Document NzmKB8GNx48ny4DLYKZbD9bD

An a c o n d a Co p p e r Min in g Co mp a n y DRAWER 1961 K. B. FRAZER Assistant Secretary and Assistant Treasurer BUTTE. MONTANA August 24, 1943 Mr. S. S. Medone. Vice President Anaconda Copper Mining Company Hennessy Building Butte, Montana Dear Sir: Herewith, copy of report of Mr. B. C. Jacobson, Metallurgical Auditor, covering initial audit of the Slag Treating Plant - East Helena, Montana for the month of May 1948. Copies of my letters to Mr. S. K. Daly, Comptroller, and Mr. E. V. Larson, Chief Clerk, Great Falls Reduction ffiorks, are also enclosed. Tours very truly. WJF/EK Enc. cc - &Mr. a. K. Daly FOR: X. B. FRAZER PNYQ 00012337 An a c o n d a Co p p e r Min in g s DRAWER 1961 K. B. FRAZER Assistant Secretary and Aaaiatant Treasurer DA BUTTE, MONTANA August 24, 11)48 lir. Z0 V. iarson, Chief Clerk Great Falls Seduction Department Great Falls, Eczxtana Dear Sir: Herewith, three copies of report of 2r. 3* C, Jacobson, Metal lurgical Auditor, coyerlag initial audit of the Slag Treating Plant -- Ssst Helena, Montana for the south of 12ay 1943. One copy of the report is for Jir* Caples and one is for your files* The other copy is for use of anyone who say find it advantageous to review it* Tours very truly. 17JF/EA 3nc# ce - 1ST. 5* 3* iteGlcne Srv*. . Daly FOR: U 3* FHAZSE PNYC 00012338 N13378.01 ANACONDA COJPER MINING COMPANY SLAG TREATING PUNT . . . ;r* REPORT ON 4UDIT OF SLAG TREATING PLANT - EAST HELENA. MONTANA MONTH CK MAT 1948 y.e d , V AUG 2? 1948 J__ W. K. DALY Audit of the Slag Treating Plant, East Helena, Montana, embraces examination of reoorde for the month of May, 1948, as outlined in "Books and Records Checked** No observations were made of May 31, 1948, . inventories. Audit included review of records pertaining to receipt and purchase of 'hot and cold slag from* the- American Smelting and Refining Cospany, shipments of baghouse fume to Great Falls Electrolytic Zinc Plant and other consignees, and compilation and valuation of baghouse fume inventories* v The report includes data on the physical and accounting features of the receipts of slag, and shipments and inventories of baghouse fume* The report is divided as followst [j SYNOPSIS OK KLANT U IERATION CONTRACT WITH AMERICAN SMELTING AND REFININ3 COMPANY ACCOUNTING PROCEDURE RECEIPTS - HOT AND COLD SLAG SHIPMENTS - BAG HOUSE FUME INVENTORIES - BAG HOUSE FUME E8RCKS AND DISCRS>ANCIES GENERAL REMARKS AND CONCUBION Pages 1 3 to 3, inclusive 3 3 to 4, inclusive 4 to 5, inclusive - ' 5 5* 0. E. C* Jacobson, Metallurgical Auditor July 15th, 1948 PNYC 00012339 m SB MM* N13378.02 ANACONDA COPPER MINING COMPACT SLAG TREATING PLANT - BAST HELENA. MONTANA MONTH CF MAT 1948 SYNOPSIS CF PUNT OPERATION The following synopsis of the East Helena Slag Treating Plant is fro* an article entitled "Fuming off Zinc from Lead Slags at Bast Helena* written by Hr. Alexander Laist, formersuperintendent of the plant* The article appeared in the Engineering and Mining Journal for August 24, 1929.$,Revisions in data to allow for changes made at the plant since original installation have been incorporated in the snyopsis *r Detailed snyopsis of Ur* B* M* Baldwin, Superintendent, was used in supplying tbs revisions* ..V Experiments in recovering waste sine from load-furnace slags were began late in 1926 at Tooele, Utah. * The first work was dons in a copper converter, and in fact the furnace now used may be described as a non-tipping converter* The design of a suitable plant for Bast Helena, Montana was begun in June 1927, and plant was blown in on December 3, 1927* This plant now consists, in the first place, of a water-Jacketed furnace 89 x 21* in area having a charge hole at one end, into which the liquid slag from the American Smelting end Befining Company*; lead fttraaoes, running 12 to 15^ zinc ia poured* In addition to the liquid slag and accompanying ekulle, some cold slag is also treated. The cold slag is taken from a dump accumulated prior to construction of the Slag Trea ing Plant* At the other end of the furnace is a tap hole which dischargee