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

Potter, Michael J.
Kyanite and related materials,   pp. 547-551 ff. PDF (564.9 KB)

Page 547

  547Kyanite and Related Materials 
By Michael J. Potter1 
 Kyanite, andalusite, and sillimanite are anhydrous aluminum silicate minerals
that are alike in both composition and use patterns and have the same chemical
formula, Al203*Si02. Related materials include synthetic mullite, dumortierite,
and topaz, also classified as aluminum silicates, although the last two additionally
contain substantial proportions of boron and fluo rine respectively All of
these kyanite group substances can serve as raw materials for manufacturing
special highperformance refractories in the highalumina category, but there
has been no record in recent years of significant utilization of either dumortierite
or topaz for this purpose in the United States. 
 Although published statistics are not sufficiently complete to be wholly
conclusive, it appears that the United States, India, and the Republic of
South Africa are the leading world producers of kyanite-group minerals. It
can be presumed that the U.S.S.R. and perhaps a few other industrialized
 Kyanite was prodi,iced in the United States in 1977 at three open pit mines,
two in Virginia and one in Georgia. Kyanite Mining Corp. operated the Willis
Mountain mine in Buckingham County, Va., and the Baker Mountain mine in adjoining
Prince Edward County, Va. C-E Minerals, Inc., operated the Graves Mountain
mine in Lincoln County, Ga. 
 Domestic kyanite output in 1977 was slightly higher in tonnage and value
than in 1976. Kyanite production statistics for 1977 (as well as for all
previous years since 1949) are withheld to avoid disclosing company 
also produce significant quantities of these materials. 
 U.S. kyanite production in 1977 was 
slightly higher in tonnage and value than in 
1976. The amount of kyanite-group material 
exported decreased compared with that of 
1976. The tonnage of imported material 
continued to be small. 
 Legislation and Government Programs.— The allowable depletion
for kyanite, established by the Tax Reform Act of 1969 and unchanged through
1977, were 22% for domestic production and 14% for foreign operations. 
 On November 17, 1977, the Federal Government announced the offering of 2,816
tons of kyanite for sale on a sealed-bid basis. On December 5, 1977, 150
to~is of kyanite was sold to one company at a total sales value of $41,250.
The General Services Administration was conducting bid openings for the sale
of the kyanite on the fourth Tuesday of each month. 
proprietary data. 
 Synthetic mullite production showed a slight decrease in both tonnage and
value compared with the 1976 figures, and output was largely of the high-temperature
sintered variety. The four producers of this material were A. P. Green Refractories
Co. at Philadelphia, Pa.; C-E Minerals, Inc., at Americus, Ga.; Harbison-Walker
Refractories Co. at Eufala, Ala.; and Taylor Refractories Division, NL Industries,
Inc., at Greenup, Ky. Electric-furnace-fused mullite was produced by The
Carborundum Co. at Niagara Falls, N.Y. 

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