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[A discussion suggested by the paper of Mr. James Gsyley on " The Development of American Blast-Furnaces," read at the New York meeting of the Iron and Steel Institute, October, 1890, and reprinted from the Journal of that Society in Bans. A. I. M. E., xix., 932.1 (Cleveland Meeting, June, 1891.) [Kote by the SecretaRy.—The three following contributions to this discussion were communicated by letter to the Secretary of the Iron and Steel Institute, and were received by me too late for insertion in vol. xix. of the Transactions.] FRed. W. Gordon, Philadelphia, Pa.: Mr. Gayley's paper calls our attention to the very expensive blunder hitherto made in blowing too much wind in a given size of furnace. It was quite evident from an analysis of blast-furnace operations that the work we are doing in America is anything but creditable. We were consuming fully 1000 pounds of coke more than is necessary for each ton of iron made, and were hammering the linings of our furnaces out in a very short time, and nothing but the very high price of pig-iron would stand the drain. It had long been my pet scheme to gradually reduce the quantity of air, at the same time increasing the burden to the maximum and decreasing the limestone, and determining, if possible, the fuel economy which might be reached consistently with the maximum production of the furnace. After the success of the Isabella furnace at Pittsburgh, which was remodelled in 1880, the North Chicago Rolling Mill Company had

Jan 1, 1892

By R. E. H. Pomeroy

EARLY in 1917, it became evident, owing to existing and pending market conditions, that a substitute for crude petroleum must be found for firing the smelter furnaces. After a review of the plants then existing, it was deemed advisable to depart from their practice and to adopt the following described system of distributing pulverized coal to the furnaces. The principal advantages of the proposed system, which influenced this decision, were: (1) Equal safety; no pulverized coal is stored at the furnaces; (2) greater ease of operation, furnace fires being controlled by regulating valves in burner branches, as in gas firing; (3) better organization; all machinery, including pulverized coal feed, is under one roof, and the organization is separate from the furnace department; (4) greater cleanliness; all machinery is under vacuum; (5) greater flexibility of application; the coal and air mixture can be piped where needed. The design of the plant is the result of the combined efforts of the local engineering staff and of the machinery manufacturers. Many new features were embodied in this design to insure greater safety, cleanliness, and efficiency of handling. After 14 months of continuous operation, the plant has proved entirely satisfactory. The building is of structural steel, covered with corrugated steel, with many windows and is painted light gray inside and out. The building floor is of concrete with ample drains to the sewer, and the building is equipped with fire and service water piping. Fig. 1 shows the east side of the building and the incline conveyor from the raw-coal bins.

Jan 2, 1920

By Wei-Kao Lu

A general rate equation is derived for gas -solid reactions in metallurgical processes by considering the contributions of chemical reaction at inter-phase boundaries and diffusion through the solid product layer simultaneously. This equation takes care of the whole range continuously from purely diffusion control to purely chemical reaction control. The parabolic law,' McKewan's equationa derived with the assumption of interface area control and the equation derived by Kawasaki et al. with the assumption of purely diffusion control are found as the limiting cases of the corresponding forms of the general rate equation. Many metallurgical processes involving gas-solid reactions have been extensively studied. The common examples of these processes include the reduction of oxides to metallic products, the roasting of sulfides to oxides or chlorides and the oxidation of metals. Gas-solid reactions consist of at least two kinds of steps; one involves the transport of reactant and product to and from the reaction zone and the other is the chemical reaction taking place at the interphase boundaries. In the limiting cases one or the other of the above mentioned steps will be much slower than the other and is then rate controlling. For example, the oxidation of metals is diffusion controlled and obeys the parabolic law.' On the other hand, if the diffusion rate is much larger than the chemical reaction rate then it will be controlled by the chemical reaction rate. This latter case occurs for the reduction of iron oxides studied by McKewan. If the rate of diffusion and of the chemical reaction have the same order of magnitude, a more detailed analysis is necessary. Thus at the beginning of the reaction when the solid and gaseous reactants are in direct contact, the reaction should be chemical reaction rate controlled as no diffusion process is involved. At the other extreme as the reaction zone moves further into the solid, the diffusion distance becomes greater and the diffusion rate continuously decreases. Eventually, therefore, for a sufficiently large sample the rate must become diffusion controlled. As the transition from one controlling step to the other must be continuous, we cannot describe this transition period by either of the two limiting cases. In this paper the author attempts to derive a general rate equation for gas-solid reaction systems. This is effected by considering the rates of diffusion and chemical reaction simultaneously from the state of pure diffusion control to pure chemical reaction control. I) DERIVATION The system under consideration is made of at least three phases, namely the gaseous one, the solid reactant, and the solid product as shown in Fig. 1. The notations are listed at the end of the paper. The mass transfer process involves the diffusion of reactants and products across the solid product layer. It is reasonable to consider that no chemical reaction will take place in the solid product layer with respect to both gaseous reactant and product. For the characteristics of local equilibrium of the system, the diffusion process is really in a quasi-steady-state. It will be proved in the following paragraphs. Then we can invoke the law of conservation of mass valid for all chemical species passing through the layer. The solid reactant sphere has an initial radius, ro, after a fraction of completeness of the reaction, the unreacted core has a radius ri, where r, is in the solid product region. Let Cg be the activity of gaseous reactant in the

