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Bureau of Mines Preprint from Bulletin 675 P L A IN T IF F S EXHIBIT CAM-330 TALC AND PYROPHYLLITE A Chapter from M ineral Facts and Problem s, 1985 Edition UNITED STATES DEPARTMENT OF THE INTERIOR ITA-Abeyta-000386 UNITED STATES DEPARTMENT OF THE INTERIOR William P. Clark, Secretary BUREAU OF MINES Robert C. Horton, Director As the Nation's principal conservation agency, the Department of the Interior has responsibility for most of our nationally owned public lands and natural resources. This includes fostering the wisest use of our land and water resources, protecting our fish and wildlife, preserving the environmental and cultural values of our national parks and historical places, and providing for the enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people. The Department also has a major responsibility for American In dian reservation communities and for people who live in island terrritories under U.S. administration. This publication is preprinted from Bulletin 675. MINERAL FACTS AND PROBLEMS. 1985 edition. The complete volume, when published, may be purchased from the Superintendent of Documents, Washington, D.C. 20402 _______________ ' ____________ ___________________________________ 1 ITA-Abeyta-000387 TALC AND PYROPHYLLITE By Robert A. Clifton1 T h e mineral talc is a soft, hydrous magnesium silicate, 3M g0*4Si02, H j0 . Commercial talcs range from the near theoretical mineral composition to mineral products that have physical properties in common with pure talc but contain very little of the actual mineral. Soapstone is a term used for a massive form of rock containing the mineral talc in quantities ranging from near theoretical to as little as 50%. Ordinary usuage usally restricts the term " soapstone" to im pure massive talcose rock, while the high-puritv massive talc is called steatite. All three talc-containing minerals (talc, soapstone, and steatite) will be termed "talc" here. Wherever possible, pvrophyllite will be treated separately. Pyrophyllite is similar to talc in most of its physical characteristics and has the formula AI20 3 * 4 S i 0 2 * H 2 0 . Production of talc in 1983 was 980,000 tons2 valued at S19 million. Pyrophyllite production was 87,000 tons valued at $1.3 million. Imports of talc and pyrophyllite combined were 44,000 tons. T h e end uses for talc and pyrophyllite are similar but not iden tical. with talc having a wider end-use range including some higher quality filler applications for which pyrophyllite either does not qualify or is used to only a slight extent. Both are used in signifi cant quantities in ceramics. Other significant uses for talc are in paints, roofing materials, paper, and plastics. Other major uses for pyrophyllite are in refractories and insecticides. Pyrophyllite, at least at present, does not share the expected boom of talc as a plastic filler-reinforcer. A technologic change likely to increase future demand for talc significantly is replacement of structural steel parts in vehicles with lighter weight fiber-reinforced plastics to conserve energy. This expected increase was delayed over the past 5 years because of the introduction of smaller automobiles. Talc is an economic filler that enhances the properties, including strength, of the plastic matrix. Supply problems have been mainly local and concerned with the distance between the consuming centers and the talc produc ing areas. Also, supply problems could develop if the export market were to expand rapidly or if there is a great increase in use in plastics. validity ol which is vcryjjucstionable. Tremolite rock, a desirable component of the talc used for ceramics, is an amphibole whose crystal structure demands that is cleave into elongate particles with parallel sides. Consequently, the ground product has been found to contain up to 20% of panicles with an aspect ratio (length to width) of 3:1 or greater. Grinding action cannot manufacture libers. These elongated particles, however, meet the regulatory definition of liber and. consequently, thev havcieironcousrv'bcen called asbestos and have had the negative health effects of asbestos imputed to them. Solid waste problems could develop if heightened demand makes recovery and processing of low-grade deposits desirable. 1 PhviicaJ scientist. D ivisio n o f In d u u n a J M inerals ' T h e q u an titie s used throughout this chapter are short tons uniesa o th e r w iK specified INDUSTRY STRUCTURE Background Soapstone was first used in the United States by the American Indians, who early recognized the ease with which it could be shaped and its heat-retaining qualities and used it for bowls, pots, cooking stoves, and other utensils. These uses furnished the term " potstone," which still is applied to soapstone in some localities. The early European settlers on the North American Continent used heated, cut-soapstone bricks extensively as warning stones in carriages, sleighs, and beds--a practice that survived until re cent times. Beginning between 1870 and 1880, tubs, sinks, hearth stones, mantels, fireless cookers, griddles, firebrick, and various utensils were manufactured from soapstone. The first talc-grinding mill was established at Gouvemeur, NY, about 1880, and the product was used principally for paper filler. From 1880 to 1900, inclusive, the annual output of the talc and soapstone industry of the United States was about 88,000 short tons valued at about $1 million. These figures included manufactured soapstone items. Size and Organization Talc was produced domestically in 1983 from 26 mines in Arkansas, California, Georgia, Montana, New York, North Carolina, Oregon, Texas, Vermont, Virginia, and Washington. Texas, Vermont, Montana, and New York, in order of volume, were the leading States and, with California, accounted for more than 97% production. During 1983, pyrophyllite was mined at five sites in North Carolina. Also, two California mines were in operation, and one U.S. company shipped pyrophyllite from its Canadian mine for processing in Philadephia. The five largest U.S. talc producers jointly provided nearly 75% of the total domestic output. Some of these firms produced talc exclusively. Others were horizontally integrated subsidiaries of diversified organizations. The principal domestic producers of crude talc and pyrophyllite were vertically integrated to some degree in that they operated grinding mills and processed the ground product in plants adjacent to the mines or in separate in stallations more conveniently located with respect to transporta tion and major markets. Part of the mineral from California and Montana was ground in Nebraska, Alabama, and New Jersey, and a substantial quantity of Montana talc was processed in Belgium prior to 1983. D efinitions, Grades, Specifications The mineral talc is a hydrous silicate of magnesium, 3Mg0*4Si02*H20. In commercial talcs, compositions vary widely. Iron-mineral impurities such as magnetite, pyrite, and limonite can be present. These objectionable impurities are removed for most uses to the extent feasible. The talc of highest purity is derived from sedimentary magnesium carbonate rocks; 1 ITA-Abeyta-000388 2 MINERAL FACTS AND PROBLEMS Table 1 --World talc and related mineral production, 1963, and capacity, 1983, 1984, and 1990 (Thousand short tons) North