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By John H. Bell

R. B. T. KILIANI, New York, N. Y.-I wish to present some figures based upon actual observation extending over a few months time which seem to prove the author's conclusions. It is a comparison of two machines operating on the same ore, in the same plant, one taking the undersize of ½ -in. screen and the other taking the undersize of 8-mesh. Each of the machines was first operated as a pebble mill, with flint pebbles, in open circuit, then with metal pebbles in open circuit and, finally with metal pebbles in closed circuit. For the first case, the percentage of oversize on 48-mesh, Tyler screen, in the discharge, varied, in the mill taking ½ -in- feed, from 37.2 to 19.9 per cent. The second mill, taking the 8-mesh feed, had a variation in oversize on 48-mesh, from 36.8 per cent: to 0.5 per cent.; so it is seen there is considerable variation in these figures. I have computed the tons per kilowatt-day reduced through 48-mesh for each machine under each one of these conditions, giving 6 sets of figures. The first of these I called 1.0 and determined the ratio of the others to this.. In the snipe way, I figured the relative mechanical efficiency according to Kick's law, using' the figures given by Mr. Taggart in his paper, for ordinal numbers of the Tyler screens. I have also figured the efficiency in mesh-tons per horsepower according to Gates' method by plotting the screen analyses of feed and product and multiplying the area by a constant dependent on the scale used. The commercial efficiency of tons per kilowatt-day reduced through 48-mesh checks very closely with the efficiency by Rittinger's law, within 1 per cent. except in one case. By Kick's law, the efficiency checks fairly closely, within about 5 per cent., with the commercial efficiency of the mill grinding feed, but when we start to grind a finer, 8-mesh material, and especially grinding very fine; with a

Jan 4, 1917

The editorial expenses for the preparation of the manuscript of the second edition, as for the first, were provided by grants of the Engineering Foundation and the Open Hearth Steel Committee of the Iron and Steel Division, AIME ; the Seeley W. Mudd Memorial Fund again sponsored the publication of this volume. The companies and research or educational institutions with which the authors, reviewers, and editors are connected also contributed much to the writing and editing of this book through their generous donations of time and travel and office expenses. And finally, the authors and others have given countless hours of their own time with no recompense but the satisfaction of a job well done. In order to give credit to the companies or educational institutions which made it possible for the members of the Editorial Board to devote considerable time to the revision of this book, the names of these members and their affiliations are recorded here as follows : W. O. Philbrook, Carnegie Institute of Technology M. B. Bever, Massachusetts Institute of Technology H. B. Emerick, Jones and Laughlin Steel Corporation B. M. Larsen, United States Steel Company A number of individuals suggested desirable changes in the book before rewriting was started. Almost all manuscripts were gone over critically by reviewers, and the resulting criticisms led to the correction of errors and omissions and greatly contributed to the accuracy and completeness of the text. Other people have supplied additional data or illustrations or assisted in other ways. While some of these contributors must remain anonymous because they are not known to the Editors, the cooperation of the following individuals is gratefully acknowledged : R. D. Allen, Republic Steel Corporation, Chicago Isadore Amdur, Massachusetts Institute of Technology Mary Baeyertz, Armour Research Foundation S. P. Bahmer, Republic Steel Corporation, Massillon E. C. Bain and Associates, United States Steel Company, Pittsburgh C. W. Briggs, Steel Founders' Society of America H. W. Briske, Wisconsin Steel Works

