American Zinc Extraction Company, Lake County, Colorado

(COp.y)

New York, l!'enrlla.r;y 15, 1910.

Mr. ,Tohn GreenouBh, Pres 't. ,

United Zinc

&

C~mic81 Co., 59 Wall street, New York. Dear

3ir;-Compl~Tingw:l.th ~'our request, I hev s rElcentl~' visited the mill of the American Zinc Extraotion Co. at LeadVille. Colo., and be g to aubmtt hl1TfJwith a report of the 1'19 su Lt ,

In makine this visH, it was my obj eot to ",.scertain, if po aea b l e , why t he use of the IntE'T.l1l?t.ional Mae;net.io '1eparators hait been abandoned by the P~erican gino F.xtruction Go. in its No. I Millt a nd if possible also to measu re thE' e xten t of t.he failure of these machines by comparing the rl'lsnlts obtained in No.1 Mill with those

obt.ained in No.2 MEl, in which a i1jffElI'E'nt ore treatment from that of thA former mill Was subseeJ.11Bn1;ly'l.doptfl(\ by the A. Z. E .• Company,

This st1K1..'has inyolvl1(\ more work than J. hail. anticipe.ted,

but I have carried it thro ugh in or de r to (]etorm5.nEl whether th e change in the ore treatment of the No.2 l'lill secured so high a mill effioiency, in zinc recovery, as to Ie av o not hinS furt!:>.Elr to be O.esinld. Thi s I find is by no means the case. There remetn s in fact so large e. margin of possible improyoment in the present mill practioe that J. have ven-turfJd to make [\ suggestion as 1;0 the ")I1.y in whdch the efficiElncy of

thfJ mill

llB.'

be Lmproved , and the profit Ln opera.ting it thereb~'

Ln-creased.

With ~1011rpllTl!1issionanit Hr. I,ippin"ott's cu-o p erntLon both at Denvl'lr and J,eadvil1e, I was afforded thE' privj.leeo of E\xamining the miD. records I and cost she e tw of ths two mills, ana. am now able to present a corspar-atLve statement anCl.summe.!",)'of ths comms:rc:l.al results obta.ined in ea.ch oase.

-2-Before refurring to these results, it me.~'be we11 to

state tMt since its or-gan izati.cn in 1905, the Internatiorn.l Separator Company has placed upon the l'lsrket a single type of high intensity Mag-netic Separator known as the "J.eadviJ.le" or T~rpeE nacbtne , Eighteen of these separators were placed in the No.1 Mill of the Arnsrican Zinc Extraction 00. in the earl~r J:l!;\rt of 1905. T.he~rwere CI.esigned to take advantage of the fact th"'.t the J,eMv.ilJ.e 7.ino bLsrde is feebly

magnatic in its nat lIral or "rlID.e oonsition, aro. was beli 9Ved to bi')

sur-fioiently ma gnetf.o to p-:n-mit its eff5.oient separation in a strong field from those non-raagno tto minE'rals whi.Qhar e uStlally associated with it, auch as iron-pyri tea, galena, qU8.rtz, etc.

These separators did not, howevar, produoe as s8tisfacto~j result s when operated under oor-£lero:l.aJ.conn.5.tions as were obtarra d by preliminary tests with similar maohines at Argentine, Kans~s, and dlrring the latter mlf of 1907 the use of these eighteen separators was aban-doned, and a diff'lrent system of ore t re".tme nt adopted in Mill No.2. Under this s~Tstemthe natural me.gnetic property of the Zino blGnde is disregarded, and an artificial and more strongl~r nP.gnE'tio properby is imparted to the iron pyrites, whioh is its prinoipal assooiated mineral, by giving the ore mixture a light roast, whoreby 1'. oertain amoun t of

sulphur is driven off from the Ilyrit.es in prodncing the magnetiZing effect.

The

zinc blenne mineral is then oonoentrated by removing

from it the more magl1£ltio iron mineraJ. by means of a low intensity type

•

of separ ator-,

In the No. 2 Mill six Olevelan d-Knowles mgnetio sep;>.rators were installed, These are of th<l low intElnsi ~r t;\,pe, and the;y treat

the prodnot of two 5 ft. x 36 ft. rE'volvine oylinder roasting frr nao e a , At the present t;il'1'" thE' No.2 MEl has been in cpor at i.on

for over two years, and it b ecomee possible to J:E.kCl a fairly accur-a te

-3-OOl"lparison of the :results obtained lmder COTnl!l"lTCiI:'J. cono.itions in N~. 2 Mill, treat ins roasted ore, with those whioh WAre previousl;), obtained in No. 1 Mill treatinB the crude or lmroastEld or A b~, means of the Inter-national 8eparator.

From the records and r-opor ts of No, 1. Mill I have tabulated the mill results for two years and one month on Fases ,gQ anCl

.&1.,

divided into three periods of 6 months. 00(1. one of 7 months. On Page 22

is given a SlU'Jl!laryfor the tota1. lX'rioc:l.. The coata of operati.ng the No. 1 Mill, divided into two perioc:l.B0 f six months each are given on PaBe 23 .•

LikeWi se in the case of the No. ::::Mill I hEwe tabn1.ated

•.

the min re suI ts for two ~7ears on Pagea 24 and 25, with a Stl.!!11.'11U·'J

for the total period on Faze 26, T.he operating costs of No.2 Mill

-for one year are ehom on Page 27. From these records the following

brief surmne.ryand eo npe r ts on of the resnlte obtl1.ined by the tllm mille may be mad e •

AVfJrage ratio of ocncent retton ,

150 tons 117 tons

ao , .l Ml.U. ao , z Mlll Inter. 8e~rP.tors C.

K.

Separators Average capaci ~7 per day (330 na~7sJ

AVfJrage cost per ton of crude ore Mill effioienoy (7.inc reCOV'l~7)

2.08 : 1 $1.95 67.1% 85.0% Zino Iron 25.75% 25.45% 35.85% 18.85% Separator 11 11 11

Crude ores (Average tenor) Zino oone entrates !l. 11

3.52 : 1 $2.39 65.9% 75.6% Zinc Iron 17.78% 29.25% 41.9% 11.1% It should be not.e d that the 8.00"13 coste do not inclnil.e

interest, depreoiation nor general expenses, whiC'h are properly chargeable to the c osts of milling the ore. The;)' are therefore praoticall~7 operat-ine costs. In the case of No. 1. MiJ.l the items of taxes. insurance, eto.,

whioh were not i=edi8otely available, bave been assumed to bear the sam~ proportion to those of No. 2 Mill as the ratio 140 : 180, and have been addfld in order to arri,re at 1.', fair basis of oomparison

between the

two ,

It will be seen from the abovesllmmary that the No.1 Mill oguipIled with the Intematiom.l sepamtorB was able to handle a larger daily tonnage of ore, 8t a 10WElrClost of mUl traatment per ton, with a higher mill aJ1[l. aepar at or- effioiClroy, or lIiro reoovary, the,n in the caae of' the No. 2 Mill, eqnipDlld with r-oa stin~ furnac ea anCl, Cleveland-Knowle

s

separator s.

In oomIX\rhJg the mUl work. it should be remembered that

ball-mills wer-e used for th'l orushing apparatuf\ of No , 1 Mill. flo large a proportion of fine (lust. was pr o duoed by 1;hem, however, th,~t they

were finally disoarded Emd rons substituted. Th6 latter pro duo sd

a reucb better granUlation of' the ora. aJ1[l. the pl3I'oentage of 0.n8t was

redno.ed from 8.9% in No.1 MiD. to 1.9% in No. 2 ~!ill, for the two per-iods unde r oompar ds on , It is evident that if the b et ter c rua hf.ng

system had been avaf.Iab Ie for the No.1 MiD., a hiBhor mill t>fficionoy than 67.1% would have been reaob ed , simply beca use a smaller amount of the ore would have bee n lost in the forl'l of 0.118t, and a 119,rger amount would therefore had baen available fo r sep""ratlon upon the International

Separators.