A m erica: U n ite d Slates O th e r TsOtal South A-merica Europe A fric a Asia an<d Oceania W o rld total 'F o re ca st P roauclion 1903 C apacity 1983 1904 1990' 1.066 120 1,109 560 1,735 25 4,047 7 553 1,400 140 1,540 600 1,900 30 4,000 0,870 1,500 170 1,670 700 1,900 70 5,000 9 .3 4 0 1,000 200 2 .0 0 0 000 2,100 100 6.000 11,000 less pure talc comes from ultrabasic igneous rocks (7).3Tremolite, an amphibole, 2 C a 0 , 5Mg0*7Si02, H20, is associated with mctamorphic rocks and occurs as bladed crystals or fibrous aggregates. Pyrophyllite is a hydrous aluminum silicate similar to talc in properties and in most applications, its formula is AlvOt4SiOjH,0. Steatite has been used to designate a grade of talc suitable for making electronic tube insulators. Block steatite talc is a massive form o f talc that can be machined readily and has a uniform low shrinkage in all directions and high electrical resistivity when fired at high temperature. Phosphate-bonded talc, a synthetic product, is equivalent to natural block. Lava is a term frequently used in the trade to designate block talc or the finished products made from block talc. French chalk is a soft, massive variety of talc used for marking cloth. Soapstone refers to all massive gray to bluish or greenish talcose rocks, which with lew exceptions have a slippery feeling and can be carved bv hand. Wonderstone. a massive block pyrophyllite from the Republic of South Africa, is a compact cryptocrystalline pyrophyllite con taining rutile (TiOa) and carbonaceous impurities. It is used as a pressure-transfer medium in the manufacture of synthetic dia mond. It has the ability to maintain structural integrity at the ultrahigh temperatures and pressures required in diamond syn thesis. Like lava, it can be easily machined in the green state to close tolerances, as required to accommodate the diamondsynthesis reaction capsule. It also serves as an electrical insulator during the compaction. Grades ol talc are most frequently identified with the end use. Important properties are softness and smoothness, color, luster, high slip tendency, moisture content, low oil and grease absorp tion. chemical inertness, fusion point, low electrical conductivity, high dielectric strength and high thermal conductivity. Properties required for specific end uses are as follows: Ceramics. --Uniform chemical and physical properties are re quired. Manganese and iron are usually objectionable. For highfrequency insulators, no more than 0.3% CaO, 1 .5% iron oxide, and 4'/c AI>Oi can be tolerated. I'amts. --Impurities that grind to colors other than white are highly objectionable. To yield the desired smooth paint film, at least 98.5To must pass through a 325-mesh screen. Roofing --A low-grade ollcolor and impure talc is acceptable. Insecticides. --Requirements are chemical inertness with respect to toxicants, satisfactory bulk density, and low abrasive characteristics. Ii.ilii i / r i l n u m lx T t in |M rrn ih t`M`s ri-lrr h iiriiiv in (hi* liM nl rrlrrriM i's a i if* i*ml ul i Iiih t l u p t r f Rubber --Many synthetic rubbers use ground talc as fillers in their compounding formulations. Volume changes, amount of filler, and particle size all affect the stress-strain characteristics of the product. Paper.--Requirements include chemical inertness, softness, freedom from grit, satisfactory ink acceptance, brightness, and dispersibility in water. Cosmetic and Pharmaceuticals.--Talc must be grit free, finely sized, chemically pure, and pleasing in color. For cosmetics, talc must have good dry slip characteristics. As mentioned above, both color and puritv are important characteristics of talc. Thev can be partially described by " brightness," which is a measure of reflectance in terms of per cent compared with the rellectance of pure magnesium oxide. The maximum fineness of talc in a given paint is often deter mined by the use of a Hegman gage, which consists of a precision steel block into which a wedge-shaped channel, 0.5-inch wide and up to 0.005-inch deep, has been cut and marked with a linear scale. A drop of paint is placed at the deeper end of the channel and scraped toward the end. Fineness is indicated at the point on the scale at which talc particles are seen to protrude above the paint surface. Hegman number and approximate particle size, respectively, are 8--6 micrometers; 7--13 micrometers; 6 /2--20 micrometers; 6--25 micrometers; 5-- 10 micrometers; 4--50 micrometers; and 3--65 micrometers. RESERVES--RESOURCES Talc deposits exist in every continent and all have similar geology. The geologic settings of these deposits have been sum marized as always occurring as a secondary mineral formed in or from preexisting rocks; low-grade regional metamorphism established the conditions of formation of all deposits of economic interest; commerical ure bodies are molded after the shape of the parent material; and that, as far as genesis studies can determine, all talc formation occurred in the Precambrian era (2). The definitions of reserve and reserve base are published in U.S. Geological Survey Circularv 831. " Principles of a Resource/Reserve Classification for Minerals," which is reprinted in the introduction to Mineral Facts and Problems, 1985 Edition. Although at least 43 countries produced talc and pyrophyllite in 1983. the better commercial deposits were found in Australia, Austria. Brazil, China. Finland, France. India. Italy, Japan, North Korea, the Republic of Korea, the U.S.S.R., and the United States. Preliminary reports indicate that three talc areas in the United Slates and one in China may soon have expanded production and larger reserves. The paper of Chidester et al. published in 1964. remains the printary reference on the geology of U.S. talc deposits (I). U.S. deposits are ol three ma|or types: those associated[with scdimentarv rocks as exemplified by the Cahlomia-Nevada deposits and those in Montana. New York, and Texas; those associated with ultramalic igneous rocks, as the Vermont deposits; and those associated with malic igneous rocks that occur in ihe.Appalai Itian Mountains and arc the source ol most 61 our soapstone. Winkler in 1974 presented the following reaction as the most probable method of forming pure talc deposits: 3 dolomite + 4 quartz + H ;0 " talc + 3 calcite + 3C.O_. ( >). Table .3gives the composition ol minerals olicn found associated with talc deposits. Note that chemical analvses like those reported in table 2 can point out the presence ol specific minerals. The CaO found in both the New York and Georgia talcs, for exam ple. correctly points out tleinoliiii tali Data on domestii reserves ol the talc-group minerals are in complete, but some tentative estimates have been published. In- ITA-Abeyta-000389 TALC AND PYROPHYLLITE 3 Table 2.--Typical chemical analyses of talc ores and products (Percent) Pure talc (T h e o re tic a l) 1 2 3 SlOp MgO* F e ?0 , TiO A ljO j CaO K 20 N a ?0 CO, H ,0 MnO S NiO C fjO j CoO FeO Less 0 for S P.-O, L oss o n iQmtion 63 36 31 96 4 75 35.98 32.95 .65 .02 .43 - 20.45 2-73 41 .06 ,21 1B .01 5.96 05 .01 * 59.15 31-34 3.36 .26 15 1 76 4 30 47 92 26.00 6 82 15 7 35 4 14 . .05 .09 00 7 51 T joui 1 A v e ra g e V erm ont carbonaie ore 2, F lo ta tio n talc. Jo h n so n M in e . V e rm o n t 3 R o o fin g granules, Southern Talc C o . Georgia. 