Document L7jKGd3dGDzLY48QBbx2Mvzg

ANACONDA COffER MIXING COiTAMT SLAG tREATlIC Pliff REPORT ON *UDIT OF SLAG TREATING PLANT - BIST HE.1PIA. MOSTAHA MONTH Of MAI 1948 30 1948 Audit of the Slag Treating Plant, last Halana, Montana, embraces examination of rsoordt for tba month of May, 1948, as outlined in 'Books and Records Cheeked** Bo observations were aade of May SI, 19*8, Inventories* Audit included review of records pertaining to receipt mad purchase of hot and oold slag fro* theAmerican Smelting nd Refining Company, shipments of baghouse fume to threat falls Electrolytlo 7An* pijnt and other consignees, and coapilation and valuation of baghouse fume inventories* The report includes data on the physical and accounting features of th* receipts of slag, and shipments and inventories of baghouse fume* The report is divided as followsi SWOPSJS OP PLANT DURATION CONTRACT KITH AMERICAN SMELTING AND RffIKDO COMPANT ACCOUNTING PROCEDURE RECEIPTS - HOT AND COLD SLAG . SHIPMENTS . BAG HOUSB FUMS INVERTORUS - BAG HDUSB FUMB BRRQtS AND D1SCRBPANCIBS GENERAL REMARKS AID OONCUBION s&s i /* S .to 3, inclusive t' - . 3 3 to 4, Inclusive 4 to 8, indusivs 8 8 :*& *' <> :< B* C.Vacobson, Metallurgioal Auditor V' ....... . - July 15th, 1948 ; K'. : 1 IV- PNYC 00012352 \ AKACOUPA COPPER jgKlKO COfAH| SLIP TKRATIK3 PLANT - EAST HBLSKA. IDKTAKA MOBTH Or MAI 1948 mmh-r i'*. -J*. smopsia o f p u iit ormnoi The following synopsis of the last Helana Slag Treating Plant is from an artiela entitled "Pusing off Zinc froa Lead Slags at last Helena" written by llr. Alexander Lalet, former superintendent of the plant. The article appeared in the Engineering and Uinlng Journal for August 24, 1229. Revisions in data to allow for changes nade at tha plant since original installation bars bean incorporated in ths asyopala. : Detailed anyopala of Hr. B. H. Baldwin, S^erlntandent, was usad in supplying ths revisions. Experiments in recovering waste sine froa lead-furnace slags wars began late in 1926 at Tboala, Utah. The first work was dona in a copper converter, and in fact tha furnace now used My be described as, a non-tippir^ converter. The design of a suitable plant for East Helena, Montana was begun in June 1927,'and plant was blown in on Decanter 3, 1927. This plant now consists, in ths first pises, of s watervJacketed furnace 8* x 21* in area having a charge hole at one and. Into whieh tha liquid slag from the American Smelting and Refining Company's lead fdnmoes, running 12 to dne is poured. In addition to tha liquid slag and acooapanylng skulls, some cold slag is also trssted. The cold slag is taksn from a duap accumulated prior to construction of tha Slag Treat ing Plant. At the other end of the furnace is s tap hols lidch discharges ths slag, freed of wost of the sine, in to 30-ton pots. Ths bottom of ths furnace la mads of water-cooled steel pipee and about 4 inches above these pistes are ths tuyeres. Therefore, tha working bottom of tha furnace is a layer of chiliad slag. Tha sides of ths furnace consist of ordinary water Jackets, mads rather stronger than in the usual copper or lead blast furnace. This is necessary because tha action within tha furnace is axtrmaaly violent, tha turbulence snob more resembling that found in a converter than in the peaceable and quiet leador copper furnace. The tuyeres are 40 in number, 20 being on each aids, are four inches in diameter, and each tuyere is * provided with a one inch coal pipe, through rtiich coal is fad into the blast air immediately before it enters tha furnace., Tha charge hole and charge floor era IS feat above the furnace bottom. Above tha charge hole ia a rectangular canopy of water Jackets which confines the gases mo that they may be conducted into the dust-collect ing system. Then c o mb a horisorttel flue of water Jackets 8x0 fsst and 34 fast long. Thisflue ia provided with e large opening througi which air is admitted to burn tha metallic vapors to sine oxide, also burning ths excess coal dust and carbon monoxide. The rest of the plant is more or leas conventional, consisting of tha usual system of cooling tubas to bring tha temperature of the gases down ao that they will not burn the bags. First cornea a water cooled domtake; than a brick flue branching into two parallel 8 foot steal flues each 366 feat long; than upright U-tubas presenting a cooling surface of about 36,000 square feet. Ths U-tubea effect about 43Jt of tha cooling be fore fUme reaches the beghouse. They are 32 In number, 37 inches in diameter, aund each ia 67 feat high. Tha system ia arranged ao that eight tubes are connected ia parallel. Finally comes tha baghouse in which are hung 576 woolen bags 18 inches in diameter and 34$ feat high. Cases art dram from tha furnace and U-tubea and forced through tha bags by a fan ?