Jan 1, 1963

By A. L. Holley

The occurrence of this gas, in quite appreciable quantities, has been observed for many years in its escape along the creeks of Western Pennsylvania, and more recently, in much larger quantities, from the oil wells in and near Venango County. Within about five years several gas wells have been struck, from which the gas has escaped continuously in prodigious quantities and at great pressure. During the last year a systematic attempt has been made to utilize the flow of gas from one of these wells, and results have been reached which were quite unexpected. This well, near Leechburg, Armstrong County, is about twenty miles northeast of Pittsburgh, on one of the side tributaries of the Alleghany River. It had been drilled in search of oil to a depth of 1250 feet in 1871, but none was found. A great flow of gas was developed, however, accompanied by a slight spray of salt water, and this has continued with little or no diminution to the present time. The gas in its escape has been discharged through a 5-inch pipe, and at a pressure of from 60 to 80 Ibs. per square inch, but no exact determinations, either of the pressure or quantity, have been made. The rolling mill of Messrs. Rogers & Burchfield is on the opposite side of the river, and it has been for some years devoted to the production of fine grades of sheet iron from charcoal pig metal, by puddling and in knobbling fires. The usual weekly product of the mill has been 30 tons of No. 30 tin plates, and 50 tons of No. 24 to 28 sheets. The well was bought by this firm for $1000, and the gas is led across the river, a distance of about 500 feet, through a 3-inch pipe. It is distributed through half-inch pipes, and at a pressure of about 45 Ibs. per square inch, to several of the furnaces, but a large fraction of the total flow of gas is still wasted at the well. No essential alteration in any of the furnaces has been found necessary in the use of the gas fuel, except to brick up the firebridge and to put in the gas and air pipes. The old grate used for coal is loosely covered with bricks and cinder, so that a slight percolation of air may take place through them. The gas is admitted through a half-inch pipe, and blows toward the fire-bridge through 18 or 20 one-eighth inch jets. The air is blown in at about 2 lbs.

By H. F. Yancey, M. R. Greer

At the annual meeting of this Institute held two years ago a new method1 of estimating the grindability of coal was described, based on experimental work carried on by the Bureau of Mines at its Northwest Experiment Station. Since that time, several organizations concerned with the testing or utilization of coal as pulverized fuel have adopted and used the method in determining the grindability of several hundred samples of coal. In addition, a series of comparative tests of this method and three others has been carried out in five laboratories under the auspices of Committee D-5 of the American Society for Testing Materials. As a result the Committee has recommended that the Bureau of Mines method, designated as the "ball-mill method," and the Hardgrove method2, previously advanced, be accepted as tentative standards3. Since the ball-mill method was originally developed and published, an opportunity has been presented to apply it to a larger number of coals and to study intensively some of the principles upon which the method is based. This paper presents a résumé of these further studies and includes a comparison with the Hardgrove-machine method. Trial runs were also made with another procedure recently proposed—the C.I.T. roll-test method4. Principles of Methods In the ball-mill method, the relative amounts of energy necessary to grind coals to the same fineness are determined by the number of revolutions of the mill required to reduce 80 per cent of the feed (500 grams of 10 to 200-mesh coal) fine enough to pass a 200-mesh screen. This is a