4 S te a tite . Y ellow stone Mine. M ontana. 5 A v e ra g e talc ore. laic T alcville. G ouveneur District. New Y ork. 6 T e x a s talc. > 100 00 100.10 100.32 100.03 4 62.65 30.23 1.51 31 trace 05 15 27 4 07 100.04 Table 3. --Approximate composition of minerals present In talc ores (P ercent) S i0 2 MgO CaO o p F e ,0 , A IjO , K zO 5 59.00 27 45 .05 57 6.80 1.18 .39 ,03 .15 4 75 101 17 H jO 6 54 92 27 20 .46 5 70 10 76 99 10 > * T a lc S e rp e n tin e (antigom e) C h lo rite A nth ro ph yllite T re m o lile A ctm o lite D io p sid e F e ld s p a r . M a g ne site D olo m ite C alcite 63 32 ** . 3- 7 44 43 * * - - 0-13 33 36 - - 18 5-14 50 30 2 57 26 13 - * > 15- 2 2 - - 15- 2.3 52 5 9 34 * 3 56 ta 26 - 65 - 18 17 * - 48 52 * 22 30 48 * * * 56 44 * formation available in the late 1950's pointed to U.S. reserves approximating 90 million tons (4). Further exploration and delineation have increased that estimate to 150 million tons, and recent reports have indicated that approximately enough new ore is beint; delineated to make up lor that being mined. Much larger quantities could certainly be obtained at prices only moderately higher than those of 1983. The largest bodies ol domestic talc ore now known are those fairly pure ones in Montana and the tremolitic talc in New York Slate. It is anticipated that additional talc deposits of major im portance will be found in Montana and other sections ol the United States. Extensive exploration was undertaken recently in Texas anti Vermont. Deposits of talc-group minerals of present, past, or potential commercial importance are known to exist in Alabama. Arkansas, California, Georgia. Maryland, Massachusetts. Michigan. Montana. Nevada. New Hampshire, New Jcrsev. New Mexico. New York. North Carolina, Pennsvkaniu. Rhode Island, Texas, Vermont. Virginia, Washington, and Wisconsin. l'vrophyllite reserves in North Carolina alone are said to total at least 12 million tons. and. although estimates of quantities are not available lor California and Pennsylvania, those States also have commerical deposits. Definite information is limited on talc and pyrophylliie reserves in the rest ol the world. However, deposits are known to be widely distributed, and the aggregate available tonnage is great. Immense Table 4.--World talc and related minerals reserves and reserve base1 (M illion short tons) N orth A m erica: U nited S tates Other T o ta l South A m erica Europe . . A frica Asia and O ceania Reserves Reserve base* . 150 10 160 5 60 5 120 600 40 640 20 190 20 400 W orld total 350 11,300 'In co lla bo ra tion w ith U S. G eological Survey ?T h e re se rve b a se in c lu d e s d e m o n s tra te d re so u rce s tha t are c u rre n tly e co n o m ic (reserves), m arginally econom ic Im arginal reserves), and some ot those that are currently suoeconom ic (subeconom ic resources). 'D a ta do not add to total show n because ol independent rounding deposits of talc-group minerals, enough to meet expanded world demand, are known to exist in a number of regions not presently industrialized. It is estimated that the world's reserves and reserve base of tale and pyropvlliie are at least one-third of a billion tons and 1.3 billion tons, respectively. Much greater reserves would be available at world prices not markedly higher than those of 1983. ITA-Abeyta-000390 4- MINERAL FACTS AND PROBLEMS TECHNOLOGY M osi of domestic talc production comes from open pit mines (2). Nevertheless, underground mines continue to be important sources of these minerals. In both types of operation, the extraor dinary slipperiness of talc ore imposes unusual, but controllable, problems. Mechanized loaders and haulage units must be pro vided v.`ith special slip-reducing tires or chains, and haulage slopes must be- kept to gentle gradients. Cribbing and limbering, when required for underground mining, must be placed with excep tional precision in order to minimize the lateral component of forces acting upon supporting members. Mining operations for the production of mineral that is to be ground before marketing are usually carried out by conventional drilling and blasting methods, but extremely good housekeeping practices must be employed to avoid reducing the brightness of the talc or the inadvertant introduction of more abrasive materials. The ext raction of material lor block or lump purposes, for crayon stock, o r lor dimension stone requires minimum use of explosives. In these- cases, masses as large as 4 by 8 by 10 feet are removed bv h a n d equipment or by sawing. Final reduction to desired shapes and sizes is usually accomplished by the use of gang saws. Technologic advances have freed the United States from dependence upon foreign sources for supplies of block steatite talc suitable for electronic components and other shapes. Synthetic block, meeting all requirements for this purpose and superior to the natural substance in dependable uniformity, can now be manufactured by applying a phosphate-bonding process to higher grades o f platey talc that are abundantly available in the United States. Selective mining and hand sorting are the methods most commonlv used lor improving the quality of the crude talc-group minerals, but froth llotation is being employed increasingly (figure 1). The softness of talc eases certain mining and processing operations. Pit-run talc ore to be treated by flotation or to be pulverized before sale usually first passes through jaw crushers and then receives secondary size reduction in rolls or cone crushers. The following stage ol grinding, down to 100- to 325-mesh sizes, is usually done in roller mills in closed circuit with air separators. Such mills arc sometimes equipped with oil- or gas-fired com bustion chambers to permit simultaneous drying and grinding. High-intensity magnetic separators arc commonly added to the circuit to achieve a product with minimum content of iron. For the more abrasive ores such as tremolitic talc or ceramic-grade pvrophyllite, this grinding stage may be carried out in quartziteor silex-lined pebble mills with quartzite pebbles as the grinding medium. Microgrinding in fluid-energy mills enables talc to compete with alternative materials in the manufacture of paint, paper, plastics, and rubber. An attrition-grinding process, originally developed for the benelieiation of kaolin, has been applied advantageously to talc to yield an ultramicronized product especially suited for cosmetic and pharmac eutical preparations. The Bureau of Mines contributed basic research to this development, and a fourth publication bv Stanczvk and Feld summarized the previous three. PA USES The members of the talc group are among the most versatile ol the inorganic substances available to industrv, and few if any minerals provide wider ranges of application. Talc minerals from different sources may present notable differences in properties, and those ditferences shape the consumption pattern. FLOWSHEET OF A VERMONT TALC MILL Figure I. --Flowsheet ol a Vermont talc mill. T he largest use of talc-group minerals is in the manufacture of ceramics--sagger bodies and other kiln furniture, samtarv ware. Iloor and wall tile, dinnerwarc, glazes, and electrical porcelains. In this application, addition of talc or pvrophyllite to the usual clay-silica-feldspar body mixtures facilitates the tir ing of the ware by allowing lower liring