the slag, freed of most of the sine, in to 30-ton pots* The bottom of the furnace ia made of water-cooled steel pipea and about 4 inches above these plates are the tuyeree* Therefore, the working bottom of the furnace ia a layer of chilled slag* The sides of the furnace consist of ordinary water Jackets, made rather stronger than in the usual copper or lead blast furaacThis is necessary because the action within the furnace is extremely violent, the turbulence much sore resembling that found in a converter than in the peaceable and quiet lead or copper ftirnace* * The tuyeres are 40 in number, 20 being on each side, are four inches in diameter, and each tu^re is provided with a one inch coal pipe, through ifcich coal is fed into the blast air immediately/before it enters the furnace* The charge hole and charge floor are 15 feet above the.furnace bottom* ;Above the charge hole it a. rectangular canopy of water Jackets which confines the gaeee wo that they may be conducted into the dust-collect ing system* Than comae a horizontal flue of water Jackste 8x8 feet and 34 feet long* -'This flue is provided with a large opening through which air is admitted to burn the metallic vapors to sine oxide, also burning the excess coal dust and carbon monoxide. . The rest of the plant is more or less conventional, consisting of.thensual eystem.of cooling tubes to bring the temperature of the gaeee down so that they win not bum the bags*;; First oomes a water cooled domtake; then a brick flue branching into two parallel 8 foot steel flues-each'366 feet long; then upright U-tubes presenting a cooling surface of about 36,000 square feet* The U-tubes .effect about 43of tbs cooling be* fore itame reaches the baghouse* They are 32 in number, 37 inches in diameter;vand each is 57 feet high* The systemic arranged so that eight tubes are connected in parallel* ''&>*.<V* - * *;' ' ' ; * Finally comes the baghouse in which are hung 576 woolen bags 18 inches in diameter^and 34$ feet high* * Gases are drawn from the furnace and U-tubee and forced through the. bagelbyVasfm ?J feet in diameter* The fume drops into hoppers which discharge into gondola cars for shipment to,the ^electrolytic".refinery at Great: Falls* The entire plant is unique in shape, being 40 feet idde and 1,000'feet^long* . /* v After crushing the coal in a Raymond mill it is fed into the furnace; by four machines, of vhich one is alloted to each quarter of the furnace, an extra one being provided as a spare*' Bach machine handles ten tuyeres* There is a bin in each machine which holds li hours supply of coal, ;and at the bottom is a chamber with a screw delivering coal direct to the furnace through about 20 feet of;:connecting pipe*>4 * V ' v: ` "i The elag, to the amount of about 600 tons a day, comes in peta>bolding 5 tons, and about 11 pots make a charge* Sometimes, when the elag stpply is not sufficient, skulls ^are 'added*: . The` time of blowing a charge runs from 100 to 160 minutes, and the depth of the liquid bath in the furnace is about 3j feet above tuyeres* From 17 to 20 per cant of coal is used, and there must be a slight'excessof .unbumed coal; the a-> mount fed depends on the condition end nature of the slag received* Bxtraction of zinc ordinarily runs from 85 to 90 per cent* It is easy, by continued blowing, to bring up the extraction to 95 or 98 par cent, hit it does not pay* Besides the zinc, any lead left in the slag is also recovered* iq$*}. At the end of the furnace opposite to the charge spout, there are .'two;,tapping notches with a launder leading from each notch, which are of sufficient size to tap out and discard 38 tone of de-zinoed elag in 10 minutes* The discarded elag is eaptied from the furnace into two: 30 ton tilting'slag pole which carry'the elag to the waste duaqp over a standard gauge track. > * *.>,T.