Jan 1, 1964

By William Reynolds

This paper deals with the results of a study of the application and development of mining machines for cutting out and removing dirt bands in bituminous coal beds. Face Preparation When one or more dirt bands1 occur in a seam of coal, the problem of elimination of impurities becomes manifest. The degree of completeness to which these impurities arc removed at the face has an important bearing upon labor costs, haulage costs and outside cleaning costs, and often the ash content of the product is markedly affected. Yet, because the present-day miller is paid for the number of tons he loads he often lacks interest in the quality of the coal. To insure a clean product, a system of penalties for dirty coal is enforced, but control of extraneous impurity content in the loaded coal is often inadequate and ineffectual when coal and banded impurity are shot as one. It seems only logical that to reduce the amount of impurities by proper face preparation before the men are permitted to load the coal is the most efficient method of preparation. Many mines with one or more bands of impurities in their seams are able to mine a desirable product with a comparatively small amount of surface preparation. In fact, three companies in West Virginia have recently changed their methods of fact* preparation, with most gratifying results. The first company (in the Kanawha field) after changing its cutting practice with the hope of relieving a sales problem, was rewarded by an approximate 3 per cent drop in ash in the product. Another company, operating in the same field, reduced its ash approximately 4 per cent by a change in cutting practice. The third company (in the Pocahontas field) found the wet washer inadequate in producing a marketable coal, and installed new cutting machines. Three cuts are now being made in each working place, and the results arc so satisfactory that the cleaning plant has been abandoned.

Jan 1, 1938

By John A. Mathews

It is twenty years since the writer made his first molybdenum steels and others were making them commercially five years earlier but the prevailing opinion seems to be that molybdenum steels are new; from time to time the daily press speaks of important discoveries in Europe and intimates that American steel makers have much to learn in regard to alloy steels. The earlier experiments were largely confined to the use of relatively high percentages of molybdenum in tool steels and permanent magnet steels. Recent developments deal with the types of alloy structural steels used for airplane, automobile, and other engineering requirements; in these, the molybdenum content is usually less than 1 per cent. The earlier types generally have been unsuccessful commercially, but the newer types of steels are becoming of increasing importance. The war showed our dependence on foreign sources for alloying metals; molybdenum alone is widely distributed in the United States and seemingly abundant. Many deposits are not now of commercial interest, owing to location and relatively small amount of ore available, but other deposits are being developed and a stable source of supply seems well assured. In tool and magnet steels, it was early found that 1 part of molybdenum was equivalent to from 2 to 2.5 parts of tungsten. The permanent magnet steels investigated by Madame Curie,' in 1898, contained from 3.36 to 4.05 per cent. molybdenum; in 1902, Dr. E. L. French and the writer thoroughly tested steels containing from 2.0 to 4.0 per cent. These steels gave satisfactory tests for permanence, but were low in residual density and much more sensitive to hardening than the corresponding tungsten products. We discontinued work with them, therefore, and have no advice that such steels have been used commercially here or abroad. Prior to the development of the Taylor-White process and the modern high-speed steels, air-hardening steels were in general use. These were

Jan 1, 1922

By David White

The submission of carefully prepared estimates of the oil reserves of the United States calls for no apology or explanation. In this country, petroleum is a rapidly wasting asset and an occasional appraisal of the amount remaining in the ground is a simple business procedure to safeguard the general welfare and the prosperity of the republic. The rumored danger of failure, in the near future, of the foreign supply on which we depend in constantly increasing amounts makes the immcdiatc review of our available reserves the more imperative. The Director of the U. S. Geological Survey, in March, 1921, requested the American Association of Petroleum Geologists to cooperate in the preparation of new estimates of the oil remaining in the graund. With the members of this cooperative committee, state geologists, regional geologists, oonsulting specialists, and geologists and engineers attached to many companies worked both independently and through subcommittees. The reports for districts, counties, fields, etc., after review by local or state committees, were discussed by the joint cooperative committee in conferences that, in some instances, were attended by the original compilers of estimates for the states or smaller areas. Finally the data were reviewed and the figures revised by the joint cooperative committee, so that the totals given in Table 1 represent the opinion of the committee, which was composed of F. W. DeWolf, W. E. Wrather, Roswell H. Johnsont Wallace A. Pratt, Alexander W. McCoy, Carl H. Beal, C. T. Lupton, G. C. Matson, K. C. Heald, W. T. Thom, Jr., A. E. Fath, Kirtley F. Mather, R. C. Moore, and David White, chairman. Oil geologists and engineers understand well the speculative nature and the chances of error that must attend estimates of the petroleum in the ground when they cover not merely prospective territory, but possible territory. Neither the character nor the magnitude of the factors of uncertainty is to be disguised. Further, the inevitable differences of opinion between geologists of equal rank and experience must also bc