temperatures and quicker tiring schedules. The quality is improved by the prevention of crazing in the glazes and the production of good white-tired bodies to which glazes of high-brilliance attractiveness can be lilted. The ceramic industry used 35% of the ground talc in 1983 and 32% of the pvrophyllite. Much of the talc used by the ceramic industry is a mixture of platey talc and blocky tremolite. The second major use of talc minerals is as filler and/or pig ment of paints. For these purposes, platey varieties of talc have good hiding power, act as pigments in their own right, and serve to entangle and buoy up particles of other pigments, thus help ing to keep them in suspension during prolonged storage. The important properties of talc to the paint industry are color, fineness, oil absorption, and chemical inertness. This is a major use. 18% of tale but a minor one. 1%, for pvrophyllite. For roofing materials--tar paper, asphalt shingles, or roll roofing--the addition of talc provides a surface that is nonstick ing, chemically inert, fire retardant, and weather resistant. The ITA-Abeyta-000391 TALC AND PYROPHYLLITE 5 Table 5 . --End uses for ground talc and pyrophyllite, 1983 (T housand sh o n tons) Use Talc P yropnyllite Total C eram ics C o sm e tics' In s e c tic id e s Paint Paper P la s tic s R efractories R o o tin g Rubber Other* 319 50 S 166 01 57 2 90 20 95 27 346 -- 50 12 17 I 167 -- 01 1 50 23 25 7 105 -- 28 13 108 T o ta l 901 04 905 'in c o m p le t e data S om e co s m e tic talc Known to oe in clu d e d in " O th e r " in c lu d e s a r t sculpture, a sph alt tiller, c ra y o n s , floor tile , fo u n d ry fa c in g s , rice p o lish in g , stucco, and oth e r uses not specified ease of processing and the low cost of roofing granules from crushed talc make them a desirable component for shingles. The roofing industry used 11 % of the talc and 8% ot the pyrphyllite in 1983. Fourth in order among outlets for domestic talc minerals is uses for coating and/or loading ol high-quality papers. In this applica tion. high-purity talc helps in obtaining a product with the desired weight and opacity, good ink retention, and superior surface tex ture. A total of 6% of talc consumption goes to the paper industry'. Talc's ability to be preferentially wetted by oily materials in the presence of water makes it a very effective "pitch control" agent in paper manufacturing. Pitch is the residual gum with the cellulose fibers that inhibits good ink acceptance during printing. The plastics industry, with needs for both reinforcement materials and economic fillers, has recognized talc as both and is now fifth among the users of talc minerals. It uses 6% of the ground talc and 1l,c of the pyrophyllite. Talc can be used as a filler and/or reinforcer in either thermosetting or thermoplastic resins. It improves chemical and heat resistance, dimensional stability, stillness, hardness, thermal conductivity, tensile strength, creep resistance, and electrical insulation. Talc also aids in proc essability, compared with other fillers. For cosmetic and pharmaceutical uses, talcs must be selected to meet the highest standards of purity, soilness, pleasant feel, color, chemical stability, and must be free from grit, irritants, or bacterial contamination. The characteristics ot talc that make it useful to the rubber in dustry arc its retention of slipperincss. even at elevated temperatures, that makes it an inexpensive mold release agent and prevents adjacent rubber pieces trom sticking to each other, and its economy as a filler in which application it also provides internal lubrication. The rubber industry used 3% of the talc in 1983. Use of minerals of the talc group as carriers and/or diluents for insecticides accounts for the eighth largest traction. Talc minerals are especially useful for this purpose because their chemical inertness makes them compatible with a variety of toxic substances while their physical characteristics facilitate the disper sion and increase the elfertiveness of those agents. This use ac counts for 14% of pyrophyllite consumption, but is a relatively minor one for talc. Use ol talc minerals in refractories has much the same rationale as their use in ceramics. This is a major outlet, 27%, lor pyrophyllite. The remaining talc uses in the United States are distributed over an extensive range of minor applications as diverse as in corporation in agents for chemical warfare, Hour waxes, and shoe polishes--anti include uses such as peanut polishing and salami dusting. SUPPLY-DEMAND RELATIONSHIPS Approximately 96 % of the U.S. supply of talc minerals comes from domestic mines and the remainder is imported. Because pro ducers' stocks are minimal, production follows demand fairly closely. Demand has been quite stable over the past decade, as indicated in table 6. despite minor recessions that occurred dur ing the period. The end-use pattern has also been quite constant, except for the introduction of its use in plastics, an increase in its use in roofing materials, and a decrease in its use in insec ticides and refractories. Substitutes Many materials, including clays and calcium carbonate, substitute for talc in it's many filler applications, and in roofing, insecticides, and other uses. However, no economic substitutes are available for many applications that depend on its unique pro perties. These application include ceramics, cosmetics, plastics, and other. BYPRODUCTS AND COPRODUCTS > The only commercially significant byproducts generated in. the course of talc-group mining and milling operations are the chlorite produced in some Western U.S. operations and the sericite pro duced with the pyrophyllite in North Carolina. Talc is a byproduct of other mining in some Scandinavian countries. STRATEGIC CONSIDERATIONS The Government stockpile goal, for steatite block, was only 28 tons in 1984. A Government task force recommended that this material be removed as a stockpile item because advancing technology, particulars' in electronics, makes stockpile un necessary. Domestic resources of talc are adequate for any foreseeable emergency. ECONOMIC FACTORS Values received for both crude and processed talc-group minerals, as reported by producers, have remained fairly stable in constant dollars since 1963 except lor a decrease during most of the 1970's. Historical data are shown in table 8. The bulk of the talc and pyrophyllite of commerce is made up of relatively low-unit-value material unable to bear the charges of long-distance transportation. Exceptional grades such as highpurity talc of pharmaceutical, cosmetic, or even papermaking quality arc significant items of international trade. Imports ol talc and pyrophyllite are minor and do not exert a decisive influence on the industry. Talc imported into the United States by most favored nations was subject, as ofjanuary 1, 1984, to the following rates ol duty: crude and not ground, 0.02* per pound, ground, washed, powdered, or pulverized. 