r/ T RAN SACTIO NS INSTITUTION MINING AND METALLURGY. ' . IIrTY-SECOND SESSION- r942-r94. Vor,. LII. ?lrBllrf,Fnp .- AT TIIE OFFICE OF TEE INSTITUTION. EALISTURY EOUSE, LONDON, E.C. 2. 1943_ i -Tt?i-- ) THD INSTITUTION OI' Reaeipts ann heenatuarlor-th' S2 D;. ImoFaE, 10!tr. c .- d. lf 2 129 19. Ralle.i^... 7,112 B6nt, I 19 183 4,, 0,, T6Lpho@... Ardib F@... 4,, ?@tage 11 LighiinS' Cto@' 10 250 ,l"l l0 0 3,085 l0 4 251 06 200 l9 7 8.lEri6 ed R€tiring Allowmcd sd Bslipt AtsD!6 ' Submi zA 0 B.iiish [email protected] In.iiiution TrcPi@r I. 6t l0 2500 ?? 10 IDtroduction B. Chomicsl (sr Orh6r t4 r0 t6 l3 l.t I I P0go 36 96 esp€cts ... ... 88 r,000 0 orod dnd rnsr€riais Opbrsrionol $p€cts ... 0 51 ... 5l 66 o! CoppER lRox rHE Lrauons osrarNDD lRou HD^" LlaclriNa 60 5I ?nEcrprrrrroN ... 60 60 (6) TypeB of iron used ... 0 50 (1) Composiiiol] ot th6 h€ep liquors 60 (2) ReduotioD or the ferlio iroD by sulphur dioxido 60 (S) Precipit&tion of tho copper by iron ... ... 82 t4) Cotrrrol of the coppor preripiuiion ... ... 65 (5) fton consunption 6'.1 E!c@ of RseiPt€ ovd Exl'on' t10,r0? 16 96 (1) Ieyout ol l€aohing erounds, sndorc mov€meri (2) Liquor Aow in 86u€rei ... A. Hisrorical ... B. Modor$ prrctic€ 6 8033 3 0 , Norp,nber lgrt, l9{2. A. 0 Il. 5 d.irn"s"^ic' LEAoETNa aND oRE-HANDLrNo 0 120 t11,066 fut (1) Cl€an 016leechiDs und6r nornsl coDditionJ... (1r CloaD ore lesrbing uoder spdcisl cotrditionr ... 4?2 160 f l35 12 9,, ditN II. CONTENTS 666 4 l0 . sbs Iscilui€ of Eysio@ ... 36930 {c1. Tho Loaohing of Cuploous pyrites a.rd tho prooipitation of Copper a,t Rio Tinto, Spai!. By J, E. T^yr,oR, t6socta,e, and ?, F. WEEr,rN, ls6oc?ats. 2 16 0 2011 d 0 14 tr1. PAPER,S AND DISCUSSIONS- c. 96 v.^f ?3 Lib!d!' st MiU Clo€e : Aa,ldie, Tare, Rtt$' 6tc. I I SECTION 630 1.1 162 12 62 I{sii!& 2s. od ) it8, oto .. 1 73 10 3,0f3 r8t3t 11 r0 rntusnce lincludirxwe.Ddtgo r@u6D; 123 0 246 la I-uche@ 96 18 46 r,300 ?lqting dd St tione.Y .. E pon6 ol Meting6 drd Jubil€6 66 l0 2,926 Sociion ot rhe L't\ ..d I cdt or Printna ?$Uc.tios: !tuNoanm, Bdkti^ sd!@6 ooDi6 ot P.PoB' Fport€ ol or DMu.ioB Md comPleiDnihd Vol$o 60, ,.s doiPta fc adv..t@ont \1u1 V). Ill. CrassrlroArrox or rHE PRDorlrr.{rD Er WasHrNo 69 ... 69 l 36 J. E. T.aYr-oR AND P. ]. !. wrrEl,Alr i iliAorul{o a1{D p&EcIptTATtON OF OOp?84lT A lrnorucuor IN th€ msssivo pyritos from th€ Rio liDto Min$, copper ocouft p:lli1iin:r'irlllerhd os sulphidos. hrsb ru€l ruquiroi.lave of orc' wers lulnps largs vith lor doating unBuitebility m6nts, end .oseoL ressoos tor seeliDs rn all€rDative mel'bod espocisl]y oDe oDo suil,sble for rrostins io lurge qusotirv Pyrircs coDrridng onlJ or tro Dot cont of copper. oo""luit "atcin"uon, tottowed bv lesrbing ol Ib€ culcirree' coov;rh \'srious mencea on s laree scalo sbout, 18?6 aDd ,rom 'onriDued :le.,owst "y A ,poot s&sh vss Fivon to rhe l;ar s"r . atout two-mon(hty inr€rvats. the surlsco boing band_pi;&€d afier oach appticaiion ur liquor. p"I"p" f"ur yoars or rhis rrearmonr, rho p€rc"ntss€ .I,:h-::""1-"t jrfr€rsod io abour 50 p6r cenr, aod r.be ooppor il-Tll.j,"..lio J)od ralsn to 0.5 por conr, oonorponJing, conlonr b,rurrer, to oDout u.7 por @nt jo tho la.8e-sized tumps snd 0.8 por.ont in tho ths €srly voe$ ol ih€ pres€nt c€ntDrv e nsw ioto view-rlai or exrrscr'in8 ths "oppor without ""." ,1" pJrit€s bJ cslcinsl'ion Tho dis(incrrve roalure of ir ;;t;;" l"ii'*ir* r""Jii' i.""l"ii'l,a pvriies since re00 is the alturo&rion oI penods a"J?U;"b ,1" *" i,' "uow€d to oridue $irh perio'ls ol lixnibni' rarnuB copp€r roolic"arron;o wbich tbo coppff is €xtrscl€d in solul'ion as subsronr'iBllv pvnles conr'sioins " ",lit",u. 50 per ooDt of sulpbur. n€arlv -- r*i *u au'O.o^eDt end presenc posnion ol lbis oxidationis rhe primsrv pupose ol tbis psplr' in motric unll's aod scwen aDslls€3 gi"* proc€ss oxtlociioq --W"igUt" i." ar6 Tytsr Btandsd. '"itoimlv B CtrnMIcaL A8PEcrB n$ 1. Cladn Ot Leuhing under Nornol Cmni^ms -Ihe msiedtrls olher 'a*' or;' io distinguish it lrom -""'lri. ". ,AmssBivo pvrits with the Iollowins alproximste i""*"a,'; comPosition : norcentsso E"';- ' zn ' pb f' etc ,4. B, s.or. s 600 |+it ;i" ii. 42'L r7l9o 05do o0o5% wii'h * i'"'**i*i r". loachi.ng, rho ore n usuallv run of-mine' c€ot 25 aboui' f-in passbg a lur r'.p' * srizzlv rJ r00 megh' dn"s *i]' "r"o*'i"' i in., ana + per "ont' miDus consisr'sd brotrdlv ot 0pplrcsrioos ti nl" t *. rsls rlu prectrc€ opurar€d as tollows : rli" uv'tu' r"u"tug ol *"r il'"i noorl "v.ruIu il. ;';;"";"'" Iormod bv ripping rorward trom e ronvenieot r"'"i *r, iu" sdvanoiag slopo hsd a vorticsl beisht up to 10 , rbruush, rrur by rsl,nts ,v€r tl,u suLmorgod l$aps.,crnrnmi',g iruo an,l orbur iutpt,ares. u,.l sujpLuric rcid, {s wu .as.opper sltpbdre, wru usuJ agEir ro " oxlonr Dy grs rl,y .asrrding. FrnsllJ, thu ti,luors wers "o*ia*"Ut" coltecrod rc pornt nf.the va for rocovery ot r,bu coppor by *"an"*;"*, tiil the sna of tho 06nturv This procosB deslt msiolv with tbo lump oto. - wi,i ll"i'ola *p"'""ion ol l,h€ domuDd lor pvotes ror sulphuric r;due. 37 .u" activirt. sllall (sprlc'rv unni"e nn" y SpADr. $trs ev, n,uo y rrurp ur tu"s Bvon. Erghr"or uo rirr,,J rt d,y ri,,,b. rr,,. ri,ru,{. p,.r,,f, 111_,Il.T:: ,on. trourr l,:iro, r th, bu. Lonra ,livunuJ ro n lbw s,r. tvhur rh. wLoj. besp^bod curr!,t. rb€ squ0res \vers p,cked :..-t:l: ll" on.t aiter snb,.un uver Dy it DBnd. intervat, Lquor wds ro-*ppljed. Erorh sar6r was cl,o o grxat tixjvisnt. buI ehu efluent soturioDs Before the mines cltne undor the presont ownenhip in 18?0' Drinitivo t0el,hods oI slroltiDs in dDsll l€trrtbs oFuPolsb 8PP'!r ocid manuieoture ThITO, Inorr$. nrd ronroined L.Lre€n 6u,000 rn,l 150,00{ tons. fiidoar i'f oru ul,,'ur 40 .,u. hr4lr wur. ntr,n,.J trrrl,,t ,,, , i;;. "i,,** Dn tbo h.llp-surtdco, &Dd lixiviunt ves ruu il. Ar frrsr,;8;;;; LDACHING AND ONE-EANDLING U"en r,t" ma; slo i. T f' *in. portion. To sopaiste rho mious I in._rhtrr js, tbe sizes suitabt€ tor rdorranrc&t roastrng turn8cos_- h6tr d -scr€ening at tbe losdim ploco€,.trcmmols. &nd toLer & .€rLrsl *.*"rng p1"", ;_" .{ll ih6 orc plus I in. wss rerurned snd wonr 6 form new ","J." hoapi csiled '.eturllod ovenizo hoape'. As rhe ovorsizo had rbour 0-7 p6r..ent.opper. lb€se h€aps wer6 \,ssh6d jusl |s Dew ones. l'oro tim€,a funb6r.srre plG g io. minus ll in. wos scr€6r,ed our, rru8hed botwebu rolts ord mixod with rho 6nos tor exporr, rhie iize beins.wuatjy. roasordbly tow in copper, tuo tow io juar,ify return lor lurth€r wesl,ing. 'l,3Br@dly sperking. rho orc undorwunr rhis proces t,,r sbour liv€ y€ars aDd tio ffnat produci,, caltod . wssh;d ors,. conrained 04 p€r coDt to 0.3 per ceDi copper. Abou, hulr-o_rnillion tone $ore pmcessed annuslly. Tho toss of oro iD iresrnenr, ilu6 ro ,ot,per oytru.tion, pynr6s oxidatiun, or.., averag€d 20 per.€nt. Accuatry, ure frmo ruqujred io rpducs [b€ coppu. conroot Lo 4 c€nc vsriud vory srodrty rro!tr hbap to hdr!. or6s Toulo ler ur a graourff narur€. .onraitring nor6 than s rormrt pmpo*ioo ,f lunps.vhich r&l1 to tho borion of thd ripping rac€, l€ached t8rr,iculally wdt. OFq wirh r} tErgu proportlun ur v€ry noo ,rai,orlai, on l,ho olber hand. wur, ,liDirutr to tosch. tn somo 38 J. t. p&EorprrATroN oF ooppsB AT Dro $YLo& aND P F wETLAx : LrAoElNo alID "*li"e ffi;;;;-;*b,p" iac-a"'i"e rhe restios sp4M! gg l0 motros b€sd oI liquor. Tbs oarly rypes w6re ot low dbpersion bur titrully rhole was srutv€d dx exrrooretJ si,opto sud robuBt typo, which threw &boui 240 cu.n. p6r,doy inro a woft€.I lield Bbout m€trcs wide by 10 m€rres long. Tho liquid fells ia lsrge drops, es shown in lies. 3 (?l&ie I) snd 4 (pr&ro II), oDd loss bI evsporation and wind-ceuyiDgjs sn≪ vo.y ile sliming over of the hoap-sufsco €Dsues, so thsr ev6D afror 100 spplioerions thore h no soious intorloronco with ih6 sir-ourrent. The oxtonc of inte ererco sufrerod in voniilstion oan bo so6n by srudying ih6 streoms of hoi oir whioh issue tuom tho supsrffciol oponings of the h6ap'su.Ia,ce and sro very visiblo wheD tho armosphero is cool about & roason:bl€ onlv tho rcpoosl' lov€' gsve up lho copper in rc-$asbed' be to hsd rle remaindor t"l"ai'g tu", ;;';i;;. Lonporsin incr"ose prosressve s *ti;r'ctorilv cases, ;" l""o rrlrro, I porjod roEctioN l{er€ so'ng i**"* **t*, indio&tios that exoth€rnic lailed io h6ot up or *i".*" *'""*'t'taolorv hoap either t "", roaulred e loos Period to do 3o' '"i''-"ir';"?'.*ma" bs since 1925, Lhe objec''ive aimed ar' dumps so Provrdrlg r'mn tho oroau;on or an eir-curlenl l'brough l'bo surphides Lo.th6 copper th; cbansins ffi ";;;-6;J-i". to th€ -isbolo l'o eppliod musr' air To do tbis "li,*"""'r'u1,. l"up, tlu surrace must oot bo srmod ovor l"-i "iii"tu r""u-'eot ". "r 'lu and e tomporature difrorcft€ mu3t €xtut toi "tine, th6 drsugbi io * msml,aitr "u,,ria, snd hunid in ths eorly nornins. tieuro 6 iptaie II) shows this ' breething' in s heep which hes b6€r washed by lprays for two y€3r8. bsviDs proved uosar'islsctorv' o''-"ut'" "p""ios m&t s33 tnoq tsls€ boLtom, koo{o Io(sUJ aB ^ni".ombleto duDp or lnt€D' sdveDritrs r"io, oi"lua rrolD the lace or tbe were lorm€d iDro pn'auel Li!6 Eigh spr€adiry-powoi in e spl&y hes anothor vslue; to oovsr s giv€n ereo, f6wor movements 8!€ roqdr€d ot, eliornorively, tor tho srne number of moves on tho Bs,no oloe o biggd ovorlsp, oDd therslore suror coverago, is eohi€v€d. Tho loyout oD the h€sps conprhos l€ed pip€s of 3-in. end 2-in. dianors! ieppod to ieee on 12-in. liquor-distribuiion pipelinos ruDning alongsido ilo durDps with, fineIy, ltr-in. rubber hos€ to ih€ spreJ$. Fo! sorvioo by dsl, waB ususllv buill' iD l'wo tiors for solorJ 'L to &llow for sotr'lemonr' i""."it""* lIreaa oI lbs bssp'slop€l'skoD l'bst l'be lumps of *i"" *""lito starred Grest car€ was each sprsyaD &166 of 42 il*" a ' i.".,'ll'l',i""-lir'". "r*wher6 bddslls ri-Des wilb flst-pi€c6!.oo rop ;;il;il"l";til";th€ a coDlnuousrv qss fo'w8rd curi€d r.h6 S-; csD: tho sl,lucturs or to too or rh6 h6sp rh6 r'*r ;; ;;-il"J;i;; proJ€cleo 3od '"etres were sound strd unlikolr to di!int€8r3{'o' "#L" "J""!al"i;*r""lotr oag bP€n tipped on suoh e veotirar'ing fii""" i6zt- base vootls' ;**;;;;i;;;;"]i "i""'li" succosaiur in providins[hocorrecL m3t-open[g€' ol vies close-up is a ';""ed l) iion- ficurs r lPlsi,o .'i'r*."z t!r'* if sho$s tbo v€olrLhng bese ol a boap wirh 3 rotaining rho omueDL solul'ioD' suDk6n-dsm "-ri" thst ot k€oping the srlac€ of 1b6 beap """*A "."U"i'' [xivisot spplicarioD proved comlderablv.moro doetr in sDito ;I 'Ourirc ils aclive lil€ tr €€crion of lho surieco mu' rn aincult wssh bv liquor oD porbeps r00 occastoas' i-"a"* " bJ ths L**"r" l"t*"en lr r'bs wssh is or rair vuLumtber'we€tr i"i l* "'*i1""1*"i'" opPungs soall€r or lbs oosr' iii,i oi r*'iu uppri"u';on stime' urd' llilin-s to il" ""Ua pr"""" l"'"" become choked up with e Dumb€r or benstrate tbeso, tbo lixiv;ant runs to soIo€ perl' wher8 oocu to8€tb6r end cba'rers r'hrousb 3t il;i";;;;""' to unirorn vsnrirotioo ss soll iffi "lJ li"'- tl" viowpoi-Jtr'tuoria"ut is to spplv tbe liquor in pui"orntii" rauDdors {oro ""?Iili"',1..^ ?€rroratsd rsrso dtops ;;;;;;;;'-' und€r """n "'" worki!8 or Bptsvs ro"our iiii i;"a i"l*". a""araealu x9 !o6i.€s is chos6n if 7-dey ayoto opersiion is coni€mpl&ied, &nd of 42x18 metrss for 14-dsy cycl€ worLing (Fig. 6; Iht€ II) ; o1l hssp-sulfecos ero m&rksd out bv tan6d lireB irro sucb &roas. WLon r[e rectangutar terntory csMot bo rigidly delineaied pert of iho hoep-fece is inctuded to oomp€nseto tor anJ d6[cii. A : i. rt i i 50,000-ton durnp will lave six sprays, each workjng siDilady in itB own dofinod torritory. Tho surf&oo worted by rhs sprsy iB a stlip mo&suring 10x2 m€tros pgl&Iot co th6 shofter dinorrsion of tho ar6&. By noving ih€ sprsy sr€adily aloDg &n iniermsdiste line o. linss, the whol€ surfoco cen b6 €ftcionily covered. tr'or jnstsnc€, lor s ?-ddy oyclo thsl€ is s contrel tiDe ooDsjliing of i&I dois specsd 1 meir6 Bport; et 4"hourly iDi€Nals the sprsy is noved oD6 scsp foNard till ii roach€B iho €nd of ths arso, when it bogins ot tbs oihor €xtremo agoin. Thero is rhus !o tong leriod whon no lixivisnt is oppli€d to the hssp a,s o whot€, suoh as obbin€d with ' pool ' washing. By tbb sysierlr tho iDi€rval boiwe€n weiiings of qny poftiolo oI oro is 7 deys {n€sleocill8 th€ a-hou$ of vash), end rhis podod is aolsd ihe ' oycl6'. It haB beon found thsi, for ev6reg6 cloan oi6 bid on mat, th€ cyole should bo betw66n 7 elrd 14 days. Vari&nrs riihin thb reDgs will be rolerred io s6 mrmsl m€thods, &nd aI oth6H as sppcial m€ibods. Imssinins s verlio&l column of olo 40 ol1 J. a. flla,oB aND P. r'. rflxrrrax : LrAoEr!{G a}ID pBDqIpTTAaION Of th€orericEuv unsfiucl'ed coluEn, sinco the liquid bv l'h€ longrh of thg is picturod as porsiug unifolDrlv &nd ore. 'Ib€ h€ights oI bP8ps vurv su.corsiv€U tbrough escb layor ol rrnm 4 to 10 mst eg, ma, in considering hquor qusni'ilios ii i3 found thot tho most D€€ful unit is tbe auount of solution rppli€d io uDit a,roq whott it i! w0,Bhed, i.o , oncs p€r cvcl€ l]hi$ iistus ol cubio metr€s por squor€ motro of wsBbod su sco is c6llbd tho ovcls quaotrtv. U tbo masniLuds ot rbia cyclo qusnriuJ ls Je'ided' elortoniog oithe cy"te o'oans that m"re llquor is us€d lrr $Esbins. lb's-raDgo uf noinut I, on wjl11.".".'l{il:1 dnd :-1*",*" murhods. wh"re hoaps a,nounr,iEg wi t.r_aoi LxJ,0,c., hrs bbo; ,,ow bo rovioqod. Aftorwsrds, ,bs b,.LwodD $n, oursir€ rbis ranse, trod or sp€ci,,t rnurl,uds in 1h! !'r[udl in,poqFibitiiJ ,,t rut,roJu.ixS o,, tr shull scblb rh6 c.W'rors 6xrbrmg. in a 50.0u0 or lr0.0o0-ror, hosp bss s"vd€t xmtreo I[€ us" or ]otorarorJ ir,vesrigarion in rbe probt€nN uDde; l*ii". uo of l,he mass ot 016 occuls. A secoxdtr'J edecl' ol 'lidviont-sp;[cotio!. Lhereroro. h ro conrrol tho l'dm]erlture' fo u**iei" tlu i€nporatu.€ of tho b€ap, ihe usual prsctice i3 to p]&oo load piper of 2-in. diemotor snd vBrvine lrom ll i'o 4 notior rong i" tire contrc of esch sprsv-oros, snd inBert deilv & rnaxirnun thernornoter fot 3 minutes in eech lipe ltecording z moon t€Bporaturos so obt8ined cou$o only roughly propoftionBl to tho true over8go tsmp€mturos, but ihe dsts are comporablo lroln dev to drv lor *ny hsrp and, sinco i,he couses ol ormr sro Bimilar, to * somo1vhat I€ss 6ri€nt from hea.P to hs8p. Tho application oI €ufrcietrt lixiviaot to bdng the orc down io air temporotuo, or near it, i6 the nle. Tho fotlowiDg gBph' Iig. ?, shows tho rise in iempors,turo &ftor rhc wesh hss been ore: epplied 'it v ltobetho noticod lbao tbe riss io tompursturo sll'€r tbe sorentb dsv is slos.'as hest losses sre bv Lbsl, stsg€ l&vge Tbe luu'hing ot a hosp on a 7'day cycle D€ccssitsles' orb€r rbjngs l'cirrg ' qutrl n€arly twice the totol lixivi&nt r€quired 1vere e 14'd&v cvcle enployed. But whoro&B viih a l4-dsv cycl6 s r!'nge of Ircm 90tto ?0'C., with en uvsmge ot 60', obtains, the ssm€ h€&p on a 7.d&s cacle viu show linits ol20'rod 50". wirb a m€so of 36"C' Ile procire rmoul ot lixivisDt roquirsd lo cuol l'bo oro doso to &ir-tenp€r&turo vsriss slighl.ly in accordanco qitb tb€ L) pe ul oto Md th; aso ot tbe hoap \4ir,h sverego cles or€ le'd oD a mat wb6ther l,bo q'rsntiry n€€d€d is sbour 2 cu.m. por sq m. or surlsce, a\€r&gg lhs b€trp8 Since or l4 days. rb€ rost-poriod hss beon 7 is &bout 3' pvrites grsvitv ol bulk specilic und thc ? IneireB in heisht, ar€ r.bin{ :l_,:]"i, ceo moro goD€ru! oositv b€ unddrstood loluiion though hotrp is to The primary pu.poss -u"*of putting " lUu sotrs cbsl havo sccurrrular'd duriug rliccolv€ and L." o. oxi,l.';oo pcrrod Durina th' r"sl'ing rh€ pr€coding 'e"ar,ing poriod, howover, as a result ol tho oxoth€rDia resciioDs going oD, us€. the SPAIN. 4l n.rr rr.,r,rny_wr.h,"r *rrr, . z to 1:"i:,:T,.,:1"-"r r"n,!,.rdturr :{i.1]1.,'*is" th€ hsap ond vico veEa. iD€trumoDi€ ere slso in TTNTO, scb wasb r€pr€s6nts onp.oxir atelv 0.10 ., r.u"g ta" i,,"ii;;;;:';; ;., ;;:;"i l;J,,1i,1"Ti.":fi:1 "".","r psr lon ot dc liuclssud is rjrur"ruru ebuui l0 cu.rr. rf s 7-dsy .yct6 rsurloprcd,axJ 5.J.rn. itq ta_Juy cyftbid.l,u.uu. so. mel,r€ cross-ssction, r[ is au ouco evidenl thsl' tho conditions ol [r;[06or. sr€ copplR 4T liIO ol 6 Fro. OAV5 AFTER WAS H ?.-Ris in rohle.aruro rit€r W.sh hos b€on epptiod to ,t6 Otu, durdrur.orrrin portirlonr res.tiuns, sucb 1*l:: ll::t *Lluk1 or.pJntes. tre oquiribflu,o borw€un rotruus 1"" "I':"1'.' and :'r€rno surptrar€si &ud Bo on, are ot lir e helD. hsd to bo Jirurrod rn rb€ b6;pd lb€r,sotvos. Apart l I $ I * ,.lnv€sriastion trom lh6 ob!rous drdicutties ol,ogelh6r mst€.ial-units of 50,000 io$, of e\perin,enting $ith rhis ,n€ant rhsr conploio iesis lasr€d Th€ sJstdmstiriDg or spray n,ov€rDents snd tho rucorJn,! .,r t€mper&rures rofl€cl tb€ €tTori ro goL sn "f.lli !11.:,j As sui,nbre h€aps ::T1"^,-:l-L:lij.l l,s,,"re i""igbt irt" [t; ;;;;,; *," ;"d; i;;;;;";"" wofu mmsured by woirs or otbor rnosos, sor€ 33s8yod ar porlods equal tu a .ycl€ or n m4tritt€ of'.ycl*F, rn 42 J. E. TAYT,oB AND P. !. wg&LAN pB{orprrarroN of ooppER AT &Io rrNTot : LBrorrrNe.aND ordor to oonoBpond in €acb osse \\ith ths wsshiDg ol tL€ ssno or€' Sincs 1998. h addition to msny loss conplote inv€stigaiions' some S0 oleeD or€ he*ps hBvo boou closely studied ihroughout thoir €xeminatron shows r.ho copp$ sulphid6s oxisiitrg as prsi$ in rhe pyriro, and iodiu[6o cbalcopy:riio pnmarr fopper mrnerar, oud cove iro (cusl snd nd8rJ oDrichmotr! or reptacemenr, torna. little fiom h€op to hesp a,nd nonih to month thst it is sufici€Dt lor pr$€nt pu+os€6 l'o s€t down tho following epprcximsto composiiion-i! granB Det The chelsctsl of tho lixivia,nt vari€s so or,. charcopyriio pr€dominsrss, csDnor be mado in rbe abeence of s r.rusrworiby .hemicat mer,bod for disdDsuishiDg reachod ,":-,"^,i.l::.