Jan 1, 1923

By John G. H. Crump, E. W. Owen, Peter P. Gregory

.Although oil Production in West Texas in 1939 reached the highest figure for any year since the inauguration of proration, drilling activity continued in the decline that had commerlced the previous year. Production totaled 79,469,341s bbl. of oil during 1939 as compared with 71,257,541s bbl. in 1938 and 75,743,000 in 1937. The number of wells completed in 1939 was 1850, compared with 2045 in 1938 and 2806 ill 1937. Several factors combined to cause the decrease in drilling activity, principally the contiriued increase in the length of time required to obtain a return of invcstment and the scarcity of important new discoveries during the past two years. Of the 1850 completions 1638 resulted in oil wells, 4 were gas wells, 168 were dry holes and 40 were abandoned locations; 1990 new locations were made during the year. The ratio of dry holes to producing wells completed was one dry hole to each 9.75 oil wells, compared with one dry hole to each 7.48 oil wells completed during 1938. This large decrease in dry holes was due to a marked decline in the number of wildcat wells drilled, there having been only 120 wildcat completions during 1939. In addition to the lessened exploration work, the deeline' in activity was largely accounted for by the slowing up of operations in the older pools of Ector, Howard and Winkler Counties. Ector County, which had led West Tcxas in 1938 with 622 new oil wells, furnished only 485 producers in 1939, but was still the leader for the West Texas district. The largest gain in activity was in Yoakum County, whew 350 oil wells were completed in the Denver-Wasson field against 152 during 1938. Most of the older oil fields have been almost completely drilled up, only a few new producers still being completed from time to time in

Jan 1, 1940

By E. C. Mahan

THE text of my talk was suggested by the invita-tion of your secretary, who said that the excess productive capacity of the bituminous industry was a matter of common concern to engineers and coal operators. Cognizant of the depressed condition of the industry, he tactfully added that in common council we might find wisdom. Certainly it would seem that the application of the best engineering knowledge available would be helpful in solving mining problems. There is no doubt that clear thinking, characteristic of the engineering type of mind, is essential to untangle the shapeless pattern which increased complication, so often mistaken for progress, has developed. There is much thinking today which neither looks forward to a logical combination of ideas nor backward to simple fundamentals. The result of that sort of thinking is hopeless confusion. Lately we have heard much about excess capacity and overproduction, along with their attendant evils. Respecting the bituminous coal industry, these terms have been frequently misused. How many of us have seen them applied to the coal industry but how few of us have understood them. I am reminded of a state-ment which William Green, president of the American Federation of Labor and a former miner from the Ohio field, gave to the Associated Press last month, in which he was quoted as saying: "The coal men must realize that conditions have altered since the World War. To-day they are producing a billion tons a year, with a market for only half that tonnage." I cite this instance as a glaring example of the flood of. loose statements about the bituminous industry with which the public is being deluged. If the general public, or some of the newspapers, had any passion for the facts, this sort of misleading statement would not get very far. Unfor-tunately, in these days, opinions are more sought after than facts, and statements by such a person as Mr. Green and are promptly accepted by a credulous public.

