Document 7OGrr71DkG8GqjrKe8aGj5gjg

FILE NAME: Asbestos in Plastics (AIP) DATE: 1960 Sept DOC#: AIP006 DOCUMENT DESCRIPTION: Unpublished Draft Report - Asbestos Reinforced Plastics t ****** ^ tr MW0 **'*-**'"'**'~*" * K t i u - N - - ^ . t b . ' b y c i H i 1| r\ SEPTEMBER I960 Bulletin No. :.-.4. O 'S w * *',:}**i**H.**-S..'*'yiA`:V*..-:^i * sy";,v ' Fiber^Characieriatic# piattc.CJiaracteri8tici . References \ ' j,`: `f . mi CO * * } i:p ] ' '' ` -A;;HPrpared W *.AiibeBtoa Com mittee . - _ ., ;,. . . . .V1`'-`'h'Ai'''t.v , U i Avf.','";.X.>;.''.,''- . ' . . . .. .. . .. . H .V : - . ... -AK S ociety.of P la s tic s Industry,.`'Inc. ZSO P a r k A venue^ - '. . . ' New Y ork 17,, New York !0^V 0C C 04235314 . .* un cn un ;jj >! - v * .- i . ` ..^i'. ( ..v _ PLAINTIFFS EXHIBIT ey} 3 \  INTRODUCTION T U . t a i l * . P v l d i . ta d o .lx p ,, * =.> . U .1.U J * " " " > "" , . . z . - - re in fo rc e m en t in MM tofoxced p lastics'* . A .R .P . (Abeatoa R ein io rcea ^ c * b ? o v l d e . industry with material* capable of meeting various propertie* or require ment*. Typical ARP P roperties or Requirement* Heat .resistance Low therm al conductivity C hem ical R*si* tance Cryogenic Rei#tanca High tdifnea* (E) ' High m echanical strength Varying electrical characterietica High toughness ' "P rem ix compound ingredient Gunk molding compound#" Tvnical ARP Product* Cooking handle uten*il* Switchboard* . . . E lectric Motor Casing . . `Lamp S o c k e t* - ' ; Dom estic'll industrial electrical panel* Commutator Ring* " . Cable insulator* ' Auto body tc Railway body p art* Housing* for auto heater* tk *}x conditioner* . . Underground-conduit* Sewer pipie Noise Insulator* , . . Helmet* . ' . . . Gun grip* ' . Incinerators / ' ' Blackout or bombproof shelter* M issile nose cone Rocket m otor structure# and insulation M issile blast tubes . Brake lining* F riction m aterials for autom atic eq uipm ent Clutch facings Gaskets . Valve* Roofing ` Acid proof tanks Gas vent tubes or pipes A ircraft ducting Chemical F ilters. ^ bulletin doe. not .c u s s fiberglass or glass fiber reinforced p lastic, which represent, a large and continuing growing industry. Ths subject of glass fiber has been reviewed in numerous BPS bulletin and literature. Also, this review other fiber used in "reinforced plastics"; such as, cotton, nylon, rayon, sisal, quartz, alum inum siU cate', ' e tc . Q rr O 4 2 3 5 3 1 5 The principal reaso n , fo r preparing this bulletin are attributed to the growing em andfor A R P and th at an education I# re q u ired in b etter understanding asbestos a* applied to r e - k fo rc c d * U . S s . Raw asbestos can introduce a m ultiplicity of- problem s if i t . are not understood. These variables ineludt conditions such a# chemical analysie, grading, blasTiflcation, snd trading conditio.. Various specification, are avaUuble, but it h a. been : determ ined in c e rtain industries where A .R .P . is used that new specification, for the use of asbestos In reinforced p lastics Will gradually evolve based on new industry requirem enta. 1. O; a\ to ; CO to*>yl Sun cn cn h is t o r y have continually weed ** * tl* . z, 000 year# a#be#to# ha# been ?