Document M4jjXBKw1OK6pKpg4QRQY3px

, P ITTS B U UGH I PLATE GLASS COMPANY GENERAL OFFICES ONE GATEWAY CENTER. PITTSBURGH 22. PA May 16, 1962 Mr. Karl Baumler Vice President Pittsburgh-Corning Corporation 4th Floor j Bear Mr. Baumler: We are pleased to enclose the following items relative to your recent request about asbestos. Toxic Preperties - fraa "Sax" Article on Asbestos - from a book by "Ladov" A quote on "Asbestosis" - from a book by "Patty" A discussion about "Asbestosis" - from a book by "Drinker k Hatch" Hygienic Guide Series on Asbestos Threshold Limit Values for 1961 - as established by the American Conference of Governmental Industrial Hygienists A chart from "Patty" on "Asbestos Warts" We asked the Library to trace down four articles on the subject. If and vhen they arrive. I'll forward them. You vill note that "Patty" quotes from a Dr. Carey P. McCord (M. D.). Dr. McCord is an authority and is retained by our company. Should you have any technical, medical or toxicological questions, we vill be pleased to write him about them. Of course, you know about our membership in the Industrial Hygiene Foundation and its services and advice are at year call. Years, ccarpg PGiSnrX. Ruddick, Manager Safety k Plant Protection 45S6 ASS PHENAMINE 322 resulting anemia i* reponible Description: Light yellow, hygro for the production of many of the scopic powder. symptoms accompanying arsine poisoning; other lymptomi re Formula: CjjHuAsxNjOj-2HC1 2H,0 Constant: sult from the hemolysis itself, Mol. Wt. -475.0 and occur during the excretion of Toxicity: See Arsenic Compounds. the hemoglobin. Hemoglobin and Disaster Control: See Arsenic Com. its degradation products are pounds. commonly found in the urine. Ventilation Control (use moderate Less commonly whole blood may rate): 5ection 2 be passed. Occasionally, the Personnel Protection: Section 3 renal tubules may be plugged by Personal Hygiene: Section 3 debris, with resultant suppression First Aid: Section 1 of urine. Jaundice, which may be Storage and Handling: Section 7 severe, is a common result of the hemolysis. Frequently there is ASBESTOS PARTICLES edema of the lungs, which may be Synonym: Asbestos dust. accompanied by cyanosia. Kidney Toxic Hazard Rating: damage is common in patients Acute Local: Irritant 1; In surviving acute affects of the gas. halation 2 Signs of poisoning usually Acute Systemic: 0 develop within several hours of Chronic Local: Inhalation 3 exposure. Headache, dizziness, Chronic Systemic: U nausea and vomiting, epigastric MAC: ACGIH (accepted); 5 million pain and weakness occur early, particles per cubic foot of air. followed by tea-colored urine, or Toxicology: The essential lesion bloody urine in the more severe produced by asbestos dust is a cases. Some time later, albumen diffuse fibrosis which probably and casts may appear in the urine, begins as a "collar" about the or, in serious cases, there may terminal bronchioles. Usually, be suppression of urine. Jaundice at least 4 to 7 years of exposure and tenderness over the liver may are required before a serious appear about the same time. degree of fibrosis results. There Blood examination shows an ane is apparently less predisposition mia which may be marked. In to tuberculosis than is the case fatal cases, the patient may with silicosis. develop delirium, followed by Clinically, the most striking coma and death. During the acute sign is shortness of breath of stage of poisoning and for some gradually increasing intensity, weeks after, arsenic may be often associated with a dry cough. demonstrated in the urine. See In the early stages physical signs also Arsenic and Arsenic Com are absent or slight; in the later pounds. stages rales may be beard, and Fire Hazard; Moderate, when ex ' in long-standing cases there is 1 posed to flame (Section 6). frequently clubbing of the fingers. Explosion Hazard: Moderate when In early stages of the disease the exposed to flame (Section 7). chest x-ray reveals a ground- Disaster Control: Dangerous; when glass or granular change, chiefly heated to decompositon, if emits in the lower lung fields; as the highly toxic fumes of arsenic; can _ condition progresses the heart react vigorously with oxidizing outline becomes "shaggy" and materials. irregular patches of mottled shad* Ventilation Control (use moderate owing may be seen. Asbestos rate): Section 2 " bodies may be found in the sputum. Storage and Handling: Section 7 At autopsy, the pleurae are thickened and adherent and thick ARS PHENAMINE tubpleural fibrous plaques are 1 Synonym: 3-Diamino-4-dihydroxy1-arsenobenzene hydrochloride. often present. Where the disease is far advanced there are usually Toxic Rating Code: 0 * None 1 Slight 2 * Moderate S - High U * Unknorrn 1 * ~~ ' i ~nmtmum '' pAaPiflr ifr of Zr&ufrd/kt MATtBrALt I .By ifJ.'Tfity/tntA SAX RzttJ^ou &38usji/)jA'Czirt''>l.Y. ,4537 ATROPINE METHYL BROMIDE large area* of fibrosis, with emphysematous change* in the apices and bases. The alveolar walls are thickened, and the characteristic "asbestos bodies" are found. Ventilation Control (use normal rate): Section 2 Personal Hygiene: Section 3 ascaridole ' Description: Liquid. Formula: CjqHhOj Constants: Mol. Wt. 168.2 B. P. U5*C @ 15 mm Density 1.011 @13`/15*C Toxicity: Details unknown. See also Peroxides, Organic. Fire Hazard: Moderate, by spon taneous chemical reaction (Sec tion 6). Caution: An oxidizer. Explosion Hazard: Explodes at 250 *C. Disaster Control: Dangerous; when heated, it emits toxic fumes and may explode, it reacts with re ducing materials. Storage and Handling: Section 7 ASPHALT Synonyms: Bitumen; petroleum pitch. Description: Black or dark brown mass. Constants: B. P.: < 470 *C Flash P. 400+ *F (C. C.) Density 0. 95 - 1. 1 Autoign. Temp. 905 *F Toxic Hazard Rating: Acute Local: Irritant 2 Acute Systemic: U Chronic Local: Irritant 2 Chronic Systemic: U Fire Hazard: Slight, when exposed to heat or flame. Spontaneous Heating: No To Fight Fire: Foam, carbon diox ide, dry chemical or carbon tetrachloride (Section 6). Personnel Protection: Section 3 Personal Hygiene: Section 3 Storage and Handling: Section 7 Shipping Regulations: Section 11. Coast Guard Classification: Hazardous Article. ASPIDILM Synonym: Male fern. Toxic Hazard Rating: Acute Local: Irritant 1; Aller gen 1 Acute Systemic: Ingestion 2 Chronic Local: Allergen 1 Chronic Systemic: U Fire Hazard: Slight; when heated, it emit* acrid fumes (Section 6). Personal Hygiene: Section 3 Storage and Handling: Section 7 ASPIRIN. See Acetol. ATABRINE DIHYDROCHLORIDE. See "Atabrine" Hydrochloride. "ATABRINE" HYDROCHLORIDE Synonym: Quinacrine hydrochloride. Description: Bright yellow crystals. Formula: CUHMC1N,0 2HC1 2HXO Constants: Mol. Wt. 508.9 M. P. Decomposes 248 - 250*C Toxic Hazard Rating: Acute Local: Allergen 1 Acute Systemic: Ingestion 2 Chronic Local: Allergen 1 Chronic Systemic: Ingestion 2 Disaster Control: Dangerous; when heated to decomposition, it emits highly toxic fumes of chlorine.' Personal Hygiene: Section 3 Storage and Handling: Section 7 ATROPINE Synonym: Daturine. Description: Colorless, crystalline alkaloid. Formula: CjfHjjNOj Constants: Mol. Wt. 289.4 M. P. 115. 5'C; sublimes at U8*C Toxic Hazard Rating: Acute Local: Allergen ] Acute Systemic: Ingestion 3; Inhalation 3 Chronic Local: Allergen I Chronic'Systemic: Ingestion 2 Fire Hazard: Slight; on decomposi tion it emits toxic fumes. Ventilation Control (use moderate rate)r Section 2 Personal Hygiene: Section 3 First Aid: Section 1 Storage and Handling: Section 7 ATROPINE METHYL BROMIDE. See Atropine. For detailed discussion of Toxicology, see Section 1 X .,4538 . ASBESTOS Definition.--The term "asbestos," as now used, is not the name of a distinct mineral, but is a commercial term applied to any mineral which can be readily separated into more or less flexible fibers. The original asbestos was a variety of amphibole, of little present importance, but sow there are several important varieties of asbestos, of which ehryaotHe is in most common use. _ Varieties of Asbestos and Their Properties.--ChrytolUt is a fibrous. form of serpentine, with which it is always associated. It is a hydrous magnesium silicate,represented by the empirical formula H*MgjSitO*, and contains 12.9 per cent of water of composition. It occurs in aggregates of fine, crystalline silky fibers, which are flexible and have considerable tensile strength. These fibers usually range in length from less than H to 1 or V/i inches, but fibers as long as 5 to 6 inches are sometimes found and an extreme length of 24 inches has been noted.1 Chrysotile fibers are nearly always brilliant white, but aggregates of fibers may vary from white and pink, through yellowish and yellowish-green to olivegreen. Its Hardness is 3 to 3.5; Specific Gravily 2J2 to 2.3; Luaier subresinous to greasy, pearly and silky. CrodioliU is a soda-iron, monoclinic amphibole, having the formula NaFe (SiOi)i.FeSiO*. It is highly fibrous, like chrysotile, but its fibers have a higher tensile strength, and a much lower resistance to heat. Its color is a characteristic lavender-blue, and it is thus often called "blue asbestos" or "Cape Blue" (from Cape Province, South Africa). Fibers commonly range in length from less than H to 1}{ inches and rarely exceed 3 inches. It has a specific gravity of 3.20 to 3.30 and a silky luster. AnihophyRiU is an anhydrous iron-magnesium silicate, having the formula (Fe,Mg)SiO*. It belongs to the orthorhombic group of theamphiboles. - It occurs in rather coarse, fairly long and usually rather brittle fibers of low tensile strength. It is more resistant to heat and to acids than chrysotile, so that anthophyliite low in iron is especially suitable for making chemical filters. AmosiU is an iron-rich anthophyOite found chiefly in South Africa. It was thought originally to be a new species and was described by Hall1 * Hall, A. Z-, "Asbestos is the Union of South Africa," Memoir No. 12, p. 15, Union of South Africa, Dept, of Mines and Industries, GeoL Survey, 1918. Hsu, A II, work cited, p. 21. 