Document NG5zE5Mx7zjVN6B1v8er7BwdQ

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. McGGLone, Vice President Anaconda Copper Mining Company Hennessy Building _ Butte, Montana ' - ...... - ........ ~~ Dear Sir: Herewith, copy of report of Mr. E. C. Jacobson, Metallurgical Auditor, covering initial audit of the Slag Treating Plant - East Helena, Montana for the month of May 1946. ' Copies of ay letters to Mr. 7(. K. Daly, Comptroller, and Mr. E. V. Larson, Chief Clerk, Great Falls Reduction forks, are also enclosed. Tours very truly. WJF/EK Enc. cc - a`r* ft* K Daly FDR: X. B. FRAZER PNYC 00012337 \s V* An a c o n d a Co p p e r Min in g s DRAWER 1961 K. B. FRAZER Assistant Secretary and Aaslstant Treasurer DA BUTTE, MONTANA August 24, 11)48 Mr. V Larson, Chief Clerk Great Falls Seduction Department Great Falls, Montana . .- Dear Sir: --... . Herewith, three copies of report of %? 2. C. J&ccbecn, Metal lurgical Auditor, covering initial audit of the Slag Treating Plant - East Helena, Montana for the month of 12ay 1943. One copy of the report is for Mr* 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. 3JF/EX 3nc* ce - Hr* 5* 3* MeGlcne Mr. y. Daly FOR: s. 3. FJUZSE PNYC 00012338 N13378.01 ANACONDA COPPER MINING COMPANY SLAG TREATING PUNT vr* REPORT ON WDIT OF SLAG TRSATINj PLANT - EAST HELENA. MONTANA . r Te c b i yor V AUG 2? 1948 ____ W. K. DALY MONTH Cy MAT 1948 Audit of the Slag Treating Plant, East Helena, Montana, embraces examination of reoorde for the nonth of May, 1948, as outlined in "Books and Records Checked** Ho observations were aada of May 31, 1948,. inventories. Audit included revie* of records pertaining to receipt and purchase of 'hot and cold slag from, th*. American Smelting and Refining Coopany, shipments of baghouse fume to Great Falls Electrolytic Zinc Plant and other consignees, and coepilation and valuation of baghouse fume inventories* = *` 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 follows* ' f) SYNOPSIS OK RLANT OPERATION CONTRACT WITH AMERICAN SMELTING AND REFINING COMPANI ACCOUNTING PROCEDURE . RECEIPTS - HOT AND COLD SLAG SHIPMENTS - BAG HOUSE FUME ` INVENTORIES - BAG HOUSE FUME EBRCKS AND DISCR&ANCIES GENERAL REMARKS AID CONCliBION Pages 1 3 to S, inclusive 3 3 to 4, inclusive 4 to 5, inclusive 0. v-L >. > *. E. C* Jacobson, Metallurgical Auditor . July 15th, 1948 : 111 PNYC 00012339 N13378.02 ANACONDA COPPER MINING COMPANT SYNOPSIS CF PUNT OPERATION The folio*ing synopsis of the East Relent Slag Treating Plant la from an^ article entitled "Faming off Zinc from lead Slags at East Helena* written by Mr. Alexander laist, former superintendent 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 enyopaia of Mr* 2* M* Baldwin, Superintendent, was used in supplying the revisions* Experiments in recovering waste sine from lead-fUrnace slags were began late in 1926 at Tooele, Utah. * The first work was done in a copper converter, and in fact the furnace now used nay be described as s non-tipping converter. . " . , * The design of a suitable plant for East 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 8 x 21 in area having a charge hole at one end, into which the liquid slag from the American Smelting and Refining Company, lead fUrnaces, running 12 to 1Vft zinc is poured. In addition to the liquid slag and accospanying ekulls, some cold slag is also treated. The cold slag is taken from a dusp accumulated prior to construction of the Slag Trea ing Plant* . At the other end of the furnace is a tap hole which discharges the slag, freed of most of the zinc, in to 30-ton pots. The bottom of the furnace ia made of water-cooled steel pipes and about 4 inches above these plates are the tuyeres. Therefore, the working bottom of the furnace is a layer of chilled slag. The sides of the furnace consist of ordinary water Jackets, made rather stronger them in the usual copper or lead blast furnacThis is necessary because the action within the furnace ia extremely violent, the turbulence much acre resembling that found in a converter than in the peaceable and quiet lead or copper furnace* " ; The tuyeres are 40 in number, 20 being on each side, are four inches in diameter, and each tuyere ia provided with a one inch coal pipe, through ifcich coal is fed into the blast air imediately. before it enters the furnace. The charge hole and charge floor are 15 feet above the.furnace bottom, v Above the charge hole la a. rectangular canopy of water Jackets which confines the gases mo that they may be conducted into the dust-collect ing system* Then cornea a horizontal flue of water Jackets 8x8 feet and. 34 feet long* 'This flue is provided with s large opening througi 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'the_ usual aystem.of cooling tubes to bring the temperature of the gases down so that they will not burn the bagsFirst cornea a water cooled domtaks; then a brick flue branching into two parallel 8 foot steel flues each'365 feet long; then upright U-tubes presenting a cooling surface of about 36,000 square feet* The U-tubes .effect about 4S of the cooling be* fore ftuse reaches the baghouse. They are 32 in number, 37 inches in