Jan 1, 1936

By H. F. Yancey, M. R. Greer

At the annual meeting of this Institute held two years ago a new method1 of estimating the grindability of coal was described, based on experimental work carried on by the Bureau of Mines at its Northwest Experiment Station. Since that time, several organizations concerned with the testing or utilization of coal as pulverized fuel have adopted and used the method in determining the grindability of several hundred samples of coal. In addition, a series of comparative tests of this method and three others has been carried out in five laboratories under the auspices of Committee D-5 of the American Society for Testing Materials. As a result the Committee has recommended that the Bureau of Mines method, designated as the "ball-mill method," and the Hardgrove method2, previously advanced, be accepted as tentative standards3. Since the ball-mill method was originally developed and published, an opportunity has been presented to apply it to a larger number of coals and to study intensively some of the principles upon which the method is based. This paper presents a résumé of these further studies and includes a comparison with the Hardgrove-machine method. Trial runs were also made with another procedure recently proposed—the C.I.T. roll-test method4. Principles of Methods In the ball-mill method, the relative amounts of energy necessary to grind coals to the same fineness are determined by the number of revolutions of the mill required to reduce 80 per cent of the feed (500 grams of 10 to 200-mesh coal) fine enough to pass a 200-mesh screen. This is a

Jan 1, 1936

By David B. Brooks

Identified potential resources of lead and zinc are lower, relative to reserves, than the same ratio for other metals, Either there is little material below present grades or, if it exists, there are no data on it. The author examines both these factors in detail, and also introduces a third possibility. In their 1961 monograph, The Future Supply of the Major Metals, Bruce Netschert and Hans Landsberg noted that identified potential resources (that is, known but submarginal resources) of lead and zinc were much lower relative to reserves (that is, known and supermarginal resources) than was the same ratio for other metals.' Put another way, it seemed that for such metals as iron, manganese, copper, and aluminum, slightly more favorable economic conditions or modest advances in technology would greatly increase reserves by permitting the exploitation of vast quantities of leaner or deeper or otherwise less valuable mineral deposits. But for lead and zinc, Netschert and Landsberg concluded that either: "(1) there is relatively little material below present cutoff grades; [or] (2) such material exists, but for some reason there are no data.'12 This situation, which they called "the lead-zinc anomaly'' has been subsequently discussed by other authors. The purpose of this paper is to carry the discussion further by examining the evidence in favor of (1) and (2) and by advancing a third alternative. There are at least two reasons for devoting time to the lead-zinc anomaly. First, while it is unlikely that we shall have to turn to alternative lead or zinc resources in the near or middle-term future, the longer run resource picture for the two metals is not so certain.3 Both within the United States and for the world as a whole, new discoveries will have to come at a fair pace to keep up with growing rates of consumption. Thus, it is important to see whether there exist lower grade or nonconventional potential sources of two such useful metals that we could turn to at some time in the future. The second reason for studying the lead-zinc anomaly is also related to resource adequacy, but is of more general significance. Depending upon whether the anomaly is technologic, geochemical, spatial, or temporal in origin, we shall be able to draw some conclusions about the resource picture for other metals. Can we expect the apparent pattern of lead-zinc resources to be repeated? If so, will technologic advances in either exploration methods or mineral processing be able to alter the pattern? Or is the pattern unalterably set by geochemical distribution? Most important, are metals characterized by what seems to be an anomaly, different in any way from metals for which low-grade or nonconventional sources already have come to be exploited, as the porphyry deposits have for copper. In sum, investigation of the lead-zinc anomaly represents a case study combining both physical and economic aspects that may open up a neglected area in evaluating mineral resource adequacy. WHAT IS THE LEALLZINC ANOMALY? There are two dimensions to evaluations of the potential of any mineral resource? The first involves the degree of certainty that we ascribe to the estimate: how much do we know about the size of the resource as a result of geological mapping, exploration, and mine development? This dimension is expressed by the terms measured, indicated, and inferred reserves (and, if you wish, 'undiscovered reserves'), all of which terms carry with them the implication of exploitability under current cost-price conditions. The other dimension to evaluations of a mineral resource involves the economic limits of the estimate: how will the size of the resource vary with different (usually more favorable) cost-price conditions? (This economic dimension should be understood broadly to include all factors bearing on the cost-price relationship. In this sense it subsumes technology because any resource is exploitable at some cost; the role of technology is to bring cost down.) The latter dimension is expressed in the terms potential or sub-marginal 'ore,' and is logically quite independent of the former. For example, we have relatively good measurements of the tonnage of manganese in low-grade deposits in this country, though they are too lean to be considered reserves; on the other hand, we are much less certain of our measurements of new lead and zinc deposits in Missouri, though there is no question but that there is a sizable reserve. Thus, it may be uncommon but is not a contradiction to talk of measured submarginal ore or inferred potential ore.