A further ad'7antage of th'3 better orv.shing system of the No.2 Mill is emphasized by the lare'lr "Los aea" of No.1 Mill as co~-pared with lIo• 2 Mill. _{In the No.1 MUI these "Los ae s'' are J:1l!),inly}, due to handling and shipping ver~7 fine products. as well a8 to the exhaust fan ventila1;ine s~r8tem, etc. The sum of the "dust" and "losses" of No. 1 11'1ill amonnting to 19.4% of tihe total weieht 0f the c ru de 0 re aotnally ccnta tne d 21.0% of the tot""J. zinc in the ores delivflred to

-5-thE'mill. In the No. 2. rodill the sum of' thl) "dust" w.o. "Los se a'", amounting to 23.5;'~of the tot-al 1'.l.' ie;ht of th€' orude ore, in:.-luo.as

the flnlphur and nue dnst lost in roastIng the ore, but th"Jse e on-taineil only 12.8% of tho total zinc in the ores c1.eliY('red to the mill. The largest 108s of

zine

in the No. 2. MiD is in thEl tl:\ilings

of the Cleveland-Knowles separators. This amounts to 21.3% of the total zinc as compared with 11.9% for the tfl.i1ines of the International

se~ra tors of the No. 1 Mill.

The high tailings losses ar e doubtless doo to the

presence of "mio.dlings" particles, owing to insnffioiE!nt o rueh tng to unlock those ~rtiolf)s of zinc blflnde anI pyri+.eB \'IM_ch are attached

together, and partly to mechanica 1 e ntanglE!ment. 0f the fine port ions of the ore. The latter ia inevitable in an~' belt ty pe of separator, like the Cleveland-Knowles, since the only s0parating force acting UDonthe fine zinc rarticlr:ls is gravi.ty, and this is almof't. negligible compared with the attractj.ng force of thE! magnat acti.ng upon the mae;netio por--tion of the ore ~

The advantage whic h the No. 2 MEl equi.pment aetna l~' aohieved over that of the No. 1 ~lill is in the higher tenor of zim in the concentrates produo ed , This h3 a ftl.ndamfmtaJ. cO!!l!!lercial ad-vantage. It rests llJ.tiI'l"tel~' upon t.he higher retort efficj.ency which can be obtained b~'-chargi.ng a ri_ch zf.nc ooneent rate , as COIDJ.l!'.redwith a low grade zd.nc oonoent.rate , into the retorts of. a 7.inc fuznace ,

Leadville zinc conc errtrate e are sold upon a basis of 40%

zinc content. With

a.

variation of

$1.

per undt added or dedll('ted for variations above or below this limit, it is evidBnt that a difference pf $6. per ton between a 42.0% zinc concentr.ate end one oontaining

36.0% zino, over-halances a higher mill cost of 40¢ or 50¢ per ton of erude ore, and also a somewhat lol'Kl1'mill efficienoy of t h e No.2 Mill.

It was obvj.ously to thE> interest of thE' AI!lE\rioan Zinc Ex-traci;ion Co.

to

aeour e zinc (loncentrates :1':>:'01'1 the I,eao.ville ores with-out the neoessit;\' of roaFJtj.ng thEn'li:!.' a proper grade of co nc en t.rate s oould be o'btaine(l in this way, In t he operation of the No. 1 Mill I feel entirely oonf Iden t th..'J.t the Int.E.nw.tional Sere.rators receive as oar-efu I ana. conscientions attention as could fair~T 'be /.'I.sked in maintain-ing them in pro per repair anc).e.djusi.ment dnrtI:¥i: the Mill's oampaign • That the entire ore treatment was, howevo x, final~T changed at oonsider-able aO.ditional e xpenne , re present ed bj' the No. 2 Mill !Dust be acoepted as 8ui'ficient evid'IDce thf:'.t cO=Flrci""l coro.itions alone controJ.led and

justified the aband onment of the use of the IntE'rm>.tional :=leparators. Such being 1;he unfort1U18te but 0SRentie.l faot, ! hs.ve en-deavored to find some expIanation of the r eaa on for this fa LLur'e of the International maobLne8 to pro perl", IJElrfom the work for whioh they we re designed.

The conclnsions I have r eache d l'E.y be briefly sUI'1Y!Brizedas follows: D.) No c hange in th8 l'l8.gnElti.o property of the J,eao.ville

zinc are ocourred, in my opinion, which l!!ieht ac count far the produotion o

r «

lower grade of conc'lntrate b~Tth'l Inte:r.rtatioroJ. separators than was 0.08iro([.

(2) There is a defi.nite lil!!it to the size of zinc b Lende ore J/8.rticles whioh can be rlJae;l1E"tically seIJl.'.rateit in the oruc.e condition. In the Q.iffioulties enoonntereit in thE" crushing a.eJ:ll.'.rtment of No.1 Mill, and the subsequent change to a o.ifferent s~TR'!;el!!of C'rnshinB' in order to prevent the proituction of an excessive al!!Olmt of "fines," it seems to me very probable that the size of the ore delive~ed to the l!!agnetic

sepnrators was inoreased somewr~t beyond that originally oontemplated for the best vKlrk of these l!!oohinfJs, and that to this increaRe l!!wt be assigned a J:lI.'.rtof the reason of their faillrre to aocomplish the work

expeoted of thel!!.

-7-(3) The Leao.Ville zinc ore e oc casionaJ.l~' oonta.in €'. oertain per o ezrtago of magnetio silioates among the:!.!' m:i.ntlral associates. Unless removed from th;, 7,j.nc ooncentrate, these magnet.io silioates would reduoe the grade of the ooncentrates produced from ores conta.in~ne them.

J

(4) The International separtttorsprov'ld to have aer tous

meohanioal d.efects, and to be crn(1.elr desj,gned when operated nnder ~om-mercialoonditions. Whilo the prinot{lle the~' embodied parmittedoorIt'ed advantages of capaoit~' and low c ost of oper a't ton to be reaohed, yet to their defeots must be assigned a certain par t of their fa:Jlure to seonre the r e aul, ts aotnally requirfJd for COl'lmercil:'J. suc oe s a,

These conclusions J: have c ons fd er ed mor-e at 1eng1;h bel 0\';1, but it will be seen from the above 811.mmUI"'J tlD, t the failur.e 0 f the

Internat-ional Separators was in 13.11proba.bility du~ to a c orebtna t Lon of causes rather than sol"l:' to the rnaohj.n~s thm'lselves.

As a result 0::; the stw~' I 118.'.'0given to this subject, I have r'eachod the concl usion that it \'I:i.lJ. 1)6 po ssj,b lEI to il'll1rovElthe pre sent practice of the No.2 thll b;o'lHD.Ug ihe high intensit~r ty]1El of magnetLc separator in treating the fine ])o)"t:l.on of the e ruee ore, ant' confining the roasting oper a't Lon &)J.01y to thE' coarse portion of the are, thus avoiding thA l"sses which now ooour prinoipRlly in roasting, and separat-ing the fine portion of the ore upon low-intensit~' separatoTt'l.

In order to a.etermine whether a h:igh-intem~ity separator

c ou.Ld be designer, which would sucoosflfnlly cone Flnt·rato exceod:i.ngl;' fine material I have made s one 1;r:lS1;s upon samplfls of I,eadv.iJ.le ore, with a

small maohIne rodesiened for t;his p\U:"pose, sinoo m~' return to ]'TewYork. The resnlt ot'tho principal test mde with this machine, ant'. also the general suggestion made €'.bove in r8eHrd to iI'lproving the present mill treatment are referred to I'lore at length h"-!"eaftElr. ~ince tho test inCl.icatAs that the 81.l8eOSt ion iR feal1ib1e, gnl moreover since I believe

the plan prpposed can be 81.',0c eSEl:fu,ll~T deve JOPE'd BDl e,Ilpl:i.ed

cO!'lmeroial-an<'l. also to the 00ns iii.erat5. on of the offie er a of the AMeriean Zinc

Extraotion Company.

Your 8 t r 'lly •

U,:l.gned) C.

0..

Payne.

(1) THE J,lAG:N!':'lF.!CProPERTY OF LF..ADVJrI,r,r; ZINC O1n~:

To ao ccun t for the fact tm,t the !nternatioml separators

failed to pro dnee a satis:f'aot;ory d,~g!'€'a of aonC'entration in treating the Lea(lvil1e zino ore, the explanation has been gfmflrally a dvano ed that this was due to B change in the magnetLc p:ropert~' of these ores which oo enz-r edca.f'tor- the No.1 Mill was built.