-1.1c,*l "."d oul a qu8urrtqhve slaremonr it"""-lnl".j spocleslnarDsssrwors. Fe"' Za Cr fe 1o'ooo loo 1 In sll cesoB th€ moiols ars pressnt in th€ solutions as Bulphetsg' 'Acid' meem frss sulphurio aoid; tr'e"' ru€&ns foEic iron' and Fs totel iron. From th€ liquor qusniities sDd asssys tho vi€lds ol coppor, zino' otc.. fron th;heap ero catculeted: This, tor ih€ whol6 life of 3 cl6sD ors heep, mBy work out som€vhst sB follows iD 814!os fron osch ton ol oiginal oft au 4g . Iic:oscoei. I;l:J:s."f.'li ,,"*: li:i::1 ectiv€ lif€. l,ooo l,ooo l,ooo 8,ooo sparN. - : Za ,'c dc'Or 10,ooo 16,000 8o,ooo 90,000 B' l0 At 1'ooo For svongo normsl loaching cotrditiong, wo csn sot dowtr th6 lollowing summary: OtuC.ZnPbFIAtBn&'' Td....,. tOO xlioimr.il: Tod.., 20 Pd @nt €IimiEi€d ,O Wah€doF: ToN 80 .' '. r00 b6 of F8hed ;; ";-;,;; ...-...Tiple{t r 126 20 l6 420 4?8 06 I,O r,6 .0.3 8 0 9.O 0,1 sO ?6 20 l9 l0 '0 026 06 l2 340 388 04 sio! 006 6q .00r 20 oo4 60 o3l oo t5 42s 485 06 006 6l * r t" The eolo*ivity of thelxt'"*""?.u" "',T"a " $ti!b thsl, th6 ooDoer and zioc so iol,o solui,ioa quicllv compurod process, hore€vor, ths orher elonoits. The meio loss ol ors in tbo is cloarlv dus to pqrilee decomposition and i'be iron sDd sulpbur ot ib;-6nsl 016 difrer lil,tlo trom rh€ orisiDsl' -pe.centice. In choosiog tresl,m€nr .ondiL;oos tbe aim is to oblsitr: (1) Quick €xtrection of ihe copper; (2) Low sbrmksge or loss ot PYritos ; ""* (3) Liquon suit0,ble fo! lurther treetm€nt' I'ron ihs viewPoint of lurth€r troetmont, tho d€8idol8ta 3r€ low contents of leirio on, sullhuric aoid, srsonio end biBnuth itr tho liquor, but it happols thsr wheo stopB s'€ takor l€od;og to a c-rai:r oiiaese elomsnts, tho i'rostoent may havo efreci ol iacreosing the propoltior ol tbe others docr"age in l'be 2 i I I : 16 2' MONTHS TEACHEO Fro. s,-Avo.aAo [email protected] ctoan OE H@ps: Monrhv yi6tda. of copp€r diffom drsrin.rly rrom thsr ot slJ rh6 ,TI€,d,Tdrriotr olDe. Dodr6s. exc€ptiDg p€rhps zinc. l,bo raprJitJ ot extrsccioD is. in prolorrion ro rhe smounc p.ur",,t, uoa iL i; *rJ *gri;; foirs ofr rapidry unrir. ar,", ;," lo:1",,r-,:.1",.r: ;;;;;; "r.*,.i"nd DxaJ b€ orjlJ on6-t€nrh of wbsr it wm in lho b€aiooirs r]:is. ar. 'r li \yasnatural ro oriampr to.on€laL€ rh€ dimrDishiDe;ield;t; tho fallihg copp€r-mo(enr of rbo oro, EDd a valuBblo rosuli ot lAler, a srm!ro urpo!6rrjat retaLionsbip is louod ro €xist. Wlsrhor 44 J. II. T.aYLoR AxD P. F. wllllalr: p<clltT.aTlotr LE-{cErNo -dND cop?llu alr Rro arIIO, SPAM. 45 Onco th! o\t roociou curvo las defin€d itsetf *nd rhe rsre is known, i6 tu.pc8ible io calculeto wi{,h conrido.Abto socruocy iho coppsr Jiold lrod ony li6ap dc o tururc itsie. devisiiotr tuom iL6 srrsighi tino visibl€ in tho e&rly Inolths . Th€so)ue cusb. o.bvi,,rlly Juo to !16 prdsoncd or.,pp* o" toefundamcntelc&use,ot 6risos through sco lbinoiion of 33ylacl,ots chesctoristic of Rio Tinio oro! onlv, it is inrlossiblo i'o losadthme the With on €xpononii&l relstionship, the plot ol o{ ths yields should bs 0, sir&ight line as showr in lig 9: this of iB due li, lx. r..!ipr,. thts coppor sulphare cou€s u, in thd iirsr sup€impoeJ on rhu copp"r yiet.ldd LJ rtrd l€oohilg lroce$ propbr _tl]ai due io oxrdsrioD of rho sulpbider ro sulphari .Dd-oxir&ciion of the tsttsr. Ic does roc sll co;e o,i in i 6,s; vesh be0au€s,somo^Dechsnicat s€trUng ot [b6 duup is required to cxpo8o rL tuuy. tsy iarerpoter,iotr ura armpl. catculalion n is possibt€. to dererr no rho emouni of the c;pp6i i! eaoh dum; ru the or! on Ir* o I "urpr,*Lu DoDLDs, shich has trppeerod as.sulpbsto. ODty nseUgibto qusotiries oppoor rrom dump8 formsd ot run_otmine ore end r,be oxlBrtablo copp€r tuoD ih€ls ihorefor€ comos out ftom th€ steft si rh€ r0 to 1, p€r c6Dr po. lnonih reio. Bui dunps fornod of Dliuor&l cr,:*1 L. urn":3 in. bbow sbour 0.s per cenl cu jo thi! rorm, aod,l,!is meam.tba, to gel thb cuslolqarJ 95 por coor, recovery oi dt tb€ erlr8ctabt€.opper (usually sbout r per cerr, on orel noede 2U mootbB oro is trearsd, strd 25 moorbs if rho uro 't.ruo-otmine I{ONTH5 oi logsitlDs of vi6ltb' fro. S -?lot The DoiDts do aduqlly tsu on s straigbl' linc wilb l'Le 'xceptioD ol tbe 6nt low months wh€n tbs Ji6l'l is srearer l'hon would bs lbs diryran' €xD€cted, as ildicuiod bv lbe docred line on lnnut oros rrneo from 2 p€r coDL ro I per cont copper_coDteDt' rl" ior.er wiU rLta m,ch moro coppor in six mouths. as a g€D€ral rnl6. l,hsn rbu Istter' But lbis is nol a luDctron of tho w$bing ar, oquul grsdes rho vields src similer' "noiitiooe,iL"'" toe-pto," oI the crlpor vielde hom numerous lreaps Wluo mo oDt sro exemin€d, ibe fact er"orges t'tret, noglecting for the linbs ald th€ st'raighr aro 0ll th€v monlbs. l6w * Lle irr.sul'. E Pxl'raction raL€s to corresPoxding idunlicsl. fllooos s-ro Dracticauv llven 28 d0vs i"i**' ro'0". ""'i"'a 12 !€r cent p"r mooth of r"."" ** *1"* lixi!iml, ol four tiuos lb€ usual conc€nlration *er enoloved, eo 1I i l,lri:ry'" I por coDb rat'e resnlied' ir"t *-* "ut st this 'rusdv reto w€ mdv call lor ir'" "'""i* lm oxpotreni,i0l copper" Assuming trn u{trsrtioD *r*;"i* rets of 10 psr cont, the following isble applid : Pmca^r^G! oF ' EFoENTE CoPls'LMCE O@ 2i1 Aft6r 3Eonihs " -6 ,; .......... ..... ..... .... - 4G9 0 12 16 ra 2L ,4 27 ,, ,, , ,, ,, ,..... ...,......-..., -.... 6L 7 ... .... ..... ... - " .. 71 75.4 ,,,.,..,,,.....,......,,.............., 35 0 ' 1t9 r .... -..., ....-... . . ,,..... ... ...... ..,,.. - ., 920 ,,,.....,,,....................,,,.. . t4 3 r.wo y€ars ot tea.bing, rbd muntNy copper yi6ld is sboui _^AIrd 100 grm.. per ron of origintrt or€, and jl, is ,,uuaify i"lftog. ft it o, ro 12 p6. c6nr pdr mon,b;o,e, io lrop il,0-10 lnhorl€ ums ]hoorelraltJ 800 g. more coppd wout,.l..Le €xtn;kd pd too or ong'nat oro. On sddy, bosover. th€ miD€ral is lound *::"'" cotrrartr abour 0.85 p€r reni cu. rbis r€prcsonts T":l z,UrU I. ol coppdr per l,on oi origjnal or€, as w€ must componssb fur rbu.uurl 20 ps .l.Dr loss or weigbt. Car"utsrions Uased on rh€ ongusi rod nn r oro sssdys aiv/, in aI cosor, s srrutu rssulr_ sbour 0.20 pFr ,!nt Cu in rbe urigjoal 016 js copper imrtrune ro obe ordinary terching process. as a "onvorient rerm. rory b, caUed ,insolubto coplpr.j .b!tThis, Imumabty s€ro rbo tescbrng conrinu"d iu,to6oiroty, ana aI r,he pyrirus oxidi,ed swsJ, slt rh€ copp$ pr€seDt woutd b€ *:"y*":l sorurioo. .Acrualty. in a fev rrdts Lo oxnauerion, s [r,tt€oDg'"ot tbe ]o8.yiojd ourves towllds rho end bas indicareJ oro slrioksse, ss siu spposr sbonrr. is onry ili:,^:I:j.1. or rDe orour or t.Bl! per.c€nt I€r monrb in prusenr pracric", uod is lhus.3m3ll coDp red with ,hu ooppor exrrscrioo r €. l,or pr8clrcar purposFs, ru td.r. e.uDorni.6x0rrrrion 6Disbd q'iihin ih€ raDge wh€ro ihe oxponenrjal lew is prQatominant. weil ID srnnr&ty, srte. two yesB of teeching, ovor-ett rocovelios in ,ri E ii 4 Iu ! * ffi 46 J. E. TAa'r,oB -AnD P r' wrrELAN: LraoErNq !&Eor?rTartot{ ou oo?pER A'! BrO TrNm, aND These s,ro only int€grotod cent ol the motsl in tho ote Iiquois now r&n8o frolo 75 to 85 per n1iDorels Th" ligher ngures sro recorded lor ths fch€r tr'"'i"a. thm thos€ in : no ., ii" i"*r"lr""' oppp1" "ppuu"" to bs sre&ter 0 30 end 0 40 b€r'qoeD in" n'"t -" ssovs t ,h" ,;;;;;;*" is *pp"i Loacung bevond l'bisr Point or th€ htt "*^t vieldod ""t ii" ovrr* 'xidized excoedg end thocoprer ""ru""-,t" 'i[" "1'1i" loss ol weisht bodics t'ho oihor *'ii"ti"" "t t"Nidered stosdv sooorh curveq hke uboso "r .l il#rn"* "'" "* "r cobD€r vield &ro no longer h€ops, end fouDd Aradrcalcbtrngornrred'ubuu producb. 3 wir.bin ih€ 7 to 14'dav cvcro mns€ ;;ii;J;;;" kopt aB condiiion' r',rso onoct; and aven under ;;;;;;;;gt tbe io ts Isss reeorarirv J"-ir' "" p",'''ir" .{1"-:.1:"j in & difr€renc6 itr tb€ m6'b8nl3m or €xrracrrou' for ie toouea -sv smau i]" 'u" 'oppor must bo protu€d thus a: apors or "t ol end ioterior rhe et lies ulphido rhis por€ ir' normullv f'lled wiuh e 'n"'pvril€ or sarta, witb a prorrr:dins bui ron o' tidss rbe Lbe sppricorioa or a rixirrqDr' Arrrons bo mrv i"nu";;o the r&to or copper vierd ri'oi. ;*" tij *'^"" "f ;;;t"fi";t* ir".#" "r'"'ii' il"it-"ii."L*"t.*'# .. ;fi;ilJ;"' ;;;";i;;;;t Mocbsnrsm eod sp€ed ot transport tl) the soltrttoD ol oxYgen inwords thlough tho (D fr'";"p;.;-;p""d ot coppe" io"r out'wards tbrough goluuoD : : or ndge' *""r"*""**u"ti"" effecrs iu sshs Bt l'b€ nodul€ on th€so work *J -i*""ii.- a"t' I've r€sulr'6d rrom laborarorJ but io concenirsi'iotrq: ;"*,;";;";;r""i;"" and iorornri sartphvsical or oT uo"leage or ths fi;;;#i;i;,; 'h€misir) 'on' useluipurposo wourd be servod bv srins ffi[;-;"i;;;,; ,", moro il€eplv ioto this ospoci h6ro' intimai e inr.rdependen"e betwe€D lor rn'''nce' 1;"-;;;:.;i" pvrit€s exotbormir ihe srronslv and herp *.'i]'^a,ir r'i'la" ' ouiput L;s iiltn;-*,'"*r"" cso quir's roo'eivsblJ cnuse ; ro ow emutl chenges io treatmPnL 'onditiurrs' ;;;'t"* '-ii]i" rhp ...l"trn.l.or"" r,o give a summsrizod viow orsDd 'rtremo tr r4-d'v LomperaLuro' ;;"j;-Jn.y,*"b *itl a"so'c orobeins uod'rsrood rhel inl'or' o oo:C. tompersturs-ir .i"r" *iLl "*.aii.* respucti\o rh€ rosulr's givl inrorood;ato "i"ll" ;;il;"' ;; whore iire wil bo or th€ rolrowiog orJur-in gr&ms i*- "u"t to' ol orisioel oto : Bi Aaid Ie 60' EosD6 ...,- ; ;;;;" .. .. Cx |O,OOO to Zn It" ti.uOO O lO0 ooo ro,ooo 6 ooo 0o O00 110'U00 ooo ?0 '4a 500 1 15 0o0 s00 6 Spall{. 47 picrures. During minbg, transir ro tho fornrition oI iho dunp, rhs oro is oxidizirS, r$ulting in &n airDonlul produciion of oll bodies iD ths 6rsc mooth o! l,wo. If pe otlii this otroci lron conBiders,rion. up rh6 outpur chJrtrct€ndrirs 0" tollows: boo, srsenic, sod bismuih yi€lds f&ll ofr very slowly: ettor iwo yesrs ih€y ars about 80 per coDt of iho oorly l€vot. Sulphuric scid yioid togins sliitlelow€r sxd oDdg BoDovlut, hShor iho! rh6iroD, th6 &gg.€t.i€ boing of droh tho Bame order of lragniiude. Ierric iron produotioD is dotormin€d €ntiloly by rh6 oondiriors of t.€er,m6ni. Ths oDly body with o ropidly loiling oxireciion chsrecr€dsric simito! co tho oopp€r, ihoush Doc &n€nabl€ to such 6xsoc cslculorioD!, is th6 zinc. Th6 ouNo roploduced h Fig. 8 shows yi€kts for a, hyloihetiool ov€rage he&p. Ud€I Domsl conditions iho pydios deconposition is elmost su&ightfoNerd to lorrous sulphoro snd sutphuric eoids: 216S, + 2H,O + lO! : t!.€SO. + 2H,SO......,.....,,,,,_,,,(t) At o low tsmldoiure & small proportion ot rho iron sppeors es loFic sulpheio : 4FoSOr + zHlso. + O! : 21.6r (SOr), + 21IrO...,,,, ,,.......,,(2) Ths acid !h..b actually sppears is usueltJ sbou[ B0 por c6nt, loss than is indi.dl€d Ly theso r€tetions. Whar, precisety iappons io th€ €xco6s sulphur is uncertain; sono is elininatea as eulptur dioxid€ €v6n in cool $,orking, snd sorlo olenontsl sulph;r iB fornsd. Tle priEcipol exllonotion of iho discrop"ncy, L;wev€r, is scid al.teck on iho various basic or acid-coosumrng mar€riols in ths 016 or tbe glourd on which ihe h6&p is forned. Tho docomposirion of an iron silirst€, tor €rsmpto. incressos the ror6t ;roo eppeuing in liquors and lowors rbo acid sr the same time I Fos'O, I HrSu. =fesOr F lfro I SiO,..,,,,,.....,,,,,. ..,...,,t3) ft may appsar siretrge to considor suoh otr attack occurring viih tho I p6. ceui acid soluiions conmon in 16sching. Bur rh; lolg timc'footo. &nd l,omperstuie musi s..p! (Iiq _10, Plote III) b6 rotrrorrbor€d. Tho phoroshows o porrion ot s lump of porphyry ehioh hed b6or lwo ymrs in e heop. Tho whire sur.;";d;; onvslops ffisoy8 60 por c€nt silics end is prectiosny froe frorn irou. ghich np.$oni3 10 per cent of the inr€rDel uniouched poriion. Th€ highor th6 &cid-cotrteDi oI tho lixiviari, th€ grear6r, es rould bo €xpoctod, is the divergonco bei$,e€D rho lold of this body &Dd ihet €xp€cied if only oquations (1) &nd (2) ere tsk€n irto seoouni. In somo special t6sts wh6rs oirouleiior of rho 48 J. E. T.IYTDB aND P' r' wEorral{: r?ElorrrNo Ar{D PAEOIPITATION OF OOPPTN, AT RIO TINTO, g to 5 tioes uh€ norm&l disor tbe.6D&r ore rosurted co^t .Assav onlv r p"r cuur" wbi' b is oormnl lor 'Dv iii u*'""'tl,J'i""a cl€sn oro wsshod -til""iJi*u",,t *'6 of the iion vi€ld.comins hom r€scrio's in culculsling oro loss ts, inlroduceg 'oms ambieuitv "ir.iil,"" rhe sxs t srste oI 'oDbintrtio' oI ihs ooppor' ;ffi;;;-i;. *o is eved l€ss csrr'ain: l'uo as rb' soounis " i"i""i *""";" * '1" epproximatian of 150 p&rtg ;* ;"Iil; foesible to 'nalo 6r solutioD rakhs lli i"-.1"grr't'.t prrts ol roerals{egoios.i.ro rollowi'g €larroD th€ obtsin **'ii"* * pvrrr'ss, lii#i-' "i 0!6 sblrDkage : Ior caloulstins Woietil@= Fe x 216+l6(Cu-zn *r'*",1"""1"J*L ;i;;;;.;.-;t; L:.,:""1:il-d;;"fv loadod q,"Lina rAB)' relor m exrracr'ion in grsros ptr too ssres ro "v.bols c*rcutated bv rbrs simnre rormura and tipped tonnrgee *irn nt" ""*'r '"il:T:#:ff;";;iJ'e 'itii *i.wet tr" po*ir'ru e**os ross orsurphur' h t'ho 6rat rew rnonrbB bu0 srtere'a'ds t-"1""i.1*' d€rieed rrom rhe simnrer rolsrioo' oeglociing wt ^r"uer the basrs &dopted lor ut€rpr€turtthe locts' oI ore rdus ross rho csrcur;ted rsr€ or *"'r'" nao aqss. For hol' normullJ-wssb€d hoaps per p.r Loitb rnd lor oooL herps pur csnt ii"titt""t''"""; tt"'" il'ff;;;i-"d;"d. i;*.1.-'".-'" r""Ji'i,,,' i i J". *;''i";' "' :b- : T.il?'- ii'r.'i J:H'.1 lil,io"''" i!"" "".i "cotror rn occor&nco wirh ."'na.tiv.lv. Cheoqes in trestm€ni r"* ll"'.'J'iJJ'i",""J";' l'",'"' - r€sulhngor€ hisher or lower temperrruo lh€ '-,rr.iJr'"to, l&sl lr€sdv loss of oro coopsled with rhe or "t.o"' .;r;lv doiormrnes tbe eono'ric cur-otr'point' r"riJi iippq vala' in spite p*"i"" in i'ho d'rerrion or 'orler workins lixi\ianl ii larser "."ili ***sed lorric iron productioDptr hmp'p3$ase iiiT"*.t'*i in ii"-."."'i""t "r low€r €orichm€nt 'opper imtr and will allow tbo hric r€duce nor a" to"C []"** r"*,"". a 000 s per cu xr' oI hrric *"r"inios r'000 b l'"""ii]" "i I'ii'i",i ""6;;;;;a'r' so'c resurrs in s vi€rd or -ea" " oI ore process€d' ton por iron ro*ic ;"' '"oo',b orrhe ioput liquor cont'aroios ffid;;"nJi;., 1'600 s lr i''^-.i-i, * i"r'. "i"'r"r' percum' 2 000 thenwbuns2500s L' J'..-. -uJ l'i nTi';"ilil fii"il;; li'l.*-. "tthcon"enrrarion bPcom$ 3000 s per cu m' ""t* it,-;6nal n"".- cr"* ,"i.1"# *ii"t""r" ore lPechioe undor cool oormsl conditions amounl or rerric irou n'oduoo a defroite from 0 3 por ooni to 0.4 per cont coppo! end 48 16! ooni sutphu. occeBionelly hosps linish l€acbilg ai a $eate. r&io than export d€m8Dds. thoss css€s ih€ mineral is put into ootd Btotsg; b, tippins s ]"noir6 Isy€r of lino woshed orc (ninus i[.) ail ftoo lacss ol ih€ dump &nd burying ih€ oponings oi th€ .msf ir Bimilar n&teti6l. A' pool ' w&sh on rh6se ffnes s6sls sll operiDgs aDd vertila,tion oe6sos, tho tenp€miuro of tbe h€ep st ono6 Islting to sbouf 25'C. In this siato th6 ore osn be loft indefnitelv l',ithour h I I i l I snd ari'l t.hi6r6ricsl sulohur oqu'vslsn[s olt tbe melals 49 On th6 othor hand, a cool vorking c&us€s rnucL loss oontemina" tion ol ths solutions by ocid, ars€nic ond bismurh, sB wsll as oeusing I$s lo8s of weislrt. h modo.n prsctico th6 iotll iiDo und€r l€eoh for ct€slr ores is two year8 0,nd ih6 loss ol or€ in rhe procoBs is ebout 20 per ceur ; 60 p6r c6ni ol tho residu&l oro iB plus I in., bui tho ooppor-coni€nt oI ihis portion is only obout 0 6 p6r cenr. Tho linEl om sss&y! aoludon se\e soid cosceorrsi'ioos ilHff;;;L;tter SPAI}I. ; furl.h6r lt Eshilrg. Pyrit$ is s poor coDducior of horr and oc &ny momont rh6ro lnsy b€, in an ociive h€rp, wedg€s or oro vtrrying in tenporsrure in sieps tuom 20"C. ]I,her6 a spray iB worling, ro 50"-?0"C. io th6 B€otion next in order lor tresims r. It woshiDg w6ro siopped ond Btsps werc not iak€n to pr€v€ni oidsrion, in tesg tbgD ion daF the hotter sections would h'v6 rooched igniiioD poiDt snd cul.rnsrion would begio. spr€&JiDg ropidty Ihrough r.ho ure. Sulpbu dioxido would como ofr in targo votume, mix6d nitb Lri oxido &Dd frso sulphur, end rh€ l&ft€r, on occssion, vould disr,il jnto the cool€r rootions ol th6 dulllp whor€ it, njghr'iBuso greot trouble dus to spoDisneous ignition du.ing lo6diDg : 4I'€q + Ir02 : 2ForO! +85Os,.,,.....,,,,......,,,.......,,,....{4) 2Fe3,:2F66 + A, ,-.......,,.....16) Wbsn liquor is opplied co or€ in incitienr o! sciivo celcination, iho h6ap sinls owing to a brook-up ol rhs lninorel. Tho 6mu€nt contains lsrgo qu;rntiiies of fr€e &cid, ond rhe €xrroction of arsonic Ioay oxceed €ven th&t of copper. OwiDg to tho presoDce of €o nuch sulphur dioxido, no louic iron is producod and rhs omuenr liquor is absoluiely fr0o lrom tbis body, that in the inpur sotuiion also being roduced: Fo,{SO.), + So! + 2HsO = 2r..osor + grrrso................ .(6) Old recor& of th6 p€riod whoD opon-oi. coldn$iion was stsn.lord practic€ show linal efiluoni soluiioDs of ihe rype ihor rvoutd bs expeFl,ed from wh'r{ bar jusl, bden said. provrded the pJrires has na vslue, and contarninrtion oi iho copper by arsoDio is nor oI account, ihis type ol lssching c€riainly giles rhe coppor v€ry 50 J. E. T-AT'[,OB AND T. T. VIII&LAN : r&Dor?TIATION OF Coppli& aT RIo arNTO, LEAOIIINO A}ID oui{klv snd al, th€ ssmo rime olitniDdtes whtrl' has clwavs been tho f€rric iron' ii.. -"- -i* .1"i"* buqb€ar in wel motbodsforogoins condi'ions speeial u" t"*ta,g und 6'.' cli -rho speciol vhen rrngo; loachiug Dor;dl tho *""J-1"' a*rt wiih enorge' lectB int€rcsiiDg manv s,r€ deslt with, m€thods * on a sho* cvcto (bolow 7-dsv' sbs iri"d i"*" "*Ui* tr,i throush sir-curreor' Iail€d' no sppr€cnblo *" I ,""1, ' 'irn" sn.l l'ho ourpuL of coppor aDd ziDc 'ell [o a"*r"o"a, l*i "* bismutb ii."t.