* diversified product# and application#. the turn of the la s t century. It'# usee, scientific t a 8 y * . . >-- *" io""a io r It1, t l . . I . a " ,U.l r f m aterial#i plastic#! t**1 * " S E f f iiS L T L T O S only identifies a fireproof cloth. . ProJucttt example, an asbestos paper product can be used ^ S i. -- *" " A sbestos occur in rock m asses. TheB They are used in the " " * ^ sheets, roofing shingles, and corrugated sheets. Ct` iUCh 18 Bldlng Bhln8leB' flat Ih. e ^ w s r r t s i ^ :rrav.:r--; s ^ ^ i T s a ^ s s s s i i ^ s - >*- -- im portance in m anufacture of textile products. j fields including textiles, packings, gaskets, r.anaral Features The im portance and com m ercial or i f s unique fib ro u s s tru c tu re , tt 1 a s p i^ a W e o r a s s ss? ^ b u rn ^ b V rock, created g " duco it fa m l. highly *- --- To t o P H ,..cut. ` VP| ! :=m .''J China, Japan, Spain, Newfoundland. Australia, Portugal, Hungary, R u a m . Central A frica, and Southern A frica. Com m ercial value la principally concentrated e of Canada, R ussia, C entral A frica and South Africa. The Canadian nebaatoa 1 considered to be superior to others insofar as essential properties of infusibility, tensile strength, fineness and elasticity is concerned. O rig in " Many theories exist concerning the formation of asb ssto .. The theories basically differ iependtog on the source of inform ation. Even though asbestos h a . been known for ages, it's geological history and formation are still m atters of conjecture. One of the theories involve the re su lt of volcanic activity which occurred thousands of y ea rs ago. The ignlous rocks had acidic intrusivea that form ed granites and feldspar-dikes, t h e u ltra -b a sic intruslves formed dunite which eventually formed P" ldo tlto and pyroxpne peridotle after coming in contact with olivine and wades. Through tho ages, these ro ck , passed through various stages of physical and chemical changes to form m iners;, known a. serpentine. T his change occurred during the tim e when p re ssu re was croatod on the rocks causing cracks in the rock. In turn, these cracks wore filled hot ground w eteri'd eriv o d from the infiltration of rain o r surface w aters. The continual infiltration of this w ater under host and p ressu re acted as a solvent;. W w ater ^ containihafed 'with .different m inerals. C rystals developed end w ere deposited in the crack ; of the rock, . . Most rocks are made of crystals, C rystals hold one of the m ost oerst oi n^ ro ' 9 m ysteries, These cry stals form basic patterns. The m inerals which make up the crystals are im portant and produce the specific different type asbestos fibers. The rock formation in Canada is a variety of the olivine which is composed of iron, magnesia, L d silicate, Water containing carbon dioxide and salt in solution penetrated the rocks. This aradual flow o f highly contam inated m ineral w ater changed the original rock from iro n containing m ineral J m a g n e s ia - silica - water. According to the geologist, this reaction took place thousands of feet below present elevation. Since i t is believed th at asbestos developed deep within the earth where ! could be TMbJ9Cted to p re ssu re and heat, ft is believed that in the case of the North Am erican C o n c e p t, the glaciers or m assive ice formation eventually removed the earth and exposed asbestoe on the surface of the earth, . During the formation of asbestos with th* continual p re ssu re reportedly moving the rock in the eraeka, The reaultant veins oi ssbestos rock were predominately broken so that m ore of'the short asbestos fibers are available, Ore Deposits 0CCO -K 3917 Asbestos is mads available to industry