Jan 4, 1928

A. V. ADAMSON,* New York, N. Y. (written discussion).-The experience of users of pulverized fuel in metallurgical work, particularly for open-hearth furnaces, has demonstrated that high ash and sulfur in pulverized fuel are a detriment, the sulfur in the coal entering into the finished product; hence, in this class of work it is extremely important, when pulverized coal is to be used, that the coal be selected with care, and only those having low percentages of sulfur be used, in combination with proper means for combustion. I have found that no general statement can be made as to the cost of pulverized coal, each installation being an individual engineering problem and necessitating a varying capital expenditure; as each installation has its own power cost, the actual cost of pulverizing varies between wide margins. It has been found that no general rule can he laid down as to either fineness or dryness; for some uses a wide range is permissible in both factors, while some classes of fuel require different treatment from others. Anthracite, coke breeze, and lignite ash will, under certain conditions, form slag, the melting point of the ash from fuel of this character being practically the same as of that from bituminous coal; furnace temperatures above the melting point of ash must therefore cause the formation of slag. However, it should he noted that furnace temperatures attainable with this class of fuel are not usually so high as those from bituminous coal, which probably explains the statement that the former do not slag. In a well designed furnace, temperatures above 2250° F. (1235° C.) will be obtained with that class of fuel, and slags will be formed. Too much attention apparently has been centered on high CO2 contents of stack gases. A high percentage of C02 is frequently obtained at the expense of the brickwork, the furnace temperature being increased by diminishing the excess air; a high percentage of C02 thus simply means a small proportion of 02.

Jan 12, 1918

By C. Stansfield Hitchen

The paper describes the application of the logarithmic wedge sector method of quantitative spectrography to the estimation of commonly occurring minor impurities in crude and refined tin. Both arc and spark methods of emission were employed and with the former a new device was used to overcome difficulties arising from the low melting point of the metal. The impurities investigated included antimony, arsenic, bismuth, copper, iron, lead, and zinc, their concentrations lying, in general, between 0.01 and 0.50 per cent. The results obtained show that the method may be usefully employed for the estimation of bismuth, copper, iron, lead, and zinc, in amounts ranging from 0.50 per cent to well below 0.01 per cent. Arsenic and antimony, however, could not be estimated in amounts less than 0.03 and 0.07 per cent respectively. Out of a total of 116 estimations by arc and spark emission, in 96 the errors were less than 5 per cent of the total quantity of the element present, whereas in the remaining twenty, the errors lay between 5 and 25 per cent. Spectro-analytical data for the several impurities studied are given in the form of tables, and curves correlating line-intensity with concentration have also been included. DISCUSSION (R. G. Waltenberg presiding) D. M. Smith, London, England (written discussion).—I am interested in Dr Hitchen's account of his investigations on the application of spectrographic methods to the assay of tin and congratulate him on his valuable contribution to the literature on the subject of quantitative spectrum analysis. Some of the results obtained in the course of investigations carried out for the British Non-Ferrous Metals Research Assn., although obtained under somewhat different experimental conditions, may be of interest in connection with this paper. Arc and spark spectra of standard samples of tin containing various known amounts of antimony, bismuth, cadmium, copper, lead, silver and arsenic have been investi-

Jan 1, 1933

By Ellen H. Richards

The water-supply of a country may be considered from three points of view: (1) its abundance and availability for agricultural purposes; (2) its chemical properties in their relation to manufacturing purposes; and (3) its quality and quantity as affecting domestic consumption. This paper concerns only those characteristics which may affect manufacturing and domestic uses. The so-called sanitary analyses deal not only with the common mineral elements found in water, but with organic matter and with those substances which, by their presence, indicate changes taking place through the agency of living organisms. Since these living organisms are frequently accompanied by others, capable, as are believe, of causing disease, the products of their action are looked upon with suspicion even when, as in the case of nitrates, that action may have taken place at a time long past. Therefore, upon the quality of the water-supply depends much of the history of a country, when rightly read, as well as much of its promise for the future. Thus, the hardness," or content of calcium and magnesium salts, gives a means of distinguishing at once between the waters traversing only igneous or other siliceous rocks and those coming from calcareous deposits. The presence of decomposing organic matter and intermediate products betrays a use of the water as the public carrier of refuse, which renders doubtful its fitness for domestic supply. In certain regions, one of the most valuable historical records is made by the relative amount of chlorine in the different waters. In the absence of rock-deposits carrying salt,, the chlorine present in rain and snow, and hence in mountainstreams and springs, appears to be derived from the air-borne, finely divided salt spray resulting from the beating of the ocean waves on the coast. If this be true, then the amount of chlorine found in a given water not contaminated with chlorides