*-rli'l "i ttl, *rnal ors losg and ursenicporJnd or i'ho c€oL to ?5 up r"U ;' ev€o sroarer degr€o coDditionc "'.i*i;". normrl When was rn Lhl lem;c siate i".ir*"a to, s low months pass€d bofor€ i'ho violds egoin ;;;";"ft"d to notmrl incrcos€d "'i"i-il--"*i"" r"*lins hes olso bsen iried rhs ors is tipp€d Beoouso ittt" t a"- *a solution passod through continuouslv oI ooppor rsio t"'"rg" i; bs itostod' snd ihe slow tl" rn tho m.rhod ".*.*. r*" "i r*.*u s standard ;;;;;,-til r'bo $irh 'iw* w€ro oporar€d ***t subm"rsed dumps sevo*r "'.i.1-1""i""" sorution€ tb. rro' terr;c iron ;;;;;";;i;;s r.."n* €qusiions hsve booD Proposod Cu,S + ' 6Fo,iSO.)r : T 4IrrO-2CUSO. T ru|oso. + 4H?sr" T 4a:do' c,is i o-e"iso.r" _ arqo cNo. aFoso. 8Etso' l?Fesu'l r cuso' l Euto cur€s"+ 8fe.(so.)' 't 8H'so' lanto-l5rsso{ lF;so.;. s"E, (7) (3) (0) (10) oro w-ar A car€ful irvestieeiion on a 50,000-ton dump of rizod leid so thet liquor contiDuellv v'6 help Ths *"*iir-".a"itt""". {€rr;o r.o mr,hin one merre or rb€ surffe Tbe gromg ""-""Jilr"*l iii'-*a*1i""" oapscitJ I'os louDd ro iall lrom 100 to 50 r'ho hesp vees ;;;il;;". -i;" i". oi ore per dav ovor r'ber'2lour $as sriu por c€ot' onginauv ;;;;. "on'"'', loachiDs "oppu. dubmorg€d olrdctor' i:r * tn"'"i'a as o copper jron solutioo is slow llo'0u3e "er "*t*"fI, p"' ' or ierri' *i,f-e.ooO "' pur' rbrougb' essav diff€ren'cs jor rho *t"rnes in"'i*"]r'.'J "i U.al" to provjdo dsra ror rnv uoe'ul Joducr iors' "'i' "'"tl "'i,Do "i1"" rhe pres'ooo ol pvri(eF bss e de'id€d l'bor -"t '," *ia hero etrect on i'he lelctioD 16r' Liquo^ Irom ;;";i." - ctrtalvdc conLaiorng coosiderabro rerric iron wilr show ;;';iri;;"', lli^-i^'iJld.r*"i"" iu-a pvnreg lilrer' and r'hes€ condir'ioDg *" .l subm"rgo'l dumps in 6Ir' '1ul ctrbcs T"ii -i'.ili.r; '"rru"i1" rjch ir rerric rron (moro tboo 5000 srdns per """ b€r€ r Pessed tboush .ub"":;.;;;;"";'., roduction vsruos or perh'ps show such riquorB l;;;Jd-";i""' 'i""ii",11, ioo'".." p"' dav pe' roo oI oru previousrv r€corded Sf.AlN. 6l Such solutioDs los€ souo fsrrio non €v€n if pr,sB€d ihougL N l€ul,ilat€d pyritos heari. Iu f&ci; lrlary yoars a8o sftempi, ;€16 mrde io produco concolltr&ied forric iron solurions in qutrnrity Ior ie!(LiDs pJritu, -ui!g rtu iruo bah rs sn oxygdrFrlrrisr. The pmcsss fdiled becousg it wos diGrulr io roiso rhe ferric iron coltoDt io r high levol cheut ly, vhile ownB co rho slownoss of the roectioll€ copper oxirecrion wds slow aDd rhe sfl1uor6 liquo! lrom the proco8s wos bsdty (onisrninofcd. S. Otl&r Ores a d Makfiuls.-].n eddiiior ro puro pyrires, i.o. pyiies rviih s sulphur coDt€nr ol 4? ro bl p€I cont, tho minoB produce tv" orhd rypb ut.re r.r tonrLug : siliceous orer, urying aboui .:5 nd curr bult,Lur, i,, wt,irb d,u pyrirus aDd orhur d{lpbide; .are rarAelJ rngroru, J iL q'rJrLz, auJ. dirrJ i.6. pyrilds uoo\oid"re, ablJ ,!nrDroiudted bJ burr"n maruirl ,lurirg mrniog, aod rhorefore ooDirining oDIy al,out 40 per csnt sulphur. Borh ih€lo r,ypes Dl&y .contain up-to.g+ per ceDi copper. thoso oros 6r€ tipped in sopu*o hesps, eDd, if Bufficiont lumpy norolial is pr6senr, er€ l€ached .oxeily as tkon or{,s, by spray-Dar morhods. Bur ft usuoly hspperu that th6 lumps ol thos€ typos ot ors ro roquirod lor sDpll,iog. lesv'ns only lbd rinos lur te0cbing, un,l when 6oes ooly arc leo.h"d. rhu L^isll. ut rhe.tuml,r rurrre,t is nor !ll,wod; .€xeo€d 3 motr€s. By periodicrlty d.&g8i'rg & rstc,outfii ov(JI cho surface ny trsoror (I'ig. rl, Irlsie ItI) ii is usuolly possible ro uso lpmys for &bout ono yorr; Irltor*{rds, ,pools' hava io b0 us€d. About fiv€-yea are roquired ro iuko the coppor-contoni down to botw66n 0.3 dDd 0 4 por cont. Th€ cines ftqm rhs SO, ioduci;on plant (doscdbod l0,rer) and e_ Bulphurio ocid works aro 'pool' woshed in E€parar€ dunps. c these Dsy contsh ut to 5 per ccnt sutphur, sod when losch;d cold giv€ lorgo nmoun{,s of terrir iron. 'lhu qudr,(itius ut rl!onus un€ rpcuiruJ to! rresr,nutrr vsrv corrridprably: l,L,J have repre{eutdd abour orre-qurrrer oI rhe total tonnoAo ledched since r. Ld!tut C. oJ 1900. OPDRATIONAI, ASPECTS ond, ore Mo\enent._'rhe ongjnal Leacw OtMds lescbine sroDnd, the Corda vollcy, and I neigbbouring Le, Tejonora, v€re \'.oll plncod to r€c6iv€ ore from rtre hiAhor sections of tho niDe. fhey $aduolly fitled, however, and sinulrsDeousty miDing w6ni deopor. To Dvoid hoisriDs, o new ruDnei, rh6 t6ri Floor tunnel, 1ym drivon, iopping & tower lev€l and smerging er o point b6low, a.Ild disient from, these odginat leoching sir€s. Work 1lrB theroforo grodu&lly transfoued to r new districr, oroo witl bo describod here.2Irs Noye. Only l,ho loyout ot this it 62 t. g. TAY' oB AND P a' wErLAl{ : pBEoerTATro!{ ltrraoEr}ro Ar{D mino f€o6ureB rslation to tho older Ieacbing grounds snd oth€r ii- .howa in Fic. 12. au r€rdiDs to ooo rcrativorv e s*i€' or i; "€h''rp "'novg' spur6 ro hold. .flusnt -#t;;; bv two n"tJ "*"#"ffiiimmodiatolv insido rhis our'rot' ;;"'-;a;"*" are locared prano ffi"ora *il;;"';;;;*" ws€ constructod rhrE * iD'rhed cao ;;b';;"po or s5', a;d hoist 200 r'ons pororho"t t" ;;;;s, ;;;;; ;fi. rn a mareharliog rrrd sr lhe torminol r'ho i".,.i-i:"".ii"""r ,u" "* aeerin"i ror rea"hing isrsirw&v -und 'ss€mbled. or srt' a doublorine ;il;';; ;ill,* ro.o,oo'iuu oo hnsth ro r'Lo bottom ol r'ho pleDo' iii]*"'i" ""i lu"" n om inbios fiv€ iD nuobor' shich iogetb€r qhero"it is tipped io receivilg sro ro som€ oxtont ;";";i;01;,, surses or iopur' tononse eiuarrv+pacod int'onds :;::Jff ii".'iT to'ri-soo+oo "pp'*i'"av inro-3ov ooe or poclors' ors i,ll" ;""r."" "s thoso pockois lrom drasn ".1" iit"ii,l" "1,"" *';" 'ischmged 016on loos subsrattisuv rovsr ,ll'*""""*i. t' stosm loco;o'ivo' il'ffift:;;: tt il"i*ti"r *i **ain" t€sching srouod ;il;#;;;;;;t?;i"ltv ""'"i" ees rze' rsz *t sto motr$ sbov6 th€rofore' iB verv liko thsl of.sn opeffmt' remaD ;o utoog those ixod lovsl trackB 8nd tbev o"t* ""*.r r"*l'Jit "o.i"e *-lii-"*,ir,l"'"."*a, LH;;;;-t"; **--"a strictrv to rbe originrr bo distjncl'lv iortuous' sould dourso 'hoir hosover' und sharp ae*v' c't bosn so t'bst son'le curvo€ sro ob*rned iru n*ua juuut t'Ia'Ls are o'pror€d rrpeg rr' wir bo s€pn thsr' rour drfforeni "".l* !lliil'-"": il*il"" il'e ili.l*'-"" au"J i!. "&:H""'i';ftil;;;' b";;;;;'dJ;;p" simultsmouslJ Also' when s lerss iDput li'* *"t" hrndlod with' Lvo or moro tippils trscls mar lii," "i*, r""1";" a"di Isvols' used oq ono ot ihe be -'or'."ioi.-tU"a fou tho 1trev round tho l€aabins ground on **ing inr'roduces a doublo cracL rron highor ol th€ *i"J. il"il'Teon trom r'he older'vslers' lii.'ii"ii '"a aho briiga r'ho liquot ssrl')' raurng Br b bact then and tr.i" -"i" ri"" loops forw*d .;";;.'cut'trns ond il:"ffi "onomiineo"iil,:i: il:';ff; i'""t" one br ooo, and 30 Jormrns the bor rom ' o'iroc paseos crose ro ff :;#;ir",b";;;' ho Novaolongeide th€ itrcolDins ore lmckB ani procoeds nl"" li tt" r€rerrou 0u' aLr"adJ "L*' terninsl marshtrUing Jtrrd i^ .1" t*our ""di" iiJi"""r tbus also gerve ror ouiput ore trtrnsport' ""*ssupplv rh€ cronos which are employed to no"-1"* 1."* lbelo is compr€t'ed' ffiH;l#;";;if" b"saps etter loschiog or ooppra at Bro trNTo, sparN. 68 Unlik€ silicoow s,nd dirty or€s, vhich r€nain iDdofin sty d?, s];,r, cl6&n Inindel, afcor laachiDg, i,r losded for export and new lo*pr oro coniinuolly lormod oD tho sii€s of old. Ii is obvious, ih6rofo;e, ihei, ir this ooso, sleed in washing oui rhs oopp€r is atr oxtrcmoly ) 64 J. E. TAa-l,oB anD P. r'. wEdLAN : LrlcErNo PB,}|OIPITATION Or, OOI:PTR "AT RIO TINT'OJ SPAIN' aND 66 iiod ot ore be;og imoorraor tecror, loedrng Io a rcduc€d qusnliry a aa"v in financiol rdoum sDd erctrtor concoD'i"'J "'**.. r"* iil","ord urb rhtrt rau bt ruu€d rcund in rrre rhe io" r"""' *cei!ins bins oI rho ioclin€' rhe $esror lii"" i'""i;l'iiiJ,ii* "i"* '" ibs ireatmenb' or€tall "'iT" economy of rur clern ores hrs beoD brousbr' down '"'""r--1,"""".tr.6 l"xp msv lalu jLree montbs ..;;;;;;;'il;;it0uoo'too rhrco loonrLs rc losJ up s;.n*,h. "'sb rnd ,. '";"#ri.;;;;; reachiDs rrou. '" ot extract;on ;t" """eromriun "rs hsnd on" tho tho inclinu on t"il"'""""# i.-"' "*" r'**"* rhe in lsi €xit trs.I on th€ othor rFis ;'J;"'ffi";";;;; iDLur' rotors oI a ili."t"i'l n"'" ir" rstour incrudesr'o the'sriss incrinod hiDs or cor'respondirg ;:il,ffi;;;i;";; 'he motres v€rricdrrv ,rl*"a sbour ? ffi:;;;";-;""* "t 2e2'm levol rboso """a ore being.the t"i iil'ir.i-"" have bs€n or projoct;ons "oan i-*""i -" "rr d't : iDLerfurins varrovs frlre<rbillsidos ir' rlo 59 009sloerr r**'"niog l,"iil"'" Lomporerriv puL rn i* a"'i*"a'in" *" formed lrom tipprng trackssbout acr$ somo r,l"li"*'r loeels, aad in ihi€ ar€r ors z1'roar60tum'round "^ i""" "* r" n'""ess6d sonusuv on i*iioo -'ii"*,n" bJ el€cr'ric i"'"" 'i" tullv leached, ore is Losd€d oa a rruckB ;orc cu rl vd * "r"r.'"t"'J'' t*i'g capac;l'ies oI'bo 6\sd rt rin€ re!€r bottom the iu,o;;;;-;uai"s t.# rr-orn isreduced i" plant (Fig ls) $here ic *a L"'" ""*""i'* t tn"rushiDg in stock piles ror ihipro€or' i. ".i," """-'';:," -anJsrorod "lrr* :l'.i"a l."-ll;'li" ori' made dsirv s ssnpl. is burDsd iD rusi -**""' l'bo burrins to lo tuur' li".-ni"""""1"r "t'uck 3 : "o'u' " ""ia follo' whioh qJitv J tu" p-4"*, tvpicol sndvBes of ' " o*,^,n*n* n g H fii fi ...,,,..... .. +s':oo 'iii ,,,,',,,,'''.', ..1............ o ol :.............. r'?q ::.::::::.::::: Mtr ....... .... 9 994 cao M*o ,...... .. 9lY Fi ;3r" Aj.o" N.,1,i" L :.::::..:::.::. To.0o' i" .Iio" .,.,.....,,,... 0 '*u 0t4 Brsb. ..... ... . 0 63 8io. r'91 W6_t3r, orysen' 6k ^'lf Y^ +N ,? ilp ii 60 I.1ro I+roo r;33 3 :l ;l ;EI r3l ."t"1 B 2 * ", Et fl i \lel Eltr ;tl '. ; 'l - :l 3l'l € st tt 6 .! .! N- ?; .9 FF e 2 I s j 6 '5 I I 3 ,9 t I p ! \ l 5{i J. E. t rl,oB aND P. l. wrrEr/AL : LEAorrrNo ^r{D pl6ro' or ths bix'r of toproost Diftv snd silic€ous oros llom ihe lovols hishcr the sloDs run out oro r*, ti" li"l* miDo outlol,B, (iudorg uu'l trlu-dult rips .uirul,lu to ul Ndvs i"i*. zggl. ' in lhe oldsr Iescling grounds,o'conueoionu i'"'"ff" "hes m"""1'""" ""pp".***"t ol lhsso nstorr'ls brrs boun r€ducod to b€low 0 S lor cenl, th€y so lott i4 srlu' on droso ocoosionc ;lox lho nino outlui oxcoeds €xport Lo r'ho botrpb i &ud 'unvursolt '";;i'"."",". *Lien the exoorl, *reaIo is lsrqo l,he dsilv tonDags coming to lhe loachirs ero'unde is olten rerv sEsll. Tb€ rnovilabl€ 'oro[arJ -shock-sbsorbsr l€schilg s€crion i3 €xbr€6o iD operstions' Tbe receiprs ol oro v l tunction oI of this ubu iev.to-dav c*iarion s;raee aiout 9,000 tons p€r ds) over [he J€Br, tbe dailv tonnages to 4.0b0. ihe losdiDs ol wushed ors varies "'-ii. r"o- zero linirs and sboul, 1,000 toc per dtrJ of ' mixod 'itiin"sir[iler min6rsl' d€rivod hon old ore BtookB i€ loaded lor trestmsnt in s conc€ntmior. Tho total tomege lo*ded workB out Ei rbout iD l€ogi'b +.OOO ioo. p* a'v ouut rho voor. Sculs everago r'9lm groutrdE' i'ho letrching in of trdcl a0 Lm. *utu iru utr,og*ttu. "oa or€'moveltroDt ths DoD ior 300 is obout requirod Tho labour lorce snd rolat€d seNioss, &nd 100 mon or€ €ngagcd in liquo! control snd washils iho dunps. A briel rs"lerence ehould b€ meds to agglomolstion ol {ssh€d 016. If, during loacbing, th6 humidirv hsid€ a clean ore ho*p uro" ilo o ticil humidiiios oi tho soli€ involvod' "*;" 'l*" "oi the ihc ot€ 'oa,kes' snd exco'rsivs quaDtiii€s of explosiv6s ars required durbg loadiDg. wirh modorn a"tive herps pruriied *"'"uine i" oniilo*up'J, no serious agglomerarion trrises I and tbig ap"pliea also if ttre ore iB finallv trnd quicklv put into ' cold * nu*.itua e&rLier' Bur' ir lho rouriou is disl'urbud "L*nu1 and ihe oro overheatg, occssionallv (akiig eosues A pbotoerapb (Fig. 1a', Plale ]ln shows Lho FS€ot clcorlv This trouble i3 i*i "i.i.* ir wbioh hove practically io bd ro'Ioinod' ). LiM Floa inCanetal -Becouss ot th€ir 'orrosive . r.bo old mited ein€ral sto'Ls, som€ Portions of 'btrroct€r' l,h" lioJo$ usod tor leochios are lor tho rlosr prrt torriud ir .""4.'. tounders..of which oboul, 10 kiloDr€l'ros, trrosLlv ol l8'itr hv r6.in. s60tion, hsve ro bo meiDl,omed Tbuso are hold togeiher b"v *oodso pees,aad *.oftrUv cauu€d strd pircb'd rDsido' "p".pu oI rho ceDrrilussl tvps wirb bJrd-l€ad bodios "iu"uit Ths and BtrinleBB steel inpenors (18 per coni Cr' 8 p€r coni Nt 3n io is diIgct-coupled stardgld typo haB slr f-iD. dischrrge, end d€tivor m' Ih$6 r'p 1,500 86-h.p. 8,00-0-volt motor ruming et IBICTIIIATION O!.COP?E& AT &IO ,rrNTo, sl,lrN, 67 .5,000 cu nr. p{r doy 1750 gats. psr ,,rirulu, r,, huuds ot trorn l20It. rrrr,ruiurr r.u ,rari 1,,,,,,p" ,li',r,. rI,., FUv,{!ru.l!. ::-l:l].1:, crn rrugor8 trrd rn uso tor sxru ,tr i,,t! li ,1 ,":,'" ,rr.ru,rur fur t[o bigsor in. .,"i,l:,ff 1,,,;,;ii,l.:T1 or c&st iro,, or rrr.,i -;;1 ;:i,:'illj* " "r+r, 'ira {[email protected] rtr, rd. rr r,,", ';;.;;jr; r,.,i,,.,ry i,,,*ir"u'; ili,l'lii, Jl i"l"ll, nto ot 2r, yulrd, irr slirb oI rd €xirHrnah ",t;il; -:-s^:"J:.liT: **:,t,r ,n r,nins and ,"r1"u"iii:"-" *'' '"^' rresn worer rs used lur washiDs che otd d dibtricr,. Iho resuking r,r,";,;;,i;;,;;:;Y'* r' tbo rejonera to ttrb, cerda a""p,, ir,i. Hi"l#j'l;lifJf tio.dtr heaps, rle edoont, ogain """,r",l,,e":i1, with oddri,i com$ bv a lorg 'lounder ro rhu NuJu lii .,u". w!i.r/ ,h€s" (dd! riquors eDrd rhe Nsro basin ,rs ]Lb:l:lj.l,* ro€ !nn.'pat dr8lriburins lovet ror ldsching Lo-doy. ,F.ron rbo r,rdu drtch rurDillg rouod rhu besin. two puuprDg siorioDs litc so/urrons tbr loa.hjoe rhe }ighor tov€k. An IS_rn. pipetire from s c-pump sratiu! siruatud nue. rh€ roor *" ;r,"riiJ alr"U".g", Dto tbrs DAin diicb es ii enreft th6 valEr "r rr,.u* rr,e recovorbd '"ine.Liquor from [h6 gravilJ cor,c;n[r,rur.fir,u pora, *a u"u drs,re.r aoouri o[ rho nnal]reaps untuenr _. ;:jJ",". l,b.ougb Cho heap3. "t ",;i;; .^91:*,::":::l* ronac6. pir,€riuus or r2.u. dismorbl coongcr iro^,;;;;"ffi;;"'j;r,ifl j*"j"jl".jj rhot parr of rhu bssin uspd ro; *" r"*u"i. r_pi"i"" ,i "j.""po;ots rrom wrrich.eoruron provido ralpine :""::1.:j.?"ll:: on rb6rho helps. u,r;de rbo acri"" ;;; 6;. :_ dr!. lT'.::.:p.,y. prpelni.s are pur ir whun required or o"lTi roor or encl ,f" fluw, ond rerb,ni srouxd .arcb rhe sotu,ion{, " custrron cbe hquor l,JL€ car€ ut, i ouy b, cors;do*r,r". g,g cn.nr.. ard ,\arD r00",000 .u.D., rhe br"as l-,-lj:.i1,_1. 1l dr.,ins rDlrdo tbo sturm baiog 400. 200, aDd 400 a"*" ."r0"",;""f". une or or, rJru on rtru hucl/irs grourJs equrrs rOO,uirO cu.ni., rDd thoust r,bo miltiotrs oi,one u, ors,o u*roo, u. lorrry long rrj,J spetjs rho ro.ords "o.o "", u ,""","r;"; i"r;";. ;";;H;;"""",:,lllr":l'dllillj ro ?0 por .eor or the 3'1"T.9,,i',9 Iisinfo th€ mino! .at "b"*carcbmonr.. rheorer.icar varies troln t5 iD. _to 45 in. wi;;;;;; c€rda aoy rxivianr ,.I1,:1'-l1l:11""t"rn sn,r rhe tuat A"*,, ourDp8 uppeer! onry appued ro rhe Ly" U*t, l* " uu"i"" l ) 58 J. E. q,l}'LoB AND P x" wllaLAnl i pRnotl'l,fa'llo}I Or CotpEli AT &IO TtNlfO, SpAIN. 69 L&AoErNo -AlrD ao'oss the gulli€s which hold tho: tu""r* i',to'.ua;t" r'urwu't' rho terrtrc"s soru- of t€n Bnell rsunk€n dams' l* ;;;;;;; a1'purrs iii" "'ii"a ro hetrpb,rr rh' drot tunrcu' Ior uir'*trtr'" ov'r rrF ;-';;i;;;i ;" ;;;',. Bv po'sine ir thruugb vipuriib lower' siill oro sprav heaps on the 'soito """; "".ii"'*"". ', ttre rotivo cie' 'or€ reacrring through il;. ffi;;,ttt"'i*ction "duion ro tlu in *rntur in su'n''r : bur' b"rrins iocidPn.c ot rerDlrll liquu! qutrnriri'b .'"-il'?"*",i "1"* a-r'i" r,hose t*". ""' do$n iom6 'ista on brotrd ;;-;ff;.;",";;;;;'i"n' lines to cive a Dor€ concr€ie picture "-ir"t"" cu m pPr dsv li'""* *i". ,' at vorious poiors rro 8 t.t00 6od small s'roaros *il"'i.i* ",r,". ***s such ss rrcsb water 'l'ho €vonruel omuet'l .-a""i-a";r" &n trddrl,iooal 4,u00 cul]l nr" ;;;;,;,;;;""." r**' .av measure I5 000 'u r.be ditruro.ce b6ins du6 to rainf&ll ""bT'i.i" rtuo! tron arod to sres un'r hedn m be&p "'"""ai"- br pumpiog th€ lirjviaD' "j;#;;;:"h-ton iri"i-i' "*"u" * *ler ;dffi;;:';;; i.v. two h€&o-D3,3srco3 ""i1"'ii'itri"'iln .r *s ."-;; ;;;;;;;.c"i"s il" iin"'"^, o,e-r.vpei actu&llr m,LioJe oo to boaps surrsc"s is about usase thus roosus $ound rn" '**g" solur'ion dopends obviuuslr riquors, ter th€ rersi'ive proporr'iuns or 6DaL effiubnr' wa-"noa, ana (sr r'h€ Row-sh€er' anJ sJbt€6 of wosbiDg edoPted IB^cE lireuoN Co$antmdd in rams Pq ctbic tu|re ..... ... !_.pp-........... ,1"": .:. I ... . . ... iiiii,'"il ."iJ' B,Muth ... ... --..,, ... ltdt nn E ... EJJt@nr 2 rd o r ......., .. !'edia i!on.......... ,....., Total l$n.... .... ..... sulphuic 6cid--- .... , ... ABonic .... ... . ..., -Itisnutn ... ........ ..... " ' ' ' ' ' ' 5r0 to 50 lo o.l o ruurld app""rios rD- r.b; ;,T,,::" Il;n€-weiors jn rhe strjct se,rso arnounu 200 2'000 100 j lio ,o 200 ll0 t6 002 s riL' rjl hv., :,'":,T,J;,,,rTil:.11] ::..::._::"0.,,n,r,", """,,n,,,yr,,^"ii.li"' purlroiu rn{lr \rri.r,l,rr . L ti, ir,,t sIxDlv i: trnaDr requfuo,nuurs. dnd rhp denciurn"rt b",r", Ly r$o uxpodreDts_(tr l,shnB n/ rerloin "";;ir," n.nr.,,,,nu,"ire'c sdtrs. !nJ (2,,.irujs,,ng,,,,",;,t ",ppt;u, r,;;,;;;,;.-il esmplo ot rtru_souF,,q grouped undur (rr may be uruDdioqed rhu rb," srream in rainy p".ioa, r* :^"1::,":,.:. , sum,ner vojumo. Dur rr " .",.jd""";; drios up almosr comoleLetv o_;". ,j Drnrog acr,vl,es hishor up, snd to so0paa6 rro,o ,i.""-ri",i r_ rbU iimo i, spproJ.hos rbo roach,ns sl";"a.li" trn,r ab"ut i.do0 graos or to,ai iroD pdr ::J,: T,,r_"", ruor( lIerr6, ur whrrh 50 per c€nr is in rho fonic.!"r", rh";J;. pos'rron varJirg lil, o ov€r rho v€ar _":lT i:,_^,"::"" od"a*,". ;rue snd moru i,,rernsr pu,npiDs .or ;i il;;Ji;#i ,j:,fl*::i rho pric6 or mppel and or scrap.ilon, l,:1'^.:,'":.::1""?,:,ls L,!rDnr, appli€d ro heap.surracee rer in cosu recenr :, ry","-'-,-"1:. , esloroer sources jDr,roduc"d. rh6 din";;;; {:T:::'- T,i': rbo * oquar amuunls Ly sraviry ri4cad;; fl,1"s"::::u::"i l* "bour r h6Bp ru busp, aod Uy ;rr*"ir ox,omar E$i'hn'nt mult b6 qll. supprr.'h" ecc€pted. SiUdous ";*;;";"""k,;;';i:,# ores rows;s fh" ul*^ €spccisry p,rlpi"gl J":rH'ifl"ill{ hjsh,",".r",,"" X'.X;t"::",;1"#;i: lr: grvff gr68to. ai,t€nt ion whon ih€ amounr mreroro or thls nopurity exi€n,at rour.es rs low, i.e. rn summ€r, as lbo torric imn caD rbon be }cpi withjn rbe capscitv ot ihu SO, *a*ui* phnt G€e p. 61). ffnel fecto! govorning tho consriiurion of tho €v€ntusl Estnnt EJJI&st Yiztlt Zinc -..,.,. Fo ic,iron, js rh6 onty impuriry inirodu.ed in r€tarivotJ large dmuunt by rtre inpur lrqoors, on.t ;n tt.,prccds N uldtrr'€J 4L Hio linlo €scb , i'* ,",, ,r'rr,i" ,"",,.'"rntru'rucur wtul€ one can chooso botwe€o iskino i, ;; z.ouo r,ooo r noo 2.OOo r,ouu eoo r'uoo r0'00o ' . 