Baskunchak

BASKUNCHAK (RU: Баскунчак) is the salty self-precipitating lake within the Astrakhan province of the Russian Federation, at the distance of 50 kilometres from the Volga river to the east, near the Baskunchak Bogdo mountain; it is the oldest productive salt deposit within Russia. The length of the lake is 19.2 kilometres, the width is 10.2 kilometres.

Baskunchak is situated within the Caspian lowlands, at the height of 19.5 metres below the level of the sea. The first facts about Baskunchak are contained within the works of I. I. Lepekhin (1768) and P. S. Pallas (1773). During the pre-revolutionary years, there was extracted by the artisanal method 250 thousand tonnes of the edible salt. Since the 1931, the extraction of salt has been mechanized. During the 1980, the extraction of the edible salt has amounted to approximately 5.7 million tonnes, or 25% of its production within the USSR. The industrial reserves of the salt are approximately 415.8 million tonnes.

The basin of the lake is the compensatory depression between the northern and southern domes of the Baskunchak salty uplift. The salty feed is performed on the account of the dissolution of the surface of the salty uplift by the ground waters, which are discharged in the form of the salty water sources at the foot of the Baskunchak Bogdo mountain and at the bottom of the lake.

More than 8 million tonnes of salts (mostly NaCl) arrive into the lake annually with the waters of the underground and surface runoff. There is being developed the salt of the modern age, which is represented by the lenticular deposition with the area of 73 square kilometres. The maximal thickness of the deposition within the centre is 19 metres, it tapers to the shore line; the average thickness is 7 metres. There exist within the structure of the deposition 4 varieties of the salt: the porous "novosadka (new sediment)" (up to 5-6 centimetres), the layered "starosadka (old sediment)" (up to 40 centimetres), the dense "chugunka (cast iron)" (up to 2 metres), and crystalline "granatka (small grenade)" (up to 12 metres). The development is performed with the help of the combined cutting-loading machines, which are mounted onto the four-axle railway platforms. The depth of the extracting trenches is 8 metres, the width is 1.2 metres. The loosened salt with brine is delivered from the trench by the salt pump onto the arc-shaped sieve, where it is partially cleaned of the clay, which is polluting it. After the coarse grinding (up to 7 millimetres), the salt is washed for the second time.