- . * mc ooo* \ m CONTRACT WITH AMERICAN SlfiLTUC AND RgFIMING COMPANT ; ` y fi \ The contract has a duration of ten years from January 1, 1941, It provides for purchase of molten from current operations of the American Smelting and Refining Coapny and also duap slag from prior operations. Pur chase of current slag is limited to a maxi mo w of 400 tons per day and dtuqp slag to a mnr! mm of 250 tons per day, al though the Anaconda Company may at its option purchase and receive any such current. slag as may bs produced in exces of 400 tons per day, . j, -^ . ' !f' * > f*?g- . . According to ths contract the purchase pries of either current or. dump slag shall Ibe the highest net amount payable under any one of three schedules (a), (b) or (c) and shall not be. less than 10$;per ton. The purchase price is to be confuted on basis of zinc assay and Engineering and Journal price for Prime Western Zinc for the cal endar month of delivery. Provisions in all schedules include payment adJustmeats, for increases-or decreases in zinc assay and quotation. In addition to these adjustments schedules (a) for both current and dump slag also have pro visions for price deductions due to increases in average labor rate .and price of ooal. During Uay, 1948, the purchase price of both alage was baaed on echedule (o). For informative purposes the contract provisions for purchase of current slag under this schedule are here summarised*., When the assay of zinc is 10$ and the applicable sine quotation is shall be 22$ per.ton adjusted as follows: per pound the base price payable (1) Add 20$ per ton for each 1that the zinc assay shall be in excess of lO0t, fractions in proportion, (2) Deduct 20$ per ton for each l that the zinc assay shall bs less then 10^,.fractions in proportion. (3) Deduct 9/32$ (,28125$) for each pound of sine contained in the, slag for each 1$;that the applicable sine quotation shall be less than 6$ per pound, fractions in proportion, .> , (4) Add 9/32| (,281251) for each pound of zinc contained in the slag for each^lf that the applicable zinc quotation shall be in excess of 64 per pound up to and including. 7,5$. per pound, fractions in proportion, and add 13/32$ (,406251) for each pound of zinc contained in the slag for each 1$ Weighing of slag is to be done by the Anaconda Conpany,. Sampling of ^current slag is to be done by the American Smelting and Refining Conpany at point of discharge from its.furnaces totalsg pots. Tbs Anaconda Company is to sample all diap slag upon arrival at tbs plant. In each case three saaples.;ars to be prepared, one for use of each cospany and one for aspire purposes, Bach sample is to represent no mors than.one day's delivery. Splitting limit on zinc is ,4* Providing agreement within this limit is not affected, the use of an.umpire is provided for. Of the three assays then reported, the middle assay is to govern. Payments for slag fre required on or before the 15th day of the month following receipt of slag, *. , ' The above briefly notes the pertinent provisions of the contract and ia not intended to be al^l.-induadLv For further data refer to contract of January 1, 1941, and amendment effective Jt^ 1, 1943, ..y ac c o d ku r g f r o c bd u bb k 1 r ..... Complete accounting records are prepared for cost of operating the Slag Treating Plant and far deter mination of metallurgical statistics. The Bast Helena Office submit a ths necessary information to the Great Falls Office where entries are prepared and entered upon the books of ths Great Falls Reduction'Department, and metal lurgical statements art prepared shewing costs, trsatmmat, production and losses. As presently constituted the metallurgical reports are relatively simple. As the operation consists of .only one plant, no complications result in determining treatment, production and losses. Only one material,''slag,`it treated, and only-one material, fume, is produced. Since receipts consist of slag treated, there are no treatment invmitorita, However, the inventories of fume must be determined, and this is the major inventory problem. Detailed informat ion follows in this report relative to inventory determination, '^*' v;`-\ .,, 7 Because the plant is a one unit operation the problem of inventory valuation is eiwple,.no in process inventories existing to require conversion to original material equivalents