3.8% ad valorem: cut or sawed, or in blanks, crayons, cubes, disks, or other forms, free; other not specifically provided lor, 4.8% ad valorem. Exports, all talc, amounted to 22% of production in 1983. After increasing from 1973, as indicated in table 9, to highs in 1977 through 1981, exports decreased in 1982 and 1983. The decrease in the constant dollar value per ton suggests the expor tation of lesser grades of talc. Most exports have been of crude material. The allowable depiction rates established under the Tax Reform ITA-Abeyta-000392 6 f MINERAL FACTS AND PROBLEMS WORLD PRODUCTION 1______ TALC SUPPLY-DEMAND RELATIONSHIPS-19B3 THOUSAND SHORT TONS UNITED STATES 1 067 BRAZIL 551 CANADA 107 11 ITALY 181 REPUBLIC Of KOREA 661 AUSTRALIA 103 GROUNO OTHER 381 NORTH KOREA 187 E I________.___ I WORLD TOTAL 7 567 E KEY E ESTIMATED SIC STANOARD INDUSTRIAL CLASSIFICATION F i l t r e 2 . -- S upply-de m a nd relationships lor talc, 1983 1 CERAMICS 346 SIC 3753 376 COSMETICS 50 sic INSECTICIDES 17 SIC Z879 PAINT 167 SIC 7851 PAPER 81 SIC 7171 PLASTICS 51 SIC 2871 REFRACTORIES rt > SIC 3787 ROOFING 105 SIC 3292 RUBBER 28 SIC 3094 OTHER 107 U nned States Res! ol w orld T o ta l . D om estic m in e s 1 Im ports .. Industry stocks, Jan. 1 . . T o ta l U S supply D istribu tio n of U S supply: Industry stocks. Dec. 31e Expons Industrial dem and ' C eram ics C osm etics In s e c tic id e s P a in t Paper P la s tic s R efractories R o o tin g . Rubber Other Total dem and Estimated 'C rud a ora m inad in c lu d e d in 'O th e r " Table 6.--Supply-demand relationships, 1973-83 (Thousand short tons) 1973 1.247 4 .7 1 0 1974 1,290 4 ,9 9 4 1975 1976 W O RLD PRODUCTION 965 4,420 1,092 4.714 1977 1.205 4.995 1978 1.384 5.667 1979 1.453 6 .1 2 6 1900 1.240 7.060 1901 1,243 6.612 1982 1,135 6.460 1983 1,066 6.407 5 .9 5 7 6 .2 8 4 5.305 5.B06 6.200 7,051 7 ,5 7 9 0.300 7,955 7,595 7,553 CO M P O N E N TS AND DISTRIBUTION OF U S SUPPLY 1 .2 4 7 1,290 965 1.092 1.290 1,384 1.453 1.240 1,343 1.135 1,066 33 30 23 20 22 19 22 21 27 27 44 . 71 448 521 420 419 370 476 487 428 390 396 1.351 1.760 1,509 1 532 1,731 1,773 1,951 1,740 1.798 1,560 1,506 4-40 521 420 419 370 476 4 67 428 390 396 304 . . . 180 103 158 212 322 267 3 16 275 311 232 218 1 .0 0 4 1.064 931 901 1,039 1.030 1.140 1.045 1,089 932 985 U S DEMAND PATTERN 346 221 185 280 317 274 323 295 387 312 346 40 35 31 37 75 69 74 59 75 45 50 43 47 42 40 47 40 46 39 42 26 17 178 158 141 191 211 193 238 198 207 171 167 80 89 67 60 69 07 105 102 08 79 01 in m (*i 60 120 148 113 111 111 55 50 54 39 50 62 63 45 62 71 41 24 25 60 93 88 95 80 128 132 102 90 104 105 32 25 16 19 52 37 40 30 36 22 28 171 364 315 57 5 9 15 30 12 94 100 1.004 1.064 931 901 1.039 1.030 1,140 1.045 1.089 932 905 ITA-Abeyta-000393 TALC AND PYROPHYLLITE 7 M aterial S te a tite dIo c k a nd lu m p , ' 1 2 5 ,0 0 0 p o u n d s as ol O c io p e r 1. 1984 Table 7.--Talc stockpile status, March 31, 1984 (Short tons) Goal 28 Total in v e n to ry 1.0B1 E xce ss to goal a uth orized lor disposal 886' Sales 1903 Table 8.--Time-price relationships (or talc-group minerals, 1963-83 A verage annual p roducer value, d o lla rs per ton Year 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 197B 1979 1980 1901 1902 1983 Sold by producers' A c tu a l p ric e s Based on constant 1983 dollars 23 20 21 90 23 62 22 67 24 86 25 92 29 38 27 41 27 51 31 10 27 22 30 64 19 20 37 60 47 00 56 32 64 64 66 70 00 92 83.57 93 55 69 02 65 14 68 50 63.70 67 81 67 73 73 01 64 64 61 79 67 07 55 52 57 42 32.91 61 41 72 37 80 74 05 31 80 62 89 43 87 12 93 55 M ine production2 R e p o rte d value 6 85 6 99 735 7 24 7 61 6.95 7 30 7 56 7.36 7 08 7 33 a 75 9 25 9 07 10.86 11 39 13 85 15 68 16 84 10.21 19 01 C o n sta n t 1983 dollars 20.61 20.72 21 32 20 34 20 76 18 16 18 14 17 83 16.53 15.27 14 95 16 40 15.86 14 78 16.72 16.33 10 28 10.95 18 61 18 98 19 01 'Includ e s pom ground ana crude 2C ru d e o n ly Act of 1SM5!) remained at 2'.2% lor domestic block steatite and 14% lor foreign material through 19811. OPERATING FACTORS The 197(5 Mining in the Parks Act, which put a 4-vear moratorium on any further land disturbance by mining at several national parks and monuments, expired in 1980. Talc mining in Death Valley National Monument had been severely limited under this law. Upon Its expiration, congress debated whether to extend the act or to ban all mining in national parks. However, no action was taken by Congress. The mining and processing ot talc and pyropnyllite inevitably causes at least a small degree ol disruption of the environment and existing ecology. However, these operations lake place, for the most pan. in localities well removed Irom ma|or urban con centrations. Landscape disfigurements and land-use conllicts are minor and localized, except in recreation areas. Waste rock from talc mines is relatively small in volume and is immobile and nontoxic. The washing, milling, and Dotation of talc minerals mav generate minor quantities of watercontarninating suspensions, but treatment ol diluents in thickeners and settling ponds is uncomplicated and effective. Recirculation ol plant water is usually easy to accomplish. The mining and milling ol talc and pyrophyllitc ores often give rise to com nitrations ol silic eiius dusts; again, their elicit is usually localized. These dust problems have been resolved at most of the major lacililies by standard procedures. Production of talc is among the leasi energy-intensive mineral operations. It is the silliest ol minerals, somewhat easier to mine than most, and a great deal easier to process than most. both the talc producers .end their customers have been cited Year 1973 1974 1975 1976 1977 1978 1979 1900 1981 1982 1983 Table 9.--U.S. talc exports (Thousand short tons and thousand dollars) Q uantity A c tu a l V a lu e Based on constant 1983 dollars 180 6,610 13,497 183 6,711 12.576 158 6 ,3 3 8 10.865 212 9,034 14,723 322 9 .1 6 6 14,114 267 12.359 17.718 316 15.210 20.073 275 14,963 18,006 311 15.095 16,683 232 12,957 13,500 218 12,916 12,916 Constant dollars per ton 75 69 69 69 44 66 64 66 54 58 59 > by Federal regulating agencies for being in violation of asbestos regulations. This happened because of the imprecision of mineral terminology, which does not distinguish between the fibrous and nonfibrous varieties of several amphiboles, and of monitoring methods that are nonspecific and terms each elongate particle of whatever origin a fiber and, by analogy, asbestos. The resulting publicity and court cases have caused some talc consumers to turn to competing material. The Bureau of Mines has participated in the development of mineralogical definitions and terminology of particulate materials including asbestos (6) and talc and has contributed to two publica tions on the subject in the American Society for Testing and Material (ASTM) (7-S). In 1976, the Bureau of Mines established its Particulate Mineralogy Unit to help clarify the confusion in particulate-mineral terminology, to develop a solid scientific basis lor research into particle-related pollution problems, and to pro vide technical advice and assistance to regulatory bodies. Employment in talc and pvrophyllite mines and preparation plants in 1983 was estimated to be equivalent to the services of 800 full-time workers. Despite the growing trend toward mechanization of all major talc-group production facilities, some operations such as sorting, are still bv hand, and the productivity ratio, in terms of tons per man-year, has not varied markedly in recent years. PROBLEMS JJuring the 1970's, it was noted that the mineral assemblages nl some jale deposits contains naturally fibrous minerals, both the asbestos and nonasbestos varieties, which are reponed as con taminants in certain ores and products. The problem was exacer bated by the lack ol semantic differentiation between some massive amphibole rocks and their asbestos varieties. Tremolile is the only name for both its asbestos and rock forms, which are chemically Identical, and give the same pattern when analyzed by X-ray dif fraction. Even if, as in the case of serpentine rock and chrysotile asbestos, there is a semantic differentiation, most analyses can not find the difference. Figure 3 is an X-ray diffraction pattern ofa typical talc sample (j) taken by Bureau researchers. The peaks identified as serpentine could bv chrysotile asbestos, and others identified as tremolite could be either its rock or asbestos form. ITA-Abeyta-000394 8 MINERAL FACTS AND PROBLEMS DEGREES TWO THETA Figure 3.