Salina Veche is an old salt

Salt

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

 mine

Mining

Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

, located in Slănic

Slănic

Slănic is one of the 14 towns of Prahova County, Romania, historically and currently known as a salt extraction center, as well as a spa town, with salt lakes...

, Prahova County

Prahova County

Prahova is a county of Romania, in the historical region Muntenia, with the capital city at Ploieşti.-Demographics:In 2002, it had a population of 829,945 and the population density was 176/km². It is Romania's most populated county, having a population density double than the country's mean...

, Romania

Romania

Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

, just 100 km north of Bucharest

Bucharest

Bucharest is the capital municipality, cultural, industrial, and financial centre of Romania. It is the largest city in Romania, located in the southeast of the country, at , and lies on the banks of the Dâmbovița River....

. The salt mine is closed for extraction

Mining

Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...

 purposes, but is open for visitors, featuring a microclimate

Microclimate

A microclimate is a local atmospheric zone where the climate differs from the surrounding area. The term may refer to areas as small as a few square feet or as large as many square miles...

 with natural air-conditioning and constant temperature

Temperature

Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

 and atmospheric pressure

Atmospheric pressure

Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

 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. Throughout the mine you will find various types of equipment for recreational activity such as playground equipment and some ping-pong tables. One area is sectioned off and is being used for medical patients with lung cancer to come and rest. The main elevator shaft that takes you down is unique in that it has no metallic parts due to rust

Rust

Rust is a general term for a series of iron oxides. In colloquial usage, the term is applied to red oxides, formed by the reaction of iron and oxygen in the presence of water or air moisture...

.

Unirea mine

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

Shaft mining

Shaft mining or shaft sinking refers to the method of excavating a vertical or near-vertical tunnel from the top down, where there is initially no access to the bottom....

 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 trapezoid

Trapezoid

In Euclidean geometry, a convex quadrilateral with one pair of parallel sides is referred to as a trapezoid in American English and as a trapezium in English outside North America. A trapezoid with vertices ABCD is denoted...

al 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

Elevator

An elevator is a type of vertical transport equipment that efficiently moves people or goods between floors of a building, vessel or other structures...

 in 90 seconds. The excavated space occupies a volume of 2.9 millions m³ and it is extended on a surface of 78,000 m².

After 1970, the mine becomes a touristic objective, offering exceptional natural conditions as a result of its microclimate rich in aerosols, which proved its well known efficiency in treating the respiratory

Respiratory system

The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles...

 diseases

Respiratory disease

Respiratory disease is a medical term that encompasses pathological conditions affecting the organs and tissues that make gas exchange possible in higher organisms, and includes conditions of the upper respiratory tract, trachea, bronchi, bronchioles, alveoli, pleura and pleural cavity, and the...

. The air-conditioning of the mine is natural, with a constant temperature during the whole year of 12 °C

Celsius

Celsius is a scale and unit of measurement for temperature. It is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death...

, an atmospheric pressure of 730 mmHg

Torr

The torr is a non-SI unit of pressure with the ratio of 760 to 1 standard atmosphere, chosen to be roughly equal to the fluid pressure exerted by a millimetre of mercury, i.e., a pressure of 1 torr is approximately equal to 1 mmHg...

 and a humidity

Humidity

Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

 with an average of 10% lower than the surface average.

One of the chambers is a salt museum named Genesis Hall by its author Iustin Năstase and it hosts the busts in salt of Decebal and Traian. There are also other salt sculptures in the mine, such as the bust

Bust (sculpture)

A bust is a sculpted or cast representation of the upper part of the human figure, depicting a person's head and neck, as well as a variable portion of the chest and shoulders. The piece is normally supported by a plinth. These forms recreate the likeness of an individual...

 of Mihai Eminescu

Mihai Eminescu

Mihai Eminescu was a Romantic poet, novelist and journalist, often regarded as the most famous and influential Romanian poet. Eminescu was an active member of the Junimea literary society and he worked as an editor for the newspaper Timpul , the official newspaper of the Conservative Party...

 or a bas-relief with Mihai Viteazul, works of the local artist, Oana Brezeanu.

Some of the mine chambers were transformed in sport courts where athletes perform their trainings.

The ceiling of the mine is bordered by wooden balconies on the whole perimeter. The balconies are used for the circulation of the authorized personnel during the periodical inspection of the stability of the surfaces from the superior zone of the mine construction. The zones with uncertain stability are delimited at the base of the mine, being closed for the public access.

Mihai mine

Located vertically above the Unirea mine and separated from it by a 40m thick floor, the Mihai level was opened in 1912 and consists of 6 trapezoidal shaped rooms with a 12 m ceiling width, 37 m floor width, 66 m height and a wall inclination angle of 60 degrees.

Mining was carried out on a descending track. Until 1942, when the Unirea mine was opened, 462.332 m3 of rock salt had been excavated. This was the first salt mine in Romania provided with electric lighting.

After 1970, the Mihai mine has been the host of several national and international aeromodelling contests, occasions on which free access of tourists in the mine is also allowed.

Salt dissolution

During the fall of 1994 both levels were severely damaged by the natural phenomenon of salt dissolution

Solvation

Solvation, also sometimes called dissolution, is the process of attraction and association of molecules of a solvent with molecules or ions of a solute...

 due to infiltration

Infiltration (hydrology)

Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. The rate decreases as the soil becomes...

 of ground and pluvial

Pluvial

In geology and climatology, a pluvial was an extended period of abundant rainfall lasting many thousands of years. Pluvial is also applied to the sediments of these periods . The term is especially applied to such periods during the Pleistocene Epoch...

 waters, which flooded the Unirea mine.
The catastrophic aggressiveness of waters flowing down the shaft gradually created huge cavities and the specialists who evaluated the full scope of the disaster decided to close down the mine.
Eugen Scrob, an I.S.P.H. researcher, came up with an idea which was to keep the mine from completely collapsing. He immediately applied a new experimental method, helped by the miners of the Slanic mine. After four years of work, the stream bed

Stream bed

A stream bed is the channel bottom of a stream, river or creek; the physical confine of the normal water flow. The lateral confines or channel margins, during all but flood stage, are known as the stream banks or river banks. In fact, a flood occurs when a stream overflows its banks and flows onto...

 was eventually regulated. Constant drillings monitored the dynamics of landslide and the piezometric

Piezometer

A piezometer is either a device used to measure static liquid pressure in a system by measuring the height to which a column of the liquid rises against gravity, or a device which measures the pressure of groundwater at a specific point...

 level. Also, huge amounts of concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

 were used to line the shaft and fill the existing cavities. All costs of these works, amounting to a total of over 20 billion Romanian lei (ROL; equivalent to 2 million RON), were exclusively borne by the Slănic salt mine.
After the water was evacuated and the hearth of the flooded mine was completely drained, the site was reopened on July 31, 1998.