either directly from the mines or through distributors. At le a s t 90% of the asbestos is obtained directly from the m ines. Most of the asbestos ^ D I -D id CO ro to - UTt cn CD I .rich to n . . * % 3 S S X Z Z Z Z Z S Z z Z ? *> *-- " m tso. toe* ~" "8 , I h . United State! i . the T .d d < . t o p P * ^ H 7oT : : p ; i X f" * u ' t r f u f . T " ~ . . ` 'c .n . d e , ,, v . . . ,, - t o y 9 < * aebeetoe u s e d / Domestic asbestos contributes approximately five percent. The a n , t o r i t o y < -- t o t . * ! .'* .Z S l T 'S T .V d t^ u . " be eo n .W .r.d one ol th . principle p tc d n c .r. o l i a t o t i * p*lo' t0 w,, u v ,, t, R n.eU are situated in the U ral Mountains. Deposits also exist in Siberia. -- -* . S =i K mc g > a IS i 3D " i X T .r;^ ^ n accordance with length o fiber, t a t tn.eeaetng ol . t o .topi, to g th o .b .eto . ber 1. en. o itte ~ ~ . 7 Z Z Z Z L Z *y the m w ntiecturer. A ,'" * ' ' i ? 5 ^ I ' a e e r i n i length cen be m .e .n re d , S t.p l. length j A v e rte n e 4 toto to- ^ - - | own to m icroscopic m easurem ents, . . n L. V i a o f leneth ra th e r than quality. Qualities which , V'O CO ro ,, o " " ' . r i n e "p r o L t . eoch . . - b e . , cement, t i l . , 4 b eri., lin in g .. , The | roject of revising the chrysotile asbestos gradss. - c" *d`" tg z s a s T ,**. S S S l i 0 b e e .. to own h ry io tile into two m ala classes of crude and m illed asbestos. dM" ` 'he Crude Asbestos consists of the hand selected cross-veinlng m aterial " * in lt'8 *"* ^ in..-.! form The M illed A ebestos consists of all grades produced by [lifercut groups ranging from group No. 1 to No. v. 4. n f . 'l 't 1 7 H lfl un cn UD ' c lassificatio n of chrysotile asbestos according to Groups are as loBow>; f C rude A lb c 10 Group No. 1 Crude No. 1 Consists basically of crude 3/4 inch tapis and longer _Group No. 2 Crude No. 2 C onsists b asically of crude 3/8 inch staple up to 3/4 inch C rudes, Run-of* Mine Crudes, Sundry . Consists basically of unsorted ' crudes C o nsists of crudes o th e r than- specified above . MUled A sbestos . V* Standard Designation of G radej . G uaranteed Minimum Shipping T est G roup :Noi' 3/(Sp.M to8 F ib re s) ... 'f:i. ' ; 3K' 3R. . . 3T ,'v. . '"si/'S ........'.....i.. *C- roaupeNt.iTo..oi4M(FSihbinregsle) Tibrei -^ riT U -V: v=.VA- A- -- . v; - t 1;\V' " ' .Group'No.. 5.(Fapdr Fibres) V . .'5M- . - - - ' 5R ' ' Group No. 6 (Waste) 6D Group No. 7 (Shorts o r Refuse) 7D 7F OCCO 35919 , RJ.S - 3 .9 - ' 7 -7 . 4 ,-7 2 -8 " '. 1 -9 -8 ;:^vy -1.3 -1 .5 -4 -4 -4 -6 " A':. - < \ . b , ' -7 ' o ' . - 5 '. o: r -4 . ' t'4 -3 -o '-2 ; 0 . rl. 5' -6 -8 ' -8 . -8 -9 -10. -9 .5 -0.3 .-0.5 -1 -2 -2 -2 -3 -3 -3 -4 -4 -4 -5 0 -0 .5 -10.5 -5 0 -0 -1Z -4 ' 0 -0 -11 -5 0 -0 -10 -6 0 - .0 . ..7 - .''9 0 - ..o - -5 - 11 0 - - 0 - -4 " 12 sv .V ,:!:> . ;<H.* . '*-`.r>s .  \ ' \ . *. * Group No. 7 (Short o r Refuse) continued.. . . 0 - 0 3 13 7H , 0- 0 2 14 *7K' ' . 0- 0 1 13 7M 0- 0 0 16 m 0- 0 0 16 7T 0- 0 0 16 A 7W Group No. 7 (Float)* . 7RF . ' 7TF ` no test ' no test*' Group No. B (Sand and Gravel) 8S . ' Under 50 pound p e r cubic foot loose m easure Under 75 pound par cubic foot 8T loose m easure Group N o.'9 ' 9T. Over 75 pound p er cubic foot loose m easure . , >' 'A. ' . ''y-il vriir Vvv\;;- V"'v i ' :ft ^ .`i;*;<1 v l "-St :1L.