15 I0 150 100 !5 00t -Ihe rhe.sJstum of llashilg adopl,ed un efruenr,is lho irdividuel hesDs lc oas Deeo 8Dovtr that vsriar,io! ol rh6 coDdir.ions ot rrscrmeot cbsrllcl,o. or the resulrurr |lquor. uthff coosrderarior,s como iD b6r€ whicb ox€rriso s pre. ponderatiDg i!flu€nco. In pBcric€, fto& ihe mon€nt toechjrs b'€iru on a clean or€ dump.o routiDo is esrsUlished qhich conf;ou; ufl wosn'ne€ods. utrty on oxrrem€ly rare occasions, wben suddsn !e&vy rornrau mrkes possibto acrudl Ioss of copper rbrough of cl€sn ires cso $oar ty affert th€ t 60 J. E, Taalo&,$rD P. F. wrrEiatl : r]EAor inBudiciont pr€oipiirtion capacity, is weshing iriorupted, end the for a fsw dsyB st mo8t. Desid€nl& h ffnal efluoDt liquor sre rectors t&kon into eooount wh€n docidjna the Lrostmsor coDdil,ions Io bo sdoplod lor cl€en orss, bui noiayio'doy or monih lo-mooth conttol o{ amusnr quelity is att€mpted though tbem ?RECIPITATION OF COPPDR FROM TIID I'IQUONS OBTAINED FROM IIEAP IIEACIIING A Hreronrcar as ssrlv as l6?0, e cooc€ssioo is recordod as haviDg been {Isted ldr ibe rocovery oI l.ho coppsr fJom l.h€ oine wtrl'ors sL iio Tinuo, prsgumaltr by pr€.ipil,aton with ;roD ln 1752 also th€ loethod is mcorded as being in u6o, this tiae to precipitaie tho coppet lron] tbo liquors obioinsd lrom tho leeching of the teaner oie! artsr nsturai c€m€otatioD, and this is plecticsllv the mothod ir u8o to-&y. At th&t iilo€ iis us; wes opposed or th€ $ounds thst tho prboi' bitst€ obtai!€d eas In€rolv iroD.osl6d wilb a frlm of roppor' 'lor, copper wtrs 6nallv valu" oI tho r,ne true nature 'soroDt 'oa d€nonst$tod bY SPArish chsmish. Apart from tridg nade in 1882 snd agsin in 1922 to precipiteie the coppor hom the liquors by msens of sulphu6ttod hvdrogen' both of-ldhioh triels l'ore of roletivoly short duiution, the us€ of iro! ss tho pleoipitsnt of th€ ooppet has boen continuod II. . B. UoDERN PRAorrcE t. Como$tim of ttu sverage 6opp€r Hedp lr@rrs -Th€ ot rh€ h€dp8 t'om the le&ching received se liquor oont"ol Jt the por cu n" tio gmm! 9,100 r0 last the ov€r hoB be€n, veara, lo$'est yearly sv€rago duing thiB p€riod beine 1,740, snd tho hiohsst s.O5il sram€ of copper por cu.m. The volume ol Iiquor h;. fro;3 m I milhon cubio m6!ros, wilb an blorsse of "*isd 6 5 million cubic mohos Tho average anolvBis of th6 nsin oonsiitu€nts presont itr tho liquor ss reo€ived fron tho heops hs8 been civen on Des€ 42 rh€ rurric trm btt Sutphur Dimdz 2. hp,h.tim'of1hs y€arly. Fer iron Dr€soDr, *'*In* it* laEoIpIIAtrIoIf oF oopplB 4T &IO TIltTo, gp,AtN. lICt ar{D -As rn tho precipil'ali'rg canols uxbouu n'""iiiLniina coDD€r, l.ho fsrrlc iron durinH reneot vearg has i*"''"a*,,i '" iu'.o," i'o' tv ."un, or sulPhur dioxrd€ producud tuom tho buroiag oI lump PJril,os lhs lonio iron roduotion plsDt et Rio Tinto con€isiB of 40 Iunp bumors in two sots of 20 €sch, e ma,ximum chstgo oI 19 iods of 6l pJritirs.por dtry boing turne,l. Tho burD ers conn€crcd to oD 2r ft. high and ; ti:;;€ru structod or shou,"", ;r, ; wirD ajar end ocid-rusisting psckina ;;t":xH:i" JHi ;ill; tho liquor is ruo. ureucbllR 6h,ni"-,r . j, do,:lf8nwhi'h .-... - a.. d^ lLruroad on rho to\yer oxir. "r r" iA-, olo$mg ibrougl o tosd cbiDD6v bbso.pcioD lowor ;;;;.il ;r, *;l :.":"i:.1* """a,", "a ;:,,,,Ti;, #::":' cuDtrinjos l;,";,,"1u xquor i. ill i,.ii- -,uu 8o! iD "li""Jl"fj sot,rrion is .r"m bevinS a oapacir, of aod is iDkoducod tiu *"r*u io avoid ross l:t*, "*por.r,u-r. rD6 leactioo is stow, roquirins "oau" l0 d;;r-l;;-";; ,r.l, imporrsur rhar *o"t oithu "b""r so, 11"'i"1,. up oetoro rhe Uquor roscbes [ho con.a "r""ra-r" ,"la :y::r,:, * ""r,",",i,et;,. ;#ffi"i:Tiifi:",x ;1,."; ll;i":,f";ui:l,i:",,:,",,;;., JiT:ifiii+Ti,:.$;:,ffi Is37 aro ;L:::"nTff:J*"-beI " r"rr"",' ;,;;;;fii : fi91i"";t. irn;"#":H:lt:$f,r,ttfi:::: py.it" u*"r, "" ... 370,8oo .... ...._l SuJphb.on@nr of : ,, 667 ovri; sutptru conrant or ii"a"surphu d,ox'do b!€n n ; ";;: .. I i;;;;;';;;; ::lililj;n::;;:il,aj,i'Y,,;i ::lililff::::HlH:""";'; 47 1 h.s 60/6 8 0oo nu"::';#; ..'.,,1;:' r"*i" i-,,*r,_a - r*." ,.,,'.....,,.,,,...,..,,.....,,, 36t,907 k8, im':,1iff ','",1*;:i.-..,,......,......,, j jf,i ji ji; ""-.::1",ff 8iilil ix'l;l:tt"1".",1 "" .. " . 0".'* j_efria iflfi:'{:i,'"':.-"i:'t:11" . , Arrer roducuor. t@tme,,t "*'-".,. .., *l iLqi*rl [ lrai "il;:'J, iii t,e. Acid " fi#^ ii#, i:'""rJF:=6U1r* L;;;;;^";;: fu#,ll,l;; ilj"jX"l i,,ru 6sure or sb0g por cu or m€ tower tetuperarure of ,be liduol ,,Ji:f :i:";:i, ;i,.T,ifili ;litH,fi:ffi i"xi :1r;ft Ll; 62 J, E, TAYLoB, aND P n. wI{rLAlt: ta$or plent This rew ploni wilt consist thei cind€$ .i' J"ti r"**" t*"i"g pvrite" iine" lii is €xp€cted I ront uBitrg rrstrinir I'Ur p.r c"rir, r . r -A "r "utphur "" sl'su'vLiou ruwor LII3D ""ry """*i" hrsd proprrtionaturv lu.o bnrn*" use'wiit te uuitr go as ro rcduc" thdsulphur loss r-h"fir "**", Tbo ov€r-rll e&icie)rcJ or rbe prrcucs will rbus be ;;;fi',""J for tho oonstruotion of 0, imoru!od - resear'b vork to rind E tn"aud ur hastoDiog or *aoctlo" of tho lsrrio itoD in ihe liquor bv SO' has tnu ""iu ch6 dcal €6cien0v ol ih€ procosB' rosultoil 'r'"."i". in on improvemeat ol thsSOz rhrough s cnlurnn ot pvritos ,i" rr",i", conrrioing When rho liqu'r withour EwLt degr,d tbe *""-.iJ r" dve ol rh€ 3u'no SO" r.sat."ni** psss€d rhrougb e sirnildr colu'nn oLr*iood' ovr'ir,e., fitr,re reduction or tb6 lerric iron wag ";"';;;;;";^"" or r,his $ork th€ rrquor conrainiDg so! in **"a,o poss tbroueh a submorged btnk or l-in' *i"ii* i" ["""'i r"U-'i*v ""i ""1"i"""1"J i;-;;;;t"'il" "*it* r'* frnes Th€ €frocr' or this has b€€D 8r€3rlJ "I ol r'be rerric iron br so! tbus oi.e,rurtiotr '"'. and $'ird' aDd tho chemicol bv sun loss of SO, "L"-r"a""ir* 70 per cunr l'o 86 per cent &bout trom UuJu"o io-"us;d --i.-'tjiiaiat;^ "C"4""" t'* aopper bv ltor" Alior r'hb n ducr;un or rhe "t ferric iron, tho liquor is reedv lor tho lr€opirut'ion ul rlc loppur' i'on' both 3crap tll" ; *i.i"a oot i" long ca"etr bv D1o&ns of used in septrrdto being sDd Diq iron beins usod. t'b€ l'so classog ilrrn 3" red'r'ion the SO, b6low tU" cnnojs ore eiru'r"d rcrcrion "'*1." ii"lir'o' *" Uo r"a r,v erlrvirJ, tbe flow or liquor lrurn Lo are built' a ten bv ru€o'gured 'ILev snd i". U;"r" ""a* -"*"r or ur"isr ir' do$n rnd rlons zrs-zssgins *"ir" 'r*", "rrJPs"l *r'ul ""1 t v o ss *ia" I . a"uii"'"i*.i,' ir *'i* 'l"cp I ti"i ' long, the totsl length therolore boirg 2'616 nch$ U"* q' *""-"ge t"ll ol 0 ?5 por cent, distribuied m folloss : " '- " 0 337" lau 28% ol rengih.-.. "i being 1,393 IiEt n Noxi jgu/o ,, ,.2so/r- .. " , ,, ,, 49.,. - 006% " 1113 "_ _-" g'u 'g.1s any At iho €nd or€ tvo B€ttt€rs ?0 by 10 bv li m desp io catoh l'be wide bet$e€n 2 m wdll tu" susponded coppor. Tbsr€ is a i6 c8ntrl Ea'h working to lscilirsto oi uu"l .f"ofi*i'" "eri6s "a*r" di"'r.Ied into leoetbs of 50 to ?0 """""*"a i"ret; "". m th€ duplicsrs caDdls beiDg cross- tli "t cle'nins or r€prir' The clnnls ero built ""a" 1." 1," "'t ""t *t IRIOIPIT,1TIoN OF OOppIA 4T RIO TINTO, LEAcrrrNG aND theso subdivisioD! so that seotions of this Sp1UN. 6g ol huJ porpbydtio stotr€ rind oro ti!6d wi o ft" **i"" -"!es or coocr€r6. ' "i,u" ""*."t";;il;"#TJi d!J i,rorocrud r,r , J,i,," ,,."d i,9yol,lo conr,.ot 6.rbarr, lu! rrvrr, Loor,rs,, ii. *,a. r,v,z l,i.'ii,i"r j;,ii,,ii"i'1;,j$"l* on nur, Brdu boorft h€td by wood€n Deas tixed ld 'o,t.s-in phnk laid ',li aroDs rho de" iI" i"x"illll ',o "r &iL ru,si.u,i,ur,,i, r,,',."* iii,l,," ;:.Xl"iT:,11J:l,,ll,1li 2 r!. it'uk drc p€gg€d on. .thB svsien ra, sDd rixed 4a,age is dorr6 to-rbe oar" toard rB ea tJ Ii\ud. iq"iih.ij,'q ;;;#;;;;JT;r",1;:,iXll,T;, CaDals of ;h iho lli# m*ru;-ll:i# **_. r;iti i,l:-joinr,ed, rr" tsid undor o-m. orametor,,33pba the courre.w,u oi , 'rbese drajmso pipes 66cb conDe.r inro ,t" 1",, Lsen$. i*i ii * p*"pi,*" r" "i.rij il?L_1l,Ji""jjl"::":""9", t" ltn*r rDPIr rF ni srep or sil er rho onds or.wberd on€ sdi6 juins $ith uDorher, *A ,t" lq*" th* Ar"" noly . rre€ rjghr tbroDsb rbe svstem Stoxkirg grounds ror iron, served bs rairw u.goo .r j ."i,il111,ji1"-i;l"l_llr,""l ";,";;'ffi rho isrser |ordor :pl.:.p.'j': "l* |l sdrv€d by two €loctric ffanos vjth masr "i ,1" ,,""u.g.f.","ai fur taDdling th€ -"-so6t3 uoo Tblo cranos, *lr"t 49 pe! c6oi or 'launupp€r tbp rortrt l€osrb ir" *"^r,,"r,"""""., rporL :1 -h:,djll in.rubs lho pro"",*,iru ths produitd"lfrux, theiu.u,,ald !r.u "bus€ iho snr6 wi ,,,.,,:;;;il;''i;ffiXr",l;,"jT:l:ff: rDg ianl8. a rnonorril pt.rcert L**.",i_"r" crprmr,o T":l:fft ;ii ?# ;Tf"L"J "";"';;,il';"",1 pr'nr. rbp ranars. ,,r ,i *""*"""Jijl Bcrup uon, lhiul' rang-s lrorn pjeccs"l* toi. ITo:,,t w$b,ns ro rb€. !f sir ltutu. *orsrrog souur s00 kg. dostr ,o .,oo, ;"d"t". "nd "tjo aLout 21g., hold abour,2,tr0 r,ons. '--- 5"rural scrap weigbing The meximx votuDe of liquor vhjch , coDv€Diurrrv b6 faoard i. dil,; ras.r tlrous! ',he pruri,,i ';'i,ii:,.,1';",'l;{ '10di"",""" llsk Iretupororuro 'xsrmuu js abooturins ";,:;;; nquor rO'C., ot +s ior* ropp.r,";;;;;; ,:"j or 'opper ,dmpera,ure is sr,ou snd or aluu, 60 roDs por dav, ru;c. i r€ ;;;"1; ;;-,f""'Jr";":i""ioi;J 3Jstem are,.lFuned. aL Z dsy iurelvdis, and rboso st Lho 6vt exd lr€ cleanod at rz-doy jDcorvals. A pl&n and a cross s€ciion of ihe tavonr nr u plaDr aro givotr iD ns!. r5 {Plat€ M asd ri in. ii""'"'"" " 'h" TIe ope.atjoD of prpcitirarins rhe coptjr r ; couuauous srd iroh ) 04 J. E. TA1'I,oR AND P.I.. W!E',{N: IJIOIIINO AND FBEOI?IT{TIOi{'OF OOpp&B 4T !.ro TINTO, is added pedodically to ke€p th€ consls fuI. Cl63ning out tha copper precipitato is done as roSuhrly as poBsible. WhoD otry soction iB duo to b€ oleenod, ths liquor flow is cut ofr by uons of eoodeD doors md l,bs liquor draiDed ofr. th6 olooring by eltornot€ly movine the iroD into tho working Bpsc€ end clesniDg out th€ precilitate es it is uncovored, finollv rctuming all th€ imn into the section, whioh is thon filled up wiih iron lrom ih€ Btock pilo snd again put iDio sorvioe. Tho procipitats, \vhon producod on sdap iron, oasily falls ofi to th6 bottom ol the ceuel whon the iroD is novod, but when pmcipiiet€d oD pig iron, it &dheres to tho iron as ls&l pr€cipit&te snd h8s to be sorep€d ofr. Any censls usirg pig iron muBt iherelore be hsndolooned. Any s€ction &ft€r cl€snjlg ia r€iumed to sorvice sB Boon os possiblo b6ca,us6 foi y rapid oddstion of tho lire procipiteto tek66 plac€ vhsn it is oxpossd to 6ir, gom€ coppe! oxid€ is thuB formsd on any ptecipits,to still adhoring to th€ ilon, and th€ oxido is sttacksd snd dissolv€d by tho ecid oD putting the closnod 36ctiotr iuto Bervico. Th€ copp€r ihus dissolv€d has eg&in to bo procipi tst6d, tbo n6t rosult b€ing an iDcroesed Lon comumpcion aDd bishor ecid neutrelization. B€forc SO! ws€ used for rsductioD of 16 ic iron, iho sv€tego strrlysis of the liquors ente ry and teaving tbe procipiteiion csnolg was ae followg : r,;;;;;;-;,"::1,,1: hes rvoffi;"';;;#il$ltl,": ,!b,rrt6 or pr€qpjtdrion af rbo coDDor, ars€Dic ard bismutb, ,o! or ,b€ bc!t. .,nd ,erucrio; or th€ f",,.i" i,"" j;;;;; prrsogF ur rh€ riquors through rho cdars. ll,l":il.i,,T"e.lh: , !o Sropn Frg. t7 is u rypical oxurnple. tr*irr U"-r""" rrrx,i" ::u: jr-*r,zal copp.r rs prc.itir,at0,l n,irty r.eutarty io propordo, r," ,h".;;;"i;; ol rho ..onors.rrot ened, bur r b;r rh6;. ,s ; slowinrq ,t""^ or prr'[i]Jriun ut rh0 .nJ ... . 2,I00 s8 16,470 1,430 1d,900 l9,t?5 t0,?40 9,040 117 a? 100 t0,875 l,e0 029 1,070 t,970 1.t 5l With the introduction and improvemsnt in Ecsnt vea$ of th6 r€duotion of the l6rri0 iron by SOi in the heop liquo$ b€fore thoy' *ri a rron rs x€Brly redDc6d b€foro tbe liouora ceDi rbu caudrs.,b,r; ;;; ;;;" ;;i,i"*:;"ii*'",:il,1# .or . iT; oBenlc rnd bhm,,rl in ihac mor.is neurrstized,o**au,li tiao et th€ Leginniug in Droourrion r.^ r6n "na* capaciiy of rh€ caDals cravorsoJ_ *":::" of i[€ incroare of rho reio of prooipitsrioD of tho ^_-1r-l: orsenrc ind b6ruuth, on,l rh! inurelse sc,d, us, rrd riquors,*,,",,,*.,i._" grviD a ereepor hll a0 rh" uf. "inl"l'j::il,lff H? "ll "n,1, sin,.u uxn€rionco fue stown rhaL ii advrsabjo I.o r€duco rh" time of rorr,a,.t l,er*een liquor and iron 'B ro t,b€ larFr slagN of tr".ipirr,ion. An exampto ie giv.n bolow snowrrlg hu$ tl,u rtutrnrirJ of trrbunic :fij,."T *. s"a Ui,lll,iU p*"ip;r"*a-,"i uburrurzed inrrFcs€ rrom rb€ bead io ibo ioil or rh€ P., 100 173 IoEos Iron ...,,..:.. ... ..... Idric ,, ,,,... -.-. ... ... Tot6l !'@ Sulphuic Acid,,,,.... ... Asenic,,......,,..,,,...,.,,.., .. BEmutb .....,,,,...., -...., .,. zinc,,,........,,,....,,....,,,,.... . ,1," "r riq"oo t"",,ou *""t. rj,, the otb€r }xnd I l,u rar€ ut !re.i!rrdrion oI;o[h ars.,i".ra U*ln",.t rncreores as rl€ l,quors pa:s r,inbe!,lown rhs co"'l,. Tl,o ;;;; wburo r,r,u I6.ro Coppo.,,,,,......,...,,,... B5 €nro' ib6.aD&h rh6 t€rric ilon coul,€nr ol th€ rsducod liquor is Dor! co.sisr€,,'ry mufb rower rhLn r." Bho'rn in i.hu ,lorase figurEs aivun, ord t. monih. ending eprir. re,t. ft th€ sociion is to be closDsd by mag[et oraDe, tho orens takog oui th€ ion aDd ploces it on on€ ol the dividing walk, men shovel out th6 preoipitaio into wooden tubs, the cr&ne ropleces the iron, ffIs up wiih ion frorh ths stock pilo, &nd th€ Beoiion is imrneditrtoly roturnod to eorvico. Il hsnd-cloaDing is carriod on, }n€n oleor out s slnell workine spaco, putiiDg this iron on the dividins w&ll Thoy thon shovet out th€ procipiteto from ihis specs and continuo Sp4M, 4.-Cabol d the Coltper prta Cu ptaipitat d 0.036 0.21o 26.4 precil,;r,l*._ftu or fi" n*.;; "*-t.or ""pp"i'*r,;*'.",.r".,'";;;;ill,o:fi,ilT :"lf:.,ir,:b", i; nrsrafarn th€ btrlatrco belweon ,oo greal a toe, ot copper in r,le ** "nd 'oxcossivu coos'mpr.ioo n"" b; "lt ::H'i.li:lilff r.*," or rhe eyll liquor .^ 1llq"' racr,ors, sucb aB a chrogo rn rho jo-". ";; can bo afecred Ly marv comDosition of fto r.ompersruo, rumbor or csnsrs "ru*rl1riq"? croa,€d, clms and LT,i:9"" or totr "l ohorged, srzo ", €ic. 6tt J. II. TrlY[OR AND P. - t, \'IIELI\]I : P&EOEIAATION OF OOpp&B AT IiIO IINAO, spAM. 67 Samptes of iho oyir tiquor or€ dra\,r rwic6 dtrily snd sssuyod for xrur,hod, usins dodi;,. iliott,yidrthio_. crrbtrtntrb. rh6 aNuy tukins retr rurnutus tu .drry out. A cuDsroot Hlnl4gr€ .opp.r bJ s colorirnornc guido,.rough bur quiio ofr€oriv€ s,nd su6ci6nr judso by, is obtoirod irolx dro cotour ot rh f;r th" ""rkrn;;; ,;";;;;;,;1" fiffi: fl':lliilTiJ: a pi"co ;r pis iron pr.,.od i" ut tluw ut tiq,,rr, tL.. fin,,ur rurruirr trtrol rL ttru _"A coppor iu rLo exir id roo tow and, coDvdrsoty. ir rbo "r,,ir,_. o":" t,. is. roo hisb. rr, is ;ishr sh"". :l .r:: or two i,-r--lt boum, .e," tb€..olour is bogiDnrng to rurn pink. ", Any vo arron in rhu copp,,r grldo ot rho oxrr tiquur ; ir,, c.tow-;;;l ? ;;;;; s< eg fi..:1""T:,""",f,, " ", "ourm tlu emoun L or bq uor €n toring :io rruro rho corrocte,r by I ho pr6cipi toiing sysre m er ibo hoaj. moro,t,;;;;;;;;;; A.onsr.anr. drip sample or bor.h rh; €Db;in; ov€r rio 24.bours is drawn ond assayod dsiry. co:su.4ption. _Tbe mosi oxpensive _a *riliq""" iretu in rb€ oosr ^"5:.r:,ot or.Ils,precrprtatren of rbe copper js iror. Duri,{ tm r"* ,"" yoars th6 B!€rago iron consumDtion fioo i"0,""" ,on8 -66 9 E.E ;.9' EA a I .""*rri" orrorn,hrrol " ii#;:,l iilT :'"ilJil:il,,:il,::l iT; i,f trLout 00 Jlor canr rrotr ic irux cotrront. 'ro rorHiiruull,s ol rh! tiquors whjch i;; are ih€- for;ic iron o"a ""rr",r" ,n" ,"[n"j" :"1:t,ir"1'l:lilig l.pp€r a rorrt or s8.2 p6r c€qi or iho l,oto-t iron -":: -J"T".unsumed Bccounl,iDg lor 22.2 per coDt of ths to[sl and u,t* rlu ,r*.ur,ir;uy .r .i,;,"i"s ,u"-i.;":::"::'u,':by tb$d "unr. (onsuo€d l,lto.oDsritueql,s vi ibus .t6arly bo iealized. rbs roduciion ot tle furric iron cooteoi or tho tiquor hss ,^,aow_ b€€n€uccu$fu raLrorry y sccomptishod htrs et eady U*" a,jr*iU"a. L_No successtul D€lhod ot appreciably roducing Ms lh" ;-" *",".J lound. {'orolul urt€nriuo to dotdjl jD the cootrol . ^uJ ",q u, ,!e eoppdr precrprrBrroD f.om thu tid,,or, and elt subs6qu6nt opornriotr€ silt, bowever. ke6p it dovn to a m,njmum. oe€n ManJ drflsroDcas oI opinioo oxisc o, ro the bosL rDeans of tb€ acid stlacl on Lhe irou. Uucb ***"1 Ituirins U r,*" a*"l, ii prupedure ib r.har of al$sys keep;ng rho iroa rros urddol g 1"* pr€cipirarion .:l1r-1'-!!: rrom copper durllg os assiusr t'be auowing it tu bocoo€ well uovored ;irh .6 *,.d "!d: "il.:'ff :,,:il: r;""i"" p^*;"" j"IJ" iqlti::",h" agDn8r oao or rb6 o[b€r merhod bss boen obreinod. E\p€ri€nc6 ar Rio Tinco :'"', has shovu rhar, orhor €qual. ,ho amouDr or B.ia neurrarzsa incromos f,,',"1:"j,:l lhind bei"" Ji;fi;;#;: oI [h6 soid pr€soot, thouSh oor aL ib€ Iig. 18 itlusrrar,es the above sierement. cho strength Tbe groph "i "i ssm6 mto. |:2 !" 68 it. g. I.