$ fast in diameter. The fume drops into hoppers which discharge Into gondola ears for shipment to tha electrolytic refinery at Oraat Falls. Tha entire plant la unique in shape, being 40 feat Ada and 1,000 feet long. 1 After crushing the coal in a Raymond mill It ia fad into tha furnace by four machines, of vhich one Is alloted to each quarter of tha furnace, an extra one being provided as a spare. Each machine handies ten tuyeres. Thera ie a bin in each machine which holds 1$ hours supply of coal, and at tha bottom ia a chamber with a screw delivering coal direct to the furnace through about 20 fast of connecting pipe.. ' The slag, to tha amount of about 600 tons a day, comas in pots bolding 5$ tons, and about .11 pots make a charge. Sometimes, when the slag supply is not sufficient, skulls are added. The time of blowing a charge Tuna from 100 to 160 minutes, and tha depth of tha liquid bath in the fumaoe is about 3$ feat above tuyeres. Prom 17 to 20 par cent of coal ia used, and there must be a slight excess of unturned coal} tha a- mount fed depends on the condition and nature of the slag received. Extraction of sine ordinarily runs from 85 to 90 par cent. It is easy, by continued blowing, to bring up the extraoilon to 93 or 98 par eeot, bat it doee not pay. Besides tha sine, any lead left in the slag la also recovered, 'k At the end of the furnace opposite to the charge spout, there are two tapping notches with a launder leading from each notch, which are of sufficient alts to tap out and discard 58 tons of da-ainoad alag in 10 minutes. The discarded alag ia aaptiad from tbs furnace into two 30 ton tilting alag pots which carry the alag to tha waste duap over a standard gauge track. PNYC 00012353 AMACOMDA COPPER HIKING COIPAHT SLAG TKSATIH3 FUNT - BAST HBU5HA. 1PHTAHA CONTACT CONTRACT WITH AMERICAN SJCLTIKG AHD RfflKIHG CQ1PAKI The contract haa a duration of tan year* from Jamary 1, 1941. It provide* for purchase of molten slag frets current operations of the American Smelting and Refining Compmy and also duap alag from prior operation* Pur chase of current slag ie limited to a maxiworn of 400 tons per dey and dump alag to a ***< of 50 tons par day, al though the Anaconda Coneany may at ita option purchaee and receive any such currant alag as may ha produced in excess of 400 tone par day. .> According to the contract the purchase priea of oitber current cr dioq> alag ahall be the highest net ascunt payable under any ona of throe eehedule* (a), (b) or (o) and shall not ba laae than 10# per ton. The purchase price is to ba computed on basis of sine assay and Engineering and Journal pries for Prime Western line for the cal endar month of delivery. Provisions in all schedules include payment adjustments for increases or decreases in sine assay and quotation. In addition to thasa adjustments schedules (a) for both currant and duap slag also have pro visions for price deductions due to increases in average labor rata and priea of coal. During Way. 1948. the purchase price of both alage sas based on acbadula (e). For informative purposes the contract pro-vision* for purchase of currant slag under this schedule are hare sunmariaadr, When the assay of sine is lCjt and tba applicable sine quotation la 4# per pound the baas pries payable shall ba 22# par ton adjusted as follower ij (1) Add 0# per ton for each l that the sine ssssy shall bs in excess of lC0t# fractions in proportion. (2) Deduct 20# per ton for each that tba sine assay shall ba leas than 10, fractions in proportion. (3) Deduct 9/32# (.28125#) for each pound of sine contained in the clag for each 1# thattba applicable - sine quotation shall ba lass than 6# par pound, fractions in proportion. (4) Add 9/32# (.28125#) for each pound of sine contained in the slag for each 1# that the applicable sine quotation shall ba in excess of 4# par pound up to and including 7.5# par pound, fractions in proportion, and add 12/32# (.40425#) for each pound of sine contained in the alag for each 1# that the applicable sine quotation shall be in amcess of 7.5# par pound, fractions in proportion. Weighing of alag is to ba dona by the Anaconda Company. . 3aspling of currant alag is to ba dona by the Annrican Smelting and Refining Conpany at point of discharge from its furnaces to slag pots. Tba Anaconda Company is to sample all dwp dag upon arrival at the plant. In aaeb caaa three samples are to ba prepared, one for use of each cotpany and ona for unpire purposes. Each staple is to represent no more than one day1* delivery. Splitting licit on zinc is .4J(, Providing agreement within this limit la not effected, ths us* of an tuplre is provided for. Of the thres assays than reported, the middle assay is to govtrn. Payments for dag are required cm or before tba 15th day of the north following receipt of alag. Ths above briefly notes the pertinent provision* of the contract and is not Intended to be all-incluaiva. *i For further data refer to contract of January 1. 