43 i ' \ IJ' u*--i,'t***** '-vV.? T ,u- *** //`O/W MCUiUC ' By- :-.r- , -- AT.ii'i-nn J ' . PuQ.fifi/SAH/.flnL tio4. (\ -44 JiON-METALUC MINERALS u a monoclinic amphiboic. Wherry1 liter examined arnomte both chemically and microscopically and found it practically identical with fcrroanthophyllitc, an orthorhombic amphibole having the formula (Fe, Ca, Hi, Mn)O.SiOi. When amoaite contains considerable aoda it approaches crocidolite in composition. Amosite is characterised,.by a well-developed fibrous structure, -having fibers of unusual length. . Lengths of 4 to 7 inches are common and an extreme length of a little over 11 inches has been observed. The fibers are flexible, but usually have leas tensile strength than chrysotile. Amosite is harder and harsher than chrysotile and is said to cause excessive wear on the teeth of carding machines. It varies in color from' a pale dirty-brown through various shades of gray and pale yellowish-green to nearly white. Acids have little effect on amosite and it withstands heat better than crocidolite. Asbeetoe, "amphibole'' aebeaiat, "hornblende" <uieatoi and "Italian" asbezio* are various terms given to the monoclinic amphibolea, tremolite (formula CaMgifSiOi)*) and actinolite (formula Ca(Mg,Fe)i(SiOi)J when they occur in fine silky fibers. This is the original type of material to which the mineralogical name "asbestos" was given. The fibers may be fine, silky and of great length, but they usually have little tensile strength. A small amount of Italian amphibole asbestos has been used for spinning, but most of it is too weak. When pure tremolite asbestos is chemically stable and may be used for making chemical filters. Mountain leather and mountain cork are, respectively, thin and thick flexible sheets made up of interlocked fibers. The "cork" variety has the elasticity and lightness of cork. It is usually from light-brown to white in color and has a specific gravity of 0.68 to 0.99. One analysis1 of mountain cork showed silica, 57.2Q per cent; peroxide of iron, 4.37 per cent; magnesia, 22.35 per cent; lime, 13.39 per cent; and water, 2.43 per cent; total, 100.24 per cent. These substances have no value as sources of asbestos fibers. Mountain mood is a compact, fibrous substance made up of interlaced mineral fibers and closely resembling dry wood. It is usually gray to brown in color. It is sometimes found in Canadian asbestos deposits, but has no present economic value. Analyses of Asbestos.--The following table shows the average composition of the principal types of asbestos: 1 Tbiut, E. Tn "AiaosiU," Am. MineralofiU, njL 5, No. 12, p. 174, December, 1921. * CixasL, Frits, "Oiryaotile-Ashesto*. It* Occurrence, Exploitation, Mining and Uses," Mine* Branch Bull. 89, p. 21, Can. Dept, of Mines, 1910. - v <: .% M *- . '"it urn .`t.r.vr--; r . Vi. ,4530,; v a . V ASBSSTOS -45 1 334 6 Chryvo- Crociao- Amoeite Antho- Amphi- - tile lit< pbyilite bols SOi........... .................................. I),n,......................... .................. fciOt ud TwOjt XjO .a................................................................. 1................................... jia0............................... ............ BiO (const.)............................... UjsOi........................................... YjQ............... ............................ 40.49 1.27 3.S3 41.41 14. 06 Tbtjl* . 99.78 61.22 34.08 2.48 0.03 7.07 4.60 0.10 99.48 49.58 2.25 39.64 4.79 0.S3 3.18 99.95 67.12 0.75 8.86 39.44 6.47 . 67.72 0.53 3.80 32.81 13.84 0.50 0.61 0.30 99.14 99.11 L Canadian ehryvouic--Average of eleven analyse* by CiaxzL, work cited, p. 3L * 2. South African crocidolite--Analjvu quoted by CiKKcn, work cited, p. 22. X Amoeite, Transvaal, South Africa--Average of seven rather widely varying analyse* quoted by VTrerut, work cited, p. 174. 4. Aothophyllite, Georgia--Analysis quoted in "Asbestos (1813-1019)," p. A, Imperial Mineral Resources Bureau (Great Britain), 1921. 6. Italian amphibole aabcsoa--Analysis quoted by Marcuse, B., "The Marketing of Asbestos," Eng. Mining Javr.-Prat, voL 114, No. 7, p. 27S, Apr. 12, 1922. Tua or Stsoctcm' Most asbestos minerals are found in veins, but some may make up the whole mass of a rock. The veins contain both cross-fiber and slip-fiber asbestos. Cross-fiber asbestos tics perpendicular or nearly perpendicular to the walls of tbs vein. Chrysotiie, crocidolite and amosite occur in this way. Slip-fiber asbestos lies parallel to the wails of the vein. Chrysotiie, tremoiite, actinolite and antho' phyiiite occur in this way. Much slip-fiber chrysotiie is rather harsh. An excess ively harsh slip-fiber chrysotiie is known as Picrolilt. Anthophyllite, tremoiite and actinolite may occur as mass fiber, the minerals forming interlocking bundles Ior radial groups of fibers. Geolooic Occukaxmcx \ s Ch-ytolilt.--Chrysotiie asbestos is found in two entirely distinct geolope associations--in altered peridotite, an igneous rock very low in silica and high in magnesia and iron, and in limestone near its contact with sills or intrusive sheets of basic igneous rock. ' Chrysotiie occurs in peridotite in veins which either form a network in several directions through the rock or less commonly lie parallel. The peridotite near tbs veins is altered to serpentine. Few of the veins are more than aa inch wide. Tbs1 1 This section and the following section on "Geologic Occurrence" are taken from Saureox, Rowans, "Asbestos in 1920," Mintral Ruaxuut of (At United Slotet, pen 2, pp. 312-313, U. S. GeoL Surrey, 1920. , .. V * fi : i f J .I .i -i vJ I' ` i ;j 11 -46 SON-METALLIC MINERALS great deposits of this kind sre those of Quebec sod of the Uni Mountains, regions thst before the World War furnished Dcariy sli the worid's supply of aibertoa. Deposits ire worked in California, Wyoming sad Vermont. Deposits of chrysotile in limestone sre rsther wideiy distributed, but compared ' to those in peridotite they sre small. The fiber may be rsther harsh, but it is very long, unbroken fiber over 6 inches in length end of the finest quality hering been found, whereas fiber over 2 inches m length is very rsrs in the deposits formed in peridotite. Chrysotile occur* with serpentine el or near its eontset with sills of olivine diabase, usually the upper contact. The deposits in Arisons end in the Caroline district of the Trensveat are of this type. Deposits In lime* tone sre found in Arisons, in southwestern Montana, end probably also in New Mexioo. AnLhophyUiit.--Deposits of mass-fiber enthophyilite occur in Georgia, North Carolina end Idaho. The occurrence of aatbophyllite has beea most fully described by Hopkins.' The aatbophyllite in Georgia uf a product of the alter ation of peridotite. The altered rock coaaists almost entirely of aatbophyllite. Hopkins points out that the fiber in the commercially valuable deposits has been greatly softened by weathering, which in this region has been very active. In fact, the snlhophyllite appears to have been made fibrous by weathering, for the fresh snlhophyllite, although it has a good prismatic cleavage, is splintery and of little or no value. Two interesting deposits of slip-fiber anthophyllite in Maryland and Cali fornia have recently been operated. Croddoliu.--The only worked deposits of crocidolite and amosite are in tbs Union of South Africa.* Both occur as cross-fiber veins parallel to the bedding of an iron-rich siliceous argillite locally known as "ironstone.'' According to tha published descriptions, the material of which the vein minerals are oomposed has been derived from the inclosing rocks as a result of regional metamorphism. The deposits oover a wide area over which they occur at the same stratigraphic horison. AclindiL and TrandiL.--Aciinolite and tremolite usually occur in veins as slip fiber, generally in highly magnesian rocks. They appear to have been formed by metamorphic agencies, which have also extensively affected tha country rock. . ,, Geographical Distribution.--The only types of asbestos of any oon- aderable commercial value are those which occur in strong, fine, flexible fibers K inch or more in length, that is, fibers capable of being spun and woven into fabrics or matted into paper and similar products. The longer fibers, that is, those over ^ inch, are by far the most valuable. Flexible fibers shorter than inch are used extensively, but are of such low value that they usually are mined only in conjunction with the longer fibers. * Houma, 0. A Report on (he Asbestos, Tale end Soapstone Deposit of Georgia," Bull. 29, Ga. Cool. Survey, 1914. 1 Hall, A. L., "Asbestos in the Union of South Africa," Memoir No. 12, GeoL Survey, 1918;. "On the Mode of Occurrence and Distribution of Asbestos in the Transvaal," Trans., Cool. Soc. S. Africa, voL 21, pp. 1-34, 19IS. . ./t '. Vrri.-.'SVV. '.Vr ASBSSTOS 47 While deposits of asbestiform minerals arc widely distributed over the world, there arc but few localities in which high-grade spinning fibers are found in important commercial quantities. Before the World War, Canada (Quebec) and Russia furnished most of the world's supply of bigh-gTade asbestos. At present Russian production is small and South Africa (including Rhodesia) is the only other large source besides Canada. The United States has produced some spinning-fiber asbestos (Arizona chryaotile), chiefly during the past 10 years, but most of the domestic pro duction has been of non-spinning anthophyllite. Other countries which are small producers are Australia, Cyprus, Italy, China and India. Canada.1--Canada is the largest producer of asbestos in the world, and Canadian spinning fiber is generally regarded as of the highest grade marketed in important quantities. Ail the asbestos now produced is of the chrysotfie variety. While asbestos occurs in a number of districts in Canada, the only deposits which have been of great commercial importance are located in an area of Cambrian serpentine rocks which extends from northern Vermont * to the Gaspd Peninsula. Within this area in Quebec asbestos occurs in three prominent belts. 1. The Danville-Orford-Bolton area, which extends into Vermont. 2. The Thetford-Black Lake area. 3. The Gaspd Peninsula area. The Danvillc-0rford-BoUon area consists of numerous, apparently dis connected outcrops of serpentine in a narrow belt about 62 miles long. The area is heavily wooded and the rocks are so deeply covered with soil and humus that prospecting and development are difficult. There has been little production from this belt. The Thetford-Black Lake area is the moat important area in Quebec and is, at present, the most productive asbestos district in the world. In this area some of the most productive mines are in Coleraine, Thet ford and Broughton townships. In the main area the total length of the chief serpentine belt is 23 miles and the width varies from 100 to 6,000 feet in the Black Lake area and to miles in Coleraine Township. . The serpentine forms knolls and ridges from a few hundred to a thousand feet in height above the surrounding country. The Broughton and the central and eastern Thctford areas contain mainly slip-fiber deposits. The vein-fiber belt, which includes western Thetford, South Ireland and Korth Coleraine townships, has a developed length of about 12 miles and a maximum width of about 3H miles. The vein-fiber belt produces the highest-grade crude and spinning fiber. * 1 The matt extensive work on Canadian asbestos is that by Ciaxxn, F., work citad, 316 pp. *\ i . M . VLH*. w^r.rm? : * / ! * * h. f \ > *j T rr i i Z ? I 1 -i: r 1 w ''i .-.-i 4 ; Ski* *>* r_ . -48 MOS-METALUC MINERALS The chrysotile veins intersect portions of the serpentine in every direlion, but they usually follow straight lines. The cross-fiber veins vary is thickness from mere threads up to 2 or 3 inches, but the bulk of the asbestos mined is from H to H inch i11 length. The longer fiber is often divided in the middle by & seam of serpentine carrying magnetite or chro mite. Usually, the.asbestos can be easily separated from the rock. Slip fiber occurs along siickensided fault planes and the fiber is arranged parallel to the walls in thin films, or in layers up to inch or more in thickness. The slip-fiber veins yield only mill fiber; it is often of as good grade ns mill fiber prepared from cross-fiber veins, but it is sometimes rather harsh. The Canadian deposits are very extensive*and the known ore reserves are large. Apparently the quality or the percentage of fiber varies little with depth. 