BORAX 415 



eastern California and western Xevada, caused tlie abandon- 

 ment of the lake refineries and the erection of new plants, 

 notably near Columbus, Nev.; at Searles niarsli hi th Aniar^osii 

 valley; and at the mouth of Furnace creek hi Death valley, 

 California. Despite the difficulty and great cost of transport- 

 ing the refined product by teams 100 miles to the railroad, the 

 refineries continued in successful operation for several years, 

 until the relatively large increase in the domestic output, to- 

 gether with the increased imports from Italy, so reduced the 

 price that the working of the marsh deposits became no longer 

 profitable and the refineries were closed down. About the 

 year 1890 it was found that the borax crust on many of the 

 marshes had been formed by the leaching of beds of calcium 

 borate (borate of lime) in the Tertiary lake sediments in that 

 region. Owing to the large extent of these bedded deposits, 

 which possessed also the double advantage of containing a 

 purer grade of mineral and of being more easily accessible than 

 the marsh deposits, the borax industr}' as it existed at that 

 time was revolutionized. A mine was started on a bedded 

 deposit of from 6 to 10 feet in thickness at Borate, 12 miles 

 northeast of Daggett, Cal., in San Bernardino county, and a 

 refining plant was erected by the Pacific Coast Borax company. 

 This company was organized in 1888, and at the {present time 

 is the chief producer of borax in the United States, as well as 

 the producer of a large part of the output of boric acid. The 

 ore at Borate consists of colemanite (a calcium borate mineral) 

 in large masses more or less connected by stringers and bands 

 in a bedded deposit of from 5 to 30 feet in thickness, interst rat- 

 ified in lake sedim.ents. The great value of this deposit led to 

 extensive prospectmg in other parts of tlie state, which has 

 resulted in the discoveiy in Death valley of enormous quantities 

 of colemanite reported to exceed greatly m value the deposit 

 at Borate. Both at Borate and in Death valley the deposits 

 are of similar occurrence, being contained in a regular stratum 

 interbedded with semi-indurated sands and clays which com- 

 prise the bulk of the strata. These beds are regarded as of 

 Tertiary age, and are supposed to have been dei)osited from 

 inclosed bodies of water. Large plants for the concentration 

 and refining of the crude ore have been erected in California : 