1941. and amendmant effective July 1. 1943. .... Accoumw) fftcciDUHa Cosplete accounting* records are prepared for cost of operating the Slag Treating Plant and for deter mination of metallurgical statistics. The Bast Belsna Offiot submits ths necessary information to the Great Falls Office where entries are prepared and entared upon tbs hooka of the Great Falls Reduction Department, and metal lurgical statements are prepared showing costa, treatment, production and loasee. As presently constituted the metallurgical reports are relatively alople. At the operation oonslsts of only ona plant, no complications result in determining treatment, production and losses. Only on* material, alag. ia treated, and only one material, fume. ie produced. Since receipt a consist of alag treated, there are no treatment inventories. However, the inventories of fume most be determined, end this ia the major invertory problem. Detailed infortution follows in this report relative to inventory determination. . - Because the plant is a one unit operation the problem of inventory valuation ia slapls, no in pro mb * inventories existing to require conversion to original material equivalent* a* ia don* on the oopper, sins and manganese plants. The fume inventory is valued on a last-in, first-out bead* on pound* of sine content. Totel cost of alag purchased, and total coat of treatment are divided by pounds zinc produced to arrive at respective purchase and treatment costa per pound zinc. Any increment to prior inventory ia thus prleed at this current oost. ary reduction in Inventory subtracted at last coat remaining in inventory. -<* y>iV. '.!& 'Vjy *e . ,. v.' * / ?T* tyl-. j * PNYC 00012354 V ANACONDA COPPER MUCINS POMPAMY _ *u SLAP TREATING PUNT - EAST HELENA. IQKTAHA .i. t .v 3, ACOOUKTINS PROCEDURE (Continued) In accordance with practice In use for other transfers of materialfro* one plant to another, the fume is transferred fron *B.a.4st UH.e1lena tAo. tAhVe. Gnr^e.aAt Falla Elect_r_ot-lyAtii.c IZii_n__ctieP_l_a_n_at. a-At c__oa.at. >Aafitr h. ari.ng ide. term.in'ed. t.h. e in. venter? valuations, the cost of sales is arrived at. The ooat as ao determined is then prorated to allocate a por tion to local sales, proper portion being applicable to shipments to Greet Falla. Tto shoe this transaction a book, keeping entry is recorded on the Great Fella books debiting Tune Transferred fron Slag Treating Plant* and credit ing Turns Transferred to Great Falls.* RECEIVED SECnOB RECEIPTS Hot and Cold Slag Hot and cold slag ia purchased from the Auerlean Smelting end Refining Company under contract dated January 1, 1941. The contract provides for receipt of nolten slag directly fron the furnace a of that company and alno cold slag fron a duap accumulated prior to the construction of the Slag Treating Plant. The molten slag is poured into ladlea or pots at the American Smelting and Hafining Coapaxy's smelter and transported to the Slag Treating Plant by rail. Prior to entering the furnace buildlr^ the cars pass over a weighing scale. Ho scale tickets ars printed by this seals, the scalenan obtaining the weight and recording the same by longhand to a Se&leman'e Report. Heights are recorded in even 100 pounds, and cars are weighed both light and heavy. During the interval between loading of the alag and weighing, cone cooling takes place which forme "skulls" around the pots. These skulls are usually Jarred loose and also enter the furnace. However, if the ekulle are not desired as feed, weight Is obtained and deduction made fron the weight of nolten alag. The ekulle so di verted are hauled to the dump. Slag from the dump also eaters the plant over the same weighing scale and weighing procedure is the same. Howevor, only cold slg treated is considered received, and nenorandun ia kept showing in ventory of cold slag on hand. Samples of molten and cold slag are obtained and assayed both by the American Smelting end Refining CoRpapy and the Anaconda Copper Mining Company. According to the contract the splitting limit is .