'While the long fiber is the most valuable, it occurs in relatively small amounts and the chief production (by tonnagek i of the mill-fiber grades. In the Gaspi Penimula area some asbestos has been found, but diffi culty of access has prevented the region from being adequately explored. A small amount of chrysotile asbestos has been produced at Deioro, near Porcupine, Ontario. The absestos is reported to occur in veins, up to 2inches wide, in serpentine and to constitute as much as 12 per cent of the rock in places. Union of Soulh Africa.'--Important deposits of asbestos occur in several localities in the Union of South Africa. The principal types of asbestos which have been produced are crocidolite and amosite, but chrysotile is also worked and will probably become of increasing importance. Transi'aal possesses important deposits of chrysotile, crocidolite, amosite and tremolite. Amosite is found only in a belt in northeastern Transvaal between Lydenburg and Petersburg. This belt, which is about 60 miles long by an average of 6 miles wide, contains throe groups of interbedded, cross fiber veins, varying in width to a maximum of about 12 inches. Tbeveina are worked by underground mining. -The principal mines are the Egnep and Amosa, situated near the farms Penge and Streatham, which furniah about four-fiftha of the total output. In the Carolina district chrysotile of good quality is mined principally in the Diepgczct and Gocdverwacht areas. High-grade, pure-white chrysotile occurs Sear Kaapsche Hoop about 28 miles northwest of Barberton. Here the percentage of fiber is very high, averaging about -40 per cent fiber and 60 per cent rock. Moreover, over 1 The best work oa the asbestos deposits of the Union of South Africa, is by Bill, A. L., work ciieji, 152 pp. See also Hall, A. 1-, "On the Asbestos Occurresea near Kaap-che Hoop in the Barberton District," Trans. Cool. Sec. S. AJne.o, voL 24, pp. 1&8-1S1, 1021. (Abstract in Eng. Mining Jour.-Prtu, vol 113, No. 13, p. 524 April 1, 1022.) The account here siren a taken largely from Ball's work as abstracted in "Asbestos" (1913-1919), work died, pp. 14-16. I ir-- vi^rr-v v--?;77*rc -- .. * v' .,;. .i. t C- r *.;' . ^ . rV-. ` - ' is -'r i r- - \ . * ; .... . =. - - *-! ^ ' - - f4S34\;. ASBESTOS A9 25 per cent of the fiber is oyer 1 inch long, compared with less than 1.5 per cent in Canada. In Cape Province crocidolite is the only variety of asbestos worked. It occurs in interbedded cross-fiber veins in a belt extending from the farm Lovedalc, 20 miles southeast of Prieska, in a northerly direction as far as Mashowing River in British Bechuanaland, with a possible exten sion into the districts of Vryburg and Mafeking. In Nalal chrysotile of inferior grade occurs somewhat sparingly. Rhodesia.'---Rhodesia is the most important source of asbestos in British South Africa. Both chrysotile and amphibole asbestos occur abundantly in many localities in southern Rhodesia. The largest pro duction comes from the Shabani fields in the Belingwe district and from the Mashaba area in the Victoria district. In both areas chrysotile of excellent quality is found in veins of the cross-fiber type. The Shabani field, so far as it has been explored, is about 6 miles long by 1 mile wide. The fiber varies from H to 2 inches in length. The Mashaba area seems to be smaller and the fiber is rarely over inch in length. The yield of asbestos fiber in the Mashaba area is said to range from 1 to 1.5 per cent of the rock broken, and in the Shabani area from 1.5 to 3 per cent. Asbestos also occurs, and has been prospected to some extent, in the Lomagundi and Bulawayo districts. Russia.'--While Russia before the World War was the second largest producer of asbestos, recent detailed descriptions of Russian deposits are not available. A general description of these deposits was given by DuleP in 1905, from which the following is taken: Russian asbestos is much harsher to the touch than Canadian, and less suit able for spinning, but before the Worid.War the production was large and growing. There are two general districts in which asbestos has been produced. The first, and by far the largest and most important, is in the Perm district of lbs Urals in which there were 25 mines in operation in 1905. The principal mines are SI miles north of Ekaterinburg, where a rone about 13 miles long by 2 to 3 miles wide has been developed, but other localities are known nearly to Orenburg. The other developed district is in the Minusinsk district on the Yenisei River in Siberia, but many other undeveloped deposits are reported in the Altai mountains region and to the southward. Before the war most of the Russian asbestos was exported to Germany. For several years after the Russian revolution no asbestos production was reported, but a small production was noted in 1922. ' See Mzxxzu, F. P., S. AfricaJovr. 7nd.,voL l, p. 1411,191&. Also anonymous articles in 5. Africa Mining Eng. Jour., ip. ed., pp. 82-89, Dcocrober, 1920. Tbs description given here is from "Asbestos " (1913-1919], work cited, pp. 11-12. * Sc* Cixxti, T., work cited, pp. 222-229. * Dili.Ia, J. S-, "Asbestos," Mineral Raourcee of the United Stale.i, part 2, pp. 702-703, U. S. GeoL Survey, 1908. _ `* -- l a*- -j t` ' 60 b'ON-MRTALLJC MISRRALS United Stale*'--Both spinning-fiber chrysotilc and non-spinning anthophyllitc occur in the United States, but the former is not found in large quantities, and production, compared to that of Canada, baa been very small. While deposits of asbestos have been reported in many states, production has resulted from but few deposits. Arizona has been the only important producer of chrysotiie, but a small production has come at various times in the past from Vermont, Wyoming and Cali fornia. Anthophyllile has been produced mainly in Georgia, but Idaho, Maryland and Califoma have also been producers. Arizona.1--Chrysotiie asbestos occurs in'several localities in Arizona, but it is mmed chiefly in two regions: in the Grand Canyon, and in the field 24 to 40 miles in a direct line north and east of Globe. The produc tion in the Grand Canyon district has been small $nd not continuous. The Globe field is about 50 miles in length and 20 mOcs in width in a deeply cut mountainous region along Salt River and covers an area of of about 700 square miles. Most of the mines in the Globe region are in four districts; (1) near Chrysotiie on Ash Creek, about 41 miles from the railroad shipping point; (2) near Salt Bank on Salt River; (3) near the summit of Coon Creek Butte, at the south end of the Sierra Ancha;and (4) near the bead of SJoane Creek, a branch of Canyon Creek. The asbestos, which is of the cross-fiber type, occurs in veins in lime stone chiefly near the upper contact with intruded sheets of diabase. Arizona chrysotiie differs chemically from Canadian chrysotiie in the very small amount of iron oxide which the former contains (Arizona usually 1 per cent or less of FeO and Canada usually 2.5 per cent or more of FeO). A part of the Arizona fiber is very' soft and silky and a part is harsh and splintery. These two phases often occur in the same vein with no visible boundary between, and are hard to distinguish. This necessitates very careful sorting and milling if a high-grade fiber is to be produced. While spinning fiber of good grade and length can be pro duced, users state that the highest grades are so fine and silky that there is a high loss in spinning. Fiber lengths up to 4 inches sometimes occur but lengths leas than inches are most common. Vermont.'--Asbestos deposits occur at four localities near Lowell, in northern "Vermont, connected with the serpentine belt which contains the great asbestos mines of Canada. The asbestos is chrysotiie of both . 1 r. 1 Soe Dfixrs, J. 8., "The Type*, Mode* of Occurrence and Important Depodta of Asbcstoi in the United State*," Bull. 470, pp 05-324, U. 8. GaoL Surrey, 191L Soe also Mineral Ruoureu of Ou VRiled Statu, U.. S. GaoL Survey, annual, for various : year*, particularly aino* 1907. * See Mineral Ruourcu of tke United Statu, U. 8. Gaol. Surrey, part 2, pp. 342-347, 1913; pp. 90-99, 1914; pp. 197-201, 1917; pp. 40-551, 1918; pp. 300-304, 1919; pp. 313-310, 1920; pp. 130-133, 1921. * See Rich xxoaoN, C. IL, Seventh Annual Report, Vermont Cool. Survey, pp. 310-330,1909-1910. ! k.; i ~ V . /f i l :w: ..V ~ . k * *. "si- * i;sv- V. /' ------ .......... .-.6V-V - -i--' . '. i;i .v-'- ^ 1 _,-.vr >'.; '>.*V i. *'. 1 * -; - ;-55S9S. - t'-'a '' . \ . *. - ..-- -^v >;. -r. y*~. - v'Z-"'' *** . ' ` *-*::'.'* * *'`* V-. r ASBSSTOS *1 the cross-fiber and the slip-fiber types, but it is so short that only mill fiber can be produced. Several unsuccessful attempts have been made to work these deposits at various times. Wyoming.--Deposits of cross- and slip-fiber chrysotiic asbestos occur la Wyoming in several localities and fiber has been produced in small quantities at various times in the past. These deposits are .located (1) on Caspar Mountain, 8 miles south of Caspar; (2) on Smith Creek, 20 miles southeast of Caspar; (3) 2S miles south of lander; (4) near Berry Creek in Lincoln County, on the north side of Forellen Peak, 35 miles from the nearest shipping point at Ashton, Idaho. Some of the Wyoming fiber is 1 inch long, but most of it is much shorter and but a very small porportion is of spinning grade. * California.--While asbestos, of both the chrysotile and amphibole varieties, has been found in at least twelve counties in California and a small production obtained from a few properties, no large deposits of highgrade spinning fiber have been developed. Most of the deposits are apparently small or of low grade, and production has been only a few tons a year. Georgia.1--Mass-fiber anthophyllite asbestos has been produced for many years in Georgia. While occurrences have been noted in many counties forming a belt across the northwestern part of the state from Eabun to Harris counties, the most important deposits are in White and Habersham counties. The chief deposits that have been worked are 3 miles southwest of Sail Mountain in White County and near Holly wood in Habersham County. In the best portions of the deposits the whole rock is fibrous and as much as 95 per cent of the rock quarried is recovered as fiber. The rocks of the region in general are deeply weathered and the workings are confined to open cuts or quarries in the weathered rock. At greater depths the rock is harder and less fibroma While the fiber is long, it is so brittle that it is valueless for spinning purposes. It has been used chiefiy for making fireproof paints and cements. Idaho.--Anthophyllite asbestos, similar to that at Sail Mountain, Georgia, occurs about 14 miles southeast of Kamiah, Lewis County/ Idaho. The fiber is short and brittle, and therefore suitable only for low-grade uses. A small tonnage was produced annually for a few yean, and the fiber shipped to Spokane, Washington, where it was used for paints, cements, pipecovering, plaster and other local purposes. Maryland.