In my opinion this has no basis of fact. The zinc

con-aentrates now being prOdnoec'l praBent the SI\1oo appe ar-s m e , anti, color, and aontain approxi:'lately t;ht> sa1'lElanoun-t of i:rCln when orysta'ls 0f zina

b1entl,(l are analyzed, aawa s the c a ae flev'lrR1 years ago , A certain

pe:>:aentageof iron ohElmic?J.l~' oOl'lM.ned With the ::line b Ie nd e d.etElrl'linea its l'lagnotio pro pert;)' , and. thiE' Bm011.ntof iron. ahout 10%. ha.s been

uni-form1~T a saoc iated wi th thE' zinc mim1l"HI up to 'the pre sen t til'l6. so far as I can asoertain.

It is 1111.itealeRr that the lll~nt'ltio property of [>, o ru de

zinc ore is mor e aocurately mown by the oLean n as a of the tailings pro-""-f! dnced in separating it, toon by the nahness of. thEt concentrates.

The No. 1 MDl pro due'ed tl:\iling s averR.ging 9.13% zino from ar11.de ores containing 25.75% zinc. While aich tailings might be im-proved upon, yet the r(mainine zinc pay bl! aoc ourrt ed for largely by the

-9-prasence of miadlings ~.rtiolEle, and also by moohanica1 entanglement of trui finer portions of the ore. In spite of f\wh tailings thE! International sare-rator's 8.ctv.o.11ymade e. recovery of 85% of the zinc. This result alone disproves e,ny perc"lptib1fl loss of magnetic Ilroperty of the crude zinc ore in l!lY o1)inion.

The zinc concert rate

e

1)roil.need b~r the J:nterna tional separators averaged for tV,{l years, 35.85% zInc , That the;-? "l:'re unabf.e to produce

c onoezrtra t es averaging 42.10% to 45.0% zinc, which the market demanded, anti. which the~' had pro duoed during their 0,eveLopnent stage, was evident-ly due to other causes in no way connec te d with the l!l1".gneticproperty of the zinc mineral it sel f.

Since ~T rElturn to NewYork I have had occasion to make a

tril:',l magne tio se~.ration of 1:'. eampl'l of the cru{\,flzinc ore, which was talten at too ti',6 of'my recent viRit at t he J,eadY.i.J.1eMin. }.'or this test I used the finer portion of the ore. I WaSable to secur-e a con-oentrate containing 42.53%. a,no' a tailings containing 7.88% zinc.

!I'heresults of this test aTE> shown on Faga 18. and prove that th 8 zinc mineral is suf'fic ientl~T magnetic for a.ll practical

pur-po ae a,

(2) SIZE OF ZINC 1',J~"clTDEORE l?ARTICLES CAPABLE OF p,FFICn;NT :'IF;Pi\RATION:

Those who have had 1)1'aot10(>.1e xperf.ence in the

m?,B-netic separation of' zinc bLende know ;'hat :>.1' the size of the partio1es inIJreases" the difficnlt~r in SOpf.',Tatj,!1Z th('l"l effidontly a Iao increases,

1. e •• the ore par t to Ie a ar e more ti.iffionlt to ~ttract. and it requires an 1ncreasine number of passes, throneh suo eeaatve fields, in order to obtain olean tailings. This is aue to the fact that with increase in size, the field-gap must also be il'.oreased in order to permit the parti-ales to pass throueh 1'eadil~r. Increasing the field-gap introduces

greator resistance in .the m.<Jgneticot rouI t of thE' electro magnet. This

in 'turn weakens the field, am. also its hold upon the ora particles, while t.he latter off tV a. grflatar "moment of r ea i.s tan oe" to Bape.ration

by reason of their greater diameter.

ll,ina hlonde pt?r+.iolos 1/8" in d.ie,meter Ere e.I :ready beyond the limit of su oe eas fu L rna.gnetio sel'Rration, in l!l~ropinion. All the

Leadville zinc ores, however, whioh I have seen ere qllite fi.nely mineralized, so that they r eqot ro to be c ruahe c1. o onsiiten"bl~I finer

than 1/8 inoh in order to 1'1'00 them from t;hElir associe.ted minerals. Tho problem of oru aru.ng ora for c on oerrt ra tn on oonat et s in effooting n size reduotion merely 1l:;I in'" pOin;; which is ne c esaary , in order to unf.ook or free, to the eroatest fFlasible extent, the different minerals of the ore ±'.rome a ch ot he r , and, at. t.he same time to produce as

little (l.uat P.S po '3sible. It is e. <1.iffiouJ.t mat tel' to tleciCla upon the

exao t screen mesh to which s uoh comp.lex ore rnixtn:res as co our at J,ead-villo should be re ducsd , If the crushing :i.s not c arrded far enough, hieh 10eses occur in eepar a tion, OWing to the zinc J.oft in the tai1-iugs in the form of attaohed, Or middlings p8.rtiolEl s, or e Lse low grade conc on'tra'te s 0,1'0 produoed in makIng oIe an tailings.

On the other hand, i:f the ornshing is c arrie <1.beyon<1.a ce:zt-tain point, so ~.rge a proportion of fine dust is made that high losses co cur ifandling, seJ?l?,ratirg and shivpine the fine produots, illS well as in roasting and Sl1Jfllting the ocnc e rrt ra te a.

The practioal lil'lit of cruflhing with rol18 may be saia. to bA reached l'.boat 24 w(lsh. ¥:ith deorAasing sizes the oapaoj.t:; of rolls rapi<1.J.y dirnishes, owing to thE' practj.oal di,fficu.lty of keeping the roll-faces free frorn groo'.rine, tI.ue to unequal wef1X.

At the til.'l'3 No.1 Mill was built it was deoided to llBe ball-mins for the crushing apparatus, in plaoe of roJ.ls, doubtless with the objElct 0:(' carrying the m.3e reduotion up to or beyontl. too limit of the

(10 )

-l~-latter, should the necessity of secllri:ng 8. [\'Ood separatton 1l1&,]ro this d.esir8ble. The ball-r'lills. howev er , ".ore fonnCl.to exert so great a "sliming" effect upon thE! or8thQ,t too tot!',l dust losses in the 'lHrioua mill operatione were 'Tp.~, high. in fMt they amounted to 18.4,% of the

oru de ore, 'and contained 21.·0,%of the tot~lJ, !lim, as can be seen from thp. SlL"ll118.:t'y of thp. No. 1 1Hll

.

_. TElauIts on Pag e ?2 •

The ball-mills were fiml1y disce.rded, anCi.rolls snbstituted for the crushing a.ppar-atus of the ilIo. 2 Mil.l. These proCl.nced 9. much

better e;rs,nulation of the ore, and notably rElducea the aust losses. Durinp.: the e xper Inen te 9.nd ohengs s in the crushing apparatus of No.1 Mill, it is to be preaunsd 1;h!.~tthe mesh of the screens was in-e r'in-ea ain-ed up to thin-e po Lrrt which Affecttve lW.enet:!.c separst tcn would permit, in order to reduce tho enormous dnst losses. This point was aLso , in all pro hahi1i ty, somewhat exc eeilea.

The above rClason~!.e:r s the moat obv Io us 0.ni d.irec t ex-p1B.nation of t.he fail ure of t.!:p. IntElrn« tioro.l f,el'tuators to brine the zinc oone e.ntr ate a to as high a (I,ser,"fl of enr I chment as was a.eRireil., and as ool\ previously been ob ta In ed,

As fnrther·8vi.d.A!lce bea:r.i.ng upon thie (l,uefltion. I have found among my records, data of a SeriEllI of tests made fur Mr. A. H. Me~rer.

in 19010. upon sampLea of J.eadville 0:>:$s wit·h th e same type 0 f t,ppe-ratus,

sent to Art':entine fo1' trial tests upon 8. le,rgeT 001'.1<1, Th0 OO'e for

th<lse tests was crushed to ]Jass 8. 24 !'lesh eCrEqm. The zinc conC'entrates ]JToitncEJ(18.'Teraged ahout 45.0% zinc, ana, thE' te.:!.li:nes were reduced. to about 5.0,% to '7.0% !line.