diameterrand each ia 57 feet high* The system is arranged so that eight tubes are connected in parallel* '/fta*** V* . Finally comes the baghouse in which are hung 576 woolen bags 18 inches in diaooter-aad 34$ feet high* Gases are drawn from the furnace and U-tubea and forced through the bagslby. ajfan feet in diameter. The fume drops into hoppers which discharge into gondola care for shipment to.jthe [electrolytic refinery at Great: Falls. The entire plant is unique in shape, being 40 feet wide and l,000:;feetMong* .V . /> 7 .. After crushing the coal in a Raymond mill it is fed into the furnace; by four machines, of vhich on* is alloted to each quarter of the furnace, an extra one being provided as a spare. Each machine handlea ten tuyeres. There is a bin in each machine which holds l hours supply of coal,-;and at the bottom is a chamber with a screw delivering coal direct to the furnace through about 20 feet ofconnecting plpe*.4 * ' ' ^ ` V' ; "`''it The slag, to the amount of about 600 tons a day, cornea in pota-holding cj tons, and.about 11 pots make a charge* Sometimes, when the slag atpply 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 thefurnace is about 3& feetabove tuyeres* From 17 to 20 per cent of coal ie used, and there must be a alight'excess ofunburned coal; the a mount fed depends on the condition and nature of the slag received. Extraction of zinc ordinarily runs from 85 to 90 per cent* It is easy, by cent inusd blowing, to bring up the extraction to 95 or 98 per cent, hit it does not pay* Besides the zinc, any lead left in the slag la also recovered* . At the end of the furnace opposite to the charge epoot, there are'two;,tapping notches with a launder leading from each notch, which are of sufficient size to tap out and discard 58 tons of de-zinced slag in 10 minutes* The discarded slag is esptied from the furnace into two: 30 ton tilting'slag pots which carry'the slag to the waste dusp over a standard gauge track. > * .* :>>, T.- . . * .' 00012340 pNYC ANACONDA COPFSR MINING COMPANY SLAG TREATING PUNT - BAST HELENA. MONTANA CONTRACT CONTRACT WITH AMERICAN SMELTING AND REFINING COMPANT The contract has a duration of ten years from January 1, 1941* It provides for purchase of molten slag from current operations of the American Smelting and Refining Company and also dtuqp slag from prior operations. Pur chase of current slag is limited to a marlacm of 400 tons per day and dtuqp slag to a ms-rf of 250 tons per day, al though the Anaconda Company may at its option purchase and receive any such current slag as may be produced in exces of 400 tons per day. ` . . ...... j, : " `.f ' . `. 'i' ; v . According to the contract the purchase price of either current cr< duig> slag ahall.be the highest net a mount 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 computed on basis of sine assay and Engineering and Journal price for Prime Western Zinc for the cal endar month of delivery. Provisions in all schsdules include payment adJustmanta, for increaaea or decreases in sine 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 slags was based on schedule (o). For informative purposes the contract provisions for purchase of current slag under this schedule are here summarised:,, .' When the assay of zinc is lQjl and the applicable sine quotation is 6* per pound the base price payable shall be 22* per.ton adjusted as follows: (1) Add 20* per ton for each l that the zinc assay shall be in excess of 10$l, fractions in proportion, (2) Deduct 20* per ton for each l that the zinc assay shall be less than 10^,.fractions in proportion, (3) Deduct 9/S2 (.20125*) for each pound of zinc contained in the, slag for each 1*;that tbs applicable zinc quotation shall be less than 6* per pound, fractions in proportion. .>,.* *? 1 (4) Add 9/32* (,28125*) for each pound of zinc contained in the slag for each^ If that the applicable zinc quotation shall be in excess of 6* per pound up to and including. 7.5*. per pound, fractions in proportion, and add 13/32* (,40625*) for each pound of zinc contained in the slag for each 1* that the applicable zinc quotation shall be in emcees of ,7,5* per.pound, fractions in proportion. . Weighing of slag is to be dons by the Anaconda Coupany. Sampling of ^current flag is to be done by the American Smelting and Refining Coup any at point of discharge from its.furnaces to;, slag pots. Tbs Anaconda Company is to sauple all dinp slag upon arrival at tbs plant. In each case three samples.;are to be prepared, one for use of eachcospany and one for uopire purposes. Bach saaple is to represent no mors than.one day's delivery. Splitting limit on zinc is ,4, Providing agreement within this limit is not effected, 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 00 or before the 15th day of the xnocfch following receipt of slag. . . .' * ' PT*p . . ., ,v. . ' . The above briefly notes the pertinent provisions of the contract and ia not intended.to be aJ^l-incluaiv For further data refer to contract of January 1, 1941, and amendment' effective July 1, 1943. /*' .! ; ACCOUNTING PROCEDURE - -/ffv . Complete accounting records are prepared for cost of operating the