the mountains was intensively practiced since prehistoric times: one November morning in 1846, workers at the top of the salt mountain near Hallstatt unearthed astonishing discoveries. Mining engineer Johann Georg Ramsauer subsequently excavated the Hallstatt graves for 17 years – one of the most significant archaeological sites worldwide. 980 graves with around 20,000 grave goods gave the name "Hallstatt period" to an entire cultural epoch of the oldest Iron Age from 800 to 400 BC.

The world's oldest salt mine already reached a tunnel length of 5,500 meters and a depth of more than 200 meters at that time. The beginning of mining salt dates back to around 1500 BC, during the Bronze Age. Salt could initially only be mined where it was found in salt domes, i.e., underground accumulations of rock salt, or close to the Earth's surface. It brought wealth and prosperity, but also disputes and competition: Hence, it is also called "white gold."

With the advancement of mining over the following 2,000 years, more and more salt deposits were developed through mining. This laid the foundations that still shape salt mining today.