Jan 1, 1968

A. MALINOVSZKY,* Belleville, Ill. (written discussion?).-I have been very much interested in Mr. Dolman's paper. We all realize, I think, that this question of developing our home industries and support-ing the new industries which have developed during the great war is very important at present. Mr. Dolman has well shown the quantity and quality of the raw magnesite in the United States, and the commercial and industrial possibility of our home magnesite and I believe, with him, that our home industries should receive adequate protection. There are two reasons, however, for believing that this may be difficult. One reason is that much American capital is invested in the Austro-Hungarian magnesite industry. The raw magnesite can be quarried and prepared for the market in Austria with much cheaper labor expense than in the United States; large deposits which are very easy to quarry and good transportation facilities also contribute to the cheapness of production. The second reason is the old saying that the magnesite found in the United States is not of the same quality as the Austro-Hungarian mag-nesite; this I doubt. Even if the magnesite found here does not in a raw state equal the Austro-Hungarian, it can be synthetized so that the finished article will have the same properties as the Austro-Hun-garian finished magnesite refractory possesses. Thaw magnesite from Greece is not the same as the. Austro-Hungarian, but it has linen demon-strated that a good refractory can be made from the Greek product.

Jan 10, 1919

By Albert E. Greene

Processes for the removal of phosphorus from iron or steel are steadily assuming greater importance in view of the abundance of high-phosphorus iron-ore and the diminishing supply of pure ore. In the present methods of removing phosphorus by the basic open-hearth or basic Bessemer process, or even by electric processes, complete control over the metallurgical conditions is either impossible or has not yet been realized. The removal of phosphorus has so long been accomplished along certain well-defined lines, that when the electric furnace made its appearance metallurgists adhered to the same old reactions used in the older processes and failed to appreciate and take advantage of the new forces at their disposal. One object of the present paper is to set forth more clearly the metallurgical reactions by which phosphorus can be removed from iron, and to show the necessity of controlling the conditions, and particularly the temperature, by means other than combustion in the furnace-chamber. Invariably, the commercial removal of phosphorus has been accomplished by oxidation. The reactions involved in oxidation of phosphorus in general consist, first, of the formation of P2O5 and second, the combination of this oxide with lime, forming calcium phosphate, which latter is held in a slag high in iron oxide. In the present-used processes, the phosphorus is never removed without the assistance or presence of considerable quantities of iron oxide. The oxygen for removal of phosphorus in the basic open-hearth process comes largely through the medium of iron oxide and furnace-gases, but not

Jan 1, 1913

By Colman Goldberg

IT is customary to plot crystallographic planes or axes on a Wulff stereographic net which is ruled with parallels of latitude and meridians of longitude. If a single crystal is placed at the center of a sphere, the coordinates of a crystallographic plane or axis are the coordinates of the point where the axis intersects the sphere. The standard (HKL) projection is the projection for which the sphere is rotated so that the (HKL) pole is at the center of the projection. Schiebold and Sachs' and many others have published standard projections for the more important planes of a cubic crystal. With Tables I and 11, it is possible to plot any plane (HKL) of a cubic crystal on a standard (001) projection if the absolute values of the individual H, K, and L are nine or less, which is almost always the case. Using the methods outlined by Barrett,' the standard (001) projection can be rotated so that any arbitrary plane is at the center of the projection. The tables are believed to be important for two reasons: 1—The heretofore published standard projections usually are not of the proper size to fit the stereographic nets available. With these tables a standard projection can be made which will be of exactly the proper size for the available stereographic net. 2—With the tables, planes that do not appear on the previously published standard projections can be easily plotted. For these reasons, the tables are especially useful in the study of optical reflections from etched surfaces and can also be used to make a standard projection for the axis which is normal to the macroscopic surface. (This axis can be found by X-ray or optical methods.) Then if the crystal is etched, the effect of the etchant can readily be determined by comparing the latitude and longitude of the reflecting planes (as determined with an optical goniometer) with the standard projection that has been prepared. Use of the Tables Fig. 1 shows the meridians and parallel which have been designated as zero longitude and latitude. The tables themselves are self-explanatory. The

