The Osiek Sulfur Mine is the only mine in the world producing sulfur using the Frasch process, in which superheated water is pumped into the deposits and melted sulfur is extracted (underground melting). The mine is located near the town of Osiek. The 'Osiek' sulfur deposit is found on the right bank of the Wisła River and forms the western part of a sulfur field stretching from Niekrasów and Osiek, through Baranów Sandomierski to Skopanie. It connects with a Miocene chemical sedimentary series, where sulfur is present in a marly limestone complex.
Presently, the Osiek Sulfur Mine produces liquid sulfur and granulated sulfur.