Slănic mine is an old salt mine, located in Slănic, Prahova County, Romania, just 100 km north of Bucharest. The salt mine is closed for extraction purposes, but is open for visitors, featuring a microclimate with natural air-conditioning and constant temperature and atmospheric pressure throughout the year. It is made up of two levels, named Unirea and Mihai. Many of the visitors come for its supposed healing effects due to the purity of the air.
The work for the opening of the Unirea salt mine started in 1938 and the exploitation of the salt from this mine was performed between 1943-1970. The exploitation was done downward from the ceiling to the basis in successive slices of 2.2 meters with a horizontal cutting at the basis and vertically along the walls. The de-rocking was made through shooting. The transportation of the resulting material was effected with the tubs up the shaft using a cage to the installation of preparation and expedition. The mine is composed of 14 chambers with trapezoidal profiles, having a 10 m opening to the ceiling and 32 m to the ground, a height of 54 m and a wall inclination angle of 60 degrees. The shore difference between the surface and the base of the mine is of 208 m and it is covered by the elevator in 90 seconds. Since 2014 the elevator is out of order. The excavated space occupies a volume of 2.9 million m³ and it is extended on a surface of 78,000 m²