Jan 1, 1953

By AIME AIME

LEWIS EMANUEL YOUNG was elected a Director of the A.I.M.E. at the last Annual Meeting as a representative of District '4, including. Ohio, West Virginia, and western. Pennsylvania and New York. He also represents the Coal Division, in which industry lie has actively participated- for nearly twenty years. Dr. Young was horn in Topeka, Kan., Oct. 1, 1873, received mining degrees from Penn State and ,-Iowa. State, and a Ph.D., from Illinois. The first part of his professional life was spent in teaching first as instructor in mining at Iowa State, second .as professor of mining at the Colorado School' of Mines, third as director of the School of Mines and Metallurgy at Rolla, Mo., and finally he taught business

Jan 1, 1937

By James J. Bean

HE task of measuring the specific gravity of the -*- operating medium in a heavy-media separation system has never presented a particularly difficult problem because the medium is fairly stable and the overflow of the separatory vessel, as well as its underflow, can be sampled easily and accurately and the specific gravity of the suspension determined easily by weighing a known volume. However, while this method is simple and accurate it does require the operator to take the sample by hand and to weigh it and there is considerable temptation to avoid the periodic sampling if everything seems to be going well, or if something is occupying the attention of the operator. Furthermore all operators do not sample in exactly the same manner and considerable practice is required for two operators to be able to "check" each other to the last few hundredths, particularly if the sample is cut underneath the drainage screen where location of the point of sampling and load on the screens tends to influence the determination. While none of the above presents much of a problem, we have all recognized that some mechanical method of continuous measurement and recording would be advantageous since the operator would merely have to glance at the meter to check the gravity and to have an indication of the trend of any changes. Also if the instrument were of the recording type, a permanent record would be available for the guidance of the superintendent. The Eagle-Picher Mining and Smelting Co. was the first heavy-media user to actually install such a recording meter. In 1946 they installed in their Central Mill at Cardin, Okla., a specific gravity recorder manufactured by the Bristol Co. of Water-bury, Conn. R. A. Barnes, of the Bristol Co., working with E. H. Crabtree, Jr. and Elmer Isern, of Eagle-Picher, made the application and worked out the problems of sampling and measuring. Their attempts to measure the specific gravity of the medium in the cone itself were not entirely successful and they resorted to an outside sample tube for actually making the determination. Because of the particular flowsheet used, it was possible to tap off from the medium return pipeline a stream of medium and divert it into the sampling tube, which was provided with a constant level overflow and a spigot underflow, and into which the bubbler tubes dipped. The Eagle-Picher installation was successful and its possibilities were recognized by the Mineral Dressing Laboratory of the American Cyanamid Co. It was decided to install a similar unit in the heavy-media pilot plant to investigate further its possibilities. Chief among these was the continuous record which it was felt would be proof of the steadiness of the gravity in a heavy-media cone, something which is not always appreciated by POtential users. Because the heavy-media pilot plant is required to operate at a wide range of specific gravities, it was realized that the unit would have to record all gravities from 1.25 to 3.50, and do it to the nearest 0.01. It would not be necessary to record all of this wide range on a single chart and the method selected was to have 4 bands, each band range overlapping the other a small amount and calibrated so that with standard charts one division would represent 0.01 sp gr. A shift from one band to another could be arranged without alteration of the instrument itself, being accomplished by a simple change in the bubble-tube lengths, as described later. Accordingly, a recording type instrument was purchased and installed. Because there were some advantages in doing so, the first installation attempted to measure the gravity of the cone proper by placing the bubble tubes in the cone. This was not at all satisfactory and the second scheme utilized a fixed vertical screen at the surface of the cone, and an external sample-tube arrangement. We were particularly anxious to make this work as we felt it would be advantageous to measure the top level of medium where the separation was actually being made, but we were doomed to disappointment because it was impossible to keep the screen clean of float. Since the top gravity of the cone is the most convenient place to sample for control, a launder about 2 in. wide was installed longitudinally beneath the