Jan 1, 1902

E L. DEGOLYER, our new president, though a petroleum geologist by profession, has always s been associated with mining, for soon after his birth at Greensburg, Kan., on Oct. 9, 1886, his parents moved to Joplin, and when he went, in the course of time, to the University of Oklahoma, he intended to follow his course there with another at a mining school. He became a field assistant in the U. S. Geo-logical Survey, however, while still an undergradu-ate, and after field experi- ence in Montana, Wyoming, North Dakota, Colorado and Oklahoma, he went to Mexico as geologist for the Mexican Eagle Oil Co. This was in 1909, and as a result he was unable to complete his work for his degree until 1911. In Mexico, he located the Potrero de Llaño No. 4, one of the world's largest oil wells, and also the dis- covery well in the Naran- jos pool; and the Colorado School of Mines conferred the honorary degree of : Doctor of Science on him in 1925. On his return from Mexico, he engaged in the consulting business, specializing in financial ap- praisement, the Union and Marland companies being among his clients. In 1919, he organized the Amerada Petroleum Co., with the backing of Lord Cowdray. Last year, control of the company was purchased by an American group, headed by Dillon, Read and Co. Mr. DeGolyer is n o w president of the company. He is also vice-president and general manager of the Rycade Corp, the Rycade Oil Corp., and president of the Geophysical Re-search search Corp. The l a t t e r represents the practical appli-cation of his inter-est in the use of the torsion balance in the locating of salt domes, in which he has pioneered, the Nash dome being the first oil field in America actually brought into production by these methods.

Jan 3, 1927

By John A. Mathews

It is twenty years since the writer made his first molybdenum steels and others were making them commercially five years earlier but the prevailing opinion seems to be that molybdenum steels are new; from time to time the daily press speaks of important discoveries in Europe and intimates that American steel makers have much to learn in regard to alloy steels. The earlier experiments were largely confined to the use of relatively high percentages of molybdenum in tool steels and permanent magnet steels. Recent developments deal with the types of alloy structural steels used for airplane, automobile, and other engineering requirements; in these, the molybdenum content is usually less than 1 per cent. The earlier types generally have been unsuccessful commercially, but the newer types of steels are becoming of increasing importance. The war showed our dependence on foreign sources for alloying metals; molybdenum alone is widely distributed in the United States and seemingly abundant. Many deposits are not now of commercial interest, owing to location and relatively small amount of ore available, but other deposits are being developed and a stable source of supply seems well assured. In tool and magnet steels, it was early found that 1 part of molybdenum was equivalent to from 2 to 2.5 parts of tungsten. The permanent magnet steels investigated by Madame Curie,' in 1898, contained from 3.36 to 4.05 per cent. molybdenum; in 1902, Dr. E. L. French and the writer thoroughly tested steels containing from 2.0 to 4.0 per cent. These steels gave satisfactory tests for permanence, but were low in residual density and much more sensitive to hardening than the corresponding tungsten products. We discontinued work with them, therefore, and have no advice that such steels have been used commercially here or abroad. Prior to the development of the Taylor-White process and the modern high-speed steels, air-hardening steels were in general use. These were

Jan 1, 1922

By Kenneth L. Adams

10.3-1. Introduction. Equipment replacement or maintenance is of major concern to every company today. It can be the difference between an efficient and profitable operation or an inefficient and struggling one. Mining equipment, as everyone knows, will not last forever. Some equipment becomes obsolete before it wears out while some may be doing its intended job, yet not economically. It is a major problem for management to make the decision as to whether a piece of equipment should be repaired or replaced. There are numerous approaches to this problem; using formulas, charts, and graphs. These would be very good if all conditions were stable. Since conditions and requirements are constantly changing, an accurate observation cannot be derived from a set formula. A formula does, however, serve as a reminder to include most of the items that should be considered when evaluating old and new equipment. In the field of mining there are several questions which enter into the reasoning that are difficult to put into an equation. Some of these are: 1. Will the present equipment produce the required output of the mine, or an increase if necessary? 2. Are reserves adequate to support the purchase of new equipment? 3. Can the old equipment be repaired to efficiently continue the mining operation? 4. What is the stability of future markets for the product? Depreciation rate, or the write-off life, is a factor that can directly effect decisions on replacement. If the initial life expectancy is too long and the price of equipment is not written off when discarded, then the original investment has not been recovered. If the write-off time is too short, then the equipment is written off before replacement is even considered. In this case, the depreciation accrual is usually used to finance some other phase of the operation. In view of the increasing prices, the amount of depreciation fund is generally too small for much incentive to replace an older unit