--Slip-fiber anthophyllite asbestos occurs in the softened . and weathered portions of gneissoid schists a few miles north of Pyle*villc, Hartford County, Maryland. The veins are generally small and the usable portions limited to the disintegrating residual material within 'Sc* Horn**, O. B., "The Aibestoe Tale sod Soapstone Deposits of Georgia," Bud. 2S, pp.'75-189, G*. GooL Surrey, 1914. rgr>?; k.1 T7 i wmm cr* .'-fir- :`v - v- .' ;I *, B2 nqn-metallic minerals 10 feet of the surface. A small annua! tonnage has been produced for several years. The fiber has been cleaned and prepared for filter purpose*. Other Stain.--Small deposits of amphibole asbestos have been reported near Dalton, MassachuseiL; New Hartford, Connecticut; Cumberland, Rhode Island; Pateroa, Washington; Bedford City and Itoclcy Mount, Virginia; Cane River, North Carolina; and Llano, Texas. A small output of low-grade asbestos (variety not noted) was produced in 1915 a few milea north of Mount Vernon, Grant County, Oregon. Chrysotile has been reported on the head waters of East Mile Creek, Montana; and near Great Falls, Virginia. Cyprus.--Large deposits of asbestos occur on the Island of Cyprus and production has been important. Both chrysotile and anthophyllite are found, the former at Amianods, near Troodos in the Limasol district. The best grades come from Paphos. Much of thl material produced is short-fibered, but some is of a grade that may be mixed with Canadian fiber. Italy.--Italy is a small producer of asbestos, most of which is appar ently of the amphibole variety. There are three asbestos districts in Italy: (1) in the Susa Valley near Mount Cenis; (2) in the Aosta Valley, from Ivrea to Chatillon; (3) and in the VallellLna district of Lombardy near Sondrio. Italy docs not produce sufficient spinning fiber for her own needs, but imports chiefly from Canada and Africa. Other Countries.1--Asbestos deposits, of both the chrysotile and amphibole types, are known in many other countries, and from some of them have come small and irregular productions, but none of them are of great present importance. This may be due to small sise of deposits, low grade of fiber or remoteness from transportation and markets. Some of the countries in which deposits of asbestos have been worked or have been reported are: Australia, China, Japan, India, Finland, Switzerland, Greece, Turkey, Portugal, Spain, France, Germany, Norway and Great Britain. Production and Consumption. TForld Production.--The production of asbestos in the principal asbestos-producing countries in the world -is shown in the following table prepared from statistics collected from various official source*. It will be noted from this table that Canada Is by far the largest pro ducer of asbestos. The figures given, however, are somewhat misleading, in that much of the Canadian production is of the lower grades of mill fiber, shingle stock, etc., while.most of the asbestos produced in Rhodesia and in the Union of South Africa is of high-grade spinning fiber. The local consumption Sf asbestos in these latter countries is very small and hence there is little local demand for the lower grades of fiber. These lower grades command too low a price to justify the expense of trsnspor* * S Ciksel, ?,, work cited. pp. 21i-2U. "Asbestos" (1513=-1819), work cited, pp. B-3X .: -- -. ......w. 'm.u. ...n. --u j.u.wm.l'iSme-w--y.g..V...w..j.j..'.t..'..I.'w...t..1!. 1 r._' J . * V%* * * `* vv-'Y *** ' *..* `* .l ... . ... ..`z :s - V S-Li-;: .v. V.*; '* lTrV-`. i . ''ly ' + .+ * yit-W i : r v j m . r - ., rtr'!',ri>mi.mi.j-nr ASBSSTOS 3 "Wojuj'a paonocnov or Aflurat 1913-1921 Metric too* 1913 1914 1911 111ft m? 1911 1919 ins mi ft 149 7ft 0 ft s 7mA4IU>............. 971 2.900 as *4 1ft* anu>>> SaU AJnm.: Stalw..................... >U 443 1,323 i.&M 9,971 7.773 9.929 17.07# lT.n# Cm............ -........... in 1.090 1.940 4.224 1.942 1.322 S.M7 i.iftS 4.*4# Cui^A. . 134.139 I7.&90 100.134 131,050 122.925 121.324 124.070 1S.0M *4.1*1 ftftm............ .......... .. m *43 - 99 123 . 1ft m l.oas 332 1.352 tio m . IldiA- * ....................................... 27ft 171 its 110 142 994 i.m; SSI e 91 90 94 la* 4*0 70 271 t--l......... . XT.494 XI.691 9,779 9.192 1.471 5.ftM C*kW Suta............... 991 1.X31 1.190 1.242 1.77# 905 1.0U !. 7*4 JL^prous*U io4L... 144.043 104.091 lift.100 1*0.479 140.997 144.215 140,342 192.336 113.9Q0 r<v ol jrt ar&iUbift. t tation for long distances. The distribution of Canadian (Quebec) pro duction by grades in 1920 is shown in the following table from Mineral Induitry: PaoDocnoN or Asbestos w the Province or Quebec ros 1920 Shipment* and la De-ignation of trade Ton Value Average value per ton Slock on hand. Dee. 31, 1920 Too* Value Crude No. 1......... Crude No. 2..,.*..*. Spinning fiber............ Shingle fiber............... Paper ftocka mad When...................... 1,026 2,830 13,683 16,784 142,982 S 1,813,457 2,295,927 3,915,562 1,852,210 5,097,416 81,475.10 811.28 280.02 110.36 35.65 446 854 1,929 1,306 18,828 8 659,259 829.438 653,115 172,476 118,060 177,608 814,674,572 8 82.62 23,361 82,432,348 Aabeetie............... 19,716 S 43,559 8 2.20 125 8 374 Total#.............. 197,321 814,718,131 ................. 23,336 82,432,622 Quantity of rock mined during the year, 3,099,122 loos. United Stale*.--The United States is the largest consumer of highgradcasbcstos in the world and the largest manufacturer of asbestos goods. Domestic production, furnishes only s very small proportion of the requirements for crude asbestos. While imports couth chiefly from >i. . n !;: i . j;\ ' I . \ V i; t i;. I,;*-- r i. rrrwTVTwp -'"JT-"1 a? * j - -jt . m1 j, mui'tJ. il\ -.r. ' .'*.** *Y' ;*Vti * ` ; V* -V '? i *` >^r tirK V; 4539 - -W XON-MKTALUC MISSRAL8 Canada, South African and Rhodesian asbestos is being used in important u ; and increasing amounts. The following table published by the U. S. Geological Survey thews the domestic production of asbestos in recent years: Ikrwtrnc Asisstos Maxxxtts r* Tax Ukttxb States, 1913-1221 Chryaoliie Amphiboie Total 4 . Year Short ions Value Short tone Value Short ton* Value 1913 1914 1915 1916 1917 1918 1919 1920 1921 32 316 808* 1,391* 392* 602 1,245 438 < 6.460 66,148 167,683* 279,270* 101,069* 229,366 661,907* 313,268 1,100 1,225 1,415 830 667 606 659 403 393 811,000 13,515 11,304 13,311 11,744 17,628 19,000 16,324 33,701 1,100 1,347 1,731 1,638* 1,963* 998* 1,161 1,648 831 8 11,000 18,965 76,962 180,994* 291,014* 118,687* 348.255 678.331* , 336,968 In recent years most of the domestic chrysotile fiber produced has come from Arizona and most of the amphiboie from Georgia. Imports and exports of crude and manufactured asbestos are shown in the following table: .i _ V\ Uxnxo States Imposts ajtd Exroats or Aaasrros1 In Ions ten* Imports ' Export* Year : Unmanufactured Manu factured Unmanufactured Menu- /_ lectured ' : * Quantity Value Value Quantity Value Value . i! 1912 63,860 81,456,012 8363,759 8 601,701 1913 86,737 1,928,705 389,664 m*# 754,102 1914 64,166 1,407,758 368,344 613,037 1915 83,541 1,981,483 137,330 764,050 1916 103,716 3,303,470 136,064 279 3 6,133 1,209,078 1917 119,739 4,521,173 65,096 632 116,580 1,932,651 1918 122,946 6,337,686 27,476 622 51,053 2,493,325 . 1919 129,777 7,369,685 257,381 999 157,416 3,529,348 1920 149,605 9,120,253 619,054 649 141,071 4,431,132 1921 64,698 2,918,802 379,868 464 101,616 2,606,428 1 Burtau CgtsctU* Cocoma 'v ti /: i~ " _ ; . -V *. - * vvi,.'i _*i * ..-a- v, .. vv*;-.*.* *-i*.- : -W;*. JLSBRSTOS 65 . Creel Britain.--Great Britain produces practically no asbestos, but is the second largest manufacturer of asbestos products. Raw asbestos is imported chiefly from Canada, Rhodesia and South Africa. alining and Mfliiag. Canada.'--Mining meihodt used in the Quebec districts may be divided into three general classes; (1) open pits; (2) *'giory holes" and shrinkage slopes; and (3) combined open and under ground workings. Methods used in mining slip-fiber differ from those used at cross-fiber deposit*, for in the latter type the long fiber ("crude") must be carefully separated from the mill fiber before milling, while in the slip-fiber deposits no such care is necessary and nearly the entire output of the mine is milled. The earliest workings were all of the open-pit type and such operations are still the most cctamon today. The overburden, consisting of clays, sands and gravels, varies from practically nothing to as much as 60 feet. Methods of stripping vary from simple hand methods, where the overburden is light (5 to 10 feet, as at Broughton), to steam-shovel and hydraulic methods for very heavy over burden (up to 60 feet or more, as at the King mine at Tbetford). After the rock is stripped, the pits are carried downward in benches 20 to 75 feet high (average about 40 feet). Drilling is now usually done with compressed-air hammer or piston drills, ranging in sire from light hammer drills to heavy submarine-type drills which will drill 3-inch holes to a depth of 75 feet. After the ore is shot down, it is further reduced in size by block-holing or mud-capping. Slip-fiber rock is then loaded directly into buckets, pans or quarry care by hand or by small steam shovel*. Cross-fiber rock is first carefully sorted and rough-cobbed to remove all the crude grade, and the mill rock is then loaded into pans for hoisting. The crude grade is recobbed, re-sorted, graded and packed in bags for ' shipment. In small pits hoisting may be done by derricks, but in large operation* very large cableway systems are used. At one mine narrow-gage can are hoisted through an inclined tunnel to mill bins or waste-rock dumps. At the surface large bin storage for mill rock is often provided, to facilitate continuous mill operation during the winter months. Where the open pits have become too deep for efficient operation, or .. where the overburden is too heavy to be removed economically, under- ; ground or combination methods are used. In some mines tunnels are . driven under the pits and the ore milled down through raises into can below (glory-hole system). A typical shrinkage-slope method is used by at least one company. Another mine is developed by a three-compart- ment, vertical shaft 515 feet deep. In th?< mine the ore is recovered by - * One of the beet recent articles on aabcrtoa mining and milling in Canada la that ' by BcKxTaza, W. "Aabesto* Mining and Milling in Qucbee;" Eng. Mining Jmr.-Pru*, vcL 113, Not. 15 and 16, pp. 617-625 and 670-677, Apr. 15 and 22, 1922. 3- r : ?/ *. i\ fh 1 -. jj; r I- V i fV t . ..i V .. ' . * - * V 5 ?* % * 4603, ... Vir. -*56 XN0ONN--MMSSTTAALLLL11CC MINERALS glory holes extending to the surface or to the bottoms of old pits. Borne mines are worked partly by ordinary open-pit methods and partly by glory-hole methods. Milling methods, used at the various mills, vary in detail, but they are nearly all identical in principle. The objects of milling are to recover as much of (he fiber aa possible free from dirt and adhering rock and to handle the ore aa gently as possible in order to minimise the reduction of fiber length by attrition. The genera! methods used are: coarse-crushing; dry ing; recruahing in stages, each stage being followed by screening, during < - < ;3 .