*I -`y.'" ,f' '1'' \ ' ^ ^ '' . * ' V" 0 ith 7R M d-7T 8rQde'' 0CC01335920 te r p ito * :# 0 , f U Ti s s a r f c is s r - E ach screen m e a s u re s 24*1/2 in c h x 14 3 /4 U T h, top bn* j W I- identifled a . Box l e n t o Mn with 1/2 inch openings, ^ ^ 4 u . clo8ed e p i c a l X : ^ ; : r ^ ; t ; : ; , m r e ; eV t h r ou8h . . * . 1 * . . . Th * - and the tim e that fib res are subjected to motion a re fixed. ^ 1 Th. . . . . procedure .. in tr.d u .. ' of m otion, the fibre in each tray ia weighed. Th. m or. lib r. r . l . t o d on Ih. .. - t : s s r ? k j s r is s J i ' -- Box 3 retained 4 ounce and one ounce fell in the bottom pan. hundred bags. ,, a ........... of C reup N o .' 4. 5, o r 7 ( l b r . . . . . W * > ' " >' " ,I0 " *" h e.e r y lot of two hundred b . j . tn .lu d .d In t h . n o m b.r to b . te .to d . . . -..11 r . t he allowed to approxim ate a v erag e w o rk -ro o m E ach com posite sam ple 0 nade^u* ^ ^ oroughly m ixed on a emooth topped table while8p a a i l n t h r o u g h the hands with 11 geg j j " etclT at n e c ta ry , ' X ' r e p ^ e d " e ^ d lot s i l l "be weighed a c c u ra te * and placed in the testin g m achine. T he g re a te s t in c re a s e in u se of f i b r e . h a . b e e n 1 ^ r t w r l J ^ T m ^ c i L r U ^d^oaT s^oliow stfh ^ e ^ r h l c i p a l a of the shaker test; however, other factors such as . g rit t e r n ta g e . viscosity, e tc ., have a bearing on nom enciature used. The Croup No. 7 shorts o r refu se " M ists ^ J J * * ^ * ^ m ^ i J ^ S l T ' s t o m ! l: nc are fib re . ^ i S r ^ U git that they are collected by air floatation. They are p r e d a t e d into , f lo a T c h l b e r i by gravi ^ settling or collected by filtering media. ' Shorts end floats have products thus causing S T S S S i . C Cie^Vnt `Sr** ilb" aJ*licatlr " d1,18 , . ; relativelynew ^or growing industries such as vinyl tile, plastics, asphalts, and ? * QCCO-1 2 3 5 3 2 1 ;o ! i 3D. 'rpa CO N> .o ; un ru asbestos-cem ent, . 0 , h ,, m e th o d , o< . U , . U t a . h . v . ^ Z Z T .X asbestos, length of fibre, fib e riz a tio n .an ^ b Standard Testing Machine . to designate degree o f crudeness o r o p en n ess. Ltd- " e8anumbor 'yetcm *. ' ` . . . . hr** from m ore than one source .order to . I* a s k ill obtained through continuous u s e o l the a iu e r Th. - m . - . . - -- the g en eral trend can be identilied. Long i J o r felts, and for filtration! and te x tile b; fo r packing and g ask ets, fp r fitted^long r P Plr e d . The m edium length fib re s . .asbestos-cem ent goods w ho' _ J _ B ! einfoictog fille r in asbestos-cem ent products! including Groups No. 3, 4 and 5, a re used ^ m agnesia insulating compounds, asb eato e p a p e r and m illb o ard ; a , ^h ^ gek#- ^ n ^ n g s . The sh o rt fib re s and flo ats -- u s tic moldings, and o th e rs . The Group No. t s 8 and 9 generally contain U r g ^ o r tio n a of minute rock and sand w hich. are not detrim ental to the finished products. . . to N orthern B ritish Columbia, the C a .s ia r asbestos grades are identified as follows: . Crude #1 - B asically of crude 3/4" staple and longer AAA - E xtra long textile fibre AA - Long textile fibre . A - Textile fibre AC- Long shingle fibre AK-. M edium long shingle fib re AS- Shingle, fibre - AX Short shingle fibre ' . A sbestos producing countries c U flic a U ^ designations do not tally with the QMbec! C ^ i U ^ ^ com parieon of relative value but r. v' " ...m... o<-- <o*. **> from different p a rts of the world are review ed. . 8. 