*. If the assays vary by more than this amount en umpire assay is requested. The middle assay of the three ia used for settlement purposes. The settlement assays are used in computing sine content for metallurgical reporta. SHIPMENTS Baehouee Fume SHIPKENT SECTION Major portion of baghouse fume production is shipped to the Great Palls Electrolytio Zlno Plant, the balance going to commercial consumers. The shipments to the Electrolytic Zinc Plant are made at cost and Great Falls weighte and assays are used to determine the quantity transferred. For more particulars,on this transfer, reference may be made to the Electrolytic Zinc Plant audit for October, IMF. . Shipments to conaercial consumers are made at East Helena weights snd settlement ia made on the basis of these waigita, metal content being determined by comparison of sellers* and buyers' essays. During Kay, 1948, ship ments were made to American Chemet Corporation, Chicago, Illinois, and to Eagle Picher Co^tany, Galena,, Kansas. The essential provisions of the agreements with these ooapanies for-metallurgical accounting purposes are as follower (1) American Chemet Corporation. Railroad weights at East Helena and samples taken by the Slag Treat ing Plant govern in making settlement. The splitting limit on sine ia $. Payment is at per pound of zinc contained in fume, f.o.b.. East Helena uhan the St. Louis price for Prime Western zinc aa quoted by the Engineering and Klnlng Journal for week of delivery is 8.25# per pound. To the 6# aa addition or deduction of .90$ per pound of alno la made for eaoh 1# in crease or decrease in the price for zinc above or below 8.S${ per pound. In the event that assays have not been agreed upon for any car befors request for en additional car,' settlement will be made on the basis of ?o zinc and final settlement adjusted.J , r* .. / t` ! PNYC 00012355 \ AMAOOKDA COPTER KIKI1C COMPACT SLAG TRRATING PLANT - BAST HSUSNA. MONTANA (2) Ragle Pi char Coiq>any. The sales price of the fume shall be based upon its sine sod lead content. In cocputing this price, the average tnglneering end Mining Journal quotations for St. Louis Prim Western Zinc and New Tork pig lssd for week of deliraiy will bs used. .The Aims will be delivered in bulk or in paper bags as the Buyer nay fron tine to tine sleet, fo.b., Seller's trackage at Its Beet Helens, Montana, anelter. In the event the buyer should elect to take shipment cf fube in begs, the cost of the funs to the Buyer shall be increased not to exceed $10 per net ton. The buyer shall pay the actual cost to Sellar of packing in bags, but Buyer 1 oust be notified in advance if packing and loading cost la to exceed $10 par not ton. When the quoted pries is 6# par pound, or lower, for tine, tbs coat cf the tine content shall bs 4f per pound, to which there will be added 90f and fractions in proportion, ibr each 1$ that the quoted price is above 6* par pound. Ho charge will be made for the lead oontant until the quoted price goes above 6.50f par pound. For each 1$ and fractions in proportion, that the quoted price is above 6.50{ per pound the ooat will be .90$ per pound. Railroad weights at Bast Helena secured by the seller, will govern in Baking settlement. A sample shall be taken b7 the Buyer, end divided irito three parts, one for tba Buyer, one for the Seller and one for xupire purposes. Buyer and Sailer shell exchange the results of their assays and if they are within ,5t of each other as to zinc and as to load, than the averages will be used in Bak ing settlemnt. Where the results as to either xlno or lead, or both, are not within those Halt-*, then the reserve sample ehall bs sent to an aspire asssyer. Of the three assays thus available, the middle result shall bs used, the cost of umpire to be paid by the party whoac result differs aost widely from the result of the uapire. -The above agreements expired on June 30, 1948, after which they were replaced by pew oontraota. IN7BHTCKT SKTIOK INVSTOPHIg Fumes in Process Throughout Plant Total zinc content of inventory is determined by the Assistant Superintendent on an accountability l role. From known weights and assays of nolten slag entering the furnace, the sino content of feed le determined. From known zinc assays on slag discharged a percentage is arrived at indicating what portion of the original ftsd r^mina In the system. The amount remaining includes allowances for increased weight due to oridat ion and for weight of lead volatilized. These statistics are calculated daily and tuwBarlstd for the aonth. 1b tha production (a so determined, (less Xt deduction for loss) is added the first of month inventory to arrive.at a total to account for. Proa this total is deducted the aetlBSted shipment of funs to Great Falla, tbs balanos being carried as in ventory. The inventory as so determined is for total sine content only. Sines a portion of the inventory re mains outside the flue and averagae approximately 59)1 sine, a further segregation is mads showing total tonnages of ;<<>.' 