< which air suction effects the separation of the fiber from the rock gangue; collection of the fiber; cleaning of adhering dust and rock particles by - rescreening; grading; and, finally, bagging for shipment. Primary crushing is usually done in jaw crushers, and drying in direct > or indirect-heat rotary driers. Secondary crushers may be of either the ' / jaw or the gyratory type. The screening at this stage is usually done on >*- long, flat, shaking, screen tables, which serve to remove fine rock waste and ? spread out the ore so that the freed fiber may be removed by suction. The final stages of crushing or grinding are done in special types of pul-. Veriaera, known as "Cyclones" snd "Jumbos," developed in the asbestos industry. RuKeyser,* in describing these machine, states: " The desired effect in the reduction of the asbestos-bearing rock is one of straight impact snd disintegration, permitting the freeing of the fiber and at the same time "fluffing" it. A minimum of grinding or shear action is desired. 1 EcKirsta, W. Ju, work cited, pp. 67i-67S. 'z . n r'* wmwmm.* * -- jmi1 -. r.* .p'- w*r w_ .f)-wr> 0 ^^u.,..i. n...i ^ . t 7 t' . S v*>. V' . ,, * ' ^ '/ . *m * * . ,.>w xij *.V * '.**'.** ? W ?? *' <>' * . *> 7 ' . ' ' > v*^f.v* - ;*7 -r * .* Vi. * *.*; . * . "' * T * - V iii ' `f If- * ' .. 7-- - - * - r'*t J ! V ` >. Vw * * y. ' Vv>.V **' " :4602 '.v .O; > ASBESTOS Z7 The "Cyclone" (see Tig. 2) consists essentially of two cast-steel impellers nipped like ship's screw, weighing approximately 1,000 pound* each and made te revolve *t a high speed (2,000 to 2,200 r.p.m.) in an inclosed chamber lined V *ith manganac-ateel plates to withstand the impaet of the rock hurled against it. If a Icv'cr action is desired, the impellers may be made to revolve in the same .direction, but in the usual practice they are rotated in opposite direction to each \ athcr. It is claimed by many that the "Cyclone" produces a great amount of V -attrition, injuring the fiber; is of low capacity, wasteful of power and neceeei- U!o frequent and oostly repairs. The impellers must often be changed every two days, owing to the high speed at which they are revolved, and must be bal ? anced on their shafts with extreme care. l t 1 K v * -rf. -- r 4 Pro. 3.--Sketch of 'Jumbo." The above considerations led to the development of the "Jumbo," a machine. Letter mechanically, which has for some time replaced the "Cyclone" on the Broughton rock. Within the past two years much experimentation has been done using the "Jumbo" on the harder Thetford and Black Lake rocks, and the machine is finding a great deal of favor with some operators who have discarded Use "Cyclone." The "Jumbo" (see Fig. 3) is really a modification of the ordi nary pulverizer, consisting primarily of a horizontal shaft fitted with a series of arms, these in turn carrying "beaters." The whole is caused to revolve at from tfio to S00 r.p.m. (as the nature of the rock dictates) in s cylindrical casing lined with suitable plates. The rock, fed from above at one end, is made to pass through the machine by a deflection of the beaters, and drops out at the other end. I i -- From the "Jumbos" or "Cyclones" the ore again passes over aseries ' < i of screen tables until the fiber is all removed from the rock by suction. " 'Si The fiber is collected in conical steel-tank collectors, passed through a \ series of rotary or shaking-table screens, to remove dust and rock particles, li then to graders. Graders are slowly revolving hexagonal or octagonal -T neons, which separate the asbestos into the commercial lengths of fiber. - . ' The products from the grades go to their respective bins from which they are packed, in 100-pound bags, by hand or by semi-mechanical packer*. ii- i. 4' r k it - f. i ? I jI c l > v:J`- ./>. * . .* V^1'- .a -*' J* .- -o ""-JrVU* ..iki r. . ' - yri .-1*: -T- a */ ASBSSTOS -50 The accompanying flow sheets (Figs. 4 and 5) after RuKeyser *ie said to be typical, one of cross-fiber milling st Thetford and the ether of slip-fiber practice at Broughton. An approximate estimate of the proportions of the various grades of fiber produced at a modern Canadian mine and mill as noted by Dustin1 Bln C1000 Tee) 1 A : i iti ? ? t i \ <r< i': I % \ t i;.\ 1 3'/ 1 . ii: > t,ii' J t min ; .. ,- 'fi * ,,W - ri '3 : ,;; is given below. The figures given are not averages and individual mills probably show considerable variations from these estimates; for example, the percentages of mill fiber shown are higher than recent averages for all operations in Quebec. 1 DcttxS, B., "Qwceruland Govt Mining Jovrnn p. 372, Sept. IS, 1S2Q. ^1 vn j>v 7-- * r\** / . .'*-5 ?? T.-.i s * v -.4605 . 1 .4 ) : i: l -60 NON-UZTA.LL1C UINBRALS Aaumx Mlkx xtra Mru, Pxodcct* I ' ;* il ; ;> !i 3 !! i/ Unmanufactured jrade* and their appronmate percentage* (a mine end mill nek ?*occrs kn Win Omtit Kia r fii Cswr From the rocit mined: Crude oibeeto* Grade I (om 1 inch)*...................... -........... ............................. 0 to 0.3 Grade II (average % inch)*....................... .......................... .. 0.3 to 0.9 Milling rook....................... 30 to 00 Mine waste....................................................................................... 40 to 70 From the rock milled: ,, Mill itoek............................................................................................ 6 to 12 Mill fiber, No. 1 (average H inch)*.......................................... 0.5 to 3 Mill fiber, No. 2 (average H inch)*......... J....................... 1.5 to 4.5 Paper itoek (average > iaeh)*......................... J............ 4.0 to 3.0 MHl iraate (or)............................................................... S3 to 94 Aebestic powder and nod*............. 44 to 00 . (and) Mil! warte.............................................. 34 to 44 r< 1 - !(* Contents of total aabeetoe: III Crude aabcsto* (grade* Noe. 1 and 2)..._........................... .. 3.0 to 3.0 - Mill dock: Mill fiben, No*. I and 2................ '................................................ 20 to 40 Paper ftoek........................................................................................... 00 to 80 ii :i % :- i . .j Total mine and mill product from nek: Total aabestoa (all grades except aabeetic)................................. 3.6 to 7.4 Crude asbestoa (grade* Not. I and 2)........................................... 0.3 to 0.9 Mill dock (fiben Noe. 1 and 2)*.................................................... 1.5 to 2.9 Paper itoek (mill fiber No. 3P................................................... 1.8 to 3.6 Asbeatic (powder and sand)*............................'.......................... 20 to 30 Total waste rock (mineand mill)............. 67 to 97 # Spinning qoallly rwioi froa U u* t 1m^. * Quality tuiUbl* for mtnufteUkrt of pp*t. ibort, bov4. tt *8uittbi fot p&iol, plot. out i United Slaiea.--The chrysotilc asbestos in Arizona is obtained chiefly by underground mining methods, usually by tunneling along the asbestos veins. In 1918, the Ash Creek mine was reported to have about 10,000 feet of underground workings arranged in four levels, of which the longest tunnel reached a point about 600 feet into the mountain. Nearly aD the Arizona asbestos has been marketed as hand-cobbed crude, as no mills have been erected. In California both underground and open-pit methods of mining have been used, but.produciion has been very small. la 1921 two mills were built, adopting the principles and machines used in Quebec. In Vermont, mining has been done by open-cut methods, but there has been no commercial production in recent years. Several mills have t " VVN V k! ' 1 1 I.V-r^A ,, ,4' V/. os ; ASBSSTOS 1 txxn built at various times, the latest completed in 1922, following the methods used in Canadian slip-fiber mills. South A/nlca and Rhoderia.--In the various sections of the Union and of Rhodesia both open-pit and underground mining methods are - used. Often the open-pit workings are small and irregular, but in the larger and deeper underground mines more systematic methods are used. For example, in the southern sections of the crocidoiitc area of Cape Province a system of overhand atoping ia used without timber. The ore is roughly hand-cobbed underground and the waste is allowed to accumu late in the workings, so as to keep the floor within working distance of the roof. Milling methods have usually been very simple in the past. In most the ore has been hand-cobbed, screened in hand sieves or simple mechanical screens, graded and bagged. At some of the operations in Rhodesia more elaborate methods of preparation are reported to be in use, but no descriptions are available. Specifications, Grades and Tests.--Since, for most important com mercial uses, strong, flexible fiber is needed, the brittle anthophyllite type of asbestos needs little mention here. The chief exception ia that of filter- fiber asbestos. For this purpose a fairly strong fiber is needed and the asbestos must be of such chemical composition that it is practically unaffected by common acids and alkalies. Tremolite ia often used for this purpose. Some of the physical properties which good asbestos fibers must possess for various uses are as follows: good fiber length, good flexibility, .. fine fibers, silkiness, high tensile strength, resistance to acids and alkalies, resistance to sea water and moist air, high melting point, resistance to heat, high heat-insulating value, high electrical-insulating value, good *'spiusability" (that is, capable of being easily spun into products of good quality without undue loss and breakage of fiber). There are now so many and such diversified uses for asbestos that not all of these properties are necessary for any single use. Thus, short fibers may be used for ' asbestos-paper and asbestos-cement shingles, while long fibers are needed for asbestos textiles. For some purposes two or more types of asbestoa with different physical properties (for example, crocidolite and chryaotile) may be mixed advantageously. ,: A comparison of some of the physical properties of crocidolite, chryso- . tDe and amosite ia given ia the following table: - -v.. fe- t. I I * lr--. |l'' !i! *>( mr .T vV'-y-.v-i ;\ .-SJ, ::V--.v `S ^ ; F-c* w. 4'* Via. u. *> -. . -vi.-r-'.*.-ir-.T:-. c - 1^1- * \ i ,r I * Ifc !!i !'n 1* u IH 2 #OX*MS?ALLJC MIHSXAL3 Cokukson or Paorsartx* or Cmtsotil*, Ciocoourt aib Ahomtx1 Qarr*o*iU Crraijl|U JjiHl TTbor ro&fth Casa*! maria**)....... *....... . iHulbu. IHwi UW arii joauii Ki*i \wy 1m 7ias &M4UAM U ........................ ................... RcauUftoo* U tad*. 4ad mm. ... T%1M............................................ Goad, Wat W- n brnUa Tarn T*ir W garni O--d a dM Ooad Goad Good far >1 md nU Wo4& gitslimt Tab M Good. Wt W ion brtUM (M Owrf t Tlx properUa mo<-ad 4-bor^ apply t* bait tnd W Mft I7p*> AalbcrfiUm. add Sxu. vara Tor spinning purposes, Canadian chrysotile is considered the best in the world. Arizona chrysotile is good, but is apt to be lacking in uni formity and to contain harsh, brittle fibers. Some users state that the fiber is so fine and silky that there are large losses in spinning. Crocido lite is not in high favor in the United States, because it is rather difficult to Sberize properly; it is rather dirty and dusty compared with Canadian chrysotile; and its fusion point is low. 