--X-ray diffraction patterns of talc sample. ASTM is addressing the semantic problem with a new defini tion lor asbestos (6'). This definition is rigorous enough to ex clude those minerals and mineral particles that were never asbestos and describes asbestos as "A term applied to six naturally occuring minerals exploited commercially lor their desirable physical properties, which are in part derived from their asbestiform habit. The six minerals are the serpentine mineral chrvsotile and the amphibole minerals grunerite asbestos (also referred to as amosite), riebeckite asbestos (also referred to as crocidolite), anthophyllite asbestos, tremolite asbestos, and acunolite asbestos. Individual mineral particles, however processed and regardless to their mineral name, are not demostrated to be asbestos if the lcngih-io-width ratio is less than 20 to I." Distance from mine to market and the attendant transporta tion costs seem to be affecting portions of the talc market. High transportation costs can make talc noncompetitive in low cost filler markets. OUTLOOK Demand Demand for talc and pyrophvllite in the United States in 2000 is expected to be between 1.4 and 4.8 million tons, corresponding to an average growth rate of 5.4% per year during the 1983-2000 period. Ceramics and Glass.--The statistical projection of 490,000 tons for ceramic uses in 2000 was obtained by regression analysis with the gross private domestic investment (GPDI) as the explanatory variable. Ceramic products most likely to experience growth rates above that of the GPDI are ceramic items for cookware, other heat-resistant applications including space and aeronautic hardware, and floor and wall tile (hightemperature products), bringing the upper end of the forecast demand range to 950,000 tons for 2000. For some uses, particularly lloor and wall tile, and, to a lesser extent, electronic and other special ceramics, numerous raw materials such as some clays and other in dustrial minerals that can be used almost interchangeably, compete. The effect of the competing material could be significant on the 2000 demand for talc-group ceramic raw materials bring the low end of the forecast range to 450,000 tons in 2000. The wide range of ways in which ceramics have and will likely continue to serve present and anticipated cultural and industrial purposes even more w'idelv supports the forecast that the most probable demand for talc minerals in ceramics applications in 2000 would be 700,000 tons. Cosmetics.--The statistical projection of 170,000 tons was derived from a regression analysis with GPDI as the ex planatory variable. Good correlation was also obtained with the Federal Reserve Board (FRB) index for soap and toiletries. Per capita real income in the United States is expected to increase by 2000, so that spending on luxury and marginally essential items, especially in view of recent vigorous promotion of cosmetics for men, seems likely to increase at a rate exceeding those anticipated elsewhere in the economy. This possibility supplied the rationale for the upper limit of 300,000 tons for this end use by 2000. Consumption of talc in cosmetics, medicinal articles, and allied products may be restrained, at least temporarily, as the consequence of a health-hazard concern related to talc. The lower extreme of the cosmetics demand forecast range for 2000 was set at 100,000 tons to allow for the possible continuation of this influence. By counterbalancing these opposing trends, middle of the range, 200,000 tons, was concluded to be the most probable forecast of 2000 demand for talc minerals in cosmetic preparations. Insecticides.--Use of talc-group minerals as carriers and diluents for insecticides is greatly affected by social and en vironmental considerations and with the number of con sumers. The statistical projection of no market for talc minerals for 2000 was arrived at by correlation with the U.S. population. ITA-Abeyta-000395 TALC AND PYROI'11YI.I.I 1! The need to guard against tun her deterioration of ecologit al balances will pt>ssii>l\ lead to increasing restric tion ol the employment of the pesticide types now current, and cither the development of sharply specific single-species poisons o r the devising ol control methods entirely divorced from to sic substances dispersed incarriers. To allow lor these contingencies, the low forecast demand was set at zero. An optimistic assessment of the possibility of develop ing regu latory procedure that would permit the continued application of formulations at least similar to those now in use was the basis for the selection of 50.000 tons for the hi gh end of the range and 30.000 tons at the probable level ol demand lor talc-group minerals in insecticides in 2000. Paints. --the statistical projection of 260.000 tons of talcgroup m inerals for use in paint in '2000 was obtained from a regression analysis using the FRB production index for paint as an explanatory variable. Because of new formula tions in paint manufacturing that might be expected to in crease the use ol talc-group minerals in paints significantly, a figure of 400.000 tons was chosen as the high end of the forecast range. On the other hand, a number of negative influences might depress the future consumption of talc in paint. Many materials, including certain steels, asbestos-cement products, and porcelain enamel panels, do not need to be painted. Also, the new and Increasingly popular waterbased gloss paints require little or no talc. The lower end of the forecast demand range lor 2000 was estimated to be 200.000 tons. By counterbalancing the additive and detrimental fac tors likely to affect the furture situation of talc-based paints, 300.000 tons was estimated to be the probable for talcgroup minerals In paint manufacturing In 2000. Paper.-- The statistical projection ol 18(1.000 tons of talc lor use in paper in the year 2000 was obtained by correla tion with the FRB total production index. Good correla tion was also obtained with the FRB index of paper and paper products. Use of talc in papermaking has grown rapidly since the mid-1950`s and appears capable ol additional expansion because of greater need for its pitch control properties; therefore, the high sitle of the forecast range for 2000 was established at 300,000 tons. There has been no significant shift toward alternate materials to take the place of talc lor this purpose. With little dropoff in demand expected, 180.000 tons was set as the lower limit of demand. In view ol the steadily increasing involvement of paper in all aspects of present-day life, the ever greater volumes of paper being consumed by duplicating machines and computer printouts, and despite forecasts of a " paperless office." 