5# grade and 70)1 grade. By visual observation tba foreman estimates the tomage outside the flue system. The tonnage > ^ * of fu in cars la also, determined by estimate (or actual weight shea available) and the sino oontant is calculated. - From the total sine inventory, the pounds of zinc in ears end outside flue ayetern are deduoted to arrive at tba sine ' *-* ' content of tha fume remaining in flues and baghouse. This is in turn oorrrarted to dry tons on a ?G0l assay basis. The respective tonnages at 55)1 and 70t assays are then reported to the Great Falls Office where they are used in the ' coaputation of metallurgical statistics. The above method of arriving at the inventory is used because the fume in the system is enclosed and Impossible of visual estimation. According to Hr. R. L. Thompson, Assistant Superintendent, the method has bean very satisfactory, previous cleanups having yielded fuse very dose in tonnage to oaloulated, inventory. r I* PNYC 00012356 /o \ * ANACONDA COPPER MIKING CCMPAMT SLAP TREATING PLANT - BAST h e u w a . id k t a n a ^ " r-':-; * INVENTOR! SECTION INVENTOKIBS Funs In Transit to Great Fall* ?! ^i ' r; The Bast Hslsna office reports daily to Oreat Falls the oar matters of fume shipped*^ Qraat Falls in .vSSrcludes la its receipts the ears duaped at the plant. Any cars shipped fraa Bast Helena and not recsired at Great Falls are therefore classed as in transit inventory, Bach car is saapled at Orest Falls and noisture percentage determined. A composite sample is eleo prepared from which sine assays are detmined. Arerefe lead and ailrer ' assays ere obtained from statament of fume received at the aino plant. By application of noisture percentages ' and assays as thus obtained, the dry weight and natal oontant of the inventory is calculated. . . ( . , 'r ERRORS AND DISCREPANCIES SBTTLBflglT VglH AMERICAN SMELTING AND RBTINUO OOIT ANT FOR SLAP PUBCBA3BD As noted under consents on ccntract with the Anarloan Sealting and Rafining Coapany tba pnrohaaa pries of either current or dup slag shall be the highest net emoust p^able under any one of three schedule* (a), (b) or lc), and shall not be less than lOf per ton. Provisions in all schedules include paymmat adjustments for increases or dsersasss in zinc assay and quotation. In addition to thaaa adjustments schedules (a) for both eurrant and d^p slag also prorids for pries deductions due to increases in averaes labor rata, effective July 1, IMS, by amended agreement between tbs coopaniea. The arrange labor rates ars determined by tba Slag Treating Plant Offioe and re* ported to the Oraat Fella Metallurgical Accounting Department for uaa in calculating the settlement. Mr. Mark Holland, Metallurgical Accountant, noted that error had bean made by Bast Balana la submitting tbs change in average rata for May, 1946. He stated that Beat Helena was advised and a nan average rata change waa raoantly submitted. , However, up to and including May, 1948, the incorrect rate increase was ussd in preparation of settlanent schedules (a) as provided by contract. Due to payment under schedule (e) being most beneficial to th* American Smelting and Refining Company for May, 1948, regardless of use of incorrect average labor rata, no revision of settlement is required. Total cnonlative wage increase per hour es used in May, 1948, mas # ,4837 instead of oorreot amount $ .3901. Summary of prleea par ton of slag as calculated fc , 1948, is as followst Schedule (a) Schedule lb) Schedule (c) (Settlement basis) Hot Slav # 6.0314 2.1108 7.3901 Cold Slav # 3.7180 . 1*7507 5*8743 Using corrected average wage increases Schedule (a) # 6,0777 # 3*8101 The American Smelting and Refining Company has bean advlaad aa to the average mage rate correction and has indicated that no additional payments are due under the contract* INVENTOR! VALUATICKS Valuation of baghousa fume is on a "last-in, first-out" basis. Metallurgical reporta were firet prepared omitting shipment of 2,500 pounds fume to Great Falls via truck. Inventoiy mas valued on production before correction of the error, valuation being #18.43 higher then it mould have been if calculated on corrected production data* . Error {'$ 'is negligible* "A *' . it- GENERAL REMARKS AND CONCLUSION ` h-r-M ' Mo errors of consequence mere noted in review of metallurgical accounting procedure for the Slag Treating Plant at Bast Helena, and no recommendations are herein made. Excellent cooperation was received from the Operating \ and Accounting Department s at Bast Helena and from the Metallurgical Accounting Department at Great Falla during oourse ' of this audit* ' ty ' Vi'