|YIFB AllD P. t. lxslr',All ) i ) pRDorprrarroN oF oopfeE, ar &ro qNTo, : I,BT€IEII(G Al.D sp!.rN, g9 lvhile tho vslue or th€ iron consumod by aoid is quiro an ot,nrorieLl6 ilnm ol rho proress cosr, onty s rslativoi smolt p-r.etrl,uAe of tho rotal ao;a pr"r"ur in tl" Iiquo". is noutrslirsd ia tho caDb, snd for this roeso! removol of mosr ot th6 aoid bv provious n€utralizaiion before precipiteiion ot the oopper wiii ev0n the choopest rodgont sveihble in iho disirict, lnogtone, is urrsconomio &t the nling p.icos of iron &Dd lin€s0ons. Almost coDrplel,e neutrolizdtion ot the ecid prosoni is Dovsr d€sireble, e! ihe 6pper precirJitation prooeeds b€tier in slighily acid sotutiols, ? l'risls of org&nic intrib ors on a ,nen ;oe[ did not sivo "r..',raSioA r, sdl{,. alv!.6 d Irun UJdd.-Iron or oll rypes is uded, difreront ryp€s .6.. giving dilToront qusliiies of procipitsro, as shown by the following (5i =€ l'tuiPitat at P,oducad lv\@hedl o€ 42 8? ^E r6 Y€ ,9 .6 T 'o:zrriurnrH rl c u:alos z I l0 so1lll 41 24 8il-t3 : o-3 !,J I I 0.32 0,6? 2,13 Dudry ihe tolu from which ihe abov€ d&to w6r€ obtain€d, tho sdDe volums rnd cl&ss of liquor oDterod rhro6 parBll€l cs[els of orF seri.". lbo cut.otT poiDt ot the pr€cil,irsto producod wss rtso sD.h lh8r in osch .Jde rh€ sdme amouDr oI copper qss prss6ni. Pie iron is.a siowor prscip ent than reils snd tyres or heovy rc.dp, which in turn is s stow€r procipitonr than tin-plate. The slowesi precipitsnt, pig iron, gives [h6 besr ond tho mosu grenular product. Tlie precipiioto produced tuo)n rin-plaio ie eo nne th*r canDot l,o sepor.i.iud iuro clessos by ony ordimry waBbing ii III. THl] PNECIPITATE BY wAsstNc 'Ihe sasbirg pistrr for tho $sviiy chssi6corioD of tbe procipirste coDsisi8 of s shoting soroon of }-in. )nesh on io which pl&y jers of wst€r. The p.eoipitsi€ is iippod dir€of trom nonomil iubB into CLASSIFICATION OF s smsll hoppor and thenco is lok€d on to rho scr€€D. Any l€at precipitate loreor ihen l-in. sizo, rogother with smott pieoos of iron, b cerried ov6r th€ €nd oi the goreetr and t&lls o! to s belr conveyor fitred Firh o msgr€ric pulloy. This reooves rho Lotr, whioh is roturnod io process, aDd ihs cl€aE leef proeipitats is couocted. Th€ minus }-in. pre0ipitei€ fron rhe shskin; so!€oD J. E. TI}''.O& AND ?. T. 'WIIILAN ?o : LT-{OIIING 'IND lals into e Dorr olsssiffor, where ii is further wsshed snd clessilied into & cosrs€r hi+-Ftde and e ffner low'grodo prcoipitote lho hioh-orede orscipitar,s falls inlo o dng el€vul'or' sDJ is pass€d ov€r .ie""l,i" pulloy lor r.Dovsl or sDv iron betu" buins "r-'"rn'". to tho stock-pile Atllreeipi' Juti'*ea i"io tot to' ' "onvoyenc€ ie t'hus rnochenicelly hsrdled plant trte whioh goos to tho washing tubs tiom tho canels uniil into i'hs is shovellod lrom ths ti"me it tho low-grsde siock-pile th€ qusliiy roaoho€ tho hish-$edo precipiLti'tro- tie lo". clessifier ovorflow ns inio 1otrs selilors' ind ji elovslled o"t ,rna convsy€d bv e motrorail to s drving shed fo! briquotting in th€ wintor, or stEight io o biqusiting g'ound ;n the g"-uor, whsn th€ briquott€s con bo sun-drisd Ail ths procipitato doos trot go to the waBhiDg plsnt, that lroduoed from il'u ro*e" *riu" of conola being so inpure and so liDo thai' its sopar&tion bJ gravilJ wasbing ioro high t. g;'"di*"'in,o "i.ru.or oiocess is nlenl, r,bo low-gro'1" ud l.r'. i. l.o'r"trrio. .l .,,!!.],!tor low grsdo is Dot worlb cl'se NrFperitrlL quottiDs uged. lhe pr€cipiL&t! srill cuntutr'ins 'otuu iroo sulohates $bjcb oct as a brnd€r' ii situplv tillod into sligbrlv 'oni' ol iron mourds, press€d dowo by tr sb"vel. sn'l t!€ moulds iolerred' 'When slowly dri6d, perticuh;ly h th€ sun' tho briquettes sei had' D&ch briquetto v,eightB sbout 6 kilogrnns of Ptcci;tdk obtatud.-Ptiot to l'be veu! 193? rbo bismuth co;[en[ sm tb" kev to Lhe ctdisi6cstron "l precrpital'o ClAses ol rb€ rotal [n€ copptr producod ro l'o -* .o.ou".u1 1n lsqroriol ss{Lvirrs s0per s0 ru 0 02 ";;"i 0 OtB b5 D;r cont co;Der, u 35 ro 0 s5 pur c-nL As snd ot r"pplr obout s0 por s;. ot in" .om;"i',e ?0 l,cr n**lry,p*king o."a"""a 'nreoioir,ete ""oi omt wes rscovorcd 'onL' in e precipitsto running 84 to 86 per cent ooppor' t.6 [o r'8 pur cent As,;Dd 0 u5 l"r cent Bi rhe bJlaD'e or 'olpor p-a'cea iei"g"paio rb€ tortn of s low-sro'le pr€ciprrsro conl'aiDing cont copper ond 5 io ? per cont As Tho figureB ione 60 to 65 for bismuth i; tho last'nsrned inBranco wdo n€ver recorded' but th€ contoDt was probobly sbout 0110 por ceni During recent {ean tho coDDor produced from Fe"ipiraro has L'Pn dtiposed or Br conrbnr is now rru lons"r B rnarror ol i" r an"-ri."'1"r,, ""d innorLrnce. C.nsuquenrlv preslnl"dsJ pra'1icP ii lo mdko twu g.ade. onty, a l,v-gr*do precipil,aro conl'sixinF abnur 62 per c€nl ;""""'.;d h;eh"r e.ad" oI 75 ro 80 pPr ' or' copper' the pro' " riLal frno coppor beins approimtrr"lJ 60 per p.'.i,on";" r,ernJor 40 per cont of low'grude' oont --rl"of high-gade procipitat€ andono general antl e lew specinl *il t. *,tu to ih€ Dir€ctols ot iho publisb th€ informstion to pornission fo; Irtd., fioto-Co., ","t1"-* Thsy erc indobted s,oknolrledgsmonts. Ai. 1.r,. :1. ,,\n,r 'r'rts r,kr, !li,ri trot,. Pt, lt ;.t, I l' . tt l\\"i' r/ \\"':" rl l ttt t tr'ta lrL, i S', L _ ' ' , ' Lr n tL I tr ' ' n ' ' r ' ' ' l. c. ll. IrrrL!r t,r,, rrrt, arD trrpavci SCALE OF f EET 5tocl fo s.lu.r 12 l!o. 16.-Pbr ot Pr..ipit tilg C.a&. il i) r!.!artr'\l\dv.'q!|lf!.rn\I'.!n\\ :;1 L,rt.l I qa^ r,!r"l .rl .1" PRnctrrlxrroN ol. ct)t,r,) r a1 rl,ro rlN,ro, s;tN-Dtsc. 7r cdrl,,'irNl ir, rLp r,.rprr: Lr;\tr. t,. WJuror urlly tur dustdined JDd,{na,!rdj{ ,,,1,r : t,, iur. C. t. HiU, wl,o wus for F,,mo 'ntur,rL yosru iI vory cloBo trssooiDtiox w h l,lo wort cov.rod Ly thi! p4por, unn wtDsu dugsoiri,',j trnd truh burb in regsr,t tu Lhe work ,td;tf;nd tho. prusenra r,ion ul rb" ptrp,.r luvts b&n uf lhb g.uatl$r vrltr.; l,o Dr.8. L L"vJ, l,r l,"lp irr rrruy lormr; trud to ltr. ti. U. L!wford n,r vi'r.,{, r1,,, pr.{,nr. riuI at rtr. t{tr{. DISCI]SSION. The PresidgDt {;\lr. .1. ALL|:N Howj,) w,,lcurkd m€rnb:rs to tho limr rrr-rir'g uI rh" Sussnr,. Owinc iu ;t r,a ""naiti,n" D€on ruund o€ce$r.y ro atrang" t,{ Ccnprllt"n. ltr"r,ngd [o bp h6td overy ofher monl,h. . There 1v6r0 two pstets ror,trd(usbiur, sxd rhoy wuro fodunrto rD be!D8 onu ur iho &utboB, Nr. Uhelln, r,r iotroducu rbo lirst. Mr. P. F. Whela,n, io iorroduciDg rh6 pspor. said tbat i[ d€innuvstjon. Loachine or cupreous pyrites sud lho prgripimrion of .opper trorl thu tiquuru l,,gan oi iuu r;orc mony docades ago. As nining sctrvitica rhoru wbr. betiev€d to origioal,o in rb€ thrrt€6ntb .eorurJ. ir was diftirutt ro givd an sxsot d6ro. lL wos c€rraji rhar t"rcbing fur coppcr ossurned large proporl,ions soon atie tbe properry *as abour r8?0, bj, "cquirea, BritbL inlordk \irh che couraee and foediel,r n@drd ro dsveto; rbo loitre onil snciitury scriviries on a gculu whicb, ro_a"j, sould b€ ronsidered laree. As s coosequ€nco, Spnin ",aook socond e]acu aponq ilc wortd s copp6r producors ror J."u u-uau,, * rotro\ins psr.imsied y"arly dv"nLse our,puts (io sonbod no.rocooL 1Yl .l{ "" ' W@kt l8?l-r380,,.__....,.._..... t4o,filo l5 r88l-r890,,...,...,,,...... 25o,OO0 22 r80r-1000.......,,,......,, 4ro,ooo t6 (r0J5......,.,..__....,,,.... 1,,160,000 !) Tnrolgh civil wsrB ond world wen, iorifr dificutties, Sonersl rBd€ d€prusio)ts. ar,d tbe succu"sive uxpsxsion, in ourpur io th€ 8l&1,$, Chile, snd Rhodosis, copp€r produciion ty hacting "on_ tiDu€d. Th€ flotaiion of sulphido and conplox gios and g-enoral lmelting practico sieedity illlproved, so ther the;s qrerhod-e wore in duo coune appliod to ce$ain or€s sr njo Tirto, but Dovo!thele$ ooppor- production by tho wet m€thod hd obslinstoty p€nisted ond held its ow liqijd'l 1o d.l'l dlolt Th6 reason was, of course, rhat, onty by this Dmthod could th6 ?2 J. g. TAYLOB AI{D P. r 1I. WEEIJA]{: I'EAOIIINO AIIIJ 1 ooppor be oxtraoied end at ih€ sam€ iime tr velusbls by-produot, pyritss irl nassivo forn, be obtaiiod. Aetuolly, in certdin norkot conditionB it vus mo!€ logicimoto to considor ih€ colpor goinod os e by-product. As nickel in tho ceses of Ini€rnotionol Niokel snd Falconbddgo, gold in th€ oeBos oI Norend& nnd Bolidor, and silver in Corlo de Pssco ores, rondered th€s€ produo€$ to 8ortro €xtonb insensitivs io tho abrupt price v&ri&tion, which coppor bdd €xperieDc6d, so an oxpondinS msrkei lor pyiioB for sulphuric ocid manulacture hsd be€n in lorge psri rssponsiblo lol ihe p€Btutonco snd oven tenor of leeching at Rio Tinto. Locol conditions hod also h€lp€d, oBpgcislly ground constituted of h&rd ilnp€Ivious Bleto with r suiisblo si ko which mad€ se&ling by dams inox?oDsive (incidentally, thiB festurc vas a drewbrck for slime'pond comtruc' tion) ; also fu€l waB oxpensive in the south of SpoiD. Th6 leaching process, of cotrrso, hod noc stood 6iil. Many €Eeinogls now to be found in Moxico, Austrelie, nhodesio, Amorica &nd elsowhsro, spont arduous Donths and y€ars in ottompt8 to inpmv€ snd €inptily it, and oiheft in dii€cting pciivities clo8oly corn€ct€d with it. In tho essurrnco that s datailod aoooult of present practico 'lr/ould b€ weloome to thoso, aDd in tho hops that it niSht b6 of sonl6 een€rsl int€r6st, thiB paper h&d boon wdtt€n. Mr. E. G. Lawford said thot one of ihe points of outsisEdirg intorest in ths psper ]traE tho ro8oerch aspoct, vhoD it wa€ re' monborod thst this ieseerch was done in weight units of meny thousands of tons, rnd i,i e units of years. A ihousr,nd ages iD th6 sight of s eoologisi wcrc indood buc os y€Bi€rday, but ihr€6 yeets to & metollurgist wes s p.otiy long time Bocauso of tho slo, reaciioDs, th€ hoaploeching process hed lor him sonething of a g€ologicel sFpoct, and this ws8 onphrsized by tho oxient io which nsburot w€atboring sgeDoios ontored irl,o .It it. was slqar,s irror€slirs, wLon .onsid.ring uxJ u,,d Proceso, to elance ai oib"rs wbicl, rlbi"ted ihe sarue ond Mr. Wbelarr in bis inhoduotioD hed briefly iouched upon ono sltfftrotivo for ths eytreotioD ol copp€r lron pydtos-nsmely, floiotion. Pyritss veried tbroughout the wo.ld, bui to oxireci iho copper ofreciivoly from the Rio Tinto pyrites h€ was feirly eortoir that 3t l€est 86 per cent Dinus-326 nosh SrindiDg would b€ roquirod th'crg w€re very fow plaDt! ir the scid indus[ry to-dsy sot up for hondliDg whot vould,be the tailings hom thut proc€ss, noD-cuprif€rous pydtes of 85 per cont minus-325 mesh. Th€rs v€re wolks in Anerios which wer€. burning very 6!0 conoeDtr0,to! gucooBsfutly, but th€ generol msrlet lor m&tori&l ol ihis Dature $'as still extromely nerrov, end €von €upposing th&t it waB gonerally scc€pt- ta ) PREOIpITATION OF OOFPER aT s,Io TItyIo, sp tti_DISO. ?3 Bbh, tu rh" si,t ruhor, rb" harrrJtirrg of rt j troduci would m€lo ntirriror, ^x tr vory lur8e b.^te. Jrd ir \"utd invojvo oirbor drvin! $uur,r-r," u, urr,,1,,,,,,,,r_*i,,,. p"y,i.^i ij :ul,:,. ", iu.voul; ol rruighr ',,,"1, ,{r l,L. \,.r fih. r crk,.. t h€rotor6, rlororion be a very 6xp€nsiv0 ond clu,)sy Drorhod of obioinilrg rn" a*r p""a""i copl,"r.nnd xur.nrtr"oui t)riLej, as cur par6d wirb tho iomhing wnxt lhr,tr'rl.ht{{ l tl d!s{ll, rt L ltrrt r0 lurd oI t,yrrtos wure lost rn rho bxtrtrcr,iun ot ,'lb!_lL, aDdr ro',,or co![4 migl,t. ar lirsl. sigbr, oppear Es o gr€al dis.r ot tbe advanl,age h6dts proc6sq, buL IJrit€s at lbe rnioo mour,b wae com,nodiil and. ir, rerms oi.os! por roD of ::l "Tr :-r":,'" " coppd. ru toss ot pJriiej did nor loor! v€ry targo. copter coutd 116 takon out ot pyrires or ur,bcr stages . tbe stobo cours" trcm ih€ ruile i,brougl rhe acid vorls r. rb€;on ble; 'r.s -l,ll jr uventue y reu0led. rn rho faso of ,oeDy Iy::l""i Dundr. s or tboLBsnds nf (ons rho oro was tirgr burnr, {orL8..ltFr sbi.h rt,e.oppur was orlracted irom rhe ar, acii burnt l)16 bJ rbu l,oogrnflid.Hpr,ddcor process, whrch consisred oI sirrns l,he crno,r!.' rotrlL wrth sslr so rtor rhe copp,r $ds leqi,hins.rh_ .ird6rB iq runrs, anrl "onu*rud'i",o precipitaring :::"]: :.1"1." luo ,nptier rtur! ljquorc on rcrbp iron. l.trat proce"s vas _rb6 om.rmt: tr" cindurs arrpr reecbing cuntained :i:lll"i"'*liy mloor.lrss tban 0.1 p"; qsrl Cu .Id usus coppe-r r€rov€rios J o:,.:""r. iu I rrar. judsed puroiy on a n,er"rrr,.gicai I":]i.l:1"1 o3$s. uF I dgrmr4-fl.r.loreon 'o l,rucosi showe,t u gr"uer rt.,r"iicul emo^ni v rhrr rIp l, rrILr,q ut rt," rrw.uttr,.uu{ Ho$ev€r, rt.l,rd iu h.un,t,bsjiz..d rh6r. \vh.rhrr th. orF !yrir,*. we, lesched sr [1lo nin€, or.whciLor it w0Jrr io tho dcid works snd rhence to ,ho L..,._,,,i:.1 H..nil. r.1,,, I,r,rF.r. dr r4!t,.J ur, iI |!nrn"nse ]rurnbrr or p'ri1r,r, I0rrrl.,',,t l,{+T"t,tri,tt Lrcrur: inr,, \trictr il rvuutJ D. 'turt i"rtndi 'rr. rrutn. .t rIr. discusriorr lv ,.nler. tr, urhe! prun_.u" hurr (r,ni. r,!rt in ur,,In,i"u"lei,"i ],:lll" drJl,.,i.!r,u' pJn(c, rnJ ju ,!,,.nrF rtern ,,rr r basis ot'iur"ly r'(r.,,r'.'l Frli.rrxry would t,. trrdd.mi,. ,r,,t ,.. prn"Li"a"l ].1,ft:" "t *: - inr-r,..rrns rdtiwal huud. Lurw.er, rb.l,orsn,bid,,1n;.1 }lblnr, r.n trccFs .,rd rto l,,s.hnq ol cuprpous pJrito". w}l€o !nn,l. d .indFr ut sbou[ 0.6 Ilrr c"nr Cu wes obtsined,.erd irr gor[e ooid rvorks rhis burxr or€ weB l€ached ir sir;ati,.r iD rr,F.r,", no.o*r; :Jl';,1:,'!: l:"d?,.*," "i. "nb Llrp tr., vals buing serv"d Ly b .rsn€. The 6frect of ^or Dcril makrng so. ro r,.ndur ta.d DDrrung ror lrotwe,,n b0 snd 60 por cetrt of the coppor soluble in diluro ocid, ond by le.rchilg i" thiJwoy;; j ?4 J. E.',r,rl'r,oR, allD P. r'.;IIELAlr : ) PLEOT.PIA,A.TION Orr rND '.EAorIlNo &ddition 4 or 5 lb. oI coppor per l,on of oro vas rccovdad Lhe rolr oro lesching conibinod wirh snnple sulphsto leaching coD' d,roted ol, tho rcid ivorkB gIfo, ihereforo, oD overtrll recoverv Dot srestty inferior to thet obrained by the l,onsnaid-Henderson too % 90 /. oorp$R AT liro trlltlo, sfarN_Dtso. process. ' Turning to ube s€ctior, oI the ptrper d€slinA wil'b precrprl0Lion, ih€ vsyln which ihe various substoDc€s were precipittrced or notri,rslizod nes showD in l,he diesram, l'i8 19. t,]... Ihis diqran was compiled from lhe &uthor'6 curves, tr'ig l7' bui sbowed porhaps rrttrer lnore vividlv and strikinglv i}l8n iho8o curves tho vay i; which the vs.ious substrnoos bohevo on their psBssgo thtough th€ csnols The colunD relsting to scid did not i" tho oxit liquors and showod perc€Dtoses, noc oI "uiJ "uo*ir'u toisl acid eni€ring ths prooer6, but of seid aoiuslly reduc€d' Ih$o *€to sltornativo methods ol precipiteting copper lrom highlv Bolul,ions wi[h vhch memb$s \iould be ismiliar, bui it wss .i inproboble th&t &ny othor m€thod waB applic6ble to tho €xl'renloly dil;to liquols $'ith wbich th€ pspet w&s oonoorn€d For eleotlolvsis the coDDor cootsut nl the liquor vss usus J 30 0O0 lo 40 00O s""." p-'""1,i" D€l!o, insread of l,Le l400 ro 2000 srsms ler A wero dcsling lrecipit8tior ol H:$ or l'v rL€ inrroducriun dir€ot bv tLS brouqhl, ebout bJ tbo r€rrous g sulphido calcium (e o'u oir,Uu nuiio* r"'e*is 'ulpbid€) ;-bic Detro with *hioh iho euiho.s whicL ev€ntuslty proa"cea H,S in tho liquor would' wiih the 6 volume of liquoi ;ith whioh tho luihorB lver6 doslins' irvolvo r"lp' r bullbide b'se urav oi raoh. l.hickoners, nllers. ul-c. the priipirall setttea very slowly strd wds e\rromelv troublesome to ianaie. Ite trcat'n-i tor ths tecoverv of coppor as et&l would precipirorion bv iron th'ru rcr r in which ih€ tiquor Na's brought wov nunb€r ol"varistions in tho With ihe mors conconirstcd liquon ilon. inio coniaci wii,h the (9,000 to 1r,000 gru'rs ler process of ths Longmoid-H€ndeEon lhe liqu"n and rh' 'crJp iron bdtwe€n rh€ cuniecr crbic netrei. pro.ipil,snt wss olt'1r se'urtd by uroebauicnl m"ani lh;- r"n_ list"d or a ro".l1]l"s cyti'dricol vossel verv Druch liko a tube nriU' lo Lho a€Dbral tuuthoil Finsll!. he would Ike to consr&LulaLe lhe suthoE on l'he;r in U" litrlJ,ru n"a bad psrsonsl conract' qirh l'bs work d"sctibFd so in conpiling involv€d the lubour he re&lized p"p* ""a t.i j ol ile r;o"o. rro*",r tiir"'eh rho bsr'el shich $rs kPpr 'btrrsed $ith tbe phutogmph ri'l' i"*". n*" lbu lors" bsrul shown in (dbic nrrr'rus ar 9r, dbuul' ,i1.. go. ir'[U v) wuold onlv hdndlu Bssontrdl $as ljquor i,"'r, * tlu'. rui"ti"uty cunc€Dtr&reil palPr' .ilu / ll ,/ xl '/ to'/. 0 Cu Bi !\o, Ig,-Coppor, bimurh I Acid and 6enr peipibr€d: roF,c rtun 6mov6d. 75 l P. r'' wrrErraN: LEAor[nrG AiID .omDl6t€ e doffripl,jotr ol l,ho op€rotions He $os sure rhst ?B J. E. fal'r,oR, ixD PBECIPITATIOI{ OF COPPTTi AT BIO TINTO, SPAIN-DISO. ?7 oubors took phco in ih€ iirEt six ]llonths, Th€ first portion oI th€ coppsr nut*ithstuldins r'bo tscL thor' ;"ffi;;; ,'; Jop* or i.r.er€* l*i-r"""n"e *i' la.',t€dlv ol limiced opplicotior trs colop&rsd took only ono port of fonic 3trlphoto whilo lho socorrd l,ool four peris, o. if ihs extrdction vas pdrtly dono by oxygeD, ono port with ' othor netallurgicel il". *lU"- t"ill* '1"i".*t of oxygen to four parts. Ths writ$s of ihe paper rtiributod rspid oxtruol,ion to oopper sulphrte, but hs rvould hovo thoughi thot coppor sulphrto would hovo Loor corvoriut ii,i,,, dutt,L f t'y 1l,o fxr.r ol tyriio n, procoeaea' n"""uli soid ho believod this vus iho first authod- on ih€ tr€''tlnonb ol Bio Tinto or€s bv Ittoss '-'"#;;d";""' s Dumber or pepers o! tho subj'at l'v p€oplo was rhe nlsot aod obtained informrl'jon 'lhore *r'. i"i trDd' br Jooos "rtU E le04' lM il" r'"*1",;,* or tbe A 3ur " ** u ,n* pap€r wil'h Ibu prsonr' it was ioiorosi'ins to r'ho Imt 85 in ph(e tslu ""ll-i^g had Lhst ii. i""-"""a*" i"i"r"o.ont r*' pur und€r sci€nr'itio rechtricar ,r ;:;"il";;" ""* pui dotn so as ro ersure perr"cL crret.ilv ** i""i'.r,- ii"i** p;;;". rne"trenicai equipme* bsd b€on introduced' ;";;;; at deriinirerur"vers s'd in dot'ir€ ;il;;;;*;;;J;*.; "ppried lh€ co$o't In'g&L'on' nuuntiries so es l,o Arvo l"a i'"."ssed io eEoi€ocv io suab atr oxt€nr' tbac ".""