250.000 tons was estimated to be rhe most prob able forecast of talc demand lor papemakmg in 2000. Plastics.--The amount of talc being use in plastics has long been of minor proportions and carried in " Other." The 8-year data now available show a rapid grow th through 1978 and a dropoff since then. Projection of these data would give a negative growth rate and no market in 2000. However, the continuing need for lighter weight com ponents in vehicles to conserve fuel supports a positive growth. The high end of the demand forecast range is based on a prediction bv Katz and Milewski who expect large uses lor plastic filling (II). Much more probable is an an nual growth rate of 1017, giving a 401).000-ton demand in 201)0.' Rifractnrir\ -- |;; ... mand has dci mwm ,i progressive shill "I - ; : fire clay raw mater i.ii . service under im pm -ih . to mechanical and i Ik mu , Among the materials limiii, manufacture ol relr.n r.....- Use of refractories is indi'-pen-iin. . trum of industrial processes, .hm; : the FRB total production imle\ . was used to obtain the statr-iii ai ......... of talc-group minerals lor ri-lt . -i - 2000. The possible development n | . m mi. stead of pyrometallurgu al ones l.u tin- . vii... u.,n ..i . number of nonlcrrous metals. (xissihle tec nut<e i.v it...- vi*i industry to methods involv ing the direi t n-din lion ii..ii ore, and long-term low growth because o| gieatrr mii.uiis in the steel industry dampen pto'iieitv :! refractory markets. These factor' plus 'inn mi o . n u. - in demand pattern in the U.S. enmoinv . .min n .to. mand for talc-group minerals for relr.n tones n. i.<mu statistical projection, so that 50,ono tons u.n i.im n .i-'tm low forecast. - The bricks, shapes, and mortar composit m u.. ulie. u>. .j\ classified as basic refractories, some ol ulin li i out.no '.m have become increasinglv prominent because ol a luiinii. t of major innovations in metallurgical practice. C.outiuu.i- tion of those technologic changes is likely, suggesting an upper limit of the demand forecast of 130.000 tons in goon. The most probable demand for talc-group minerals tor refractories in 2000 was forecast at 100.000 tons. Ruofinfi.--Demand for talc minerals in this u s e is. I.iseis associated with new construction, but replacement n>"l- ing is independent of this activity. Correlation w i t h d i e gross national product was used to establish the stansiu al projection of 180,000 tons for 2000. Talc minerals in the grades suitable lor use in roofing can be low in unit cost, and, because ol excellent perlnr- mance and general availability, are subject to only limited competition from other materials in this application. I alt - group minerals, at the expanse of alternate substances, arc likely to command a greater share in the roofing materials industry which, because of pent-up demand lor housing, appears due for an extended period of expansion. Because of these consideration, it seemed reasonable to place the upper boundary of the demand at 360.000 tons ol tale- group minerals for roofing use in 2000. Probably the most influential restraints on the use of rooting materials are the mounting costs of real estate, labor, and building materials, all factors favoring the con struction of large apartment houses of the highrise type, in which the roofing area per person is much smaller than in one-family houses. To allow for these contingencies, the statistical projection was used to establish the lower limit of demand in 2000 at 150,000 tons. In view of the scant probability of an early decline in building costs and the strong effect of the trend to multifamily housing needing less roofing per family, 200,000 tons was selected as the most probable forecast lor the utilization of talc minerals in rooting in 2000. Rubber Products.--The statistical projection of 47,000 tons of ttfic minerals for rubber in 2000 resulted from correla tion of talc-group demand with projected gross private domestic investment (GPDI). Although a number of alter native substances compete actively as rubber fillers, the ITA-Abeyta-000396 10 MINERAL FACTS AND PROBLEMS Table 10.--Projection and forecasts for U.S. talc and pyrophyllite demand by end use, 2000 (Thousand short tons) 2000 C ontingency forecast for U nitea States End use1 1983 S ta tis tic a l p ro je c tio n s 2 Low Forecast range H ig h P ro b a b le C eram ics C osm etics In s e c tic id e s Paint . Paper Plastics , R efractories R o o fin g Rubber Other T o ta l ..... ...... 346 50 17 167 81 58 25 105 28 108 985 490* 170 0 260 180 -- 75* 180* 47* - - 450 100 0 200 180 80 50 150 40 100 1,350 950 300 50 400 300 2 ,0 0 0 130 360 60 200 4 ,7 5 0 700 200 30 300 250 400 100 200 50 200 2 ,4 3 0 'G round o n ly ^S ta tistica l p ro jectio n s, provided by the B ra nch of E conom ic A n a lysis, are d erived from regression analysis based on h istorical tim e series data and from forecasts of econ om ic in dicato rs su ch a s GNP and FR8 index A sta tistica l projection of zero in d ica te s that dem and w ill va nish at or before the ye ar 2000, based on Ihe historical relationship P rojection equations w ith a c o e f f ic ie n t of d e te rm in a tio n (R -s q u a re d ) le ss tha n 0 70 are in d ic a te d by an a ste risk f ) . Table 11.--Summary of forecasts of U.S. and rest-of-world talc and pryophyllite demand, 1990-2000 (Thousand shod tons) U nited S ta le s : T o ta l C u m ulative Rest of w o rld : T o ta l , C u m u la live W orld: Total . C um ulalive . .. 1983 984 -- 6 ,5 6 9 -- 7 ,5 5 3 -- Low 2000 Forecast range High 1,500 21,100 13,900 170,000 15,400 191.000 4 ,8 0 0 43.000 16.300 187.000 21,100 230.000 1990 P ro b a b le 2000 1 .4 0 0 8,500 9.200 56,000 10.600 64,500 2.400 28.000 15.000 178.000 17.400 206, QOO Probable average annual 1903-2000 L (percent) 5.4 _ 5.0 -- 5.0 - talc-group minerals will probably continue to command most of their present share of the rubber filler market. The most probable forecast of demand for talc minerals lor the manufacture of rubber goods in 2000 was estimated at 50.000 tons. Other. --Removal of the high growth " Plastics" uses from "O ther'' uses and considering the historic stability of this category even with new markets, the 2000 demand seems unlikely to exceed 200,000 tons, which was taken as the high end of the range for 2000. In a number of the end uses making up the " Other" category, the talc-group minerals are subject to active com petition from other materials such as asbestos, clays, dlatomice, feldspar-silica mixtures, vermiculite, wollastonite, and synthetic products. Other applications may be declining or becoming obsolescent because of changes in construction methods. These contingencies ap peared to justify a low demand of 100.000 tons. Consideration of the diversity of uncommon characteristic possessed by the talc minerals and the possi ble emergence of new applications for these versatile materials were the principal reasons setting demand in other uses at 200.000 tons in 2000. The end-use pattern for the talc minerals in most in dustrialized countries probably conforms in general to that in the United States. Some countries, deficient in