Jan 1, 1968

By Albert McIntosh

One of the most interesting as well as important factors connected with the petroleum industry is the consumption of motor fuel. A few years ago we always spoke of "gasoline," but when natural gasoline and benzol became more important it seemed desirable to include all of these products in the petroleum statistics and so there was adopted the term "motor fuel," which embraces these three products in their entirety. Gasoline always included all stove and motor gasolines, high-grade naphthas, cleaning naphthas, solvents, varnishmakers' and painters' naphtha and gas-machine gasoline. "Motor fuel" includes all of these products also; therefore, technically the term "motor fuel" is incorrect, but as the total quantity of these non-motor naphthas is small their inclusion does not distort the results to any appreciable extent. When the Federal Oil Conservation Board appointed its first semiannual forecasting committee early in 1930 to project the demand for gasoline and crude oil into the year 1930, it was necessary for that committee to formulate a method of forecasting. It adopted the system in use by some of the oil companies at that time, of using automobiles and per-car consumption. Six months later the American Petroleum Institute also formed a committee for forecasting, which adopted the committee principle of asking each member to produce his own forecast of demand by any method he thought best and to give a full explanation to the committee. The result of the latter method was to get the benefit of as many different methods of forecasting demand as there were members. The writer does not recall any two members ever using exactly the same method. By studying the different forecasts and their methods, there evolved a composite opinion, which was presented to the industry as the committee's estimate. The same method has been followed by the American Petroleum Institute or Planning and Coordination Committee ever since.

Jan 1, 1935

By G. W. Healy

G. W. Healy (union Carbide Metals 0.)-The author's paper is a useful contribution to the store of maps of chemical activities of oxides in multi-component slag systems. It is also a good example of the utility of the Gibbs-Schuhmann technique for calculating activities in a system where that of one of the components has been measured. This paper Koh and Caugherty. This plot is reproduced by alor in X-ray Metallography. Because of this nonlinearity, preparation cf suitable standards and/or correction for absorption and enhancement are essential in microanalysis. However, our objection is not the conclusion that Dr. Aaronson has arrived at nor the technique he has used; but only to the foot-note credited to V. Macres. The level of chromium that he was concerned with (less than 3 pet) is so low that the deviation of uncorrected Cr-curve will be negligible. Besides Dr. Aaronson has used chromium intensity from martensite and set it equal the bulk chromium content of the alloy. Using this chromium-intensity as a reference, he has calculated the amount of chromium in the ferrite. This amounts to the same as using an internal standard. Since the chromium content in austenite and ferrite are almost the same, enhancement due to iron in both will be the same and therefore does not need to be corrected. together with the author's recently published one1 on the CaO-FeO-Fe2O3 system will be most helpful to others learning to apply Schuhmann's method, which merits a far wider application than it has received to date and should greatly aid our understanding of equilibria between metal and oxide phases. As shown by okcen" its use may even be extended to sections of systems with any number of oxides. I have some questions as to the selection of equilibrium constants made by Dr. Turkdogan. He has chosen one for the formation of Fez03 from FeO and oxygen which gives Fea3 activities 50 pct higher