Slag Treating Plant and for deter mination of metallurgical statistics. The Bast Helena Office submits the necessary information to the Great Falls Office where entries are prepared and entered upon the books of the Great Falls Reduction'Department, and metal lurgical statements are prepared shoeing costs, treatment, production end losses. As presently constituted the metallurgical reports are relatively siaple. As the operation consists of-only one plant, no complication* result in determining treatment, production and losses. Only one material,;slag, 'Is treated, and only.one material, fume, is produced. Since receipts consist of slag treated, there are no treatment inventories, ..However, the inventories of fume must be determined, and this is the major inventory problem. Detailed information follows in this report relative to inventory determination, *.?..- -* - /*' ,, ? . Because the plant is a one unit operation the problem of inventory valuation is aiiqjls,:no in process inventories existing to require conversion to original material equivalents as is done on the copper, zinc and manganese plants. The fume inventory is valued on a l&st-in, first-out basis on pounds of zinc content. Total cost of slag purchased, and total cost of treatment are divided by pounds sine produced to arrive at respective purchase and treatment costa 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. , " y:;\ " ''W. ` ' .l*;*''""' V " .............. PNYC 00012341 .. ; *. m ANAOONDA COPPER MINING OOMPAKI SLAG TREATING PUNT - BAST HELENA. MONTANA ACCOUNTING PROCSXJHS (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 Fieri at cost. After haring determined the in ventory valuations, the cost of sales is arrived at. The oost 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 entry is recorded on the Great Falls books debiting "Fume Transferred from Slag Treating Plant" and credit ing "Fume Transferred to Great Falls," .* RECEIVED SECTION RECEIPTS . 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 CoBpaxyve 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 scale, the scaleman obtaining the Height 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 between loading of the alag and weighing, some cooling takes place which forms "skulls" around the pots. These skull9 are usually Jarred loose and also enter the furnace. However, if the skulls are not desired as feed, weight is obtained and deduction made from the weight of molten .alag. The skulls eo di verted are hauled to the dunp. Slag from the dunp also enters the plant over the same weighing scale and weighing procedure is the same, Howevor, only cold ol^j treated is considered received, and memorandum is 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 Company and the Anaconda Copper Mining Company, According to the contract the splitting limit is ,4%, If the assays vary by more than this amount an unpire assay is requested. The middle assay of the three is used for settlement purposes. The settlement assays are used in cooputing sine content for metallurgical reports. SHIPMENT SECTION SHIPMENTS Baghouee Fume " ' - '4-f . Major portion of baghouse fume production is shipped to the Great Falls Electrolytic Zinc plant, the balance going to commercial 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 made at East Helena weights and settlement is made on the basis o: these weights, matal content being determined by comparison of stilers' and buyers' assays. During May, 1948, ship ments were made to American Chemet Corporation, Chicago, Illinois, and to Eagle. Ficher 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 saoples taken by the Slag Treat ing Plant govern in making settlement. The splitting limit on. sine is ,s. Payment 1s at 6* per pound of sine contained in fume, f.o.b,. East Helena when the St, Louis price for Prime Western zinc as quoted by the Engineering and Mining Journal.for week of delivery la 8.25* per pound. To the 6* an addition or deduction of ,90* per pound of sine is made for each 1* in crease or decrease in the price for sine 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$ sine and final settlement adjusted*. p"rc<x 4!. ANACONDA COPPER MININ3 COMPANT SLAG TREATING PUNT - BAST HELENA. MONTANA 1.: 4#' SHIPMENT SECTION SHIPMENTS (Continued) Baghouns Fume (Continued) . - (2) Eagle Pichar Company. The ealee price of the Aims shall be based upon its sine and lead content* In cooputing this price, the average Engineering and Mining Journal quotations for St. Louis Prims Western Zinc and New Tork pig lead for week of delivexy will be used. The fume will be delivered in bulk or in paper bags as the Buyer may from time to time electp f.o.b., Seller's trackage at its Bast Helena, Mont ana, smelter. In the event the buyer should elect to take shipment of fume in bags, the cost of the fume to the Buyer shall' bt increased not to exceed $10 per net ton. The buyer shall pay the actual cost to Seller of pecking in bags, but Buyer must be notified in advance if packing and loading cost is to exceed $10 per net ton. When the quoted price is 6$ per pound, or lower, for sine, the cost of tbs lino content shall