as ia done on the copper, and manganese plants. Ths fume inventory is valued on a last-in, first-out basis on pounds of sine content. Total cost of slag purchased, and total cost of treatment are divided by pounds zinc produced to arrive at respective purchase and treatment costs per pound zinc. Any increment to prior inventory is thus priced at. this current cost, any reduction in inventory subtracted at last cost remaining in inventory. ,f ; . PNYC 00012341 ANAOONDA COPPER MINING COMPANY SLAG TREATING PUNT - BAST HELENA. MONTANA ACCOUNTING PROCECUHS (Continued) In accordance with practice in use for other transfers of material from one plant to another, the fume is transferred from Sast Helena to the Great Falls Electrolytic Zinc Plant at coat. After haring determined the in ventory valuations, the cost of sales is arrived at. The cost as so determined is then prorated to allocate a por tion to local sales, proper portion being applicable to shipments to Great Falls, To show this transaction a book keeping entiy is recorded on the Great Falls books debiting Tu b s Transferred from Slag Treating Plant" and credit ing Turns Transferred to Great Falls," RECEIPTS RECEIVED SECTION Hot and Cold Slag Hot and cold slag is purchased from the American Smelting and Refining Company under contract dated January 1, 1941, The contract provides for receipt of molten slag directly from the furnaces of that coupany and also cold slag from a dunp accumulated prior to the construction of the Slag Treating Plant, The molten slag is poured into ladles or pots at the American Smelting and Refining Company'*'e smelter and .transported to the Slag Treating Plant by rail. Prior to entering the furnace building the cars pass over a neighing scale, -No scale tickets are printed by this seals, the scaltsmn obtaining tbs weight and recording the same by longhand to a Scaleman's Report, Weights are recorded in even 100 pounds, and cars are weighed both light and heavy. During the Interval batmen loading of the alag and waighlng, some cooling takes place which forma "skulls" around the pots. These skulls are usually Jarred loose and also enter tbs furnace. However, if the skulls are not desired as feed, weight is obtained and deduction made from the weight of molten .slag. The skulls so di verted are hauled to the dump* Slag from the dump also enters the plant over the asms weighing scale and weighing procedure is the earns, Howevor, only cold ol% treated is considered received, and memorandum is kept showing in ventory of cold elag on band, Sanples of molten and cold elag are obtained and assayed both by the American Smelting and Refining Company and the Anaconda Copper Mining Compary, According to the contract tbs splitting limit is ,4%, If the assays vary by no re than this amount an umpire assay is requested. The middle assay of the three is used for settlement purposes. The settlement assays are used in computing sine content for metallurgical reports. SHIPMENT SECTION SHIPMENTS ; Baghouae Fume V! " Major portion of baghouse fume production is shipped to the Great Falls Electrolytic Zinc Plant, the balance going to coranercial consumers. The shipments to the Electrolytic Zinc Plant are made at cost and Great Fall: weights 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, 1947, . Shipments to commercial consumers are mads at Bast Hslsna weights and settlement is made on the basis o: these weights, metal content being determined by comparison of sellers' and buyers' assays. During May, 1948, ship ments were mads to American Chsmst Corporation, Chicago, Illinois, and to Eagle. Picher Company, Galena, Kansas, The essential provisions of the agreements with these cospanies for metallurgical accounting purposes are as follows: (1) American Chemet Corporation. Railroad weights at East Helena and samples taken by the Slag Treat ing Plant govarn in making settlement. The splitting limit on. sine is ,s. Payment is at 6 per pound of sine contained in funs, f.o*b, East Hslsna whsn the St, Louis price for Prime Western zinc as quoted by the Engineering and Mining Journal.for weak of delivery is 8.25* per pound. To the 6* an addition or deduction of ,9Q* per pound of zinc is mads for each 1* in crease or decrease in the price for zinc above or below 8,25* per pound. In the event that assays have not been agreed upon for any car before request for an additional car, settlement will be made on the basis of 70 zinc and final settlement adjusted,. v m ANACONDA COPPER MINING COMPANT SLAG TREATING PUNT - BAST HELENA, MONTAKA l'; 4.