Jan 1, 1963

By A. B. Kinzel

MUCH work has been done recently in an attempt to analyze the physicochemical mechanism involved in the production of steel by the open-hearth process. . This has resulted in reducing the process to a series of interrelated phenomena obeying the usual laws of mass action and diffusion. Of these, the reaction of the iron oxide and carbon in the molten steel is of most interest from a technical point of view as it con-stitutes the main action in the usual steelmaking processes. A. L. Feild1 has formulated a basic differential equation expressing the open-hearth reactions and Hefty has done considerable experimental work on the determination of a number of constants involved in the basic open-hearth reaction. In considering the application of the law of mass action. to the reaction FeO +C ?? CO +Fe, the iron will be taken as constant, as is the case in the open hearth and the carbon monoxide pressure will be assumed' constant at one atmosphere. From this xy = m at equilibrium, where x is the percentage weight of carbon, y percentage weight of iron oxide and m the weight-concentration equilibrium constant. While it is customary for physical chemists to express equilibrium constants in terms of molar concentrations, the constant is here expressed as the product of the percentage-weight concentrations for ease of comparison with the constants quoted by Herty and by Feild, and for more ready applicability to the open-hearth reactions. Herty and his associates have attempted to calculate the value of this constant from data on open-hearth heats. So many variables affect these results that an adequate calculation presents very great difficulties. A value of 4 X 10-2 was first arrived at, but this was later changed to 1.6 X 10-2. Feild, in order to illustrate the operation of the differential equation of the open hearth, has assumed a value considerably lower than Herty's, namely, 1.0 X 10-2, the largest value consistent with certain theoretical

Jan 1, 1929

By H. M. Merry

The graphic methods and records described in this article have been developed, with satisfactory results, for the use of executives of the Chino Copper Co., in Hurley, N. Mex. Particular attention is directed to the use of large wall-charts, the quick reference display of large charts, the scale notation of metallurgical charts shown in Pig. 3, and the inclusion of mesh extraction on screen analysis diagrams. To properly comprehend the operation and metallurgical results from a concentrating plant, a daily record of essential data is kept, usually involving the dry weight of ore milled or treated, dry weight of concentrate or metal produced, assay values of heading, assay values of tailing, assay values of concentrate, and percentage of extraction or recovery. In addition it is often necessary to record moisture, pulp density, or dilution, percentage of weight of oils and reagents employed; screen analyses of grinding conditions, oversize, etc.; assay values of non-valuable or interfering substances; cost data; and such special information as may be required. GRaphic Presentation . Close analysis is necessary of a daily operation involving such a number of factors, the relation and influence of which may be of great importance in the treatment scheme. When the analysis is made from a numerical tabulation, the chance for one or more obscure, but perhaps important, factors to escape notice is considerable, therefore the need for an accurate, readily digestible presentation of metallurgical data is obvious.. Graphic records of milling operations are frequently used, but owing to the wide range of magnitude and values, and the number of factors involved, the customary practice of assigning different values to the same ordinates, as in Fig. 1, results in a complex and intricate record which makes little appeal to a busy operating official. The methods shown in Figs. 2 and 3 are devised to display such data in a clear and legible manner, without confusion.

Jan 1, 1920

By Theron Wasson

Michigan produced 16,637,000 bbl. in 1937. This makes it a record year in the history of Michigan's oil industry. During the year 953 wells were completed; 779 within the limits of established fields and 174 wildcats; 616 new oil wells, 68 gas wells and 269 dry holes. Table 1 has been arranged in alphabetical order of field names. Production figures for 1936 have been corrected because December figures were estimated. In this year's summary, December production is based on actual reports. The Leaton and Mt. Pleasant fields have been re-defined. Mt. Pleasant production north of the south line of Denver township, Isabella County, has been included with Leaton in accordance with usual practice in Michigan. The locations of fields discovered since the last map was published1 are shown in Fig. 1. Activity during 1937 Buckeye Field.—The Buckeye field of Gladwin County was the center of greatest activity during the year and was responsible for the increase of 4,700,000 bbl. over the state total for 1936. Buckeye produced 6,428,-000 bbl. in 1937. In this field 328 producing wells were completed during the year—over one-half the oil producers drilled in the state. Buckeye was subject to voluntary and cooperative proration from April 1 to the end of the year. Other pools of the state were not prorated. The new production at Buckeye is from porous Dundee limestone of Devonian age, similar to the older fields. Other New Fields.—The Sherman field was second in importance as a source of new production, with a total of 1,532,000 bbl. Salem township, Allegan County, on the southwest side of the Michigan Basin, was developed during the year. Production at Salem is from the Traverse limestone at a depth of 1600 ft., and 52 producing wells have been drilled in this pool. Other active pools were Clayton and Adams townships, Arenac County. The Bentley pool, discovered in October 1937 southeast of

