278 



UNITED STATES MINERAL RESOURCES 



Natural graphite occurs in three geologic environ- 

 ments, and the distinctive qualities of the graphite 

 in each give rise to three categories of commercial 

 deposits. 



1. Veins consisting of 75-100 percent graphite are 



of commercial value, but they are only found 

 in a few places where they cut igneous and 

 metamorphic rocks, commonly of Precambrian 

 age. The graphite is marketed as "lump and 

 chip," "crystalline lump," or "amorphous 

 lump," in various classes depending on particle 

 size and purity. 



2. "Flake graphite" is the commercial designation 



for graphite that occurs as flakes disseminated 

 through layers of metamorphosed carbona- 

 ceous sedimentary rocks. Commercial deposits 

 contain from about 8 to more than 20 percent 

 graphite. The thickness, toughness, density, 

 size, and shape of the flakes vary by the de- 

 posit. 



3. "Amorphous graphite" is a commercial designa- 



tion for any massive, very fine grained graph- 

 ite, most of which comes from thermally meta- 

 morphosed beds of coal. Deposits of commer- 

 cial value generally contain at least 80 percent 

 graphite. 

 Industrial uses of graphite depend upon the char- 

 acteristics of the three natural graphite types. Fine- 

 grained, relatively low cost "amorphous" graphite is 

 used extensively for foundry facings, certain refrac- 

 tories, and as a source of carbon in steelmaking. 

 Flake graphite is prized for high-quality lubricants 

 and for high-quality crucibles and refractory ware. 

 "Amorphous lump," or vein graphite, is also used 

 in lubricants and refractory ware but is especially 

 desired for carbon brushes in electric motors. The 

 uses of the graphite consumed in the United States 

 in 1969 are summarized in table 52. 



The industrial importance of the three types of 

 natural graphite is reflected in the tonnage of U.S. 

 imports shown in table 53. Amorphous graphite, 

 chiefly from Mexico, has averaged about 80-85 per- 

 cent of total imports. Shipments from Madagascar 

 and Ceylon in recent years have been on the order 

 of 4,500 and 2,500 tons, respectively. Although the 

 proportion of Ceylon graphite classified as crystal- 

 line lump and lump and chip (vein type) is not clear, 

 it probably amounts to less than 50 tons per year in 

 recent years. 



The only domestic graphite mine now active, that 

 at Burnet, Tex., produces flake graphite. Deposits 

 of similar material, however, occur in many other 

 places in the United States, chiefly in Alabama, 

 Alaska, New York, Pennsylvania, and other places 



Table 52. — Consumption, by uses, of natural graphite in the 

 United States in 1969 



Value 

 Use Short tons (thousands) 



Batteries (') (^) 



Bearings 104 $51,307 



Brake linings 1,066 368,998 



Carbon brushes 688 285,869 



Crucibles, retorts, stoppers, 



sleeves, and nozzles 4,639 780,793 



Foundry facings 8,028 1,017,221 



Lubricants 2,702 492,316 



Packings 409 182,983 



Paints and polishes 182 27,997 



Pencils 2,190 666,095 



Refractories 5,554 735,419 



Rubber 225 73,054 



Steelmaking 6,624 578,386 



Other" 4,853 1,093,359 



Total 37,164 6,353,797 



* Withheld to avoid disclosing individual company confidential data; in- 

 cluded in "Other." 



2 Includes adhesives, chemical equipment and processes, electronic prod- 

 ucts, gray iron castings, powdered-metal parts, small packages, special- 

 ties, and batteries. Data from U.S. Bur. Mines. 



Table 53. — Tonnage and value of 1969 U.S. imports for con- 

 sumption of natitral graphite, by countries 

 [Data from U.S. Bureau of Mines] 



Total 



Country 



Value 

 Short tons (thousands) 



Austria 20 $2 



Ceylon 3,517 402 



France 16 9 



Germany, West 1,535 246 



Hong Kong 337 8 



Italy 18 8 



Korea, South 618 17 



Malagasy Republic 5,042 507 



Mexico 43,269 876 



Norway 4,037 334 



Sweden 44 4 



Switzerland 6 2 



United Kingdom 20 4 



Total 58,479 2,419 



in Texas. Deposits of vein graphite occur in Mon- 

 tana and New York, and deposits of amorphous 

 graphite occur in Rhode Island, New Mexico, and 

 Colorado. The unproductive deposits are not eco- 

 nomically competitive with foreign sources of natu- 

 ral graphite. 



Natural graphite now faces competition from sjti- 

 thetic graphite, marketed as "artificial graphite." 

 The commercial name is a misnomer insofar as it 

 implies an imitation, because the product is really 

 crystalline graphite produced in high-temperature 

 furnaces from petroleum coke or other forms of 

 amorphous carbon. Synthetic graphite is a product 

 of high purity, but it tends to be finer grained, less 

 dense, and more expensive than most natural flake 

 graphite. Synthetic graphite can be substituted to 

 some degree in all of the uses of natural graphite, 