* SHIPMENT SECTION SHIPMENTS (Continued) Baghoune Fume (Continued) (2) Eagle Picber Coupan/. The ealee price of the fhma shall be based upon ita sine and lead content. In conputing this price, the average Engineering and Mining Journal quotatione for St. Louie Prime Western Zinc and New Tork pig lead for week of deliveiy will be used. The fuse will be delivered in bulk or in paper bags aa the Buyer may from tine to time alect, f.o.b, Seller* trackage at Its Bast Helena, Montana, smelter. In the event the buyer should elect to take shipment of fume in bags, the cost of the fume to the Buyer shall' be increased not to exceed $10 per net ton. The buyer shall pay the actual cost to Seller of packing in bags, but Buyer must be notified in advance if packing and loading coat la to exetad $10 per net ton. When the quoted price ia 6$ per pound, or lower, for sine, the ooat of the sine content shall be 4$ per pound, to which there will be added *90$ and fractions in proportion, ibr aach 14 that the quoted price is above 64 per pound. No charge will be made for the lead content until the quoted price goes above 6,50* per pound. For eaoh 14 and fractions in proportion, that the quoted price is above 6,50* per pound the cost will be .804 per pound. Railroad weights at East Helena secured by the seller, will govern in making settlement. A sample shall be taken by the Buyer, and divided into three parts, one for the Buyer, one for the Seller and one for umpire purposes. Buyer and Seller shall exchange the results of their assays and if they are within .5% of each other aa to zinc and aa to lead, then the averages will be used in mak- ~ing settlement. Where the results as to either zinc or lead, or both,, art not within thosa limits, then the reservo sample shall be sent to an umpire aesayer. Of the three a a saya thus available, the middle result shall be used, the cost of umpire to be paid by the party whose result differs most widely from the result of the umpire. The above agreements expired on June 30, 194B, after which they were replaced by new contracts. INVENTORY SECTION INVENTORIES Fumes in Process Throughout Plant Total zinc content of Inventory ia determined by the Assistant Superintendent on an acoountability basis. From known weights and assays of molten slag entering the furnace, the zinc content of feed is determined. From known zinc assays on alag discharged a percentage is arrived at indicating what portion of the original feed remains in the system. The amount remaining includes allowancas for increased weight, due to oxidation and for weight of lead volatilized. These statistics are calculated daily and summarised for the month. To the production r.s so determined, (less It deduction for loss) is added the first of month inventory to arrive at a total to account for. From this total is dedictsd the estimated shipment of fume to Great Falls, the balance being carried as in* vseitoxy. _ . ` T i<. The inventory as so determined is for total zinc content only. .. Since a portion of the inventory re* mains outeide the flue and averages approximately 55% zinc, a further segregation ia made showing total tonnages of 55$ grade and 70% grade. By visual observation the foreman estimates the tonnage, outside the flue system. The toanag of fume in cars ia also determined by estimate (or actual weight when available) mad the zinc content is calculated. From the total zinc inventory, the pounds of zinc in cars and outside flue system are deducted to arrive at the zinc content of the fume remaining in flues and baghouse. This is in turn converted to dry tone on a 70% assay