The screen mosh through which thf' OTE> is now oJ"1u"hed tn

Ho. 2 !(ill is 14 MEl sh. E'Ten with f;hE> (lom:varati'T"Jly hoo.vy wire (No. 20 B. & C\. ga.uge) nsed in this soreen, '1;00c1El,w Mesh openine i8 still

con-si(t.erab1~' greater than the.t; of /".:110. 20 mesh Hcmen, whiC'h, it is my

recollection, was finall~! decided upon an the, proIJer size to which t1;le ore should be oruahe d for separation in thE> go • l~iJ.l.

In tho conflict botw0en the necessit;,' of avoj.ding hj.e;h dust Lcs se sand seC1Iring 8, smoothly runnd ng e rua hine d opar-trrsn t, ~.nd . the ne co s sf t;,' of obtaining :rich ocnoe rrt ra to s ±':rO!:'l thE> aeparatIng

de-part:'lent, some sacrii'ice was &.PIJt,reIltJ.y msde of t.he re quLre merrt u of the latter, as sh ov.n D;,! the a ver age till10r j.n zinc of the e onoe zrt.r-a'tos , This, as already stated, se en a to me to 0 ITer a 'TAr;,' probable an{l

reason-able e xp.Iars atd on to ec conn t , in par+, at Leatrt , for 1;he f8.Eu:re of the Inte!'national Separators to roach the Gllerp,f) of oo no e rrt ra't Lon c1.esired.

vL1.le o ro s corrt at n prj.nciIJalIy the j.J·Ol1 snJ.phicles, IJ;,!::r:ite unO. ma re

a-sdte , with a var~'i1l€: amoun t o f- z:i.nc b Iendo 8.nc1.g,uena, irrEl£;tllarl;,r

distriblltod throueh them. ~hf\Y also contain c\ amaL'I amount of :p~'rrhotite quartz, and 00 casional1y SUC'll siIiontes D.S Garne1; a nd :?iIJidoto, whose pr e s-once is probably aua to qontaot l'lGt8!'JorphiFll!l, sioe the Lead'T;LJ.le ore d.e-posi ts 00 our along oont aots be twe en intrud od por:vh~Tr~Tshe \3t, a s.no. Iime-stone. Garnet ancl.opidote 801'8 sOl:'lewh,1; morEl magnetic th80n zinc bJ.ende in B strong field. If the or·;) 8nppl~T for 1'00 No. 1 Mill oontainod a

certain amount of. thos.! maGnetic silicl.,tes, e.no. no attempt was JIDde to

TOmOV€! them from th'3 zine bJ.FJnt1.o,they wonlt'. natnrally tend to lower the

grade of' the oonoentrates produoecl from sucb ora s.

:linoe tbe 0 TIl sup]?l;,T for t

m

J;eac1.'Tille LEll is dr~\wn from

various 8Ou1'oa6, it is r'lasoooble to aBSlU'lCl tU\t the ore mixture

2.ctual-ly Clontained from tiJ:'J'l ;;0 tir-)I> var;ying amolmts of thfJse magnetic sili-cl'ttes, a:nO. that their presana", may 1:\100 eXllJE.in, j_n Dart, the lower zinC! tonor of the oonoEl!1\;rates proc'll1,<"p.d,as 00J1111a1'eclWith those obtained originally from ores free fr omth,' se 1.1JC1enGt ic silic ate s.

-:1.3-(4) _{TH" INTF.H1'A~~IO:HA1HAGN:c:'i'ICfiFJ"ARATOR:} TYP}1 E: T.he de sign of t.h I a maolu na proved to [)0 crn0,~ p,ncJ ill conceived wheri put to the teFrt; 0:;' e omm-rre La.Lwork in No.1 1\15.n. The ail.jnstmente and. r epa ir e were made wit,h great (lLfi'icnl+.y. Close oont.r o.t over thJ rc su Lt e prodnc ed became 1':mct5.call~T 5.!!lpofJf'll bIe , and to keep them in operation undor the oonditions of dust antl. rlifficu.lty prevailing ill the No.1 MEl, appears to OOVA becorie .u.most 1:\ TIHt1;I8Tof phy aicsL har d.ahi.p to

thfJ finnl 801jaration of thA ore waf' reached onl~r after IJ9,SSl1eEJ 'thro ug h

doubt as to whdch OnE', or more t.han one, of 1;h" series was performing its proper work, an d onl~' nftoT a consitlera1)letollYJ£\e0 of ir1perfeotly ae psr a te d oro h,'1.(1.been tmr ne d out, oou.Ld th,> d5.s(JoYElr;)' be riad e of some

f

la~ of adjustPlent, and 8. remed;)' t'.I'plied. Ii; was t'J?IJaTentl~' like driving: six hnrse s tondom,

0.'

e. &1.11 obligfld to f'ae e ba okwaz-da ,

to.iJ.ings 8,S fr e e ",,8 possible trom zi.ne , sa.nce tho s epa ruto d prodnots rr om the h\s·t 1!laC'hin(~f1 of' the ser I e s wonH!. n at ura Lly be of a lower

grade then that obte,i.na(J from 1;11",fi.rst, i1; is e vt d ent that bJ1 nix-ill€; the Ior ner with the l11t+.er, thl) finill produot, would be 0 f a lower

One of the l'lri.noipal causes of troll1)I'l so eme to hEW8 e.risen gr[l.(lp- than if th e aepar-a tIc n co u Id btl l!l!!.devJi1;h a fewer nunb er of passes.

from 'tho laok of convenii;lnt provi.Bi.on to k0ElD1;ho seLB,r"t,ing drums in

seP-I:JS to 1".1<YO been TIlUohereatt1T 1;han tht'.t on til) othc,[t', T.his oaUf36d

th" drivin6 bolts in "burn". I),nil split. and. thE' Rllaft be11...ill{:;R to heat,

Aftor th8 separa1;ors hx. bRAn ple,oad in 11<1e thp- orig!.nal

oiling devioes for the ahaft hea:ri~fl Wli're (Usoarded, ana. the bearings . were all drilled and tapped for horizontal grease-onps on the side of

the greater pull. None of the b~arings hOO.been provided ~th dust-oaps, Which probably tended to further increase the Qutting and heating of the bearings.

Shaet steel guio.e pIe.t'ilS ware provided on the siofl of the field, through vhioh t,hfl ore was allowfld to pas e , These plBtes were qUitfl thin (No. 14 gauge), and held in plaoe with 12 machine screws. Th(l ore, striking these enide plates, woult9.gradus.lly wear them away, and cut off the haads of t.h ~ s orews, so the.t in ma.king l'E!}i8.irs the

aorews had to be drilled out, at the e xpenaa of conef.d er abl.e inconven-a.ence ana. delay. The pedflste.l besr rngs at each sioe of the machine supported t,hE!arooture drm!! 15" above the base-frrone. The magnet at tim'ils exerted such an nnbal8.n('ed pull upon thE! a:rmat11l'e that the ped-es1;a1s _re raised en01p off their seats to jam the a1"l!l'lll.ture,against the pole-pinoe, and stall the machine. The pedestals themselves pre-vented convenient acce sa to the division pJE.t6S unde'r the smat rr e drnms, and for practical pur poses the index pointers on thE' side of the pedestals proved of little value in ('ontrolli~ the position of the division platest

At the tim", of I!lyvisit, with on e or two exe ept i.oze , too teeth of the armature t'l.rums seemed to be fairl;' sharp am in good conni tiQn for use. Dnring the oronP1'.:i.gnof t,h'il No. 1 Mill oonsi ders.ble exp'3nse was incnrrfild in the pu roh aae of n ewar-nat u rs discs, ana. other re-pairs, in order to kp,ep the separators in go od \'lorking order. For the year 1906 the !'Elpairs on the sepe.rators amourrtad to 6.5y{, 8.net supplies to 6.0y{ per ton of or e treated. These costs saen hiBb and indicate at least tha t oonsoientious e f:fort was made to keep thE>machines in good operating concHtion while they were in use , It is aprmrant, however, from the abov e that the desien of the International fler;eratQr was faulty a.nd ill oonoeived, ane. showed lack of knowledee or experienoe 0 f the work

-15-it was r e quLred to perform. Unc.er these conditions, while +'he ad-varrbage a whioh the No.1 IHll ha.d ov er thf'l No.2 Mill, shown by the compara't Lve Sllm!nary, to handle H laresr tonnage of ore e.t B low cost;

were entirflly dn" to the pr tncd p.le 0 f sepa.ration embodied in these maohLnea , yet on t.he other hand, the failure of the No.1 Mill to

pro-d1lO'l8S r to h oonoentrat138 as VElre required, 1lI'8.ll cue, in

re.rt,

in my

opinion, to the clefects of their desi.gn.