'Crocidolite and amosite, usually mixed with some chrysotile, however, are used much more extensively in England and Europe. Amosite fiber is harsher than chrysotile, and is rather dirty and dusty to handle; it has been used but little in the United States. Asbestos is often erroneously called a refractory material, but it can not properly be so classed. Crocidolite fuses at a relatively low tempera ture to & black glass. Both chrysotile and amosite lose their water of composition at a moderate temperature and become inflexible and very brittle. Nor has asbestos alone a high heat-insulating value, compared with such materials as basic magnesium carbonate. Asbestos is non combustible and capable of being woven into fabrics, and these are the properties upon which much of the value of high-grade asbestos depends. The quality of asbestos and ita'suitability for most uses may be easily determined by a few simple testa. Length, color, silkiness, flexibility and, to some extent, fineness of fiber and tensile strength may be deter mined by inspection. A sample of asbestos should be fiberized by rub bing or crushing between the fingers. Single fibers may then be tested for flexibility and tensile strength by bending and breaking. Several fibers may be twisted into a strand or yam and again tested for flexibility and asassros *3 strength. Asbestos of good quality should be easily fiberired, waft, *uky, strong, flexible and easily twisted into a strong yarn. Fibers K inch or more in length and otherwise of good grade are of commercial interest. The grading of asbestos for market varies in different districts and at different plants. In Canada there are two main grades, crude sod fiber, fjr'n of which are divided into subgradea, in each case based on length of fiber. Crude, produced entirely by hand picking and cobbing, consists of all cross-fiber asbestos over % inch long. No. 1 crude consists of fiber over inch long (average 1 inch). No. 2 crude consists of fiber from to M inch long (average % inch). Mill-fiber grades have not been well standardised. They are based on screen tests, but different producers use different classifications. Screen tests are made in a standard testing machine, which consists of four trays, 24 by 14 by 4 inches, fitting one on top of another. The top or No. 1 tray is fitted with a screen bottom of 2 mesh (No. 11 wire); No."2 screen is 4 mesh (No. 17 wire); No. 3 screen is 10 mesh (No. 18 wire); the bottom tray is a solid pan. The nest of screens is fastened to a frame, so arranged that it may be vibrated horisontally with a l)-inch throw, by an eccentric revolving at 300 revolutions per minute. In making a test, 1 pound (16 ounces) of fiber is placed in the top tray and shaken for exactly 2 minutes. The residue on each screen and in the bottom pan is weighed separately and the weight recorded in ounces. Thus, a fiber testing 0-8-6-2 (total 16 ounces) is one of which 8 ounces is retained on the second screen, ounces on the third and 2 ounces of shorts is the pan. While grades made by different Canadian producers vary some what, Marcuse1 states that the following fiber tests may be taken as averages: Long-spinning fiber...................................................,... 2-8--4-2 Medium-spinning sad oompreased-sheet fiber.....'.............0-8-6-2 Pipe-covering fiber*....................................................................0--5--8-3 Shingle stocks....................... Piper sad millboard stocks 0-1K-9X-* 0-0-10-6 Cement stocks...................... 0-0-6-11 Shorts are not sold on length but according to color and cleanliness. Color is of prime importance. Atbtslic is finely ground asbestos sand mill tailings. . 1 Mx*crest, B., "The Marketing of Asbestos," 2ng. Mining Jour.-Pmt, voL 114, No. 7, p. 278, Aug. 12, 1SZ2. vj ajuywy.-o-.rswj.i yV?.>**i\*3. jv.'rvyy'r.t *jw /it.*** -64 XQS-M27ALUC MINERALS Grades of South African and Rhodesian asbestos vary somewhat, but seem to range about as follows: Quaa D C B ,A S X DA DB 1earn or fan Over IH to 2 inch* 1K to 15a or 2 inches K to 15$ inches 5i to )* inches Up to H inch Sftiags Discolored fiber up to inch Discoiored fiber boger than 5* inch Markets' and Prices.--The United States is the largest consumer of asbestos and manufacturer of asbestos products, with the United King dom standing second. Before the war the chief international market ing point was Eamburg, but during and since the war New York has taken the lead. Much of the South African and Rhodesian asbestos is marketed in London. Some of the largest manufacturers of asbestos products own mines in Canada or elsewhere which partly or wholly supply their needs for raw asbestos. Smaller consumers buy either directly from the producers or from dealers and agents. Asbestos crudes and fibers are packed in 100-pound bags and sold at a price (including cost of bags) per 2,000-pound ton, usually f.o.b. car* mines. Crudes bulk about 40 cubic feet per 2,000-pound ton and fibers 60 to 90 cubic feet per ton. Sand and shorts are sold by the net ton and shipped either in bags or in bulk. Most producers have certain brand or grade marks (thus X, XX and C grades), but, while the same marks may be used by different producers, the grades do not necessarily correspond. Most asbestos is sold on sample and test. Prices on all grades of asbestos increased greatly during ana after the war, reaching a peak early in 1921. In 1913, No. 1, crude soid for 5320 to 3350 per ton, and early in 1921 it was quoted at over 53,000 per ton. The average value of all grades of Canadian asbestos sold increased from 526 in 1909 to JS0 fn 1919. After the peak, reached in 1921, prices began to fall rapidly until pre-war levels were nearly reached. In May, 1923, the following prices were quoted in the Engineering and Mining Joumal-Preu: Asbcstot.--Crude No. 1, 5500; No. 2, 5250 to 5325; long-spinning fibers, 5135 to 5200; magnesia and compressed sheet fiber, 5100 to 5150; shingle stock, 565 to 5S5; paper stock, 535 to 542; cement slock, 520 to 525; shorts, 39 to 514-- all per short ton, f.o.b. mines, Quebec, Canada. Utilization.*--The uses for asbestos are so many and so varied that a simple enumeration of all of them cannot be given here. The main * See Marcuse, B., "The Marketing of Asbestos," work cited. *See CiJiin, T., work cited, pp. 2S5-2S9; also anonymous, "Asbestos," Tariff Information Survey N-20, 56 pp., U. S. Tariff Commission, 1921. i 5 a "f; .^r . ?warn1 jjy r fw y - .f*. " \- v* !- # <.-'---V; ^ ~ '' ' ^ f IV`V- ** . ' , "' *..t: . ,1'. ' v J ' .. y. i >. ii- V. . : l` . ; :4C-1Q. ` *' Vi" j ' V- .* jisBssros 65 uses for asbestos fall into a few fairly well-defined groups, namely: (1) asbestos yarns, cordage, cloth and similar textile products; (2) asbestos .paper, compressed sheets, blocks, etc; (3) asbestos-cement product*, auch as asbestos shingles, lumber, corrugated siding, etc.; (4) heatinsulating cements; (5) boiler and pipe coverings (asbestos plus basic magnesium carbonate) and corrugated asbestos paper; (6) as an ingredient in paints and roofing cements (shorts, aabestic, ground anthopbyllitc, etc.); (7) asbestos fibers used as such for filtering, packing, etc. From primary manufactured products, such as asbeatoe yarns, cordage and paper, a multitude of secondary finished products are pro duced, such as automobile brake-band linings, steam packing and pipe coverings. It should be noted that, while very long spinning fiber is essential for some purposes, the bulk of the asbestos marketed is for use in products in which much shorter mill fibers may be used. Brown1 has given a very good summary of the principal uses of asbestos. BIBLIOGRAPHY ( ; The literature dealing with asbestos and asbeatoe product* if extensive and a complete bibliography cannot be given here. The brief bibliography given below contains aome of the more important works, particularly those which have appeared in recent years. Reference* marked thua (*) are the moat detailed and comprehensive, and those marked thus contain bibliographies. Atbcsioe, monthly magazine published by Secretarial Serrioe, 246 North 17th SU, - - Philadelphia, Pa., first issue July, 1919. ' JebaLot, periodical published intermittently by Turner Brothers Asbestos Company, Ltd., Rochdale, England. Auxx, M. A., and Bcn.ru, G. M.: "Asbestos," BufL 113, 31 pp., Arizona Bureau of Mines, University of Arizona, 1921. Bowixs, Ouvrat Chapter on "Asbestos," pp. 388--101, "Political and Commercial Geology," Srcaa, J. E., Editor, McGraw-Hill Book Company, Inc., New York, 1920. V ` Bnowx, J. Coooix: Notes on "Asbestos," Bull. No. 20, 31 pp., Indian Ind. <t Labour, Calcutta, 1922. *Cixkel, Fam: "Chrywtile Asbestos, Its Occurrence, Exploitation, Milling and * - ' Uses," 2nd ed., 316 pp., Mince Branch, Canada Dept, of Mines, 1910. JDilira, J. S.: "The Types, Modes of Occurrence, and Important Deposits of Asbes tos in the United States," Bull. 470, pp. 606-624, U. S. Geol. Survey, 191L Dcxrraji, B-: "Queensland Mineral Deposits, No. 3, Asbestos," Queensland GotL Mining Jour., roL 17, p. 372, 1916. "Ball, A L.: "Asbestos in the Union of South Africa," Memoir No. 12, 152 pp.. Dept, of Mines and Industries, Union of South Africa Gool. Surrey, 1918. Hall, A. L.: '`On the Asbestos Occurrence* near Kaapache Hoop in the Barberton District," Trane. Geol. Soe. S. Africa, vol. 24, pp. 168-181, 1921. Eorxixs, O. B.: "The Asbestos, Talc sod Soapstone Deposits of Georgia," BuIL- 29, pp. 76-189, Ga- Geot. Survey, 1914. \ Horiixs, 0. B.; "Asbestos Deposits of Georgia," Trane. Amer, Inet. Mining Bngn - voL SO, pp. 964-973, 1915. *Baoww, J. Coooix, work cited, pp. 9-12. .. Tv lA *r at svj ! j > yj *r .. r : ^ (' .1 i ii < :l n :'i i: V '1I 6 MON-METALLIC MINERALS Hueiaim, W. D.: "The Black Istke Asbestos Area," Eng. Mining J'w.fToL 112, No. 10, pp. 365-368, Sept. 8, 1921. . Hcaaaim, W. D.: "Milling Asbestos On in Quebec," Mining ScL Prat, pp. 822-836, Dee. 31, 192L Minc-cst, B.: "The Marketing of Asbestos," Eng. Mining fov^Preti, toL 214. No. 7, pp. 277-278, Aug. 12, 1822. Mixmii, G. P.: "The Noo-metallic Minerals," 2nd ad., pp. 183-197, John Wiley A Sons, Ine., Se* York, 1910. RiCXaXosoK, C. H.: "Asbestos in Vermont," SaxnLk Annual Report, pp. 315-330, State Geologist of Vermont, 1909-1910. BcKetsex, W. A.: " Asbestos Mining and Milling io Quebec," Eng. Mining Jena*. Prat, ttjI. 113, No*. 