high- quality clays suitable for those purposes, use talc-group minerals extensively as fillers for paper, rubber, and other products. In other nations, ceramic applications predominate. In view of the number of countries without abundant competing raw materials, and considering a more rapid growth in underdeveloped countries, the low side of the rest-of-world forecast demand range is not expected to fall below 13.9 million tons in 2000. the figure calculated by relating demand with expected growth rate for gross world product. The estimated high side of the range of talc demand forecast for 2000 is 16.3 million tons, and the restof-world probable demand is 15.0 million tons, correspond ing to a growth rate of about 5.0% per year. Developing countries have growing needs for ceramics, refractories, paints, etc., that produce exaggerated growth rates for talc and other minerals. Summation of domestic and rest-of-world figures in dicates that worldwide demand for talc-group minerals in 2000 will probably be about 17.5 million tons, the result of a growth rate of 5.0% per year during the remainder of this century. Forecasts of U.S. and rest-of-world demand lor talc- group minerals in 1990 and 2000 are summarized in table 11. Projections and forecasts of U.S. demand for talc-group minerals by end use in 2000 arc summarized in table 10. ITA-Abeyta-000397 R e serves . C um ulative d m a n d . 1983-2000 I t \ \ 1 1 I'YIM H'HYUI.ITK Table 12.--Adequacy of U.S. and world talc reserves tThousand shon rons of talc} U nited Stales 150.000 28,000 Rest ol world 200.000 178.000 11 W orld total 350,000 206,000 Adequacy of Supply Rescrvt-s ol laic and pyrophyllitc in the United Slates are at least 160 million tons. The resen e base is much larger, and many limes the quantity ol' the reserves would be available with a moderate advance in prices. Cumulative domestic requirements through 2001) lor talc-group minerals, using the probable demand, will be '28 million tons. To maintain the constant ratio ol domestic production to domestic demand would require a total cumulative output between 1583 and 2000 ol 37 million tons. Domestic reserves stre more than adequate to meet the foreseen requirements. The cumulative demand for talc and prophvllite In the rest of the world, based on the probable demand growth of 5.1)'/c- per year, is 178 million tons, bringing the probable world demand for talc-group minerals through the forecast period to 206 million tons. About 30 countries regularly produce talc or related minerals on a commercial scale, and potential exists tor even more widely distributed production in the future (4). Kstimates based on the scanty evidence currently at hand indicate that the quantities of talc-group minerals potentially obtainable in the rest of the world might total 200 million tons, and that a moderate increased in the offered price could bring perhaps double that tonnage into the market. The entire rcst-ol-world reserve base ol talc minerals that would lie minablc at higher prices is probably dose to 1 billion tons. This, coupled with the known existence ol additional un workable at moderately higher prices and with the high probabil ity of further discoveries of major new deposits, makes it evident that the supply of talc-group minerals during the ,`orcast period is adequate to meet the forecast demand in the rest of the world. Possible Supply-Dem and Changes A straight-line projection to 2000 of domestic production during the past 21 years, shown in table 13. suggests that talc and pyrophylliic produc tion in 2000 might be 2.0 millions tons il this historic trend persists. This compares with 2.6 million tons ob tained by assuming that the 1983 relationship between produc tion and demand prevails in 2000. Denial of access to domestic resources could seriouslv alien future U..S. supply A major resturn e area. Death Y.dlcs National Monument, was under Congressional restrit lions as to further land disturbances, and no increase in production occurred Irotn Table 13.--Comparison of U.S. talc minerals production and demand, 1963-83, 1990, and 2000 (Thousand short Ions) Year 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1970 1979 1900 1981 1982 1903 U .S . demand 794 050 022 830 000 876 941 946 979 942 1.004 1,064 931 901 1,114 1.136 1.020 1.007 937 820 905 US. p ro d u c tio n 804 890 063 095 903 958 1,029 1,020 1.037 1,107 1,247 1,268 965 1,092 1.205 1.325 1,453 1.240 1.343 1,135 1,066 > 1990 2000 e Eshm aied. 1P ro ta r n e fo re c a s t Iro m (a b le 10. *21-year trend projection ' 1,400 *2.400 *2 .0 0 0 *2 .2 0 0 1 ,7 0 0 0 2.5OO I976 to 1980. This moratorium was not renewed in 1980. The moratorium removal had not. in 1984. had a noticeable effect on Death Valiev production. Limitation of access to resources on public recreation or conservation lands could limit the growth rate of ihe talc industry. Operation ol some open pit talc and pyrophyllitc mines may be restricted lv environmental concerns However, some opera tions probable can be continued indefinitely by switching to underground mining, and improved techniques ul landscape rehabilitation will no doubt be applied to minimize the en vironmental problems faced by those unable to be so converted. Technologic advances that would best benefit the talc industryin the next two decades would be those that could bring about improvements in mining machinery and development of better and more cllicient automatic equipment for the benc-liciation and preparation ol the mined product for the market, particularly to reduce- hand sorting. ITA-Abeyta-000398 12 MINERAL FACTS AND PROBLEMS REFERENCES 1. Chidestcr, A.H.. A.E.J. Engel, and L.A. Wright. Tale Resources ol the United States. U S. Geol. Sure Bull. 1167. 1964, 61 PP2. Roe, L.A., and R.H. Olson, Talc, Ch. in Industrial Minerals and Rocks, Am. Inst. Min. Metall. Pet. Eng., 5lh ed.. v.2, 1982, pp. 1275-1301. , 3. Winkler. H.G.F. Petrogencsis ol' Metamorphic Rocks, Springer Verlag, New York, 1974, 320 pp. 4. Engel, A .E.J., and L.A. Wright. Talc and Soapstone. Ch. in Industrial Minerals and Rocks. Am. Inst. Min. Metall. Pet. Eng., 3d ed., 1960, pp. 835-850. 5. Suinczvk, M .H., and I.L. Feld. Ultraline Grinding of Several Industrial Minerals by the Attrition Grinding Process. BuMines Rl 7641, 1972, 25 pp. 6. Campbell, W .J., R.L. Blake, L.L. Brown, E.E. Cather, and J.J. Sjobcrg. Selected Silicate Minerals and Their Asbcstiform Varieties: Mineralogical Definitions and Identiftcation- ,__ Characterization BuMines IC 8751, 1977, 56 pp. "fT" Clilion. R.A. What is Talc? Delinitions for Asbestos and Other Health-Related Silicates, ed. by B. Lcvadie, Am. Soc. Testing and Mater., Philidephia, ASTM STP 834, 1984, pp, 158-174. 8. Ross. M., Kuntzc, R.A., and Clifton, R.A. A Definition for Asbestos. Ch. in Definitions for Asbestos and Other Health-Related Silicates, ed. by B. Lcvadie, Am. Soc. Testing and Mater. Philadelphia, ASTM STP 834, 1984, pp. 139-147. 9 Katz, H.S., an d J.V . Milcwski, Handbook of Fillers and Reinforcements for Plastics. Van Nostrand Rcinhold, New York, 1978, 639 pp. OTHER SOURCES OF INFORMATION Bureau of M ines publications: Talc and Pyrophyllite. Ch. in Minerals Yearbook, annual. Talc and Pyrophyllite. Ch. in Minerals Commodity Summaries, annual. Talc and Pyrophyllite. Reported annually in Mineral Industry Surveys. ITA-Abeyta-000399