SUGGEi1TrON FORPH?; IIJJPROVEMBNTOF THB PREEENTPRAOTIGF.OF NO.2 MILL. A etu(l.~Tof th<'l present mill treatmE'nt of thll American Zinc Extraotion 00. shows that it is def<'lo+,jve in the fbJ.lovoing respects:

(l) A ver~r low zino re covery , The s1J!!lnBry fol' two years

shows 65 •.9%. In other words, onl~T two-thirds of the zinc in the ores purchased is shipped in thE! form of co ne errt ra.te a, Of thE' losses, J.2.8% occurs in roasting, and itnst, an(!. 21.3% in thE! seI'!:'.rated tl'j.lings of the O-K machines.

(:;) A oomparatively Emall capacity, Bnd r€llativ€'ly high

oost of treatment, dne to tho ti.me Tflquired to pass the ore through the roa ati ng fllrna 0 ea •.

(:3) Loss of snlphnr :1.nthe magnet;iz1.116 ro a flt, chie f1~T from

the fine iron pyrites, whioh would otherwise ba a'Vailable fur Sulphurio Aoid production.

The .sugBestion whioh I desire to 0 ffer as to the

improve-ment of thE'> p reaerrt min praoUc('l 5.s 8S fonows:

(A) Remove the fin"l portion of the o rud e ore by

screen-i116, after it

me

b een o ruehe d approximately to thE' size of tho present mill-feed.

(B) ROast only th<'l coarse portion of the ore, and sepa r-a.tre it upon the present low intensity magnetio separators.

(e) Size the ftnl3 portion of the are, and separate each aize upon high intensity maenetio separators in the crude oondition, for the pro duotd on of rioh zinc o oncerrt ra te a ancl.ol'laIl tailings.

If the fin"l portion of t.h e o re is aaeuned, for the moment, to be that below 100 Mesh in size, it \;Quld includ.e 25% to 30% of the total mill-feed as the are is c ru she d gt present. By relie"ing the rOBst ine furnaces of this proIJOr1;ion of thetr work, sl1?JY25%, the mill tonnage oould then be inorensed from J.17 tons to 146-1/4 tons per day, and the oost pSI' t.on correspondinel~' r'e duc ed , sinoe the sam oru ahfng maohinery and pmctioa Uy t. he aame lBbar foroe could handLe the in-creased tonnage. It is moreover quite probable that the proportion of the fine ore oouId be ooneid.erabl:;' increased beyond 25%.

Sino e th e lOflses of zinc i.'.nd su Lphur ooonr prine ipally

in roa attng the fine portion of t;he ore, or rnther in over-roasting it. sino~ it is a.iffioult to c ont ro L the magnetj.zing r oest of uns Lze d are partioles, the 1088 of zinc in the roasting rurnac e , end B large propor-tion of the sulphur could in this V\'8i)' be at one e pr overrt ed ,

Moreover, this treatment wonld also tend to Lncz-aase the effioienoy of the elevelancl.-Knowles separators as well. In over-roasting fin'3 pyrites IJI?,rtioles, they are practically oonv er te d into oxides, whioh are only feebl~' l!le.gnetic. In the attempt to separate such particles with a low intensity maobtne , the;)' are either l~ft with the zinc produots, or else th~y onrr~T with them l". oertain amourrt of the

fine zino into the iron product. This impElT.:t'eotseparation c ou'ld , th er e fore , be much improvP,d by the 'mUTe remoV!:'.lof the fin'3 portion of the ore, and treating it indep,mdfmtly of the 0oar ae portion, in the

crude or unroasted oontlition upon high int<msity sepgrators, esp'3oially designed for handling suoh material.

By raising th'l zfne reoovery of t,he Cl'3"eland-Knowles

-17-Separators in this way to say 85%, and allowing fue same efficienoy for the high intonsi~; separat,ors, the total mil!. reoovery oould thus be raised about 20% above t hat now obtained by the pre sent mill treat-ment.

This ad.van taes, lo".S "'011 as fuose of BI'eater mill capacity ann low"r oost p sr ton, offer an opportunH;y of ample reward for the euoceaa of tho endeavor.

Thil feasibil:!.t~' of t;hie etleeestj,on, turns almost entirel~r upon tho Question as to whet.her- a type of hieh intensity l!l!?B!letio separator can be o,esigned, whioh ahE'.11 'be oapablE! of sellara1;ing effi-ciently the fine portion of the r,eM,ville ores in the crude or tmroasted oOlldition. In order to promptly reach a oonclnsiotj. as to the po aar-bili ty of doing this. I took a small ooparator whioh I lJail, previottsl~T cons trnoted for another pUTIJOBe,and r e modAled it I?fter m~1re turn to New York, by IJroviding it, with a new feedine dflvioe and a new type of separating o~Tlinder, esp"cially deaiened fur treating fine material, In order to illustrate in a general wa~1the apparatus used, I have at-taohed hereto a photograph of it taken before :1.t was r-emode le d ,

In making this trial sep er "tion. some delay oc ourz-ed owing to t.he faot that the first tests were made with the finest

portion of the :No. 1 sample eent me from r,ea<'.vU.lEl. (dust i'rom th e orush-ing department) and only after sflver!\l trial seI'I.',r"tions were made

was it disoovered, by means of a powerfUl microscope, that the mater-ial oontained a considArable peroentage of magnetio silioates.

IlJ, sepa ra.t ine thE'!No. :3 sample. there fore, I was abl e, by removing a larger proportion of th e first maenE'!tio head s,

to

separate enough of the msenetic silicates to hritj.g the zinc ooncentrate up to 42.53% zinc, with a recovery of 75.2% of the total zinc in the fine portion of the ore treated. This re/mlt ooulo, doubtless be

oonsiderably improved upon w:l.th ncre tLme to adjust the separator,

ann determine the 0ffeot of variations of field-strength, speed oft he se par ating- drum, at c •

TRIAl. SEPARATIOlf OF

(NO.3) 3AM.PLFJ OF

onusasn

MI11-F3:I<ID FROM TH::>;AIDlRICAN ZINC EXTRACT ION CO., L":ADVILLE, COLORADO, WITH i\PECIP.L FOH1>!OF MAGl.'Il'ETIC SEPARATOR.

J;'ine portion only of this samplE>was used fur the sePJ,ration; 1. e., the unde r size frol!1 86 ro(Jsh ao re en , This amount of the are, amounting to 27.9% of th" total "BS divided into further sizes b~'

so r een a 0 f the following l!1E1sh; viz: 109, 130, 163 and 200. Each size was sellarA."t$il inclepenf..ently, an« t.ho sep er at.e d products combined as follows;

J;'ead Mt\g. Heads 2lno t:onete , Talllngs

WEIGHTS: Gma 2081 222 924 935

%

100% 10.65 44.40 44.95 Gold ozs. 0.01 0.01 0.01 0.01 "lIver o as , 2.67 2.08 2.10 3.38 Lead

%

6.'72 3.15 2.50 11.75 AS3AYA: Silica

_"

9.65 12.26 6.89 12.00 Iron n 20.00 17.50 11.20 29.20 2ina n _24.'75 21.95 42.53 7.88 Gold 100.0 10.6 44.4 45.0 Silver 100.0 8.3 34.9 56.8

%

OF TOTALLead. 100.0 5.0 16.5 78.5 CONTEXTS Silica 100.0 13.4 31.3 55.3 OF FEED- Iron 100.0 9.4 24.9 65.'7 ,l<! • Zino 100.0 9.5 76.2 14.3

The ab ove trial separation shows tha t a

eo

00. zinc ecneen-trate can be obtainEld, With a fair rEleO'TPiry~ fine portion of the crude ore without roasting it. This ino.icatE's a strong proba-bility that the samE' plan 0f treatm<lnt can be worked outS110eesefully

on a oommercial scale.

