123. 



4.2 About 60% of the salt is produced as brine, natural and artificial. 

 Natural brines, occurring in porous formations, are pumped to the 

 surface and evaporated. Artificial brines are formed by drilling wells 

 into beds of rock salt, pumping in water, which dissolves the salt, and 

 then pumping the resulting solution to the surface. Salt is more eco- 

 nomically produced by this method than by mining. But the process of 

 solution eventually causes cavities to be formed beneath the surface. 

 Where the salt is thick and underlies a large area, the overlying rocks 

 may eventually be left without support and caving follows. 



4.3 Most of the brine brought to the surface is supplied directly to 

 chemical plants in which the sodium chloride is used as a raw material 

 for the manufacture of other sodium compounds and chlorine, useful as 

 reagents. A smaller part of the brine is evaporated to produce refined 

 salt for human consumption and for many industrial applications. 



4.4 About 20% of the salt production is obtained by underground mining 

 of salt deposits. By careful selection of the source bed, salt of great 

 chemical purity is obtained for use in chemical applications. Large 

 amounts of rock salt are also used for highways, for stabilizing the 

 surface, and, in winter, for ice removal. 



4.5 The accompanying Table I gives the salt production of the United 

 States in short tons, according to the form in which it is produced, and 

 by state. Values are also given. The amounts of rock salt and salt in 

 brine produced are estimated but are reasonably accurate approximations 



5. MINING OF ROCK SALT 



5. 1 Rock salt was mined at fourteen localities in the United States in 

 1953. The distribution of these mines by states is as follows: New 

 York, 2; Michigan, 1; Kansas, 3; Louisiana, 4; Texas, 2; Utah, 2. The 

 location of these mines is shown on Figure 1. 



5.2 The principal operating mine in New York is that of the International 

 Salt Company at Retsof , Livingston County. ( lb ' The salt is produced 

 from a bed in the upper part of the Salina formation that has a thickness 

 of 9-10 feet. The mine shaft is 9'x26' and has a depth of 1063 feet from 

 the collar to the bottom of the salt bed. The salt dips approximately 

 1/2° to the south. The capacity is about 4,000 tons in 8 hours. The 

 mine commenced operation in 1923. About 60% of the salt is extracted 

 and 40% left as pillars. Assuming a production of 1,200,000 tons per 



