Usolie rock salt deposit (western part) is the part of vast Angara-Lena basin. Modern river basins of middle and upper courses of Angara River as well as river heads of Lena and Lower Tunguska are comprised in the deposit.
Lower Cambrian, Jurassic and quaternary deposits represented by Usolie, Belaya, Bulai and Angara measures form Usolie field. Usolie measure is the main object of CDPS Usolie production and represents the rock salt layers, from 11, 5 up to 84, 8 m each. Distance between beddings is 880-1400m.
Development of salt production process is more than 300 years old. So, in 1669 Onisim Mihalev founded salt-works in Eastern part of Siberia. Several owners had been replacing each other by the end of 17 century. Salt-works owners were merchants, princes, and monastery.
At that time cost value of the final product was extremely high, but the capacity of salt works was extremely low. Brine had the low concentration just about 9-12%. It was produced from the first well at a depth of 190 m. Up to 1862 salt production was carried out in 8 chaotically black salt works located. However, workers toil was later accepted as hazardous and “unsuitable’ for health.
Way towards upgrading of complicated and expensive dietary salt production technologies was long and thorny. Specialists were sent to the Eastern Siberia, Usolie deposits in order to find more suitable methods of salt production. In 1875 Ministry of Finance sent L.Pershke,Mining Engineer for acquaintance with state of things at Usolie salt producing plant. He put forward a lot of reasonable suggestions regarding the technology improvement. |It was his idea to resaturate brine in salterns. This method was first applied in 1911. In such case at the end of the process brine concentration increased up to 15-18%.
The first well, with the saturated brine production was drilled in 1924. Its depth was 692 m. However, it was also penetrated through just upper salt level.
Currently brine production is carried out on the Eastern part of Usolie deposit located on the left bank of Angara river close to Usolie Sibirskoye (Irkutsk region). It adjoins Usolie Sibirskoye from the north-west.
Deposit reserves at the present moment are more than 4 billion of salt. Usolie deposit is the largest in Russia.