15 and 16, pp- 617-625 and 670-677, Apr. 15 and 22, 1922. Bohmajls, A. L.: "Asbostos and the Aabcatoa Industry," 107 pp., Pitman and Sana, London, do date, probably 1921. TaSEK, Srxra**: "The Geoeaia of Asbertoi and Asbeetiform Minerals," Trau. Amer. Inti. Mining. Eng., ToL 57, pp. 62-98, 1918. Waones. P. A.: "Asbestos," S. African Jovr. Ind., toI. 7, No. 2, pp. 251-270, 1917. Yotrxa, J. B-: "Eo* Asbertoe-prolected Mels! vsi Dereloped Commercially," - CSem. MeL. Eng., toI. 28, No. 6, pp. 244-247, Feb. 7, 1923. Anonymous: "Asbesto* Manufactured Products and Uses," Sou Material, pp. 1OS- 113, March, 1920. (Anonymous: ``Asbertoa" (1913-1919), 34 pp.. Imperial Mineral Resources Bureau (Great Britain), 1921. Anonymous: "Asbestos," Tariff Information' Sumy N-20, 56 ppn V. B. Tariff Commission, 1921. Anonymous: Chapter on "Albertos," Report on Mining Operaiiont in Ou Prorinet gf Quebec, annual, Quebec Dept, of Colonization, Mines and Fisheries, Bureau of Mines, Quebec, Canada. Various author*: Chapter on "Asbestos," Mineral Retowca of Ou United Slaitt, annual since 1899, U. 8. Geol. Surrey. Various authors: Chapter on "Asbestos," Mineral Industry, ""'! McGraw-Hill Book Company, Ioe-, New York. ` -> .ii * '-4 5 V. t * r- f V fh.suif Td-y-f-J., k a: , t a V*: *** '* - ./ ':*/ t* -3-*/,, [. v * ' IA6112 -- . a-JV* y 'r' i. '4 ' .i J 4 3. J OUST IN THZ CAUSATION Of OCCU?AT30NAU DISZAS* -511 of aluminum by physicians for therapeutic or prophylactic purposes, makes only metallic alumiaum available. Some investigators, notably Hannon," have reported marked success in the treatment of patients with severe disability. However, when purely objective criteria have been used to measure disability the results have been aomewh&t less striking. Gardner, Dworski, and Delahant!4 have suggested that variations in response to aluminum therapy may be due in part to the nature of the dust that has caused the silicosis. They suggest that dust which is primarily free silica may react with aluminum more readily than dust which contains high per- * cent&ges of iron. The use of aluminum generally in industry for the therapy or,JL. prophylaxis of silicosis should be contemplated only with the utmost caution. L ASBESTOSIS Asbestos is a hydrated magnesium silicate. More than 90 per cent of the raw mineral used in this country and Great Britian is produced in the Canadian chryso- tile mines. Asbestos is used in two general types of manufacturing processes. It may be used either by itself or mixed with other insulating materials such as diatoma- _ ceous earth for fireproofing, packing, or insulating; or it may be combined with cotton and woven as a textile for fireproof and heat-resistant clothing and other substances. Lanza" estimates that there are about 10,000 persons exposed to asbea- ' tos in the United States. Most observers feel that the incidence of asbestosis in American asbestos workers is quite low. Asbestosis has, however, been reported more frequently in England and Canada. Lanza, McConnell, and Fehnel" concluded from their study of asbestosis that: Prolonged exposure to asbestos dust causes pulmonary fibrosis different from that produced in silicosis and demonstrable by roentgenogram. Clinically it appears to be milder than silicosis. , _ . Definite cardiac enlargement frequently was found to be associated with asbestosis. A predisposition to tuberculosis, due to asbestos dust, was not indicated al though it was not known to what extent asbestosis may add to the mortality freon ' pneumonia and acute nontuberculous pulmonary infections. Sympiomt. The onset of asbestosis, as of silicosis, is alow although symptoms are apt to be somewhat more marked than in silicosis. In silicosis there may be marked x-ray findings with little complaint of symptoms, whereas the opposite is ' likely to be the case in asbestosis. As in silicosis, dyspnea is the cardinal symptom. Anorexia occurs frequently in advanced stages, and cyanosis and dubbing of the fingers are apt to appear with greater constancy in asbestosis. . Paihology- The fibrosis in asbestosis is diffuse and tends to predominate in the basal portions of the lungs in contrast to the generalized nodular fibrosis of silicosis " J. W. G. Eaanoa, Tram. Con. Intt. Mining Met, 4t, 180 (1P44). "L. U. Gardner, M. Dworski, and A B. Dclshsnt, J. Ind. Hyg. Tosicd, St, 211 (1944). "A.J. Lanza, J. Am. Med. Auoc, iBf, 26S (1936). . "A. J. Lanza, W. J. McConnell, and J. W. Fthnel, VS. Pub. Health tfcpli, St, 1 (IBM). 1 '-reuses/4C tlYA,rut Am* Totifittr* fot. JT , PArty > ?<>%.'r-iTtrrejesc,tsJcs) :46i4 7"'y..lii-" '--W 212 XDWiJU) X. OAXT with a predominance in the upper portions of the lung. Bronchiectasis and bronchiolectasis are frequent, especially in the more fibrous portions. Whereas the prolifera tion of fibrous tissue is caused by chemical action in silica exposure, it is induced by mechanical action in asbestos exposures. Gardner" found that the fibrosis-producing character of asbestos could he almost eliminated by grinding the fibers so that no particles more than 2 p in length were present. As previously mentioned, asbestos is classified among the inert dusts. ----- Microscopic Anatomy. Johnstone" described the microscopic appearance of the lungs somewhat as follows: in the early phases of the disease there is thickening of the alveolar septa which results from fibroblastic proliferation. The alveolar paces contain numerous phagocytes. With progression of the disease fibrosis be comes more marked; the alveolar structure gradually disappears, and in its place there is now dense fibrous tissue. The few alveoli that remain in the area of fibrosis are lined with low cuboidal epithelium giving them an almost glandular appearance. Scattered throughout the lung in both the diseased and healthy parts are epindle-shaped structures described first by McDonald." These bodies are 20 to 100 n in length and are bulbous on one or both ends so that they appear club- or dumbbell-shaped. They are brownish in color, do not stain, and give a Prussiarnblue reaction for iron. Simson" has produced these bodies in guinea pigs by experimental exposure to atmosphere containing asbestos. Lynch" concludes that these "curious bodies" signify exposure to asbestos dust but do not necessarily indicate asbestosia. X-Ray Examination. For an excellent review of roentgenographic findings in both silicosis and asbestosis the reader might well refer to Pendergrass." Character istic differences in the roentgenographic findings in silicosis and asbestosis are tabulated below: ' * Ai&UtM St&OMM Fibrosis diffuse (film may have (round glass appearance from pleural involvement). Findings may be either bilateral or uni lateral. Lesion* largely ia the lower one half at two thirds of the lung field*. Emphysema in upper portion of lung Fibroei* nodular. Findings characteristically bilateral. Lesion* predominately in the upper tarothird* of the lung fields. Emphysema in lower portion of lung beIda. Control. Prevention of asbestosis depends entirely upon preventing exposure to concentrations of dust sufficiently high to produce the characteristic reaction. " L. TT. Gardner, find. Med, t, 43 (1WO). R. T. Johnstone, Occupational Dhtaoci. Saunders, Philadelphia, 1942. "S. McDonald, Bril. Med. /, X, 1025 (1927). F. W. Simson, Bril, fifed. /, l, 8S5 (1938). K. M. Lynch, 1. Am. Med. Auoc, JOI, 1947 (1936). " ". P. Pendergra*, `Roentgen-Ray Diagnosis in Silicosis sod Asbestosia,' ia A. J. lanra, SSUotit and Atbcitori*. Oxford Univ. Press, New York, 1S3S. .**,*** }* mu uiy* -; .ti '- . -v ts~- 4615 BUST IN THX CAUSATION Of OCCUPATIONAL DUXAaX 213 Dreesscn, DallaVaile, Edwards, Miller, and Sayers- have found evidence to indicate that 5,000,000 particles per cubic foot of air is a satisfactory figure for the maximum permissible atmospheric concentration of asbestos to which workers may be exposed. Definite permissible standards, however, have not been established. * VI. Dust Causing Minimal Fibrosis or No Fibrosis .i ' Gardner" has pointed out that any known inorganic dust other than free silica and the asbestos silicates may produce nonspecific dust reactions, as described oo page 4S6. X-ray markings may be found in other conditions such as chronic infection and heart disease. No interference with pulmonary function or disability is produced by dust of this type and there is no influence on susceptibility to tuberculosis. A. SILICATES McCord,1* from a number of sources, has compiled a list of the commonly used silicates, which is presented here: Olivine--a magnesium silicate widely present in all basic rocks. Many Tarieties of this (toss are known. Calcium eSicalc--nonexistent in nature, but a common product of industry; may be found at blast furnaces and in production of cement and hydrated limes. Other silicates of calcium an known. TTiZtmiie--a sine silicate (rare). Sodium tuiasle (mein)--the well-known water-soluble silicate, commonly called water glass. This is widely used in industry, notably as a filler in soaps. This is the only crystalline silicate oi odium, the others being amorphous glass. TtcmoiiU--a magnesium-calcium silicate. Azbezloi--treraoiite. eetinolile, chryaolfle, or amianthus. aS of which are essentially mag nesium silicates. Jade--another form of magnesium-calcium silicate. Crocidolile--"blue asbestos." It is a sodium iron silicate. , Talc--a hydrated magnesium silicate with extensive industrial application. Soapdane--a form of tale. AgaliU--a variety of talc resembling asbestos. It is used in the coating of paper, and as a ' paper filler. ifterzehaum--also called aepiollte. It is closely akin to talc. Serpentine--hydrated silicate of magnesium. It is a oommon building stooa. S&imanile--aluminum-containing silicate. The source of many stone tools of the (tone age Topaz--a semiprecious stone of silicate origin. Chemically it is sin aluminum fluosHicat* Futter11 earth--a hydrated silica-aluminum compound, associated with feme oxide. Kaolin (hcoliniie)--many related silicates of mixed constituency. Claye--hydrated aluminum silicates containing iron. Titanium, qyartx and mica, ars Cicely to be present in claya. , W. C. Dreessen, J. M. DailaValle, T. I. Edwards, 1. W. Miller, and R. R. Sayes*. US.Pub.Health Bull. No.2SJ (1938). ** C. P. McCord, Ind. Ued^ X, 4 (1933). ` -- 14 KDWAJLD X. DAJtT Firt day--refractory dxyx, Ior b xlkaliea, but high is iron and titanium. Ulira,marine--t fOic&te of *Iumbum. It is widely used u a pigment, sad there arc many arieliei, bduding blue*, red*, green*, yellow*, violet, and whit*. Uica--a large group of (iucatoa of different chemical constituency. AH are cbaracteriud by eK-ir veii-knovo tendency for cleavage into thin abeeta. It is dens rely oaod in industry, such aj in electrical work for insulation. .k Carrvi--complex siL'catcs of aluminum, iron, calcium, and magocaium. Besides being a semi precious gem alone, garnets are used u -vetch bearings, in gem cutting, polishing, etc. Fddrpar--* large group of aluminum silicates entering bio scan/ minerals, for raample, granite. _ . Pe~m\diU--a sodium-aluminum silicate of complex structure, much used in vater softening. Laaa--mixed silicates of volcanic origin. Pumice--volcanic, glass}', spongy lavs. It is primarily used as a polishing agent 0 Shalt--a loose term applied to elayi and other silicates that have been subjoe ted to high pressures b the earth. Slalt--a substance of clay or shale origin, that baa been subjected to high pressure and has metamorphosed. It contains or may contain much free silica. Slcji--products of metal blast furnaces that contain native impurities as *ell as miner** such as dolomite introduced as fluxes, etc. Almost all forma of silicates may be bciudecL Tree silica may be present Silicon carbide--carborundum, a synthetic minarah Suundum--another form of synthetic silicate, akin to carborundum b chemical structure. made. I * It may be stated with some certainty that none of these dusta, unless in com i bination with free silica, will produce Dodular fibrosia; and proof of disability from breathing such dusts is lacking. '' i !i ' B. NONS1L1CEOUS DUST ! Nonsiliceous dusts such aa caicite, calcium carbonate, gypsum, limestone, ii i Portland cement, and pyrolusite dusta have been listed in the classification of Miller and Sayers aa among those causing an absorptive tissue response and, ac cordingly, are not considered aa producers of pneumoconiosis. Apparent X-ray Soaulalion vilhovl Fxbrotit. Only brief mention will be made of baritosia and siderosia. Pendergrass0 reports having seen several patients ex posed to barium dust with widespread dense modulation typical of that seen in ' simple silicosis. The individuals examined were symptom-free and not incapacitated. \ Sander has described a similar condition caused by the inhalation of iron oxide fumes at welding operations. Exposure to iron dust or fume may produce an x-ray picture characterized by generalized nodulation. Autopsy specimens have revealed i that the nodules are collections of iron with no tissue reaction or fibroeia. j . . .. ; . "J.W. Miller *nd R. R. S*yer, VS.Pvb. Henllh JJep/4, St, 254 (1941). . *0. A. Sender, J.lrg.Hyt. Tosicol, U, 79 (1944). 