Jan 1, 1938

By C. S. Trewin

ZINC, in its wrought form, is produced commercially in rolled strip, sheet, wire, rod and tubing. Wire has been made periodically, but due to the fact that slight drafts are necessary, the cost of production is greater than for the more common non-ferrous metals which are made into wire. Notwithstanding the cost, zinc wire has certain special uses for which it is particularly adaptable. Rod has been made both by rolling and extrusion, the product, however, has not indicated great commercial value. Tubing has been made from strip from time to time by forming a strip around a mandrel and either electrically or gas-welding a longitudinal joint. Recently a tube manufacturer has succeeded in making a fair quantity of this material. Its commercial adaptability is still to be determined but anyone who desires it can obtain quantities of the smaller sizes. Inasmuch as strip and sheet are commercially the most important, this paper will be devoted to these products. In the broader sense, zinc is not alloyed. That is, there are no combinations comparable to the various copper, aluminum and nickel alloys. It has been recognized,, for some time, that the lead and cadmium occurring with commercial zinc have some effect on its properties and such alloys as may be said to exist are those made from zincs containing varying amounts of lead and cadmium with a relatively low iron content. The foreign rolled zinc will analyze higher in lead than the domestic grades. A representative foreign analysis will run 1.1 per cent. lead, 0.07 per cent. cadmium and 0.02 per cent. iron. The American grades vary from zinc approximating high grade. and analyzing 0.08 per cent. lead, 0.002 per cent. cadmium and 0.015 per cent. iron, to the lower grades in which the lead will vary from 0.3 to 1.0 per cent., cadmium from 0.10 to 0.5 per cent. and the iron in the neighborhood of 0.02 percent.

Jan 1, 1927

By R. B. Schluter, M. M. Fine

Development of a process for winning copper from pelletized chalcocite concentrate is underway at the Bureau of Mines, Twin Cities Metallurgy Research Center. The new route from concentrate to metal by which the Bureau seeks to eliminate matte smelting and converting includes a two-stage fluid bed treatment. In the first stage, pelletized concentrate containing 32%Cu and 7% S is first desulfurized to less than 1.0% S in an oxidizing atmosphere. In the second stage, the calcine is metallized by reduction with hydrogen. Thereafter, the reduced product plus 10% CaO is routed to a smelting furnace which separates metallic copper from the gangue. Recovery and Cu content at this point are in the 97-98% range. This product must be refined to remove sulfur and iron so the metal is suitable for making wirebar copper. An important feature of the process is fine concentrate pelletization prior to fluid-bed treatment. This permits a shorter reaction time, a decrease in dusting and easier subsequent processing. In a broad sense, sulfide copper pyrometallurgy is a batch sequence in three separate vessels, i.e., a reverberatory furnace to yield matte copper, a converter to produce blister copper and another reverberatory furnace to produce fire-refined copper. Matte-smelting has remained relatively unchanged since it became a universal practice some 50 to 60 years ago. It is now serving a wide range of smelter feed materials, but many concentrates are not immediately amenable to the process. There are abundant copper resources which lack sufficient sulfur and other elements lo sustain the full chemistry involved in matte-smelting. This necessitates adding sulfur to make the product fit the process, and usually none of the sulfur is recovered. From the standpoint of pollution alone, the development of a smelting technique for low-sulfur concentrates not requiring the addition of sulfur would be a significant gain.

Jan 1, 1970