0C C 039-Z classificatio n of A frican C hrysotile '^ 1 & CliGl CtiG2 C&G3 . ChG4 C&G5 Longi crudy textile fibre Textile fibre ' . Long shingle fibre Shingle fibre Short shingle fibre or paper stock V R A /-2 V R A /-3 V R A /-4 Textile fibre Long shingle fibre Shingle fibre HVL/2 ' Textile fibre ttV L/3 Long shingle fibre HVL/4 Shingle fibre . HVL/5 Short shingle or paper atock vMsauli - G rade 4 } . Shingle fib re s M sauli - Grade 5 ) `. F ro m m ines in the Shabani d is tric t of Southern Rhodesia ) ) From the Maahaba ) d istrict of Southern ) Rhodesia ) From the Havelock ) Mine in Sw itzerland F ro m the Msauli Mine n e a r Swaziland b o rd e r in the T ransvaal m ; f l vV.' . , Classification of Russian Chrysotile M ark A ccording to s4i f-g . .1 , ' " * . . . V Grade' TffiS. . Texture U. S.S. R, Standard Ja n u a ry 1, 1952 tm - ... ' P ' 2, /. Textile Long shingle H ard (crudy) H ard Sem i-hard J-l J-2 P -2 . 3 m : -'/I '- ` .$1 < >*^.1 '* 4 - t7iti . .*.'... *- , , |v :. ` - 5 Shingle Short shingle. It p a p e r sto ck ' Paper Stock H ard Sem i-hard Soft Hard Sem i-hard Soft . Hard Sem i-hard J-3 PJ-3 P -l M-3 . J-4 P-4 -M-4 J-5 P -5 '"A. ' .r.evl. . J .. 6 Soft H ard Sem l-hard ' M-5 J-6 P -6 a : *. 1 ' . ".'STShrlft?vil ` M-Jfc*, 1 ., , 7 ij;'.! * " ,, ' ... Soft. U nguaranteed U nguaranteed OCCG12 3 S 9 2 3 M -6 . K-6 K-7 7-370 7-450 9. 7-520 o 3G0 r - 'T o CO A5 19 i. W -j : c V SfiVl- ' ..... . '* .i! ,.V . i-'j A 'JJ m Grade P lan ificatio n ol R ussian Chrysotilr; TVBg_ Texture Mask. A ccording to U. S .S .R . Standard January I. 1932 U nguaranteed 8-750 C lassification of A u stralian Chryeotile G rade 4 - 2_inch fib re s and longer Grade 3 - 1 inch to 2 inch fib res Grade 2 - 1/2 inch to 1 inch fibres G rade 1 - 1 / 4 inch to 1/2 inch fib res Glassification of African Amoslte Group 1 D3 Group 2 O il OX Group 3 MD M W3 K3 Group 4 S2 swSK Group 5 GW GK Produced from hand-selected long fibre at Penge Mine only. Long - over 3" in length ... . Produced a t Penge from run- of-mine fibre after longest has been hand-aelected. . Minus 3" plus 3 /4 ,r. As above but graded by color. Generally minus 2-1/2" plus 5/8" From Penge mine From Penge mine - somewhat shorter F rom W eltevreden Mine From K rem ellenboog Mine Generally minus l/Z " . F ro m Penge Mine F rom Krem ellenboog Mine F rom W eltev reden Mine Generally minu a 1/2" F rom W eitevxeden Mine F rom Kromellenboog Mine In addition to the above grade, there are several from the WEG from the M altpedrift area i . probably the m ost u n ifo rm ly p rep are . sim ilar in length to Group 3. ' T ,,. other , , . d . . H .t.d to t . r . , .lo , & tu v e 'bM n bicluded tn'o r f . r to 1. different grades:- die,too .1 Ut. . a . I * " ' <* th' i0* O C C O W ^.^4 i mfNlM:) ww. GUALiTYOf=THCCX * Cape Blue (Crocidollte^ E - plus 2 -1/4 laches D - plus 1-3/4 - 2-1/4" C - plus 1-1/4 - 1-3/4" No. 1 or B - plus 3/4" - 1-1/4" No. 2 o r A snd R2 - plu# l / 2" ~ 3/ 4" No. 3 o r S . MS s a d R i - plus 1 /4" - 1/2" X, SBC, H sad SS - V arious s h o rte r g rad es 0 1 the foregoing, the longer grades d tn ^ to No. 2 o r A .sre m ostly head-cobbed, T ransvaal Blue (Crocldollte) TX - P lus 1-1/2" T i - " 7/B" - 1-1/2" T2 - 1/2" - 7/B T? - 1/4" - 1/2" "Long" - MLS and NC300 about 1/4 to 3/6" T4 - and "shorts" m ostly m inus 1/4" ' Most of tb s above num bers have fallen Into disuse. The p re se n t p ra c tic e is to re fe r largely to "long" and "short" for the hulk of the T ranevaal production. .Theresia