-19-In that event th'3 Loeae s which now o oour mainl;' in roast'-ing and separating the> fine portion of the oro, can be largely pre-vented, and the profit of operating the La!:1.dvill<>mill oorrespondingly

increased.

It should alBO be pointed orrt that the plan which I MVO 811£;gFlstedshould be of 913peoial 8clY8ntage in treating the Leadville silicious ores, as WEllJ. as the h(lav~ sulphides.

The Hilica in the silicious ore s seems to cc our' both in the form of free quartz, and aLso in the :!'om of magnet Le silioates. The latter appr-oaoh th,) zinc bLende so nearly in Bpeoific gravity that the attempt to f'ree the zino cone flntrates from silica by tabling

t.hem can onIy succe ea at the expenae of heavy l0SSElS of

the

fine zino •

,

THE AMERICAN

zmo

F.XTRACTION CO., I,F..ADVIT.JJ:,COW. 18 1NTEHNATIONAL MAGN1;T19 SEPARATORS

TREATING CRUDE (UNROA"TT<~D)OR";".

STJID.1ARYOF RSSULTS ]i'OR 7 MONTHB, JUNE 1st to Dec. 31st, 1905. (;rude oras Z:tl'JC.i Cono. li'e. (Jono. Dust Losses

l LES. 47551261 25343595 15206589 501~17 1987760 WEIGHTS:

%

100.0 53.3 32.0

Ie

.5 4.2 (Gold 0.034 0.0281 .035: .0341 .120 (Silvs] 6.25 5.61 6.35 _8'38 8.51 (Lead 3.46 2.54 4.33 5 2 4.0 ASS-ilYS: (Sil1os 2.67 2.53 2.65 4~¥ 0.14 (Iron 26.03 18.57 36.65 16. 63.50 .(Zinc 27.8'7 36.92 9.51 35 •.7 32.60 IGold 829.336 356.265 269.588 85.474 118.009 (Silve] 148771.83 71024.59 48314.1F---- 21006.33 8426.79 (Lead 1642291 642261 658045 260532 ,.,--81453 METAL (Silios 1269607 640751 402596 223468 2792 CONTENTS (Iron 12374775 4706758 5570533 836930 l2.60554

_"

(Zino 13252186 9353723 1445431 J.803962 649070 . (Gold 100.0 43.0 32.5 10.3 14.2

%

OF (f,ilveI 100.0 47.8 'f'''' _{32.5 14.2 5.5} TOTAL (Lead 100.0 39.1 40.0 15.9 5.0 CONTENTS (Silioa 100.0 50.5 31.7 17.5 0.3 OF CRUDE (Iron 100.0 38.0 45.0 6.7 10.3 ORES. (Zino 100.0 70.6 10.9 13.6 4.9

SUMMARY OF Rl<:3ULTSFOR 6 MONTHS, Jan. 1st to J\me 30th, 1906.

.rJ~s.

52443764 25793360 18751700 3872000 4026704 WEIGHTS: 100.0 49.2 35.8 7.4 . 7.6 (GOLD •03lt .027 .032 .030 .050 (Silver 6.31 5.71 6.32 10.48 5.40 ASSAYS: (Lead 4.04 2.98 3.74 6.85 3.15 (Silioa 2.42 2.66 2.19 5.32 0.97 (Iron 25.10 18.00 35.50 17.20 25.10 (Zina 25.50 36.60 9.10 32.10 24.40 (Gold 826.975 365.197 302.331 58.040 101.407 (Bilver 165442.60 73689.87 59582.5 f-c 20289.02,....,10881. 20 METAL (Lead 2118325 '770405 966089 265173 126658 CONTF..NTB(Silioa 1265588 686901 411559 206059 38931 (Iron 13187001 4647420 6661230 667446 1010905 (Zino '1 13371926 9437638 1707241 1243081 ₉₈₃₉₆₆ TGo1d 100.0 44.8 36.6 7.0 11.6

%

OF (f)ilver 100.0 4A.5 36.0 12.3 7.2 TOTAL (Lead 100.0 36.4 45.6 12.5 5.5 CONTENTS (i>ilica. 100.0 54.3 32.5 16.3 3.1 OF CRUDE (Iron 100.0 35.2 50.1 5.1 9.6 ORES tZinc 100.0 70.6 12.7 9.3 7.4 (BO)

-21-NO. 1 Mgt.

TH~ AM7RICAN 7.IN0 F~TRACTr.ON CO., L~DVJ1L~. COLO. 18 !NT.BRNPTIONAJ. Vu\.GN";T

to

SF-Pi\RATOR S.

TR~ATING CRlIDE (UNROASTED) OR3S.

Cr da 0"'<18 Zinc Oono Fe Cone Dust

SUMMARY OF R'iSUJ1I'S FOR 6 MONTHS, JULY 1st to Dec. 1st, 1906.

u ..

.

i _{• •}

•

.u ~ Ll:!:i. b.LUi::e585 l::

-

20478060 800 8124315 WEIGHTS: ~ 100.0 43;2 33.6 9.8 13.4 ((+ole. .0282 .023 .030 .02 .040 ( Silver 6.23 5.32 6.5 9.37 6.22 ASSAYS!' (Leae. 3.8 2.67 5.11 6.31 1.1 ( Silioa (,.68 2.42 2.,35 5.41 1.54 (Iron 25•.64 18.06 36.38 17.88 27.35 (Zinc 25.2 36.69 8.15 31.2 26.4 (Gold 860 .674 3()4.852 311.516 81.70 162.59 ( Silver 190224.02 70326.53 66455.98 28171.25 25270.26 (I"eM 2324267 706907 1047806 379255 90299 METAL (Silioa 1569775 638775 481058 325157 124785 CONTENTfl (Iron 15647001 4\103133 7450556 1075205 2218107 ( 7.inc 15377731 9690668 1670319 1876167 2140577 (Gold 100.0 34.4 36.2 9.5 18.9 ( SHver 100.0 37.0 34.\1 14.8 13.3

%

O:B' (Lead 100.0 30.4 45.1 16.3 8.2 TOTAL (Silica 100.0 40.7 30 .6 20.7 8.0 CONTRlIlTS (Iron 100.0 31.3 47.6 6.9 14.2 OF CRUDE ( Zim 100.0 63.1 10.8 12.2 13.9

SllMMi\.RYOF RRflTIT,TS FOR

p

MONTHR, JAN. 1st to ;TUNF, 30th, 1906.

JiBS. 46001433 22308570 14'{.t8400 ~~ 5554763 WEIGHTS:

'%

100.0 48.5 32.0 7.4 12.1 (Gold .0242 .0224 .0324 .025~

.t>J7-S-«'"

oJL1ve r 5.43 4.88 5.36 _'7.96 6.28 (Leed 3.84 3.a5 5.20 6.00 2.17 ASSAYS ( Silica 3.24 2.61 2.79 4.94 2.18 (Iron 25.08 20.45 34.80 24.20 2l .85 (Zinc 25.0B 33.55 10.18 32.80 25.65 (Gold 567.637 250.171 238.727 43.847 34.892 ( Silver 124955.29 54470.03 39471.49 13581.24 17432.531 METAL (LEad 1767964 6951113 746683 204981 120387 CONTElilTS ( Rilica ~4.90921 578841 410215 168770 333105 (Iron 11528182 4561902 5126004 627787 212489 ( Zinc 11523362 7481296 1497734 11120321 11-424011 (Gold 1UO.0 44.1 44.1 7.7 6.1

%

OF (Ril veT. 100.0 43.6 31.6 10.9 13.9 TOTAL (Lead 100.0 39.4 42.2 11.6 6.8 CONT1'JNTS (Siliel.'. 100.0 38.8 27.5 11.3 22.4 OF CRUDE (Iron 100.0 39.6 44.5 5.4 10.5' ORES (Zinc 100.0 65.0 13.0 9.7 12.3 ( 2J.)

THE AMERICAN ZIBC 1<::XTRAGTIONCOMPANY. J.F..ADVI1LF.. COLO.

18 INTBRNATIONil.LMAGN~IC fl~ARATORS

TREATING CRUDE (mffiOMlTJm) ORES.

SUMMARYOF RBSULTS FOR 2 Y,:RARSAND 1 i~ONTR••1UNJiJ1. 1905. TO .nmE :30.190'1.

