Vast ancient salt mines discovered inside an Austrian mountain

Archaeologists exploring Hallstatt’s prehistoric salt mine in Austria have identified an Iron Age complex unlike any previously documented at the site. Multiple extraction chambers run in parallel, sometimes above and below one another, and have so far been traced for 300 metres. The chambers are about 25 metres wide and 20 metres high. Their layout suggests miners followed the mountain’s main salt seams, adapting their methods to its geology.

Previously, ancient workings were known only where later tunnels happened to cut through them. Since 2022, researchers from the Natural History Museum and Salinen Austria have used core-drilling equipment to investigate untouched areas hundreds of metres into the mountain. Instead of the single enormous void they initially expected, they found a network dating to a phase of salt mining that began in the sixth century BCE.

Salt has preserved an unusually detailed record of work and daily life. Deposits up to nine metres deep contain burned lighting splints, broken tools, textiles, clothing fragments, wooden bowls with food remains and human waste. Researchers say human genetic material and DNA from consumed food have survived in the sediment.

The finds open a new view of Hallstatt’s changing mining techniques and show striking similarities to remains from Dürrnberg, another Iron Age salt-mining centre. A separate restoration project is also securing centuries-old tunnels so earlier discoveries can be studied with modern methods.