no recognition smong the m ajor producers th at greater standardization ie desirable. A ustralian Blue G rades No, 1 No. 2 No. 3 Long fibre - 1 in, and over P lus 3/8 to 1 in. ` Minus 5/8 In. .11 OCC-0 JZ X 32 5 to `' t COiI ' ro sVP ! r M inina. Milling and P rocessing ,, a * ,,< t o * , - a * , - . " " - h ^ s " * .'te y ." m ` H b .r . ' un., t o .p p to d to t.ly 9 *" " . used, this discussion will pertain to Canadian chryso e. j t,e m ining operation Involved predom inately O riginally, w hen the m ines w ere o p e n e d ,th m i P ^ ^ mining operations have 30 s - CpM ,, , t o O u se d to obtain th e long asb esto s A b et TM f r m ^ end8 o fib e rs . F ib e rs id e n tifie d ro c k by m eans of h am m ering away fibcrB ftre not pr0C<!9Bed through a- 0E 1 / ] c r u s L g ^ d u r i n g th'e m illing o p eratio n of the sh o rte r fib e rs. . The content of fiber in the rock co n sid ered p ro fita b le when the r *CDVC^ ** asbestos. Variables such as L d size of deposit determ ine whether a low ` approxim ately 5% to 12?. 111 Camda rlch areas a r e c o n a d o ie d to reC 0 V 8 t The asbestos, a . obtained i 3 SS5 3 S . VUch has to be rem oved by the m anufacturer in th e own pi to,t " " is' ' . t Vnrter fibers. D ifferent processes or system s are r a" t o " ^ " ^ " " ' "^ bundles of fib ers. " ^ -- *" " a " - *-*' " d to C ro IP : At o . t o t o u ^ :r . IL H fo r spinning. ___ } to.-J 12. 0 "C 0 )3 3 j3 G r o i B ^ o r d e f t o iim pliiy extraction of the fiber from the rock. separation is accompli*hed. " J r T ^ L ' S S & Z Z L L " " 1co" ,h m t fib o ra. M artaat. to taiito try a a l.l tor tongth. ' ""* to -- . -- ~ S' z s r t s s s B n s s i T J L - - r ~-- - " ** " e k "" "y different location*. n. * * * t s s j s e e "*e - lining, packing, aBbe*to-ceinent,. and others. -- - ' " *br,k' . Since m o st of the a s b e .to . mine* a re consideration in developing a m in ^ * ^ of the asbestos to the custom er. involving the hauling Coete ,or consideration is to set up proper operations Many asbestos m ines handle tons per hour la n ecessary ince the y ie ld of the average , r ^ ~ -- - " * " . <-- >>" fiber* tend to bcome the mo*t profitable product*. Two m ethod, cf mining exist. The i\z z * " r Z = T e - ......-- rock*. V n ir r Srooo4 t o . . a r . o r r i. V ay to a. m r O o i . ol t a t o .l t o i . . . ..4 - & `7 ^ n r . tion. It i* mined in te rra c e s cut out from the roe* ana in c * 7 . found principally in the ric h abeto* deposit*. Xh. the o r e a r e connected to h o ists. In_ Quebec. * ^ larg est com m ercial cable way *y*tem u a .. a, J *" " 13. 0320 DUR si ^ t s S5B I s. LTi --J CD 1 I ' t Unirai and m ultiple benching is related to the m ore conventional open p it method identified Sp: r f d ^ S d e V te u c k ta u la g e technique. In the inclined cable operation, the floor " ; ; f l 7 TM " x n n ;" 0 . ^ r L ` .! W cable. . x . . t. II lcH c.d 1 , 1. PPxed- m a te ly 20 degx.. F ox tru c k o p e ra tio n ., tha angle 1. a p p .o x lin a te l, 15 S the BPiral benching operation, the p it develops into the form of a larg e bowl. The m ultiple benching technique is used w here spiral benching is not feasible. G enerally, P0C* form ations a re located in the larg e asbestos deposit o r a re a s. The b a rre n rock form tlo doe. not p ern d . c o n t i n t . p l r l cp.xa.io. a . 