*" r""i,""a""il t""rs. tho exr'rscri;o wes now accoropliehed -d;;ilJ "r""u'* crodir to arr sho had b6oD sssocietod i;;; procoss' th€ tho dovoiopnont of"6at with "Lt-*.i* he 1,i""" o"por;irb rhe plesoDt' rh6re was s point " sr'ateoont^wlb *Ja ill" ti l*" "r'iiJoted tn tbo 1904 pspor a culs 'ti. i I I I I I I I i i I i th* ;; copper exisued maiolr ss tbo rso sulphid€snin€r&r ';;;; ffiA;:" ; ,*';.""""t psp€r th€ p'edominent oopps w&B stet€d to be chslcolvriiii {CuFeSJ' ";;;";; exp"rimenrs should trot be alrosorhor overlook€d' U s BuJoN s,-" iri"i"Jti'*'"*l lad bsetr cstriod out bJ r'bo A I M E' the io bv sulliv"n poper in a Ii-vl"'""'i -6;ri;'. somo int€F "'t-u,"d obtain€d sDd ;in;'ab puro t.ok ;; ifi. oghr hoLp Io e\plsiD .l'ilirr"'ur"'i- o". ,reating them, wbichbosps ol Rro rinto lt i"-"""i.i" .*"tl*" r.aLing piano io r'he hod ao ! be obramod !h€r€ tLur wduld h€lp oosine€rg I "*'*"*"r*a i-""ri""i"n*', bv all exp' roenloru thsl mass aclion --'a tui" ooulJ ror' be duplicated in rbs lsborarorJ' i',i;"i".*"ir"' .r*n i" understaod ""fj""ri-* *,1 better wbat wos happoniog iD the hoops' I I I i I t place C'"S. S"rIvan rhoughr thst lho rosction too] was ooovsrted into t";;;1".^; Fii*. ono morecuro or copp€rsecondrv' oD further cus ioio molerulo ;,'il- ;;? ; secoDd r'o cuso{' oxidi"od was cus r,his sulphato ierric *il "*ii'i""i If thiB eoid,"i"rii-""t" il" '"-ding sulphur to €ulph;lio rspidlv fairlJ ."aotio. took'plam, har of !h€ ooppor w&B oxrract€d ror tbe rapid oxtracrion st Rio rinto whioh ;;;;;;;*; l LabolstorX expsrinonts had deternrined th&t chslcopyrito we! very diEcult to split up, end whon grourd to 350 m€sh erd tresied for two ruonih8 with oxcess of forric sulphote, only q por cert cxireotion w!€ obcoined. ExperimoDts h8d d€tormin€d ihtrt oxtroctiotr f.on chslcopyrito by csrelul regulacion of the hest as v€ll as the proper addition oI ferrio sulphato soluiioD. Evory auihoriiy had siet€d thsi ch&loopyrit€ could Doi bo i.€stod €cononicsly in snyihinglikoredsonoblo tim6 sithout c&relul sti€nl,ioD to this troatnont. Th8 sfrnil,y ol sulphur for coppor vas {eI known, &nd edvdntseo rvas only obttrinod \r&s takon of this in $molting copper ores. Tho iron could b0 elininal,ed by oxirloiion, whilo tho coppor ftInanr€rl o! e motts of copp€! Bulphjd". In hesp-le0,ching oxnctly ths opposito tooL pleoe. 94 psr coni ol th6 copper wds di$olvod fron ih€ sulphido in two yoars, snd oDly 18 per cont ol ihe iron fron iror pyrit€. It $,as difrculr' to nndorutaDd this, unless it was thqi iLo pyriie was p t&t€d by &r imporvio,rs lilm ei, an es,rly siag€ ol tho process which prevenied To show ths connoxion of on€ irduslry with anbibor, h0 *ould ooko a oor:rporiron of ono poini in th6 treatnent of gold or€s. 'lhero hed be€n two papers recenily prosenied io ths Inltiiution on 1,h6 extraciion of gold by cyaDid€, st [he St. John del Roy nino snd iho Globs &nd Phoenix nine r€spcctively. In boih oe8ss, in otdor io rend€r th€ sulphids ol iron illmune tho oro was giv€n agitation i$etm6nt \rith air Dlono before lhe iniroduction ol oy&nido. This ueetmeDt eppar€Dily co&t€d the sulphides aDd pr6v€nted tho oyeDide fm'l eotbg otr then, and ii mighi bo thst the irotr riDersls in the nio {into ores weio coeied in this w&y whilo tho copper ine$ls rvors not so smonablo to it. l,ssily, thors was Do rientioD msds in th€ peper of v/hai haDDetred l,o th€ small qusDl,iry ol silver in tbe oro. Som€ Inhos ; iie .ournern UDited Sl,ares, wbrl6 using isnk loscbiDg. extrscl,od e littlo silver. Wos silver isk€n out of the Rio Tinto oro, 8nd if ** it t"***a on the copper precipiisto ? "", 'l 78 J, t, TAYLoB aND P. Mr. J. E. Ferrlloll Bdid 11. it v$s ebout 15 y€ors sinco ho wss on w6! in Spsin, was the result of th€ corobinstion of e uniqu€ o.o ond ih6 clim&t€. The ore ir$ssiv€ pytit€s) wes unique in thot ii csnie.l no saDsue or west€ wiih it-it wss fot prsctiosl purpo66s e homogen€ous ninor6l-end without the dry Sp&nish clinete it would be slmost inpossible io osny on the procssB. As a leaehing proc€ss th$o oporotions in the south ol Spein wore un€xsmpl€d anywhoro else; no scid oi other l€ocbing sg€Dt vss us€d, fr$h wator only wos supplied to the hstrps, ond ths nsssive plait€s did With regord to tho fornerion of the heapa, the depths which the suihors had given were sbout the dopibs whioh h€ rsmemb€rod; the le&st depih at which ths process hod been found to commonce was 3.5 metros and hesps hed boen l,ried up to S0 motres Wiih the latter dopth, how€ver, crushing of the minorul duo to its weight hsd been s€rious, snd 20 Detrer, evon wiih s hard rosiscsnt pvritos, dod es the naximum &llowablg depth. On€ srgulllent ageinst a deep h6op, of course, was ' chaDnelling ' of the wash waier, but in his own oxperi€nc€ ihere had never b€en anv teg sorious difrculiy f.on thh couso. Ih€re wos d big difrorenc€ betw€€n pyriies tuoln difleroni nines tr€ reeerds thet l€&cting cspscity, end lrcn e visit undorglound at th6 verious min€s it wos evsn possiblo to tell which niDeral would wssh dpidly snd which would be refractory, trom ih€ ilo workirg -oppoarenos oI tho minersl itsolf end the strfe rYidth of piacos. Thus, at Rio Tinto, wh€E thoro was s high solphur snd 'iow gilioa ninoral and ihe pyrits wss under st.ain, the workingptacos were'quite nanow, being only sbout 2 netres wids; but at the mino atiih which he wes connectsd fo. flnv vesE, t'hs pvriie hsd r low sulphur (4a+ per coDi) and & hieh silios conteni (sl io 5 por cent), &nd the stopes rvere carrisd lrom w&11 to wrll with widths up to 20 meires {ide. This Concepoi6n minerst wos v€ry relractory, and dl kinds of diffioulti06 had besn eniicipatod in rabing ihe tonp€.tture in iho lirst heop to tho point ai which rBsction becan6 gsteblished throuehout tho heap. Iires vero €ven lightod in the v€ntil6ting chimneys, but th€ final solutioD wss very simple. Luckily, thor€ wore ferrio liquors ovsilsblo, sDd these w6r€ brought on to ths hoap, which soon stortod.to hoot up. pri[clfl,larroN olr corpuL wrraLAN: LEAortlNo ArrD tho Spenish pydtes bolt snd ho felt h€ wss boing rethor bold in melioS sny comtn€nl.q al, 4ll on s pspur $hich wtrs risht ul l,o d8l,o' Hic r€mark. tborefore, would bo aeneral io characl,€r' This procoss, which they us6d io oell 'c6mentetioD' whon ho was ususlly ) The ossontial lesiwo of tho Conoopci6n h€ops was th€ orushing AT rito TrNao, !PAIN_-DrSC. ?g t,h€ ninfrrl lo o littlp ovcr 'lurDacc sizo, (ro poss 2l,ir. ring), though iho tiDes Nero oll nrixcd nr wjrh rhe tu,np ninerol. The luDt,(ndun, rl, rvlich s h.ot wrs kotr dct0ndoit oo rtro plriicular lyrito, $hoiher rArdity oxntizoLt€ or nor. At his own nire they riinod al ko,pi'U rLc tcmpersrure of ih€ herps b€twoon 10"C. tnd 80'0. ; if rllorv.d tu rise ro 90.C. wis s;riing no&. ol e t-ll dslger poir)i dt slloDitrDoous coD,LustjoD, trnd it ro 4u1'. w,h),r,c 1F..,r,,. \,.ry irr,r-rlpcr. tr il[ tonrD€rorrto Hiu ",,urr.rr.,r, TiDto r,rnd"r lhpir'r,,ulur \urti,,a syJ,1n, thFy w"rc now msirlHinirg Ib"ir hrrps rr as t"rv o nrern rernperature rs r0.(. (or 86'l'.-a Ii v dry roxritersrue in ihe souih ot Spoin for iho lrrly tru[urnn rroutha). ln r'pec' ui rh,. rL',trt wsbl,ing or tbe hprps. h" sN D,,i re thdl lhao ws any vqj Arp&t rdv0xr.,g€ iI the pprayirg o\er rho old irngatrorl ,',erhoJ oll 0rt ct{ssps oI r,tr;res. Ho hflJ found rhoi spruJrng l!'d Lu€l lori."rl,ty efibrriv6 ol, I ouco!.i6n; "^(rh"F. d.rJd, wh-I lrore,J. pusiblJ ir' pipurc was aim"ulr Lo obrain, worhins in ilm ordinary wdy by irjgeiion in rectarigulor beds €uromer flx,l tuight srill be.un,iddred'strrisro.r.{J,;Frbnd. fiu got r,b6 iDrpro$ sron lrom r,r,d I'nt,^r. huwptur. thJr ar nio Tinru rhey Jscribod the r€,,,arl,rbly luv ri,nu r,, $In,b rl,F \d.Lrrg ot ,h" b;sls bad bs,D rdured {r\o J, trF, ru s srur, r\t, nr rn th; ntrJying sJstpnr. liio aptarcntly d€peDd€d otrnost o" ttu SO. _Tinto method for the rodtciion -ti*iy of terric ro teHous iron in the heap liquoE. 'l'h€ r.otLad us-d rI r,,any utbei mines $a.F s .titr,6r, of cledn pyriro o\or slrh ihe trquors romirg our of rhe b€sts were passed and 6n0rgod reducod ro rhe forous sttrre. B€st ;r sll was a "ubmprsed tiho. of .rr€fu J siz€d pyrite bsving s d€plh of obuut 4 n,crrcs. He r,olico.l, h"so,ry. raL sr Hio 'iinlo rhpy slrll us€d d filror toJ to sorne Ftrghl. LXreDL, bd.euso lho 8ulloru m.llion-J rh rheJ pssqpd thc SU, irnp.€gnsl.od liquorN lasr of 6ll through $bar ivJs practj.J y o submb.g"Jnf,".. Tu rbo prp.rpirario! sJsrer,r rr ess nor atsotuiety nerpssarJ tu use tho very wide channets rnoDiioned in dro p.por; ,i oil"r nrnres in ih€ Prcvince, ctnun€ts tuoln 0.gS ro 0.50 motle wido hed been Inrgely us6d. H0 thoughi rhoc tb; groer advenrego wiih. Da(ow c.hsnnels wss thotthetiquorc were ceused ro rippl€ agsinst rho' iro , and thi! combating of th6 iron producod s betio precipitarion. 'l'ho role of the Irco sulphudcacid ir rh6chonnels suu-"a to be ftut ol a csialytic &gent, soncwlnrt according io the following equstions: ' Io - Hr\O. FbSO. T 2a I.'.! (so.h + 2H _ 2tbao. + rtrso. ' (Nscotrr H). 80 J. B, T YLoB aND P. l. wrrDLAN : PF,NCIPITATION Of COPPEIi AT IiIO TII.ilO, r,DaoHrtro rtlrD There wss not, &s ftrr es ho tomemb€rod, a 1'orv lsrgo coD€umption of acid; ths,t was,sqlphuric eoid noulrslized bv thssolution ol non' \{ithout gorne scid iD tho liquorg ihero would bo no &lpreoi&blo ol coppor. 'procipitation The biggest itonof oxponso in tho whol€ pmcess of h€op-{oshiDg end precipitstion of th€ liquors wss the consumption ol iron' Thooretioal anounts of pure itun roquirod lor iho reection! tsking plscs p.ocipitstion ohannels w€ro os follows : - in thepr€cipiGte the copper: 0 89 kilo of iron per }ilo of (1) To oopp€r. (2) To roduoo lenic to lelrous iron : 0 50 kilo ol iron Iornc iron reducod. (9) To n€utrs,lizs acid: 058 kilo or ler kilo of iron per kilo of HgSOI neutralized. On sn a,vers,go good liquor this gsvs e liitl€ over 1 tilo of iroD theoreticolly conrumod por kilo of coppor, eDd the eversSo nio Tinto rsButl oI 1 66 kilos of cotnmorcis,l iroD (90 pd cont l'€) pe' kilo tuo coppor weB slightly better then what' he used to do wit'b liduors udel l,he besl, oondirioDs. 'Control of the pro"ees *ss ojTecled' as l'be aulhors hsd poiDred oul,. bv m€usulinc rho volume ot tbe I'quors lsssirrg rhrougb lhe channeb aod tebne gsmples of tbeln at legulsr rt'rqvule ll'u method iD uso et his orvn min€ fot measur4 voluD€ wa8 to p$e th6 liquolB over s woir'gauge nsdo of harde$d load, using o righteDclo;olch for smsl q;antiri6s, atrd r rerl'angulsr gaug€ Lor ]atser Froro l,he approprirto hble ooo coul'l ger rho volumb cuintities. irsmediatelr. Tbe drip-s,,'iple menriouod in tbo papcr wur' ho i"r"" ir the uzua,i wv bv nreons of a +'in l€ad iube ".w*"a, quort botils, ih€ semplo beiDg a 24-hour-one' Winchesier and' o job trnd lho Th6 r€qulstion ot rhe wsrer wss oI course & 24-hou roru sarlpler rbo -An in-.huse ol tbe caDols bsd to Be€ i'bsrmeLe or tpsl's smoll strd v€rd &lso requied to driooi.np oriierlv, " This irscl'ured a rresblJ plugins vas dolp bv ,nJi,*ii iiq"'"* oiece of ilon inlo th€ liquor. snv coppor pr€sent sholving uP at lnce. and rendenog it poasible to male a rough ostim'l'ion ot [,be smout D€ndins r€o€ipt dI lbe asseJs' l**"'"r *ip* c;uld be divided inr'o:-{d) rbos€ iuoidenral $ashod ore' dnd r,o tU" pto** i'trl lbe coppor lockod up in i'h6 ie) ,h"i**. thlr;"n s*;t in tb€ sxil' liquon lron rho pr€cipi' (br l.bo so-asllod avoidoble losses bur shich iult;o" ""ur"; " nanolv, soepss€ of ooppor liqlots *eiu "'oidobts, "rtoeuil"" "ot ioio tlu g.oo"oa unds! tho h€apr, and loaLs and oYorflows lloID lh€ pr€cipitstion csorls. SPAIT{.DI6O. 8I h€rould here tiked ro hove h&d aciuol ligures Io. coscs, .I'inaily, vhich woulJ bsvu put rb! tinul €mbatlisbirrg rouch on rho maaorve ormy..ul .hur nru,o"ru,l l,y rhu rurLoB irr rhib vdJ vElusbt€ contribucioD io ih€ ? 'anrdciiors. rhrr. trrr. Fonno h0d mod€suy ro,rsinsd .rrom !. reicrnng 1:W S^,ft ""lJ rJ ,6 v{lusLtu arliclos on rbis procesg rFhich b6 had Mtsin!.Maqd@ some ydsrs aso.r rre (cbs 1p.",'*:il.*ojoga,dj,,g resdrdbd rhose afliclbs n" u ,""ay *o""" or ::l:lib_l':d,,i,'b" or\lys ro'onn,trron thib u,nque op€rerion in rbe sourh of Spain. 'rn€ v0ruo ot lh6 pnper xbi.! rh6 sulbors had oo* pru,"nt"a, l" thorght, i{as noi onty lls s careful r€cord of rh€ sp""fu" pr""J*" which hed b@D dololop(l trr ltio Tn,fo, L,ur slso b€L*" iiai"a""ua many of tho turld{iDientsl dilticulrios whicl had to bo t&c"J;;; oveno',ro in rny prucess by rvtrrch hschrDg up€rElioDs $rro con_ ducred ror tho rucovery of.€tativoly smrlt porc€nrsg6s of muraurc cort€nt8. tt woutd bu res,l wiih inr€resC by thoso rvt" w[D sucD prubtoDs. "-, A".fi"g His own inrd€si the peper concred chiofly in rhe ch€mioel aspecfs of tbe ireairneni which rvere desnibedin S""ti";; (pp. S&-51j, rb€ gt€arer pan or sbicb retar€d [o .ctea" O," L6,c]i;;; condirions.. Ai,6r roviesrns rhe proreaure prioi ]n':l:r._\ulmst to 1925. tho rboru had given o vory.loor uDslJsig ot cbe raitors vnr.n o{d t}Fotr B(udioJ Ly s.icorilird y arrang€d obs€rvarioDs on rn6 Deaps th€mselres, or€r long periods ol fim€. Tho oursr,andino jd&rurce ol,rlb.,rudilrtrrions iu prs.rir€ wbrnj bad been adopred' as rDa r€su or tL'd wnrk wb.o: rtr Crntrojtcd vsnr;talion oirto ldps oy,rno prorEron oI .omltelo tsh€ borroms or,msis,; (z) pi€voorron of rb6 furmalion ot slmes oD r, surrac"a by a suirBblo J'stnLurron ot rhc wsr"r by sp€ciJt sprsli"g o*ungur,Jnts Svtng 3 nrgL bpru'rdrng posur : rgr coslrct ot ldr p*o_* io .,oia rD6 €ver-prsFnr dnng"r of rbe ruafrjuns lecon,iog r,oo r0prd snd proceeding to npid ond unconrroleble conb*ti".. rU"."".tioi s hrq srdeu. ro s,ore U," r"^"h,d pr;;;;; "::rl": Y, 1' r.qu,rpl ,ll''."".? lh.,l, .. ,r.".q ro n,e€c Lb€ dorranrls or iro6r.. '.,.... As fuflhbr aolo marker.rDg. evrdpnc€ ot lhe csr6 wirb $bi,:h tbe alrthors h&d msde usefut d€ducrions froln ihoir targe,s"sle ols"r;; . bdd.L@n. inrrodu..d. rbar *p*""t;,r ;r illlj:-l. l1l ,,erD wbr.h tbuy bad epplied ro tb&r porion ot .opp€r tl" nopp"i conr€ur xbrc! mn be.st€crrwly and economrcaly 1"."1,"d j.volro a diminishing yiold ";;;; conororon3 wbrcb wirh th6 'n.vudbit lopse ol tin6. ,";"";T:rL"":,",T,";l*.,)ii"f;:;;.Jr"r]:iiff ;: j,1: M, M.rEr.M.M.. l ) 82 J, II. fAYLoB aND P. F. wlrEr'AN: Lf,ao rNg AND nNs€I's Mt. R. Murray-Ilughos thought th€ snswor to }tr' tlifferilg el€'lri'al loteniitrls ol tbeso o"*i"" ip Zz, wue in rl,e ;i.*"b. ;ot lbat lhgre $us s cuoring on rbu lvri(es Dr. David Willia,es asked il there wore sDy lttclual ovidonoo t" i"ai""t" 1l* th€ roeciioD rneDiioned iD equetion (5) actuelv anv JefrDire reasoo i"J"i** ;. ,n" l*o'. "DJ whorhPr rhero was troilrte' was sulpbrde lonouo i"-*ip"" tn"' t,bo apparont'Jv rar6 pJrrl€ ol hAin' iorded bv ibo disinl€crelion -i;;;;i;"' isr r.l" bsd iDi'!oduc€d a hvporbeticdl iroo Ehicb "utlo., did Dot €tiEt is tho oro or in rbo 'er(sjolv "tr*r"l i"SiO.. ,1" leaps vere foud Thorb wN Llrlo.doltbr' -""^i ""1' Jl;"n boo i.*"""..i1"1 tl" *ia Llquirs wero le"ching noo md slLa[og dump3 tbo boncsrh il" '"'"1*" blocks End slso rrom rhe sl&tes lrom iiil ri"i"'r-1i." a ccrrtrin smouDt or the ocid rsr'cle s' cblorri'o miDerals sucL ;;;.h,t;;" l""rvi"" "r *""'p*"" ;ho [quors- wbioh r'bdol'J but ou eor;chsd **"-"l ""l"a t rolper rn rbe boaps *li;" -'*1""r"i*Ur" but in pro\rous '0" ** -"i""*,ri,' contain€d in chalcopvril'd of se'oDdsrv zonu oI oro roioed {rom tbo so.Ihsr. tb6 "*"-rii" roct'nrlv il;;;r';" sresior thao it hsd be6n had been hoap'g iLe pleced ob ri"rT-J "1"r""'"r," in th€ ore giv€ could auLhors the wboth€r to ask a*UtJ*. U" would liks from w&s leecbod vhich copp€r s'irh ia"i ,1" *r",i'" "!eed '"" "r chslcopvrite sDd cbalcociie r,hi nirerulg "trou *p.i" surphid€, covorit€' cus' rotnins tm rbP rehtiv€ly ." tl" a"^* *a *-a"reJ wbel'h€r it reBuh'ed lrom m vhuthor it .'.ia--ii*i Jr""t sulphsio od cbalcocir'o culs lt chalcopvrite oD .i"-a* ," ,1" aotion ot coppe' sulphats roacl'iotr bv doposit€d wes t'be covellirs -ttr""*alhstcoppor "l"ti"i ""*"a'""11"f" sulplsr€, €sp€cisllJ ir Bulpbunc scid p&st r$o dbcad€s noBt or th€ ;il;;;; 'i'*i".r-""* indicsted th&r' crusbcd shale;tumersed iD werL *p"ble of robbins tho solurion or all irs "opp€r -.'*r:"**i"iv -*ii "* ""r"u". shorr' periud He inquired i'bd€Ior€' .,ir,i" bud evor bboD -i.",n". Ln" Ji'" soors beoearh ihe toachios heaps lost thoro weB beins a**-'* "h€thei rouch ooppsr commoolv {€r€ ""-'-J"al" rho slareb i"-Is**,,"n. Alongqide the orebodies con*a i-urenB;Lv ksolitriz€d bv desc€ndins solulioos "ir'"."i sulpbrdes' tbs or oxidetion durmg rormed ."iJr" ,"r"lU" scid wherb'r rbrs rvpe oI elroretion hsd l'een noted ;fi:;;;d*"; in the slste doo$ undorlving ihe-ho&p8' PnuoltlTlrrtoN oti oofl,DJr lT &ro TlN'Io, sl,alN_&oM. g3 OONTRItsUII'trD IiEIf ARKS Tho outhors sre ro b6 con$&iuloted on ih€ Dr. S. I. Lel'Jr: ma8tsdy presonlEent of iL6 iruly enormous msss ot dora oollscrod over l,en Jeors. dnd on tbe ios,gbr snd trbility wirb which tho dsis b8v€ Lben useJ Lu sr v6 si.tuar and simple.orctusions ss to rb6 ooun€ ol th€ loecbing snd p.scipir&iion. I peid many visits to Rio Tinro ovor tho y€ars during {hioh the oarli€r poriol rhe \rork wasceni€d our, and was muohinpressed by th€ ingenuity snploy€d in collecthg dsrs ond uiilizing rsBuli8. Tho diflioultiss ot dorormining woiehrs, volunos, temp€rtiures snd compositions of tiquor! ond oles in whai s.e iu .iveri and 'nounl,ains of mor€rials. alwsys rn flow snd olways varJ'Dg. w6ru lsr€d and solv€d wirb r€mrrkabl€ pari€nco and skil. 6fr001, No hsr pali€n.e &nd ingenuiw w€ro r€quired to rabulsto sod corrolul,e rho dJl6 obrainud, snd ro urrivo ar tbo elug&nr. d6ductiotri which have been drown troD thom. Iho lact that n1osi oI tho copp€r csn be rcmov€d by washjng wiihout tho loss of mole thoa & traorioD ot rho or€ is in itsst roE8rkabl€. It is also signiffcant thot ihore is e morc or 16Bs ooDsiant $siduol proportion, sbout 0.8 to 0.4 p€! o6ni oopp6r, which c&n only be obtoined by complete desiruciion oI ths pyriros. Tho uniformity of ih€ messivo Rio Tinio or€, and this corstancy ol tho rosidu{il copper, sugS€si strongty that tho solubto ond in8oluble coppo. oro v€ry cle&rly difrorontiated in ih€ o!