be 44 per pound, to which there will be added .90$ and fractions in proportion, Xbr each 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 6.504 per pound the cost will be .804 per pound. Railroad weights at East Helena secured by the eeller, 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 as to zinc and .3$ as to lead, then the averages will bs ussd in mak~.lng settlement, fthare the results as to either zinc or lead, or both* are not within those limits, than the reservo sample shall be sent to an umpire aesayer# Of the three assays 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, 1948, after which they were replaced by new contracts# INVENTORY SECTION INVENTORIES Fumes in Process Throughout Plant Total zinc content of inventory is 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 slag discharged a percentage is arrived at indicating what portion of the original feed remains in the system. The amount remaining includes allowances for increased weight, due to oxidation and for weight of lead volatilized. These statistics are calculated daily and summarized for the month# To the production r.s so determined, (less 1$ deduction for loss) is added the first of month inventory to arrive at a total to account for. From this total i9 dedictsd the estimated shipment of fume to Great Falls, the balance being carried as in* vsntoxy. _ i<. 1 -. The inventory as so determined is for total zinc content only. .. Since a portion of the inventory re* mains outside the flue and averages approximately 55$ zinc, a further segregation is made showing total tonnages of 55$ grade and 70$ grade. By visual observation the foreman estimates the tonnage,outside the flue system. The tonnag of fume in cars ia also detsrmlnsd 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 fua remaining in flues and baghouse. This is in turn eonrerted to dry tons on a 70$ assay basis. The respective tonnages at 55$ and 70$ 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 ie used because the fume in the system is enclosed and inpossible of visual estimation. According to Mr. R. L. Thompson, Assistant Superintendent, the method has been very satisfactory, previous cleanups having yielded fume very close in tonnage to calculated inventory# PNYC 00012343 INVENTORY SECTION INVENTORIES . r "` Fuse In Transit to Great Fall8 t. : ' .. . The East Helena office reports daily to Great Falls the car numbers of fame shipped# Great Falla in cludes in its receipts the cars dumped at the plant# Any cars shipped fraa Bast Helena.and not received at Great Falls are therefore classed as in transit inventory# Each ear is sampled at Great Falla and moisture percentage determined. A coapoeite 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# $y. application of moisture percentages - and assays as thus obtained, the dry weight and aetal content of the inventory is.vcalculated# * '/" * gaaaRs a n d d is c r e p a n c ie s SETTLEMENT WITH AMERICAN S1ELTING AND REFINING COMPANY FOR SLAG PURCHASED As noted under comments on ccntract with the American Smelting and Rafining 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 theae adjustments schedules (a) for both currant and dump alcg also provide for price deductions die to increases in average labor rate, effective duly 1, 1943, by amended agreement between the coapanies# The average labor rates are determined by the Slag Treating Plant Office and re ported to the Great Falls Uetal urglcal Accounting Department for use in calculating the settlement# Ur# Mark Holland, Metallurgical Accountant, noted that arror bad been made by East Balm&a in submitting the change in average rate for Uay, 1946# He stated that East Helena was advised and a new average rats ehange.was recently submitted. However, up to and including Uay, 1948, the incorrect rate increase was ussd in preparation of settlement 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 rate, no revision of settlement is required# Total cumulative wage increase per hour as used in Uay, 1948, was # #4827 instead of correct amount $ #3901# Sunnary of prices per ton of slag as calculated for Uay, 1948, is'.as follows* . ' Schedule (a) Schedule (b) Schedule (c) (Settlement basis) Hot Slag ,:: `i 6.0314 2#U08^j 7.3901' ' " Cold Slag M: . .... 3#718Q_ ' 1 1.7507; v 5.8743 ]- Using corrected average wage increase: Schedule (a) . # 6.0777 . . . , * 3#8101 The American Smelting and Refining Company has been advised asito.the average wage.rate . correction and has indicated that no addtiitoionnaal payments are due under the contract. , * V*. '*{Qgh ; < , -yy 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 corrects of the error, valuation being $19.43 higher than it would have been if calculated on corrected ^production data# Err GENERAL REMARKS AND CONCLUSION ` ....... ..................... ?>' *.:** - r.' ' 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 cooperation was received from the Operating and Accounting Departments at East Helena and from the Metallurgical Accounting Department at Great Falls during cou of this audit# ' - PNYC 00012344 3 i \ . t .1 -- ... . ... -- .-----1 *TTr"'"*V>r?nV. -- .