0 . fflfta .n . *>* LX . occur in the one area. This type of operation is re fe rred to as m ultiple benching. . Underground mining operations occur and generally tie in with open p it operations. D ifferent techniques a re usod. ' In m o st c a s e s , m ines are developed w here asbestos occurs on the surface of the ground. New m ethods of finding a sb esto s deposits a re being developed in o rd er to find asbestos ore not exposed to the surfa-ce. In m ining operations wood is not used because contam ination would be detrim ental to the jnsuiufocturing plwits* r Milling A sbestos - 't A fter the asbestos o re is m ined, the m aterial goes through repetitive crushing operations t!}i> to s e p a ra te the a sb e sto s and ro c k . C rushing and screen in g o p erations ^ - T^ oe $ o n eratio n s a r e r e f e r r e d to as m illing1'. Special m ill equipm ent is re q u ire d for these operations. The m ethods used In the various mines are basically the same but generally . `h differs in reg ard to siae which depends on mine capacity and type of fiber. l In m illing the two m ajo r objectives a re to sep arate asb esto s from " d -p r *V8SJ` i reduction in the length of the asbestos fiber. - The value of asbestos fibsr depends mainly on fib e r length. The objective of preventing reduction in length la v ital. E xtraction of he fiber from L rock requires repetitive crushing of the o re. After each crushing operation, free fihor is removed by air-suction. In o rd e r to successfully rem ove aebestos, the m at e ria l m ust be dry. The mined asbestos contains m oisture which v ariee depending on w eather conditions and season of the y ear. The m oisture is rem oved by m eans of m echanical d rie rs. The dry fiber can then easily be rem o v ed by a ir-su c tio n . The p rim a ry cru sh er, usually of the Jaw type, has the capacity to handle rocks up to 48 in e ls e , weighing up to a ton o r m ore, and crushing them to approxim ately S to 6 in w idth. ' C rushed rock is c a rrie d to trom m el screens. These ecrqens are large revolving cylinders with various also openingB. The trom m el screens only p erm it the relatively email rocks of ap p ro x im ately 5 " to 6 w idth to continue through to the secondary stage of crushing. Thie type cru sh er is generally a gyratory or cone type cru sh er. 14. OCCO1235328 4 .4-v '*"1 3 i D : G 'i ia r to i CO N>, ij O : L H ___ ! UQ 1 f- fi Crushed rock is dried in tower or ro tary d rie rs which vary in tem perature from 200E\ to 1 .000F . . A fter the drying o p eratio n the ro ck s which range in sin e fro m 2" to 3,r a re fed into a third crushing unit which is either of the gyratory type or cono typo. The crushed ore and fiber a re fed to heavy shaker o r bum per screen's which are operated by means of eccentric drives. Pow erful a ir suction hoods rem ove fiber. The rock passes over the end of the screens. The undersise m aterials paos through the screen and is fed to a iib erizer for further treatm ent. Additional shaking screens a re used to separate fibers Into long, medium and short categories.' Duplex shaking screen s are used. The long fibers rem ain on the top of the screen . The medium fib ers in the lower screen and the sh o rt lib er passes through both screen s, - The ro ck which was p assed over the end of the heavy shaking screens continues to other ' c ru sh e rs. The cycle is repeated whereby the crushed rock passes over shaking screens ' and in tu rn fiber is rem oved by air-suction. j A fter the fourth crushing