4617 &FFSCTS OF DUSTS AND FUMES UPON MAN 45 knl treatment it u good u anything that can be offered for these tragic . result* of past ignorance. ________ -_____________________ Asbestosis. The pathologic change* produced by aabeatoe are not like those of silicosis. The asbestos fibers group about the neck of an alveolus and stimulate the formation of a diffuse fibrosis. There is no definite migration or transportation of the dust particles to-the lymph nodes and no formation of the fibrous nodules shown in Fig. 16a. As the fibrosis increases, the reduo tion in lung area causes serious dyspnea. Lansa (273) suggested that the enlarged hearts noted frequently in his cases of second`stage asbestosis may be the result of the increased work of the heart resulting from this condition; it takes more work to pump blood through the asbeslotic than through the normal lung. Gardner stated (175, 170): "On grinding these fibrous min erals to a very fine state of subdivision they do not become more irritating but practically lose all power to provoke tissue reaotion . . . ." Vorw&ld et al. (433) continued the animal work initiated by Gardner and concluded: "The duration of exposure required to develop the pulmonary reaction to inhaled asbestos dust is inversely proportional to the concentration of long fibers in the atmosphere; as the concentration is increased, the reaction develops in shorter time." In silicosis it seems to be a general rule that, after a certain ' . point, the victim's condition grows worse even if his exposure to dust has ceased. But Wood and Gloyne (455) stated that they have seen patients with asbestosis "whose condition appears to have remained stationary since stopping work in the factory," but they advised definitely that the individual with asbestosis be removed from his dusty job. Merewether (311) and Lanza were less certain on this point. Asbestosis Bodies. In the lungs of patients who have died after prolonged exposure to asbestos dust and in the sputum of . men with considerable asbestos-dust exposure are found what first were called curious bodies and later asbestosis bodiet (Fig. 18) (140). While somewhat similar bodies can occur in the lungs of coal workers and even of normal persona, it is admitted that asbestosis bodies in sputum are characteristic of asbestosis. Stewart (402) gives considerable diagnostic weight to their pres ence as do Sparks (397) and Gloyne and Merewether (184). . . . - . 'fair* "ZflDvjTA'AL'&urr :7 : bziiocsa * Hatch i4613 -46 INDUSTRIAL DUST Asbestosis and Lung Cancer. The British require autopsies erf persons -who have allegedly died as a result of industrial exposure* such as cause asbeatosis or silicosis. The 1947 report of the Qiicf Inspector of Factories (25) states that, of 235 cases of asbestosis autopsied between 1924 to 1946, 31 or 13.2 per cent were com-' plicated by carcinoma of Lhe lungi or pleura. This figure should Fia. IS. Atbcstosu bodlw in jputum. UJl* Zlimam* JUf. 140; onrimy J. iruiuii. Byg.) be compared with that of their cases of silicosis of whom 6884 were autopsied over the same period and in which 1.32 per cent showed cancer of the lungs. This latter is about the rate reported in the 1946 census in the United States (13 per cent of all deaths were from cancer and 1 per cent from cancer of the respiratory tract). We do not imply that our American pathologists and our hospitals are less careful than the British in collecting data from autopsies. For example, Vorwald and Karr (434) at the Saranac Laboratories reviewed such data from their own experience and concluded that "inhaled dusts," except those containing recog nized carcinogenic substances, "cannot in general be considered 4613 H itJ W W EFFECTS OF DUSTS AND FUMES UPON MAN -47 u etiological factors in the development of pulmonary eardnomi." But we still are a bit envious of the tidy way in which the'British assemble their industrial data on morbidity and mortality. i. (A / industrial Hygiene Journal 161 C. RECOMMENDED CONTROL PRO CEDURES: To prevent exposure to high concentrations of amorphous silica dust, process ventilation and/or en closure arc the best means of control. For some operations a dust respirator approved by the U. S. Bureau of Mines may be satisfactory, JV. Specific Procedures A. FIRST AID: None. B. SPECIAL MEDICAL PROCEDURES.(1) Prcplacement: Clinical and chest radiographic examinations should be made on all persons, prior to job assignment. (2) Periodic: Since there is only lim ited information about the harmful effects of amorphous silica in in dustry, exposed personnel should have careful periodic medical ex aminations, including chest x-ray. Pulmonary' function testing may be useful. (3) Treatment: No satisfactory treat ment other than removal from ex- posure, and therapy for any com plicating infection. ~7. Literature References 1. Coopsr, W. Cn et al: Industrial Hy giene Foundation Transaction Bulletin No. 30, 1S2-194. 2. Drinker, P. and Hatch, T.: Industrial Dust. McGraw-Hill Co., Inc. New York, 1954. ` 3. Fraser, D. A.': AMA Arch, of Ind. Hyg. and Occ. Med., : 412, 1953. ' 4. Laacbis, J. S.: Ind. Med., 7: 470,1938. : 6. Palicard, A. and Collet, A.: AMA Arch, of Ind. Hyg. and Occ. Medv 9: 389, 1954. 6. Scherers, G. W. H., et al: AMA Arch, of Ind. Health, 16: 125, 1957; ibid, 16: 203, 1957; ibid, 16: 2S0, 1957; ibid, 16: 363, 1957; ibid, 16: 499, 1957. 7. Smart, R. E. and Anderson, W. M.: Ind. Med. and Surg., 1: 509, 1952. 8. Tebbens, B. D. and Beard, R. R.: AMA Arch. Ind. Health, 16: 55, 1957. 9. U. S. Public Health Service; California Department of Public Health; Nevada State Eealth Department; Oregon State Board of Health: Progress Report of Study of Pneumoconiosis Hazards in the Diatomite Processing Industry. 1953. Asbestos L. Hygienic Standards A. RECOMMENDED MAXIMUM AT MOSPHERIC CONCENTRATION (8 hours): 5 million particles per cubic foot of air (MPPCF).3 . (1) Basis for Recommendation: Experi ence in industry,1, and ani mal experiments.* * B. SEVERITY OF HAZARDS: (1) Health: Long continued inhalation of asbestos dust results in a form of pneumoconiosis known as asbes- tosis. The primary effect of inhala tion is an interstitial pulmonary fibrosis. The disease is characterized by asbestos bodies in the lungs and sputum. Based on roentgenological examinations, asbestosis can be clas sified as minimal, moderate, and advanced. It is a serious disease in . some instances, but more frequently ; : it remains nondisabling for many years, even without appreciable ; symptoms, as long .as some other serious disease does not supervene to cause death.1 Chic-, symptoms of advanced asbestosis are variable cough, dyspnea, sub.-temal chest pains, decreased chest expansion, weakness, emaciation, clubbed,fin ger tips, and curved fingernails. Any appreciable decrease in the amount of asbestos dust in the breathing atmosphere will cause a decrease in the incidence and severity of asbestosis. Individual suceptibility varies.* There have been reports of an increased incidence of lung can cer in persons with asbestosis.1 (2) Fire: None. C. SHORT EXPOSURE TOLERANCE: Not applicable:. II. Significant Properties A fibrous magnesium calcium silicate which., occurs.in various combinations as white, greyish or greenish masses, either compact :oc of long silky fibers, flax-like and readily separated. About 957r of comraerical asbes- : tos is chrysotile, which is derived from serpentine, .and is. a hydrous magnesium 16B AprH, 1958 silicate containing from 12 to 14 per cent water of crystallization. HI. Industrial Hygiene Practice A. RECOGNITION: The spinning and weaving of asbestos, in combination with other textiles for fire proof and heat resistant cloth, results in dust exposure. It may be used by itself or combined with other, materials for valve packings, gaskets, boiler lagging and pipe cover ing, protective clothing, shielding ma terials, and as automotive brake linings. In the building industry it is used in the manufacture of asbestos cement products, heat insulating, and fire proofing materials. B. EVALUATION OF EXPOSURES: As bestos dust may be sampled with the electrostatic precipitator or by the impinger methed using alcohol or alcohol and water, as the collecting medium,4* * and dust counts made by the standard light field technique.4 The recommended maximum atmospheric concentration of 5 MPPCF is based upon the impinger sampling procedure. C. RECOMMENDED CONTROL PRO CEDURES: Prevention of asbestosis depends entirely upon preventing ex posure to concentrations of dust suffi ciently high to produce the characteris tic reaction. Enclosure or local exhaust ventilation are the principal means of dust cont/ol. U. S. Bureau of Mines ap proved dust respirators may be worn as protection for some operations. IV. Specific Procedures A. FIRST AID: None. B. SPECLiL MEDICAL PROCEDURES: (1) Preplacement: Clinical and radio- graphic chest examinations prior to job assignment. (2) Periodic: Exposed personnel should have periodic eTim>AT examinations for signs and symptoms of asbes tosis. These should include exami nation of the sputum for asbestosis bodies, and chest x-rays of good quality. (3) Treatment: No satisfactory treat ment other than removal from ex posure and therapy for any com plicating infection. V. Literature References "1. American Conference of Governmental Industrial Hygienists: AMA Arch, of Ind. Health, 16: 261, 1957. -- 2. Cartier, Pacl: AMA Arch, of Ind. Health, 11: 204, 1955. 3. Doll, R.: Brit. J. Ind. Med^ IS: 8, 1955. 4. Dreeszn, W. C., et al: Public Health Bulletin No. 241, Supt. of Doc., Wash ington, D. Cn 1938. 5. Drinker, P. and Hatch, T.: Industrial Dust. McGraw-Hill Book Co., Inc., New York, 1954. 6. Fairhall, Lawrence T.: Industrial Toxicology. The Williams A Wilkins Co., Baltimore, Md., 1957. 7. King, E. J., et al: Thorox I, p. 188, 1946. -- 8. Lynch, K. M.: AMA Arch, of Ind. !Health, 11: 185, 1955. 9. McPheeters, S. B.: J. Ind. Eyg. f Tox., 18: 229, 1936. 10. Page, R. T. and Bloomfield, J. J.: Pub. Health Repti. 52: 1713, 1937. 11. Patty, Frans. A.: Industrial Hygiene and Toxicology, Vol. 1. Interscience Publishers, Inc., New York, 1948. --12. Smith, K. W., AMA Arch, of Ind. . Health, IS: 198, 1955. ^13. Vorw'ald, A. J., et al: AMA Arch. Ind. Hyg. and Occup. Med. 8: 1, 1951.