basis. The respective tonnages at 55% and ?0$ assays are then reported to the Great ;Falls Office where they are used in the coaputation of met&Ilurgical statistics. V< * The above method of arriving at the inventory ie used because the fume in the system is enclosed and impossible of visual estimation. According to Mr. R. L. Thompson, Assistant Superintendent, tbs method has been very satisfactory, previous cleanups having yielded fume very close in tonnage to calculated inventory. PNYC 00012343 INVENTORY SECTION INVENTORIES Fume in Transit to Great Falls The East Helena office reporta daily to Great Falla the car nvnbers of fume shipped* Great Falla in cludes in its receipts the cars dumped at the plant* Any cars shipped frco East Helena.and not received at Great Falls are therefore classed as in transit inventory* Each ear is saapled at Great Falls and moisture percentage determined. A coopoeite sample is also prepared from which zinc assays are. determined* Average .lead and silver assays are obtained from statement of fume received at the lino plant* By. application of moisture percentages and assays as thus obtained, the dry Height and metal content of the inventory is>calculated* * ERRORS AND DISCREPANCIES SSTTlMiT WITH AMERICAN SMELTING AND REFINING COMPANY FOR SLAG PURCHASED Aa noted under consents on ccntract with the American Smelting and Refining Cospany the purchase price of either current or duap slag shall be the highest net amount payable under any one of three schedules (a), (b) or (c), and shall not be less than 10$ per ton* Provisions in all schedules include payment adjustments for increases or decreases in zinc assay and quotation. In addition to these adjustment* schedules (a) for both currant and dump slag also provide for pricedeductions die to increases in average labor rate, effective July 1, 1943$ by amended agreement between the coopanies. The average labor rates are determined by the Slag Treating Plant Office and re ported to the Great Falls Uet&l >urgical Accounting Deportment for use in calculating the settlement* Ur* Uark Holland, Metallurgical Accountant, noted that error bad been made by Bast Helena in submitting the change in average rate for Uay, 1946* He stated that East Helena was advised and a new average rats change.was recently submitted* However, up to and including Uay, 1948, the incorrect rate increase was ussd in preparation .of ssttlaaent schedules (a) as provided by contract* Due to payment under schedule (c) being.most beneficial to the American Smelting and Refining Company for Uay, 1948, regardless of use of inoorrect average labor rats, no revision'of settlement is required* Total cumulative wage increase per hour as ussd in Uay, 1948, mas t *4837 instead cf correct amount $ *3901* Summary of pricesptr ton of slag as calculated for Uay, 1948, is'.as follows* :^ Schedule (a) Schedule (b) Schedule (c) (Settlement basis) Bot Slag ,;; f ,# 6.0314 8.1108 ^ 7.39G1' ' ` Cold Slag` %>V*. % *y 3*7180-. ` U75075*8743 Using corrected average wage increase* Schedule (a) $ 6*0777 [ , $ 3.8101 .* .. * The American Smelting and Refining Company has been advised as^to.the average wage, rate correction and has indicated that no additional payments are due under the contract. , ' * -f ` ` ' '$}. INVENTORY VALUATIONS Valuation of baghouse fume is on a "last-in, first-out" basis*; Metallurgical reports were first prepart omitting shipment of 2,500 pounds fume to Great Falls via truck* Inventory.was valued on production before correct!' of the error, valuation being $18.43 higher than it would have been if calculated on corrected ^production data. Err is negligible* \ H' GENERAL REMARKS AND CONCLUSION :iv No errors of consequence were noted in review of metallurgical* accounting procedure for the Slag Treat! Plant at East Helena, and no recommendations are herein made* Excellent oooporation waa received from the Operating and Accounting Departments at Bast Helena and from the Metallurgical Accounting Department at Great Falls during cou of this audit* . - *' ' 'j PNYC 00012344 :J i \ .... . ... -- .----- .