€. Mors light misht be rhown on thi; iDier€siing quosriln by lesulm miGoscopicsl examiDaiion of tb6 or€ before and duing th€ Ioacbing proc$s. The esbsblhhment ol tho ru16 ihs,f tho mt€ ot extracrior of rh6 soluble copper, under tLe sam6 conditions of lssohine, is proportionBl to cho p€rcont&go of coppor pros€li at any time, is a vdu&blo echievepent, lui ii is not €asy to so6 shst light it tbrows oD iho Ilschonisl! of th€ extreotion. Whilst, ss ths Auihors point oui on ptrg6 46, the rst€ ai which the copp€r is €xtmoied as sulphots Inu8i be iDdu6Dced by pbysicsl fsciorc, periicularly by th€ rates of di{usion, ihe exponerl,iol cours€ is consisteDt wiih abeDioel conversion by f€rdc salts of copper sulpbide peliicles, unifonnly distributod in & poro]rs me38. That this.t€actioa does tsk€ ptsco is indicat€d by th6 obs€rvaiion ihri ft€6 sulphur is pr€soDt in th6 ors efter loaching. 1t is prcbobls th6t this ft€o sulphur ii formed gFe"+ CuS - 2to,,+ Cu,,+ S, rsihgt than by diroct ati&ok by th6 oxygen of th€ eir. Ii is not i2 84 J. II. TAYLoR AND P. 1I. wlotr,aN: r,lAclrNo AND PRAOIPITA1ITON OF OOPPfui AT RIO TtnI,.r,O, impossible thst fro€ Bulphur night bo lolmed bv oxidation in th€ prbseoce ol lluo acid. ac'co.ding to the equnl,ioo ,Cua i O! + 2HrSO. - lcuso{ + 'll,o + is locurod v b sucL 8rerr, qurndries :|":lii!,:l]! phrsicura.on',ror srrilin8 e\a,upro ur h€x,i;!r unsinodrins ::,,ill::::li ""_." Sr' Mr.. A. but ono would oxpect dirsct ondstion to proc€€d by nor€ sddi-it:.n J. Caddick : I €xrond io Mr. TsJlor snd Mr. Wh6l&n rb6 ox(olhnr paper describing ::-T::::'r.b*.pyr,l:s,n9 rho pr6,.ipir ion ol oxyg€n to tho;lphide, rsthor th&D bv soparstiotr ol tho sulphido strlnhu itr tLo lreo 3bt€. Wh'Le'er rt" mocbabisn mrJ be, howeror, rbe estrblLhrn'Dt of th€ expotrentisl !ul6 iB of greot volu€, since tlo iiDo roqui'ed fo! ocoDonio extreciion ol tho copp€r, with IniniDuln lo8s of fl€ighi of tho ore, csn be dei€rmiDod sfter & fe}" monih8 of veluable rosull, of the work is lh€ rul' i'hat temperaooiiro od withh & coupsraiivolv nerrow r&ngs to nust b€ turos svoitl unn€ooBssry loBs ol oro. It hsd b€er €sisblishod bv lone L€ oxpsrioBc€ pr;or io rhe presetrt ineoBligerioD thsl hesps musl rang€could l'omporsturo but Do d€frDite Itor'ot,oo "otd, ".i,hur,oo h6 lsid do$D. sDd it was Dot LDosn hos l'smp€rstureB and ra(e8 nr arrrsction could b€ conuroued. Th€ authors beve Dow pruvsd Lhrt fteo accBss oI oxlaoll with close con[rol oI temlersluro is r€quir€d. TbeJ h""" *rso etovir l'"w 'e"lilal'ion cen bo &chjovod bv the morhons ol furmins l,ho heaps, ond ho$ tornpbr4tud c3" rrequeoev aod b"s lopt w;tbin eoy dearreJ range bJ e4jusrins Ih€ irt€nsiiY of ibo sprsy w8sbiug. rm enecu ol io.poroLurs coorrol are sbown to bo of Sreati3 ooononic importonce. Sinco ths rste of ooppsr extrooiiotr of relotiv€ly [t;b &foci€d bv toDrpersture, ohereas the ral'o ss tsDperoturo rspidly verv pyrites risos desiruotion of ths bv prev€I ing increases, the bost yiolds oI'q'eshed ors aro obtaired omueol' il" ,"^r*t"* fioo risiog r,oo hBb AnslJses or th€toru1'errbv low liouon slov, hovevor, rhtrl, fonic iroD is rsvourod tuies. ll, is neoessary, rhoreto;o. Lo balsn'o rbe vsluu or rlg i.".""*a yi"la ot *arnea o"e kom low r€mperaruro exl'roclion LIJ oosL ol reduc'os tb€ incr€ased qumtilies of lenia iron ""einet in' rhs liouor obtain€d. with ioprov€d reductioD ol l€trio iroD' ir t'*.-'"" oogsitfo to incroaso tho vi6ld ol vasbed or€ Tbo ol Ln,; wo,u now gohg on lo imp'ov€ Lbu redurlioE should SPATI{-EEiI. 86 rh6 los.bins rinto. or p.arlic. is in tbppiDs wirh rb6 pr€ciso or copler &r Rio :].l,ryeo,s lj:.,_:1""1 l*-*,,9 ln rFgard to rt" ri.try ot Uru prr.rj,,e o; R;u Tintu, cb€ tunds,lenrar.b&nge r-n b"op form",ion Look plJ.o in r9r9 vhon Mr. u3bor!..chd .Man'ger uf .\ayo Dopsrrmcur, conmoDced H€ap 1l oLjec'ive was,o sur * 1,, i,_ap nnd consoquerit Y,,-u:- T* e tuithor sccororsLod rueotrox_ or.h€r berp, Hmp.No. a0 vrrh a d6pcb :, "* rhe ^,Yll!-r\-11::o'* doublo heisbr or pri"ea;ng le"pr. ile Tlll',-.", by rhe rormatiuo or this :1"1":-""-€mbod,ed hieh h6sp rs iodrc6r6d m roterrotr to sn experimootsl b6ap wjih s dsprb ot u ze m€lro iorDod a lew y6ars esrler tban Hosp No. 40. Fteap No. 40 was a botd sr€p fo!\ard. soms rwo.rhrrds ot o lirrlls: \rron ron$dored m rroD.roDs oi plrirm beitrg pur ioro rhe hoap. Thu ehnoge vss h". ddiriunsr d6prh Lra,,onsrrsrins ropi,rir; &,,ir i-,."l.illllr:. emrrJ ur ,lb@r gMerd[ion ' and rb" prarr.icubrtrry rr quicLor "oppor ,oxtracrrou. tbe n€od ror ber,rpr corrrol and t.,cliog ."ihoa and I rhirk ir, was on Heap No. 40 r b"a! sprars ::::111j":::ll wero nr8t $ed I'r ltrrg€_scJlu opdro oDs. fbllins oI the lumpy mroerrl ro ihe Lo ol)r.or tbo , Tbrough th€ *",.r'",1"tl sys,em vss obrainod, rbo rumps beins ::,"1-.^,"::,gf urnzeo Lo rorm arr duci8 into ibe boriom o, tUe leap. f ,Inets 'trow boing torned wfth s€leci€d Dinorsl shoDtd und;biodry prov€ moro ofrciont. rho^seraso iron consumpriou du ns th6 pasr of .ommorcial iron per iotr oI coppor Lhu aremsu copper conrent or thu liquoi ae ".t ,rhr y€als has ru"li-'"-.!,"J b€eD J.56 toDs , ll""*T,:dool*.1 the toscbrtre or tho hoaps hm Leen 2.100'graos i€ldl:d A su,nmsry by lbe wrirer ot rbe r"sulrs over s period or 2l reduoiion ye&rs sr th6 Cord& ond Nsya tanks showed the foilo;ins ror&tioD between copp€r coni€nr of th6 tiquors €nrering t'ho iank; ond tb6 prg rron coDBumptior. Ina*ive ;osolubls miDaal would " '1"r, in oqu€ous solution' rorciions have innuenced the courss of Th6 coffumption oI 1.56 tons of iror fo! s liquor oL,100 g.sms copper por cub;c mecre spposrs o! tb€ bigh sid:. espr,.tjy U or oo*ia*utts valu6. The obssn&tion ihrt by Bulphur djoxido is groatlv hssien€d bv the p!$eDco liquor of th€ ; most irr,eresriog snd uDoxpecr€d: ir could herdlv .i "esur's iluiuro* "*ir,i' r"*""* l"#1""" dense' The ecoouDt oI tho oporstionsl m€thods bv vhich ihe treco8s8lv b;vi; r€g3rd to l.hr stopq rikpn ru ru,lu.6 rhe omounr oI rorric rron €ntoriDg iho tenls. No doubi ihoro is &n oxplansrion snd ! J. II. TAYLon ANI) P. 86 I f, wgnLAN: vould be vety intorested to C6rdd -..,,,...,..... 1 ..... ,.- hem Mr. Taylor's snd Mr' 3,206 l,!8 t,111 t4? t,141 1,4a1 l odl 1722 in quslirv Tho oarl,iculo$ qi\en iD the pep€r lor rbe didure ce uv contrm nr ir"o pro;ucod rrom dlfrerent kiude owr obsorvotions, viz. :t{irb -l. Pis iroD gi\os s pr€ciprlsra ilightlv lower in ' opfbr' bul "r;;;iG* ;;"" ;;" ;;i; tbm steei rails or r,nDed cuLtmss 'rb" DEouDt ;pp* is srea'ter ihon when usine r&ils or tinned cuti,i!83. 2. - St€61 l'.i"' but e rsils siv€ tho highost ooppet cont€ot lr€cipitsto usil e p;s iron TL€ produc€d bJ sto€t rarls is s[out ooo produced ;b€D using pis ilon' **.t"ionto"r, ila' vle' f""I coppor fro"tt'"r*1"" "r toir to t*o+u'a"-inot in iho prcoilitoto 3. With iinD€d cui,tingB tho arnount of arB€nic -' J"*i-*l ugl"i thon wh€n usins st66l rsils or pis iron' lect th&t Mr. C. T. IIiII: Mr. l'ennoll co r)D€nts on i'ho the os ni" iirrc *ri"" "l-*t "Diir€lv upon sulPhu dioxid€bnersod moon3 lilte$ to tho uso oI s 1""r" irol. He i" "Jr"" thst this neihod i! hishlv r,""*n 'iers rogordod ei Lb't '"ilil". "r """*", ;;;;;"-;,"*1" in tbo Pruvincu or Huolv' rrv ovu \ibw h {rderr-her'r rhe or in bliro iron terri' ;;;i;i;;", "", '.."duc€ rhe fscrs seerrr ro be rhai t'r rit" pro\ idP'3 iiiJ""l" tu."**'v **i* *l''n"t sulpbur dioxrde roe'rs al irB qurlsror to ^"r".tr.r solution' reducB '-li ferrio iroD hthst s,t trll iho nin€s where subnersed pviies hisher ""t'""rUr" ffli-a" s"e u""d ihe hoap i'empsrei'uros aro considerablv in orl thot to sav nio rl"to. Ii i" "r'o quite sar'r ;;;;;;;; 0't such high workiDs trr€ ii *"* """*, "";" * "thor or tho Loops sulplur prcduciog rruellJ rhum so Dels ol '"-."',t"t*',ut *", o""" r" o" nro in nra'' s In t'bes€ rondirroD. ;l;iil; dio{ido in iilJi""" tl"i 'i*" "r ,ho liquors oro c&rrvins Eulphui thrcush 3 is sent or liquors *bolo-mixturc rt'" *l* ""r"ri"r "rJ ll. I^yr,'1ts rNr, l', l. lVIrr,aN: 'l'h Lr lrir|.,1(trr,?n^ I'laL I't,it(, r ,1th P,(il)ih h rft\,t,l"t tt kb'I'kt.,N)]uir. f /, J, ll. l,\rr!,k rN', t,. t,.. \\,r L,,\N ,nr IittLni4 4 t nltrt ls I ttih,,tt th( 1 111iljtrlnh rl t\,rll, tt \tn,,li,r,,;ri P&DCIf|r.ll lox 0r. co}pnR.1T fi,ro TrNl,o, SIAIN-REM, 87 subnc.g{d pyrite$ litl,rr tho str\nrLrr dioxidc is rno{le t,o r0uce with tlo ry?r.g0 oontdrt oI tor.ic sult,l,dio trnd ih€ rodnction is nccomplishrtrl l,J llitrt rr,rns, tlF tyrjtog hovil8 l;ftkj or no oltucr n) iisolf. I boliove ihis is born€ out by tbs irct th&t th€r€ is pmctic&tly no losB of pyriles frorn ouy of those submergod lilters snd it is hsrd to beliove, ihor(fore, ihirt ih{r pyrito! hlrll oDt€red inio dny r€scrioD. OD fi,, oihsr hrnrt d sub,uorsod lilior of vo.y lDrgo dirroDsioDs wds triod out et Rio TiDl,o wilh poor reuulis. Th€ relisou Io! rhis 1rss, I belioye, th&t ltio'I'nrio ho&ps sre vorkod ei very mucL lowor te'npomtures aDd ihilr, in r€ceni years, thor€ has bceo vory liiils ai e poirt trppro{ching igniiion, rnuch loss oll tire. Hence urore wAs no sttrccioblo sulphdr dioxido conrsnr i uny oI iho Rio Tinio liquors rDd.l do not hosiiots to soy ihsi rhe l.iio Tinro subnorged tilto. failed si[itly on that eccouDi. This is born€ our by ihe faci ihet exoellont roduction w&s obtain€d whon liquor containirg rdded sulph\r dioxido woB €ont througb tho lilior. ID l&ct, advdntrso wss trken of this point lotor wh6n ihe llo,rsheor wl8 iuch ihat prociically rll of tho heaps liquor vos son hroush tho SO! ploni and theDce tbroush b&nks of subDerged pyriros. Thoro was a remarktrble accBlerdtion ot rodrciioD by goiDe rhar ryny eB cohlarod wiih tho oldrr nothod oI {llownra tbe rcacrion to proc.ld in tbo iiquor in,t of contlic(, wjih pyriies ot orbor Bolids, &Dd tho indioation is, es I llav€ soid, that sulphtu dnrxide ond oro I f€rric Bullhaie ratrct rrpidly on tlio surloco of pyires. Mr. FeDnell r,nrr to rl,ts wid.r pre.i!,r0tiu', .hbrndlr ar R'o snd I do not thiDk ihai the.o iB lDy trttemrri io mtrk€ our a case lor iheso, excepiing thrt tbey are obviourly berior ndopt€d lor vorking ihan ihe nnrrower rhlrnnols, p ticutaity wh6r€ orano lilrio Dr- \Yillifins ssl6 for fMltral evidonce ihai IeS is turxrod in ihe heaps. lIiB €vidence iB Doi €,rsy to odduce, bui ir is s litile diilicuh to se€ why Dr. Wjlli.iDrs should bo looking for iriolii€. I ilin[ he would lgr€o uroi tJrrlotito ;s connlorly found viih pyrito and thc lro down 01 }yrite io tc.rotrs sublrido is a si,rplo-oDough reoci,ioD i! lvlioh l]to l,yrito sivoB up oDs rron ot sulphur. tJrito is easily d€romposod iD this vay, upon heecing iD iho 0,bsence 01 air, rDd thi, is ploinly ihe roocrion which Mr. lvhalln listralizor ni his equorion (5). Rosording iho poiot ih,t orushed sh. o wili iako.rho copper our of s solu[ion of coppd sulphato, it {ould soeii ihor suchocrioD nay w6ll be duo lo iho prosence of carbonaie or othor olksline couponenr ol iho shale. Ihs lio TiDto liqtroB, witl their high ecid conreni, nould b€ unlikoly to bo robLod ol copper i rhiB woy and it would ) 88 J. E. TAYr'oB -aiD P a: wsar ^n : ri^oErNo P&Dcrfrtallox oi- cop.Pl'n 4T AND qudDritios thst Mr' WheloD found appreci&blo b€ surprising l'o heur of coppor bolow tho tu8ls ....^.h-.dutuburiDtl,6oru rt' Dr. Levv areo rerers ro r'bo ::i:"i"'"1 pl"'"|'"''' i'",*. tx lr:*:;$: lH:;4 [r:i"":l,'".,uir:*i1lil ;* :,ILlr j{t'mx;ii'i*:"*'* l"\Y''; '"j#$}ffi*'"#H[tr$dffi -'Jl ;; ;XT:i"i:i'.:T".t r'"Y' :'l:" jltl l::,:::::lt'+;::" 1: i'J l::il [xTl'-Ill;"*"J"1'JlTll';Jii:il.-li.n;;m11r"fi ; w**t***n$fi[$ffi Hix;tllff nTi;i1i",114':$,';*r+n*+,"','"'* :::n'Tll"illl;rxx""::,i:d jiidii'llii:l;i:;r;lllr" i$"i:{t' *rn";iri*'""*l'.;.tiY;:r* in liIilii?'Ti ''t""ut'"'" "ovored did coPpor' os n'rcb scid as rheY rirues the papor contaioea Iive *t"o" TO DrscussroN *q,"': *lffiuG"'c*t"*-",:' ,n". "f::"llll lll"l,ll';l*:l;1il: ". disuinquished bY erl Lhe l,ll ii'*""* *-,oi ou'so*s' .'T,:."i; "ii"' l;J"".';ill,:"Tii'Tl.'tii'ff '1"'T iil'iii'i''i"'""''" :ft t,lh','s,"i:fl;t;mn:::".'"tlljli:'tm:':;m: :'i::ll'#;i;;ff ;;;i nio rio'lo o'es i*roquestion"d' RrO TINTO, SpAtN_rl1pl,y, gg h ihis Joply w6 will firsrly isko up sol)l€ isoloiod poiDrs roised I'y in(lividuel €ont'ritutors, .lDd rhsn go on to tro&r, o tift.l€ morc Iully, tho subjolts of sxrrocrion uiochoxisrD ond tiquor oh&root€ristic8, which lrou6€d nosi, guoral irrerosr, boing r;foHed io iu oDs folm or enourer by lnosc spcrheft. Wnlian RD$ell asks whrr luppens to rLo stn0.ll qu&Dtity _l1r. of silvor in thc ore. The washod ore obrained is higher in ritver ihan th€ origiral uovssh€d ora Only rrsces of sitvor tu,v6 beon iound in ih6 liquors betonr precipiirrion oI the coppor end in tho copper precipitat€ obtoined. Vory lit e silv€I is ib€r6for6 gxiractod frcm ih€ ore. Ifr. J. H. !'onnell's difiiculty jn visuolizing whsr itr tho peper, for brovity, is t€rm€d ,cool workine', in e disirict wher6 Ebedo loop-raturus in rhe nin€rtes fl,) ond uver *ru comrnon, ir {sry undoNraDdsble. In rhis coDnoction i, is nocessaly to rem.rDb€r Lbe tury srtr lt L€di ftrn,lJrtivit,J ul l,rokoo r,;siv6 pynle i thd3urfa.ooto durot wilt Ld r.u LuL ro tuuch on r suurmer sftonoon, but only 12 ir. beneaih compusiivoly cool ors wi Nr. A. J. Csddr, k r,hixLq rh prusenr-day jron consurnltion is high Io! s liqud ot 2,100 g-',' p.. hdving russrd to sle!3 r,al6x ro decr€dd€ rhu rurric rruD"ul,i",n"1.", contenr. rVe rbjnk rhr,. on re06.riuD. ho will agrue rhJi rth copp€r srsdo of lbs tiquor is Dol, l,bc ooly mdrerial tdror rrrd rhrr verirtioo tn ecrap.irou usuge is govenod rnostly by tho quaniitio! ot sc snd ronic irox l.;onr. ln rhN runD"(run. wirl pn.J,,urintrnrJJ pyriric rntbor 0htrn "iticeous irea o,Ir, th" trrid (onr"nr ut liquu6 is v.ry u,ucb higher thon in the liquo^ to vhich Mr. Caddick,s 6gure, r6for. Th6 ecid cortont hls iD tdcb iDcre$od coDsid€rably b;yond rhot sccountable for by ,ho niiroduofior of tho prrctioo oi roduoing lorlic sulphate with SO), dnd rho epp'l€nl,ly higher irou coni suinption js lnaidy duo [o noutrDlizorion of somo of ihis oxrro acid. In I[r. C. T. Hill's conrribuiion rhis poinr is ve rak6n.. Dr. David lvillirms calls us to sccounr for posrularing o very hyloihoticBl iron Bilicdi€ io expldir ihe t,, t""o[ "."-uqoiu,t""*, liquoE, of iroD and acid yiold fron pyire. Ou. preseniorion (Equetion 5) rvos porhsps en over*inpliiicstion urd our assunp_ tioD, unjustiflobls. However, iron is presenr, often ovor 6 por conq in iho porphyri€s, chloriios, ond sldi€ norn& y borlmd by le"ch liquoB, snd wlii{,liDg eDd L,olinizacion ot ih€ steie floor ores under of ihe valleys, to o depth trsuolly beiwo€n 4 in. and S in., is wid6sproad. Sovout studies lai16d to liud any signifroani ci€{p of copper in the decomposed laycre. 90 J. Il. T-aYLoB, al{D P. i. lvrrELAN: LEAolrlNG ,A.lrD Wo ooms now to consid€r ths ch€micel proooBses coDcorned io le&ohin8, round whioh, in tho msin, ths discussion centrcd' Sp6ak€;s doBired lurther informstion, tor ih6 most part, on ilro following mattoru : (a) The thernal deconposition of pyrit€ to loavs o mst€ri8l of low6r sulphur coDtent j (b) Oidation oi nrsrivo pyriie to iron sulphsts, accompanied by seleciiv€ or ptof€r6Diial extraction ol coppor; and (c) I;duciion Il pyril,es. of lsrrio iron iD Iiquors by Bulphur dioaid€ and/or lixiviation of s mod€rn sctivo pvrii€ dump is €toppod' temp€r&tures ris€ r*pidly; in 16Bs thsn 14 dovs th€ rormetio! of ;bn6ntrl sulphur besins tu some portion aud, il proventiv€ noesY€s 'ero not immodiately talon, an almost unconholabl€ r€0'otion sDr€sds tbouah th; h6&p. Ths ve roosidor' in agreomonu nitb lrir. C. T. Ri ll, io be a Lhermsl d€.onlosition o I pJrir € in l'o olemont8l sulphur s,nd tho inpurs lellous sulphido ususllv oelled ' pvrhotiie ' when ideniified in oreg end slss€. Tho Isttico cofttentB of pyEhotits, ond ot troilite, tho sulphide roforred to by Dr' D&vid id€ntical Ttoilit6 occu$, chetact€risticsly, jn Wittlutnu, """ m€csodieB, s'h€ro oxaess of iron and other ooDditions makoB possibl€ th€ lormstion of rcely puro forrous sutphid€ (FoS)' bhirviDsky(r) (192?)* propo!€d ths r€s,ctions set down below, for t.oilite formrtion itr moteoritos : (llr OFo T 90 r s - OFo + SO' + O : 2Fo T SFoO r FoS 'the comoosil,ioo of PvnhoLil,€s' produc€d ro svsr€ms qhero rondirioos oxce€s ol suiphur ral,her thsn ol iroD obraim' and where ih€ subjecf being are less extrene, hag beon giv6n muoh atteniion, of th€ Much psst 100 veors of morc theD 150 pepors in tho d€ffnite &ssign e rc€d ih€ sssunod Jo eerlier work was roMod by chollioel iolmula-I'€3so, Fo.S,' IeuSo, I€6S?, F6?Ss, Fesso' Fe,S-, I'e.S., !'6trSl!, I'oPS$ aad I'eS havo all et ono timo or u'"L'i"p"'t",i'r". ii,ti '"t*,t aDd &rtilicial pvnhotite€' solids of.vdrieblo composiiion woro gen€r&Ily homogeneout When i"a cslled isomorphous mixruros or sohd solurioos' '"*.J"a. conesp';oo ot iDpure pJrrhor;{os as solid solutiom ol a 'niional ferroug gulpbide ond gulphur bocslns possiblo Otr this eiow, now goneraUy occopl,e,l, pyrrhol,il.e or rr"rLil,o aro synooJmou8 t€rDg for th€ end-membor oI s .or;€s of soliJ soluliotrs E. T. AlloD and his co'workors(r) (1s12-191?) prspsr€d vorious py[hotites by iho thermsl deoomposition ol pvrito and showed psbnih€sid rcfs. to lhe @locbd rr6€nces 8rv€n 6t rh€ end 'F'cue ol tbB roply'. to lho di&@ion. ,'ii# pltEcrprT,lTroN o] coppjtR At riro TrNTo, sparN_riEpl,y. gl ih&i the reoction.wos rcv€rBiblo. Th6y rolrosgDi€d thoir r€sults . by thr! iuil,trvirs oquriion, which w h ortvanieso rnighr roploco Dqu&ti0D 5 in the psper _-: !'