cycle, the rem aining rock is fu rth e r sep arated by m eans of fib e ria e rs . The fib erix ers b re a k the rocks by m eans of im pact or d ire c t blow of high speed hm m ere. The crushed stone ia again fed through the shaking screen in order to remove additional fiber. The m illing operations axe continuous. A fter the crushing and suction operations, the 1 asbestos is cleaned, graded and put in bags for shipment. During the operation fiber co llectors which are conical eylindere perform the firs t step in the cleaning operation. C urrente of a ir c a rry the fibers into designated are a s whero additional cleaning can occur over screens. The p ro cess of separating asb esto s fro m rock during the m illing operation takes into account the specific gravity difference of the two m a te ria ls. A fter the fluffing o r fiberialng operations, the dry asbestos can be taken away from the rock by m eans of a ir currents. A m eth o d which is n o t g e n e ra lly u se d involves the w et-m illin g operation. In the w et m illing operation thofiberixed asbestos will float on w ater. G rading of asbestos fiber is conducted in special designed g rad ers. Long ro tary w ire screen s of various s ite m esh a re used. The sixe m esh determ ines the length of fiber. In g e n e ra l, the g rad ed fib e r is s to re d in b u rlap o r Jute bags of 100 lb s , The fib ers a re com pressed in ord er to reduce bulk. 3m =ni & a n6 XA ; D j G CO N>; r - -? CO CO OCCO 15. 1 ' a M J; 'f if I 'i H ealth and Safety fa c to r * With the development of the asbestos industry, contamination of the air with sm all asbestos fiber p articles produced hygienic problem s. Hygienic m easures w ere not well advanced when the firs t mining operations w ere developed. Since the dry processing method is used in mining and milling asbestos, sm all fiber particles a re picked up by a ir currents and dl.s tributed throughout the m anufacturing plants and in the neighborhoods, th e asbestos particles or dust which developed could becom e harm ful to the people who were constantly exposed to it. Asbesitosis i* a Special type of silic o sis bu t does n o t occur n e a rly as o fte n . A pproxim ately 10 y e a rs is re q u ire d fo r a p e rs o n to develop asb e sto sls if he is constantly cxposed to the dust. However, since protective m easures are provided by the different " m anufacturing plants, it is extrem ely ra re that a person develops asbestosls. Chem ical analysis can be made of dust in o rd er to determ ine concentration of asbestos . dust particles. Information Is available as to what the maximum concentration of dust ; should be to elim inate any problem s. V arious safety m easure# axe available such as w ell . ventilated areas, special m asks, and w ater sprinkler system s. Proper Alteration techniques are available which w ill collect dust particles. i With proper precautions, th ere is no problem . Periodic m edical exam inations of w orkm en j a re preform ed in ord er to keep constant check on their health. Apparatus used in con* j nection with the asbestos industry should bo sealed off ag ain st outside a ir as much as j p o ssib le and should w o rk wi> a d ra ft under negative p r e s s u r e . The passag e of the d u st j into lungs through the resp irato ry system is dangerous. It i im portant that proper p re - ' cautions be taken by all companies which handle aebestos. ro . co: to Q : O C C 0423S330