Rock salt can be produced by:
- evaporation of sea or saline water,
- leaching, i.e. salt dissolving with water in the deposit,
- underground (or open-pit) mining.
Currently salt is produced in Poland solely from the Zech-stein deposits using underground mining and leaching techniques. In total, approx. 3.5 million tonnes of rock salt were produced in Poland in 2015, or 17.2% less than in 2014.
Over the past 15 years rock salt production in Poland ranged from 2.9 million tonnes in 1997 to 4.2 million tonnes in 2013. A decrease in the total output reported in the beginning of the 1990’s followed the closure of “Solvay” Soda Works in Krakow. Subsequent fluctuations in the domestic rock salt output were due to changes in the demand for crushed salt used for winter road conditioning, climate change (ever shorter and warmer winters) and increasing market competition from rock salt producers.