Crude

or~8

Zino cono.

Fe Oono , Dust Losses

Tons 103509.52 49926.97 34577.37 9158.ffl 9846.77

WEIGHTS:

_%

100.0 48.2 33.4 8.9 9.5 (Gold .0298 .0258 .0325 .0293 .0424 (3il ver 6.08 5.40 6.18 9.04 6.30 (Lead 3.79 2.82 4.95 6.05 ·2.12 ASS:lYS: ( flilica 2.70 2.55 2.46 5.04 2.53 (Iron 25.45 18.85 35.80 17.80 28.90 ( Zi.,.c 25.75 35.85 9.13 33.00 26.40

%

OF (Gold 100.0 41.4 36.4 8.7 13.5 TOTAL (fJil ve r 100.0 42.9 34.0 13.2 9.9 CONTENTS (I.ead 100.0 35.8 43.5 14.1 6.6 OF CRUDE ( Silica. 100.0 44.9 30.1 16.2 8.8 ORES (Iron 100.0 35.8 47.4 6.0 10.8 ( Zino 100.0 67.1 11.9 11.2 9.8

..

TH~ ~~~ICIENCY OF TH}~ !NT~lliNAT!ONA1 l{AGHETIC SEPARATORS.

T%na 84504.34 4992.6.97 .,, 34577.37 WEIGHTS: 100.0 59.1 40.9 (GOld .0284 .0258 .0325 ( Silver 5.72 5.40 6.18 (Lend 3.69 ?'.82 4,.94 ASSAYS: (Silioa 2.51 2.55 2.47 (Iron 25.80 18.85 35.90 (Zinc 24.85 35.85 9.b5

%

OF (Gold c 100.0 53.2 46.8 TOTAL (Silver 100.0 1'15.8 44.2 CONTENTS ( Le1'.6. 100.0 45.2 54.8

OI!' CRUDE ( Silioa 100.0 59.9 40.1

ORES (Iron 100.0 43.1 56.9

-23-No. 1 MII.L

T1f~ AMER!CAN 7.INC ~~R.Jl.CT!ON CO~[PANY. I.F.ADVIUE, COLO.

CRUDE (UNROASTBD) OR~}S TRF..ATED UPON18 INTERNA'1'IONAI. MAGIUiT!C SEPARATORS.

S!1M1.[t1.RY OF MILI.!N(l CO'JT'il FOR 6 MONTHS ,Tan. 1st to ,Tuly .2nd, 1906.

Unloatl.ing D:Q'ing B6IJfi'.l'Bting I,ol!ding and sampling ani!. o rush ing antl. shipping Total per ton Total per ton Total per tOIl Total per to~

LABOR

&

rf.

rj

rf.

r/

SUPT. 5510.49 21.3 8322.94 3J.• 7 6889. '/8 26.2 3965.91 15.1 POWER 645.60 2.46 4353,.62 16.6 3624.33 13.8 COAL 871.40 3.32 , SUPPLIES 619 .04 2.36 385.86 1.47 2430.73 9.27 1668.46 6.36

REPAIRS

1439.49 5.48 7264.09 2'7.70 IG34.34 6.}~3 176.01 0.67 1 TOTALS 8215.62 31.6 21197.91 &0.8 14579.18 55.0 5968.26 22.7"1 TONSMILLED: TOTALCOSTS: COSTPER TON:

26,221.9

$.49%1.07

1.90 \,

SUMMARY OF MULIlW COilTSFOR 6 ~iONTHS JULY 1st to Dec. 31st~ 1906.

Unloading J)~-ine Separ8ting Loading

and sampling and orua hing and shippingg

Total per ton Total per ton Total per ton Total per ton LABOR& 1L7

.Ii.

I"

-v.'---'--'

SUl'T. 5360.84 9652.59 31.6 7914.02 25.9 4684.10 15.4 POWER 685.26 2.25 4764.13 15.6 4729.45 15.5 COAL 865.12 2.83 SUPPLIES 504 .92 1.65 507.13 1.66 %1.92 3.15 1438.98 4.72 REPAIRS 1519.50 4.98 6732i35 22.05 2041.64 6.69 285.77 0.93 TOTALS 8070.52 26.4 22521.32 73.9 15647.03 51.2 6408.85 21.0 TONSI~nJ.ED: TOTALCORTS: COST PER TON: 30,511.3 $52647.72 1.725

AVF~~GECOSTPRR TON FOR YF~R 1906: $1.79.

Crude or es lIino Cone. Fe. cono , Dust Losses

TRF: AMERICAN ZINC J<:XTRACTION CO., LEADVILI..E. COLO. 6 OLEVELAND-KNOWr,r.:s MAGl'iET.IO i'lEPP.RATORfl.

TRF'.ATING ROAflT:rJI)ORES.

SU]ffi~Y

OF RBS!JLTS FOR 6 MONTHS, DEC. 1st. 1907 to

JUNE I,

1908.

LBS. 39253022 13916300 155520

g

0 755000 9029722 WEIGHTS:

%

100.0 35.5 39. 1.9 23.0 (Gold 0.024 0.02l 0.03 0.02 0.02 (Silver 4.96 5.3 4.96 7.6 4.3 ASSAYS (Lead 3.20 5.0 2.20 6.3 1.9 (Silioa 3.60 6.5 2.9 7.2 1.8 (Iron 26.40 11.85 48.8 18.9 10.3 (Zinc _{22.10 42.2 8.35 25.7} 14.6 (Gold 478.903 140.508 233.316 7.63l 97.447 (Silver 97444.88 36804.52 ..385Gl~OO 2856.95 19222'.41 METAL (lead 1259732 696330 344270 47720 171412 COlllTENTS(Silioa 1413286 907650 434930 54700 16006 (Iron 10324993 _{1650150 7600100 142420 932323"} (Zino 8675770 5872216 1297417 223546 1282591 (Gold 100.0 29.3 48.8 1.6

ro

.3 (Silver 100.0 37.8 39.6 2.9 19.7

%

OF (Lead _{100.0 55.3 27.3 3.8} 13.6

TOTAL_CONTENTS (Silioa 100.0 64.3 30.8 3.8 1.1

(Iron 100.0 16.0 73.6 1.4 9.0

OJ!' CRUDE (Zino 100.0 67.7 14.9 2.6 _14.8

S1JMIilARYOF R"~SULTS FOR 6 MONTHR Jtrn:E 1. 1908, to DEO. I, 1908.

LES. 45017897 10345300 23022100 _{999000 10651497} WEIGHTS:

_%

_{100.0 23.0 51.2} 2.2 23:1; (Gold 0.027 0.026 0;03 0.022 0.029 (Silver _{4.82 5.8 £1.1} 7.0 3.0 (Lead _{3.31 6.0 2.3} 5.0 2.7, ASSAYS (S11ioa _{4.45 !'3.15 2.73 6.5} 5.0 (Iron _{31.1 10.3 50.0 24.6} 12.6 (Zino _{15.7 42.5 7.7} 21.7 6.2 (Gold 617.303 103.453 344.820 n.297 157.733 (Silver 108600.98 _{30151.50 58885.00 3519.20 16045.18} METAL t.Lead 1495365 617100 _{536200 50035 292032}

OONTENTS (Silioa_(Iron 2051180 841900 605550 65415 538315

14153831 1067820 11500500 245510 !L340001 (Zinc 7056305 4408430 1769249 217770 660856

%

OF (Gold 100.0 _{16.7 55.9 1.8 25.6} TOTAL _{tSilver 100.0 27.8} 54.2 3.2 14.8 00NT ElIlTfl (Lead _{100.0 41,3 35.9} 3.3 19.5 OF ORUDE (Silioa 100.0 _{41.0 29.5 3.2 26.3} ORES (Iron 100.0 _{7.5 81,4 1.7 9.4} (Zino 100.0 62.5 25.0 3.1 9.4 (P.4)

Crude ore s Zinc cono , Fe. Cono • Dust Losses

-25-No. 2 lYIIJ,L

TH3 AM~RICAN ZINC! EXTRACTION CO., LEADVITJJ,E, C010.

6 C1EVBLANJ)-KNOWT...":S MAGNRTIC SEPARATOr- fl

TRFJATUrG ROA"TBD ORRR.

