Output of the United States borate producers reached approximately
1,000,000 tons in 1957, nearly four times the average annual production
of 1941-45. Increasing consumption for long-established uses and
several new ones accounts for the rise; further rise, for new uses such
as high energy fuels, lies ahead. Among known borate deposits, the
largest are at Searles Lake and Kramer, which supply 90 percent of the
world's recorded production. The Kramer ore body, which is very large,
consists of remarkably pure sodium borates in Tertiary lake beds. At
Searles Lake, also large, the borax is produced from brines pumped out
of salt layers which are the residue of a dessicated Pleistocene lake.
Prospecting for borates is now more active than it has been for years.
The best prospecting ground is in the alluvial-covered basins of
western Nevada and particularly southeastern California, in concealed
sections of Tertiary continental sediments. Several playas or salt
flats that resemble Searles Lake were test-drilled for the U. S.
Geological Survey by a contractor but the holes encountered no borates.
Drill holes near Kramer, however, encountered a deposit of colemanite
in lake beds.
