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Bureau of Mines / Minerals yearbook: Metals and minerals 1977
Year 1977, Volume 1 (1977)

Potter, Michael J.
Feldspar, nepheline syenite, and aplite,   pp. 375-381 ff. PDF (789.5 KB)


Page 375

  375Feldspar, Nepheline Syenite, 
and Aplite 
By Michael J. Potter' 
 The quantity of feldspar produced in 1977 (table 1) was slightly lower than
in 1976, and some sharp ups and downs took place during the year With the
severe winter of 1977 transportation mining activities and gas supplies for
customers were severely curtailed Because of these problems there was a temporary
shortage of feldspar later in the year when customers began to catch up.
Costs of electric power, fuel for drying, and equipment were advancing at
the rate of 10% per year or more. Transportation costs of feldspathic products
wei~e also 
steadily advancing. 
 In the latter part of 1977, Indusmin, Ltd., of Canada purchased all shares
of LawsonUnited Feldspar and Mineral Co. in Spruce Pine, N.C. Indusmin produces
nepheline syenite at Nephton, Ontario.2 
 Legislation and Government Programs — According to provisions
of the
Tax Reform Act of 1969, which continued in force throughout 1977, the depletion
rate allowed on feldspar production (both domestic and foreign operations)
was 14%. 
Table 1.—Saljent feldspar statistics 
1973 
1974 
1975 
1976 
1977 
United States: 
 Feidsoar produced1 short tona.. — 
 Value thousands... 
 Exports short tons__ 
 Value thousands..... 
 Importsforconsumption short tons_ 
 Value thousands.._ 
  Consumption, apparent3 short tons.. —world production thousand
short
tona_ — 
791,900 
$12,830 
9,554 
$466 
367 
$26 
782,713 
3,050 
762,723 
$11,396 
18,319 
$662 
92 
$4 
744,496 
3,319 
669,898 
$11,728 
9,543 
$507 
290 
$23 
660,645 r2,895 
739,684 
2$17,531 
6,144 
$352 
93 
$18 
733,633 r2,936 
733,963 
2$17,186 
6,202 
$394 
242 
$8 
728,003 
3,045 
' Includes hand-cobbed feldspar, flotation-concentrate feldspar, and feldspar
in feldspar-silica mixtures. ' Data represent a more refined product and
sre not comparable to previous years. 
3Measured by quantity produced plus imports, minus exports. 
FELDSPAR 
DOMESTIC PRODUCTION 
 The quantity of feldspar in 1977 ready to be put into final form for use
(that is, the total quantity of hand-cobbed feldspar, flotation concentrate
feldspar, and feldspar content of feldspar-silica mixtures) was down slightly
in tonnage and value compared with that of 1976. The values in table 2 for
1976 and 1977 represent a more 
refined product. 
 Feldspar was mined in 10 States with North Carolina in the lead, followed
in descending order by Connecticut, Georgia, California, Oklahoma, South
Dakota, Arizona, Wyoming, Colorado, and Maine. The combined output of the
first four States named amounted to 93% of the U.S. total. 
 Most of the feldspar used in glassmak.ing is ground no finer than 20 mesh,
and 


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