SUMMARYOF R}i3UJ..TS l''OR 6 MONTH;:;,DEC. I, 1~08, to ,IUNE I, 1909.

LM. 41158363 10564620 21035500 639000 8919243 WEIGHTS:

%

100.0 I· _{25.7 51.1 1.5 21.7} » (Gold 0.026 0.02 0.03

o

.02E 0.0 ( Silver 4.6 5.2 5 ..15 6.3 2.5 (Lead 5.7

5.7

4.75 4.9 12.5 ASSAYS ( Silica. 4.2 7.6 4.9 2.3 2.6 (Iron 30.3 10.5 49.0 22.8 10.0 (ZInc 16.1 41.4 7.8 19.6 5.6 (Gold 532.315 105.646 315.55 8.38E 102.r:-! (Silver 94506.13 27243.00 54190.00 2018.50 11054.63

METAL

(Lead 2333559 598:320~ 442120 31468 1261131

CONT EJ!lT S ( Silica. 1714895 805100 fiW/650 50910 231235

( !ro:d 12461875 1102300 10316500 145740 897335 (Zinc 6638530 4379265 1635107 125016 499142

%

OF (Gold. ·100.0 19.9 59.2 1.6 19.3 TOTAL _~Silver 100.0 28.8 57.4 2.1 11.7 CONTENTS Le8(1 100.0 25.6 J.9.0 1,3 54.1 OF CRUDE ( Silioa 100.0 47.0 36.6 2.9 13.5 OJ:ES (Iron 100.0 8.8 82.9 1.1 7.2 ( Zinc 100.0 66.0 24.6 1.9 7.5

S~~ARY OF RESULTS FOR 6 MONTHS, JUNE 1st

to

DEC. 1st, 1909.

o

o

LB:'l. 28133885 _{9033100 13892200 602080 4606505}

WEIGHTS

_%

_{100.0 32.1 49.4} 2.1 16.4 (Gold 0.026 0.02 _{0.03 0.03 0.0210} (s i ival' 4.J. 4.8 _{4.3 6.2 1.8} (Lead 2.5 _{4.3 1.7 lL3} 1.3 ASSAYS ( Silica 5.1 7.2 _{3.7 10.3 4.6} (Iron _{21.1 11.2 4'7.6} 20.2 3.6 ( Zim _{19;8 41.4 9.0} 23.8 9.4 (Gohl _{366.893 90.328 208.415} 9.04 5ellb~ ( 'inver 58268.40 21947.00 _{30252.00 1878.80 4190.6}

METAL

_{CONTENT 8}

_{( Silica}(Lead 709753 384250 2398J.0 26088 59605

142Bli27 648000 _{50B050 61955 210522} (Iron 7949605 _{1050500 6609300 121265} 168540 ( Zinc 5561060 3'740632 _{1243700 143120 433608}

OF

(Gold 100.0 _{24.6 56.9 2.4} 16.1 TOTAL ( ::Jilver 100.0 37.'7 _{51.9 3.2 7.2} CONTFJfTS (Lead 100.0 _{54.2 33.7 3.7} 8.4 F CRUDE (Silica 100.0 _{45.4 35.5 4..3} 14.8

RES

(Iron 100.0 13.2 _{83.2 1.5 2.1} ( Zinc 100.0 67.2 22.4 _{2.6 7.8} I (25)

TH~ AM~RICAN ZINC EXTRACTION GO., Lt~ADV!LL~, COLO. 6 C1EVEJAND-KNOWLE~ MAG~~TIC SEPAF.ATORR.

TRRATlliG ROAfiTSDOItES.

SUMMARY O:B' Rr~SULTS Ii'ORTWO YEA:is: DBC. I, 1907, to DEC. I, 1909. Crude OX'flS

~anc

Cone. Ffl. eo no , Dust Losses

Tons 76781.58 21929.66 36750.90 1492.54 16603.48 WEIGHTS: _~ 100.0 28.6 47.9 1.9 21.6 (Gold) 0.026 0.0l? 0.03 0.024 0.025 (Silver 4.68 5.30 4.% 6.90 3.40 ASSAY'l: (Lead 3.77 5.23 2.13 5.22 5.38 (Silioa 4.30 7.30 2.96 7.80 3.00 (Iron 29.25 11.10 49.06 21.90 ~0.03 (Zino 17.78 41.90 6.73 23.75 8.67

%

OF (Gold \100.0 22.0 55.3 1.8 20.9

TOTAL (Silver _~OO.O :~2.4 50.7 2.8 14.1

CONTENTS (Lead 00.0 39.6 ?,7.0 2.7 30.7

OF CRUDE ( Silica '100.0 48.5 3~.~ 3.5 15.1

ORES ( Iron '100.0 10.8 80.3 1.5 7.4

(Zinc 100.0 65.9 ?'1.3. 2.5 10.3

OMITTING "DlT'1T" AND "WSS}~S" FROM ABOV," ilfJMlJARY TO

. Tons 58680.56 21929.66 36750.90 WEIGHTS;

%

100.0 37.4 62.6 (GoM 0.026 0.02 0.03 ( Silver 3.37 5.30 4.95 ASSAYS: (Lead 3.29 5.23 2.13 (silica 4.78 7.30 2.96 ( Iron 34.75 11.10 49.05 ( Zinc 20.75 41.9 6.73

%

OF (Gold 100.0 28.5 71.5 TOTAL (Silver 100.0 39.0 61.0 CONTENTS ( I.eail 100.0 5914 40 .6 OF CRUDE ( iJ1J.ioa 100.0 59.6 40.4

ORES

r

Iron J.OO.O J.1.9 88.J.

-27-No.2

r'lnL

TH~

AM"~ICAN ZINC ~~\CTION

CO., LEAilVILLE, COLO.

ROARTED ORRS TR":ATBD UPON 6 CL:s-v"SJd<.ND-:JOl'01?1T,F.!lMA.GNETIC ~F.PARATORf'j.

Julv 1st to Dec 1st 1908

<;1~D~RY

OF

MILLING

CosTS

~~R 6

MONTHS.

•

-

• .

.

,

.

..

.

Ii

Unload.ing Drying Roa.."tirg T,ol',ding

and sampling and. Crllshirg and. BepaTating ano. Rhipping Total ner

toy

Total

-n"...

,!:" ... '1' .~'!:"-1 ""'... +~VJo..t..a.l....pe.r_to.zL..

LABOR

&

_"7

_r/

_r/

_1.

_'

SUPT. 3760.55 16.7 7137.68 300.8 8049.65 35.9 2824.10 ~2:6' POWER 703.65 3.1 5235.45 23.3 4035.65 18.0 COAL 1225.00 5.4 SUPPLIEB & REPAIR, 1053.60 4.7 3615.91 16.1 5469001 24.3

TOTAL

$49045.90 $2.J.8 n II

TOTALS:

$5517.80 M.5 17214.04 76.8 17554.31 78.3 2824.10 12.6

TONS M!LLF~:

22421.6

ABOVR COSTS:

$43210.25

TAXER,

INS. & MIA.,

fD935.65

$1.92 per ton.

SUMHARY OJ.' MIJ.LDTGS COSTS FOR 6 !40NTR:'l.

Unload.ing Dr~'ing Ro!'.s tirg LOl'ld.ing

anCi. Sampling arid Crushing l~nCl. Separatine and. !'lhipping . _{~otal Del' ton Total}

»e r tor Tot;al TIel' to' Total per _ton

LABOR

&

SliPT. fJ,.428.62 2!b.5 8830.56 43.0 7005.40 34.1 3539.04 17.2

POWER 866.57 4.2 4731.98 23.0 4283 .53 20.8

COAL

1214.95 5.9

SUPPLIRFl

&

REPAIR~ 12564.87 12.5 533&.27 26.0 55J.8.56 26.9

TOTAL: $484J.8.35 5386.8J. $fi3?05.16 ~\2.36per ton TOTALS: $7860.06 38.3 20111.76 98.0 16807.49 81.9 3539.04 17.2

TO~, MILLED:

20fi12.?

ABOV1<lr.O~TB:

TAX})S, INB.

&

MI~.,

"

"

AVERAG": COST P'JJ:i. TON FOR YF..AE, 2.13

n tl

" II

Incl nil:i.ne

Taxes, Ins., 2.39