.S. : + (l.n) S ...,,,........,.......,...,,,,..._.......,...,.,(12) Jons and lvillorlls(3) (192?) r€achod simile. conclusions, whioh wero fu.th6r conlilm€d by & tairly lecent siudy of pyrhotits fo.m&tion rnodo by Hiiitig snd lrilrm!n({) (1986). The qu€stion ihorolore atpsds io bo, not wh€rher pyit€ decon pos€s in liniiod air supply, but rethor si what tompemrure elimiDFoS! nS of eiion iho ffIst stom bseins; Korhney(') (19i1) sevo 200"C. $Dd vorious other locer iDvostissrors vsluoe borwo€; S00. sld 500'C. UDder conditions simuloting ihoso insids a h€ap of pyriros our work indicsiod thai somo Rio Tinto pyritos oxo"rs an appreciable digsociation pressuro et slightly bolow soO'C. M-r- J. E.Tonnolt, iD Btrossins ths vsriBrion in boheviou during loaching .nd jvoethodng of difiorent ssmplos of pyriros, &nd rh; Ioot that o troinod ey€ cdn oltoD dorecr rh6c€ difr€roDc€s boforehoEd whoro ch€mical anslyses lsils to do so, mad6 o vorJ worrhi,hilo to rh€ discussion. tn slito of numerous iov€sti_ gstion8 siored el, rrsckiDg doi,n rb€ impudtr, or srrucrurel chcrsc_ aotrtriburion t€ristic, which pyrire ro disiDresreto snd to folm sulphstos rapidty, and oiL€r ,ypos nor€ slowly, nb olesr answer can yet bo given. tr'or 6ach pert of copp& io th€ ore thero is 60 pefts, appmxi- netely, of pyrite, y6t Phon.8o per c€nt of iho former h; beon €xtraciod only 20 per c€trt of rhs pyrito has gono into solurion. Th€ roason or r€asons for this pr€ferential oxid*tion aro di{ffcult to fon)u10,t6. ilr. R. Mudry-Hughes suggssrs ihat ditroronr €l€ctricol potontirls nay bo respomible. Infornaiion now evsitebls (comporo Gotisohalk atrd Buckler(6)) indic'tos tft € difror€nco i! the E.M.F. developed iD cortain medi^ by ohalcopyrire end pyrii€, but iurihor investigetion nisbi brins to lighr a 86D;Izerion oonn€ciiDs elociiclrl potenriel with rho raas or ;ulph;rizoriotr. Sovoral cupric lelric lulphides h've beotr r€poruod, bui in mony o&sos their exi'ruonc€ is Doi well ost&blished. Cholocits (Cu!Si, cov€Iiie (CuS), 8nd chatcopyrito (CuIeSr, cornmond s6n;rsl Bc06ptence, both as ]ninerats &nd as chernic&l individuots. UnJor_ tunaioly, itr iho prcsencs of pyrito theso sr6 convorriblo oro inro iho otber, in circumstmc€s noi ac p.osoni procisoly detined. Zeir snd hi6 co'worksnf) (1906), lor jnstsnco, found rh&i ohalcopy. e, whon h€ated with a solutior of cuprio sulphate in a6&6d tub€s, in composition ro chalcocito ond g8v6 products corresponding covdllite. Itr snsi1er to tho querigs ot Ur. Willieln nussol and ) 92 J. lJ. TAYLo& -rND P Ir wuELArt I LltacAlrto Dr. Williams on reletivo oxidizabiliti€B of t'ho sulphides in Iijo oory ,bi,e thst wo hsvo fou d Do breek in the iioto o.u", *u "p" lt** "t *pper yield ploitod bv us to indicdio a suddeD "r-**" cha,nss in tbo nntoriat leing oxidiz€d }]iihor tho oxidotion or retos of tho difrerent oopper sulphides ars ol tho srlne order' tr to exe'cis€ enough is stow step t"rneition one oxidrtion or nradomindbin! inBudnce is Tho blue citioc on plrire rol€rred io bv Dr' Darid \\illirms occurrenoo its foutrd occrsionslly h€r€ ond ihoro in t leeoh€d dump ; ' inv'riablv iudicsios a hiqher.orp€r conleo! lban tbsl' Josir€d;o washed ire and i,bu co;dirion probablv re8ecrr locol liri!istrL sl,srvetion. In tho sbs€nco ol an X-rav siDdy, or oiher r€al ie l"***, v,o h€sitate to oocelt the th€orv l'het this verv ""ia*"", aial colour tudes Th€ covellito. artifrcraliv-oroduced .apidly ii m,iet sir rod lhiB msJ bs D€roly sn oxsmplo ol rho pecuu"," colou" ofroote producsd bv thin filn ol md'nJ divene saltg ed ssdiment&tion Produoig. r' Williarn Ruseou On the whole, w; think the suggertion provo to be ihe ms'in wiu hordlv thst a fflm prot;cts tho pyritos in heAp-lo6'hing' b€ctrube causins oxidation;selectivitv. oI cundistriburiol siroll" witb no fecud $d ure unliks floLarro-n, con whicb of cours€ phoses, the betw€en psrticles ors ditioned often be exploined nore or less satisl&ctodlv bv hvpothsses involvi.s euoerffcial coetings shoee urisrFnc€ 'an rroqDeDLlv be provsd' oveo sornetiu,es bb isoltrtod. HPsp-losching reeotions go much deepor tbsn s unimolecular sudsco lavor' occur e coriplex msdiun, and in corditions of h€dt-iDsulation' hurnidjr,v. oressue, snd so on rhich aro dimculr [o ruproduco on on lha possible innuPDce ol whi'h rherotore' a labomtorl ecale. or to"t- ,,fr .n"t "- "nd little iDlormotion h available. In anv oveni if a liln is pres€Dt' muEt trlmost certainly b€ gesoous : othor tvpes are verv unlikoly in acid silutiong. TLat coppot sulphides are attacked bv f€rdc sulphat€ solutions' evon in theiold, on the lines of Dqustion€ 7;8' and e in tho poper' hrs bsen shown by nsny worke*-€.s, Whiibv(3), 1929 Dvon if it it w€ro provsd, howsver, tbat forric sulphoto solulion attackg thaD pvrite, an assunpiion ihat tho coppe" suiplidos more ""pidly is thus quite loid lar€ vould bo f&r soloctivo loaching mechenisn lrom iugtirioi-ihe oxisronce of ferri' sullhare ai rbu sesl' ot ' I'RI)OIPUIr\TrON Al{D roocti;n would remsin to bs provod All our srnell-s'ele work st Rio Tinto on protNding soit idgeE' 0,nd solt-sheets in cloavage olcnes ol the oliJizios pvrii,e. has indi'0td lhot slrhough Jollow iorr;c sulpbaLe enneabydrsr" rs conipr'uous in t}e orrtnr portrons ol Ot Copl'jri 1T r,ro tINTo, spArN_RlrFLy. 93 €xiNding enousfaiions, tho pftpond€rs,rco of trivet€nc irou fells ofr imnodiotoly on ontering fhs pyriro, end only f6.!ous iroD exisrs de6p within iho DAcrivo ore, whore copper sutthiile docompos ion nu8i I'o occompiisho(l. ti iB Irdssiblo ihdr ferdo sulptrsre fornoiion, won jf ic ig thr usuai Iini recognizebto r€sulr ot py"it" "uutl*ing, 1fl,t6 srogo iD tho chong€s which occur, end that this body,.for from lillnrg rho rnojor rolo os a coppor oxrracror with shrch ir E .iedir€J b-y so'trb wr erF. ptay. no pr* ";gn;ncnnr wh&ievFr. Again, sltbough her€ anstrricst dimcuttios m&ko doGoite stJteu,€nrs impossjbto, rbero is a higb probabitiLy rhei where copper is b€iDg brought into soluiion in acidio condiciona d6op witbi! tbo luo,py pyrite tbo prepond€rst;ng aoion is nor constirutes only o sulphut.. Ltt b:sulphito or son,e sriI more thionar'ed iun. tho &Dolyres ol or6s end liquoE givon in ih6 pspor it vil -bo_nrom roaliz€d thei itr the sphere of reaction rnany colnpoona" .o* oxirt, any ono of which, ovon if prss€nt in emalt concenrration, noy profoundly str€ct tho incidence ond relotive rateB ot oxidation snd €xtraction. Ii is worrh roD€mboling thet s&lrs of ersonio in ss woal as 0.005 pff conr soturiuD ha\u pro\6d €xrrsordinsritJ od6ctjv.. tor JUrrs, in onsuring proferenrial &U0ok oq iro; oxid$ rqrl,er 'trrny rhan rlru rnerol jn inLtLrstriDl }i.klins lroctic6. lesohirs r€sctions tako l l&oo in & viscous rnediu;, a j€ny of concentratod inorg&nic sali6, conrain€d in rhin slirs or copins;i€s. A.r€scl,ioD ,oediurn ol high vic.osity mry iD'orfo.o wir; pFito oxrd8troo 1l) tr groul.ur degrd rbsn jt does .opper sutphido decoD_ position. A ropid chein rescrion insy bo nainiy inBrtum€Dtsl in coppd sulphid€ oxidoiion, a stow hoioroeen€ous oDe in priro Co$idoraiions such as the forsgoiDg indicato ihot cauiion is neoded to avoid rcscling promoture and etroneous conctusions on ihe oause or causes of oxiderior solociivity iD ho*pl€sching. Hoppily, 9n th6 proctical scal€, only v€ry f6w facton_such a;, tho dogre€ of ventilation ellowed, peiodioiry of lixivianc appti_ cation, aDd so on-csn bo vai6d at roasoDAbl€ cosr. Neverthel€ss, oomplgt€ DnderBtanding oI ths mochenism involvod in ihe r6acl,ioos qbich brinq enpper. zinc, arsuoic, iron, €tc., rnto solurioD would be a heip in arranging opiiDrum oonditions foi loaching s difforsni iyp€s of cuprilorous pyrit6s. I'inaUy, it romoins to anplifv sliahily tho bri6f roferenc6s iD tho p&po! to feric iron reduction by SO! &nd/o! pyrirss, &E rhis ho! b€on iho subject of sone controversy. Two aspects bsve ro bo distinsuished-(ir) reduction, and (b) pr€vention of ro-oxidsrion; tho Becond w$ noi, p€rhaps, sufrcionily Birossod in the p&por. l l J. II. T YLoR AND P. I'. wrrDLAN: l,EAcrIrNG aND PlirlcrtlT,rnoN o!. cor'ptr& aT nlo Trnto, SI'AIN_Ri)I'LY. 95 On manv occssioDs & liquor wirh onlJ l'rocos oI f€rric sulllol'e' cooinc l"rom sorne deep bed of submerged plrires ho' buon louDd r" eoonulste D conconirsiion of soverd hundrod gl&ns por cu' pror,ocnvd r.riun. [videx o i{ a.cu,nuioring thsr m0try re0crioDs rn sulul,ro'r procuu,l LJ & ,l,siu rn€chunistu. A lno(hanism or rhiR typo, whoro (xN ]n,k ir d l,trrF.toir of touotrs sulptrotu rnoluculeB 94 rroiro of triveloni iron on norolv irLsflring 60 vd! of opeD iourders, or s,rfre"ing sola€ slight coscadins in contrct with dirE. P"Eoiakl!l sbowod thut cupnc eulphate rnarkudly arnulentces lhe oxi;tioo ol aq. ienous sulphrl'o enJ suss€stod rhat ' 'rpruug ir'a eulohcro acr,e aa u c&tior bv slturDdri!ulJ oxidizrrg auLl n urr r-u r-Fer or Fe' cu'sor I lso,rr , 2i'oso. + 2cuAo{ : I,6";+Cb'.,,.....,.....,.....,,......."'......."'......,"'.....,,,,.._..."(13) It is con€rsllv &sreed l,bst a l€rcb liquor cool'aining no lorric *rpl*J" r o*1a;i vory Blowlv. if &L all sheD slored in s dotr oI i'"t *"t.U.* pvrites so long ae no ext€nsive freo surfoc€ rilterod' so "i t'ber liquor iae*' dne* n r'.',""1. ""-*a. 6mpl'v taok' wirhour elc€ssivo rir .-"a into &n "rsof ir'""."i"ri"' prep{ed tor thoo s siroiltrr solul'ion scrsp-iroo aod roplacomeL( ol the reducr,ion Tbo explaoatioo simullaoeomlv lhrowo probablv hes in Ric6s disco!erJ{10/ (1926) a co;Dl€to removel ut dusr lroin squ€ous solul'ioDs ctru36s rhsre;o o'curins of oxidarion r"dcrions ly cupric ions, tho cop!€r boing ontv &ctive' .ro oontact. oxidize more,losll i""rr*". l" *i**"1" """"* **"'"** "i'ir',, thst .*".1'tL *a.a"ti- viLi oul *hicl "ototy""a el tho surla"ee of the dust lerlirloB Thar '\eD ooosrcnllv. cstr brios Ebout s nor6$orrbJ iDbibitioD a,i', "liii"i "L;-i*';"" Lv BaileJ('l {1995) where liquor8 u"u' It."ian,l"' I'n" "tosn sDd i."" lee' oaes"a tb.o"sb pvriies frllera ond larer IeruIorsrilJ oLt0ined qualirv orflu€nt ."i*r'..rlt r" a"'*, ;.iit ror the good as il""ii U" *'* ro the dusr.'r€movios luucrion or lDl'beoth'plrrres {ords' r it exercisee *aucing actioo "Ji"' '"nf,"l. "i," '*"in" borb rodurog fqrio jroo 0,nd srabiliz.q lurrous roo. .""ir" -" 'i.-"ff ***'*"i"" "t SO' is also sn elbci"n" sroi'iliz€r'lt'Iloro is 3 prqbabiliry accelsral.ed dusl' eliEinariuo is soall tbe "i.olchomi'al Iiootics however' l'har l'qo o\iJr?aLlo ""^i""1"r""" io rhe same solui,ion, bove B n,rrLual pru[,cri\s i"ai"". ii ".r"rr, mor€ slowlv rhar il ir' wore lres€nr rlone' "-ai"i"e "i*i.'*"l iir" *"" "*"ilro 6 6od exampleg wbirh ha\o s b€drjns on 'L€ ruks ro ;;;i"", r"; under ooosidorstion' Gusiscol is add€d ro is druxide (!/ Sulph'rr sairs .1" oxidstion of Iorous "'.i.", in Danv absotpuon oxvsdn bv ieed Lo provent discolorotioD. p*p"*,;ons.(rsr The &oti-oxvgen ot -guriscol wljub "1"i.*"""'i""r JJ"l* ai"*;a"i. in" ""ses oited-is i!varisblJ a subdao'o comso smtrll ig ii"et s"scept;ne m oxidstion; frequsnrlv onlJ mutual iietion or it is neoaed, howover, to brins aboDt & mo'rkod isrr,,nol,ilirs,l,orrur trru,ti,,,rr. Lyrumutorn,ut tuoboromhinr(ioD $irb a Drolu.ulu ot bulth,r. dio\iJe, woutd ejlptain rho t&rge of6ci ol a sm',ll 0Dounr ot t1,,, .n,,tio\ygoD . tf \ro tu bor usFumo ihar SOr nulon,l,s Jr,, q rrr{r" ,-cr,ivu, b.,i,,s,st,u.id y clusoty !rkud trr rhb rhir li.t,ri,l-6,.,- ,jrrurtd{u. wl,ux rr*,(r;o.pt.r; oxygen tuusi Lo aLsorLad. !nd rte tufluus sutpbsto pr;Lsbly "b,ins stare, rl be.omFs stiJl omier tu und€mland the por,ency of retarivsly snDll coDconiraiions of the sss. Orhor fiuol*, oi Luu"" beon advanc€d io oxpltrin redcrion r€raldsrion phonom€Da.(r.) "o**, Mr. C. T. ltill!6msrks rhar in roosi bJd.omotdlurgical work! iD . th€ pynte boh ol Spein aoJ I'urrugst loech tiquors rrom hor b€aps, callyrne considera,ble sulphur dioxids in soluiion, are pasaoi through pyrir6s filtsrs. Wbero rhis is doro, il is obviousty imp;ssihte to disenrsogle rho effocL of rhe pFir6 from rhai oI tbe drsFotved gas, rn !6ducilg f€Iric sutphsr€. At Rio Titrio v6 hav6 rried rbo compotiDg mocbods ot r6du,,riou s6poral,€ly, aDd frratty in corobinction, on s scsl6 ldg€ enough, wo. think, io svetr ouc scci.lonrel vorisiions. A b0,000_b; pyrii;6ti6r vss lound.to roduco feftic iron, bui ryhor€os in rbo lirst vear ir redmed 100 grdms pbr roo of 016 por day, ofter lour JdB i{,s capacity Isd f0ller bJ i0 per .€trt. Nor ouly did ir, prov" I stov Delhod, bur rho sD iD8errbte ono, ae increeeod tiquor rhroughpur ceN6d uo vorihwhil€ ris€ in tho ionneso of hivolontlr;" etimin',t"a. Strright SOs roduotion is nors Sexibt€, bo0aus6 tho saruration csn b€ sdjusr€d. fron ilay r,o daJ, ro the duiy r€quir6d. Alr.hough tho 0t6mlc8l emciency of rbo p.ocess cs L€ msde rcasonebJy respect obl6, the reoction i! slow, loquiing &bour 10 days for conplorion.. The coDtrolliDg tsctor booones thorofore ih6 sioreg€ u"uituUtu, W€ uBed 0. dan of 100,000 cu. merros cepaciiy \vhile "p,"u mducing obout 20 ions pe. doy of fonic iroD. When & beDk of sized pyrite, jn all sbout 9,000 ions, was rippedt ihis don io lo.m a porous berrior rhmugh which tho 3br_ to pass, ih6 cepeciry ol tho ptent es a vhoi;, in spit€ of the slight docrease theroby csused in storego capacify end oonsequonuy in reeofion time, uDexpectodly ross s"bsian'tiolly. Possible explanaiions of this sre sei down in whs,t folows: (1) Th6 borrie! 6v€nod oui tL6 cross-socriollel fow of liquoi. Before iis introduction psrr may hov6 rokon e very dirocr. psth betw€oa inl6i &Dd outler Btuio€s, so that donl c&pacity w&3 not b6ing fully us€d. l:iquor sempiing st voious. aoross chorSsd liquor hsd .l ) J. 1I, TAYLOR AND P' F' 96 WXET/AN' th€ PlsciDg of t'bu .l6bths and locutions' boloru snd eltsr in Lbis respect' but Dot &kmiUed Jor tlisLll,ssiok, -\oEmbu t\)Ilt, ttJ4!. il".#. "r,"""i-""# t.provom€nrreBulls' onouch to sccouDt tor ih! buti€! rtrpidlr wrrh lelri' suLphote orr ,, ii?i"r"i"" a-;..ia" reucrs rhis view is exnresred b) Nr' c.r' '-' i* "*i1"" "i*.'"s bv rar'orsi'orr wor! wbicb iiir]i"li-,,li*,, supporr€d li^'1,-,i- .*r,. tn'1," o"etlr more ofieclrvo rhaD iDerr' r€' ;rss -iD rccurorar'ing r'ho oi ll#*'J"""t -t*'-*, * brokon oijecLion is rloorv rh€ to seriour I'lllltb€ incoming hquor' ll*11. ,t'i NotoB oD the^Na,Ddo Gold Mi!6, Utbswoswo, Sourher! Rhodeoia. lly Sl^Nr,xy J. N,\rrftN, M.]J.E., .l$ocidt€. orutieriD pvrit6 '*noDded ue oxpocted to slimo ov€' the ll-'"i "i# "r'i "'a'""d crtarvst t'be """r" in sorution ro inrap""iLore ;ffi"";;;-; rim€ lrr sci'Lve c€orros ru * 'ory short h. .laRtrovinc 'i Lh€tsllins occur' ofi iD esci€ocv did Dot .1"J" *:t'ta dusr cauied br tssch riquo$ is tie ... t"' !^::';;,ir,;'1"", or in promo!;og th€ r€ectioD b€rr'€6D THE tollowix,i iir1t"""'t*t"' *a *rolu dioxido This bodvioiss r'eppod. iJ-i" ',u"i"""u*tt;e l':'i"':::::. fu conceorruted tbsr€ia rorm oI ,r " uoduBrely bigh-gr8du qudrLz rhroudb nns ur rbe otb"r variairons or rhe grevrtJ crusbinF ro Jbour s0 rD.sh in conjuncrion l{lrh 'nilt.phto an sroelgamario! JDd/ur bhtrkvt jtrskes. Ar rh€ Nando nrtne a m,Dpdtrti!ety big| rorrragu ,,1 !ury luw-gnrde lodc ,nstler B ( - l-in. ,n6r,, rLruugl, rn ,upact Lreaker, erd i:1:sd;c?ciB'r cJ&m{l€d ,lir€.r. 'lbeso rn es }trvc drty b€En record€d becsudo rDd usu8t descnplonr uf ,huse wl$ elaLuraie plants snd o v,ry LiR cJt,itrl -r rb,ir didposJt, rbern ro inshl "nsbtilg ,u.::ri': dnir. ,,,r .rnpruy, numro. or..tigury poiJ 1l:.lT* \u ctJim wLdrquer, r ir msdu crallsmo!. as ro sny urigin;tiry i, tho methods onployd or ruy,rpccinl technicel skilit"ir"g *q"i"J as ";";. ion sbich arrows it ." Iuo'tion ;fi"fJ,i;;;/;;;t'"ser somo carrving banier' Lhe il;"o"r reavirg :::;;il";;r'; lroe rrom suspeodod :i:ff;';ff"';;J deirg 'ereii""tv sgsiost' ooosoqu€nt oedauioa' to" Iiii-],J""r,r"'"u,rors;tod -r"ii'i"i'Lii* J"nt";rion is !6rbaps. tho mosi stt*cr'vo : work cl€erlr r€mails i'o bo done berore out pdPdr bv €nrpbaBizing tbe "."','i""r'i*tu; ",iTAnalirv iB reoch€d Wo b€gaD anv rtr'irq m ond leschiog a'' Rio rmro lL is i,3' ii"#'t'"]'n" ii how.oucb srir"i"tiiT"':"fl,::,i; bvdrolnersuu-"Jl,iyJ;;" botore rbis siogle oxsEpls oI ffiili*;;'" &nd rrs solvod' nJsteri$ il's {orked oul,, lil"".r1"*J". stressing rr!folded. lll E:'ry]TX* ' RltBENcr6 f#.Y-:i111': l..,'1"1" irer2r: oid r' 4r' "i',f ii i+.,**ffi ry:##dmi',tli;'jj'rs;;; ?' 16 I0I'r j'.e*'i',f;f a x r'"tot' rb'd l, ii }"i'S*l il+#l pmpb.,6,6 (!e26) ( j:i l,:;"*t;*rf ff{J.iLi'l.'i'". o*. *ir{rtf,#iti#i:.li::r;'{:,'i';13:li"'$'u,'*'' i;a e'v c49r,,1s;.3i,1.it03xr llil ** !."afiii..l u,,r-, d..s.ru,. rh" r,ir,ing er,d ,,,iltitrg opordrions oI or rbo jn',1),.r guto ,r,,,cs rn Suurhbrn lthodcsid. I,hesB operrtiolu.r& Bolrowhoi dil]crdri fron chose ot the rnsjoricy of rni^ms ij, hrb rlJ$. ,u rhJr. qdlurtrlty. I lby pul, sr,ru roooago or on€ ; n*''- " u'a*' lli i:H"d,f*.ffi;lr*#;.ii;'dii#;.' ,,i ,b. rd,. ou ,hd ),ie,,ru .vin€, ,,:::.,"^t!-'lr :'.ll:',.: um8s$qe. rh prolDl,lJ r}rl, oi d s x,i-uu,ne pit.hing w€{r,, wirh sr &vn&ge dip ot 52". I'he toorwaU oonsisrs of a *ghty rnota_ morplosed corslomoBie, vhioh is ovortaid by a senor oi altered lnd.dirtxrL€d tuiI., .rn,l.sir,r rnd turpbyries $irh rll.D bands ol chert.. Ih,d€ iur,r rbo ,,,uir g,,td_Ledring IuJo (b€e cruss_section iIu opbncut. Iis. 29). A nu&b6r ot orhel'ocks such as chlorire.sohist, dolodto &Dd o,. r, bur uke rhe.ursromurate do nor. appo&. i,bodgh 1"::'l:1**l*r lo De or ony rmmbdrat€ scoxomic vslub. {.c'"rn1*"1 loerure ur rh€ lode is BourD, vonou8tJ .teLurmjnod as errber I * dy[J striki]rs norib ond very wesrhor€d glsnilo or pory[yry (eno'rn ox lbe properry m qraDir") enrloding s distinotiv€ (r€eD mrce.oous Dneral.
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