Jan 1, 1951

By James J. Bean

HE task of measuring the specific gravity of the -*- operating medium in a heavy-media separation system has never presented a particularly difficult problem because the medium is fairly stable and the overflow of the separatory vessel, as well as its underflow, can be sampled easily and accurately and the specific gravity of the suspension determined easily by weighing a known volume. However, while this method is simple and accurate it does require the operator to take the sample by hand and to weigh it and there is considerable temptation to avoid the periodic sampling if everything seems to be going well, or if something is occupying the attention of the operator. Furthermore all operators do not sample in exactly the same manner and considerable practice is required for two operators to be able to "check" each other to the last few hundredths, particularly if the sample is cut underneath the drainage screen where location of the point of sampling and load on the screens tends to influence the determination. While none of the above presents much of a problem, we have all recognized that some mechanical method of continuous measurement and recording would be advantageous since the operator would merely have to glance at the meter to check the gravity and to have an indication of the trend of any changes. Also if the instrument were of the recording type, a permanent record would be available for the guidance of the superintendent. The Eagle-Picher Mining and Smelting Co. was the first heavy-media user to actually install such a recording meter. In 1946 they installed in their Central Mill at Cardin, Okla., a specific gravity recorder manufactured by the Bristol Co. of Water-bury, Conn. R. A. Barnes, of the Bristol Co., working with E. H. Crabtree, Jr. and Elmer Isern, of Eagle-Picher, made the application and worked out the problems of sampling and measuring. Their attempts to measure the specific gravity of the medium in the cone itself were not entirely successful and they resorted to an outside sample tube for actually making the determination. Because of the particular flowsheet used, it was possible to tap off from the medium return pipeline a stream of medium and divert it into the sampling tube, which was provided with a constant level overflow and a spigot underflow, and into which the bubbler tubes dipped. The Eagle-Picher installation was successful and its possibilities were recognized by the Mineral Dressing Laboratory of the American Cyanamid Co. It was decided to install a similar unit in the heavy-media pilot plant to investigate further its possibilities. Chief among these was the continuous record which it was felt would be proof of the steadiness of the gravity in a heavy-media cone, something which is not always appreciated by POtential users. Because the heavy-media pilot plant is required to operate at a wide range of specific gravities, it was realized that the unit would have to record all gravities from 1.25 to 3.50, and do it to the nearest 0.01. It would not be necessary to record all of this wide range on a single chart and the method selected was to have 4 bands, each band range overlapping the other a small amount and calibrated so that with standard charts one division would represent 0.01 sp gr. A shift from one band to another could be arranged without alteration of the instrument itself, being accomplished by a simple change in the bubble-tube lengths, as described later. Accordingly, a recording type instrument was purchased and installed. Because there were some advantages in doing so, the first installation attempted to measure the gravity of the cone proper by placing the bubble tubes in the cone. This was not at all satisfactory and the second scheme utilized a fixed vertical screen at the surface of the cone, and an external sample-tube arrangement. We were particularly anxious to make this work as we felt it would be advantageous to measure the top level of medium where the separation was actually being made, but we were doomed to disappointment because it was impossible to keep the screen clean of float. Since the top gravity of the cone is the most convenient place to sample for control, a launder about 2 in. wide was installed longitudinally beneath the

Jan 1, 1951

By R. B. Gilmore

It has been the custom of the Railroad Commission of Texas to hold hearings each month with respect to existence and imminence of waste of oil and gas in Texas and its prevention, and to issue orders restricting the production of oil to the reasonable market demands and allocating production to the various fields in Texas. The practice of designating the actual days during the month on which wells are to be shut down was discontinued in the order for November 1942, and orders issued thereafter contain only the number of shut-in and producing days for the month. Orders issued by the Railroad Commission are divided into two main subdivisions, the first a general shutdown order of all oil wells in the various fields in Texas, and second, the exception of certain fields to this general order. Table I shows the producing days for all of the fields in Texas for 1944 under the first of these classifications : The fields that have producing schedules varying from the general order may be divided roughly into three subdivisions, as follows: Table 2 shows the producing days for certain fields that were prorated as a group throughout 1944. Other fields which were occasionally included with this group were also prorated under the general order and by special orders. The producing days for these irregular fields are shown in Table 4. In Table 3 are listed fields that were exempted from any shutdown days during December 1944, the majority retaining this exception throughout 1944. Certain fields included in the general order were added to this group on the first day of the month shown.

Jan 1, 1945

By Arthur Crowfoot

As a result of work done, on an operating scale, in its experimental mill during 1920 and 1921, the plan here given was proposed for crushing, grinding, and concentrating low-grade sulfide ores at the Morenci Branch of the Phelps Dodge Corpn. The flow sheet is designed to recover 85 per cent. of the total copper and 95 per cent. of the sulfide copper from ore assaying 2.0 per cent. total copper and 0.3 per cent. acid soluble copper. At present, 1400 tons are treated daily under the conditions of this flow sheet, two 700-ton units having been installed in the 4000-ton concentrator. The run-of-mine ore will be reduced, in the dry-crushing plant, to —6 mesh and then delivered to the concentrator feed bins. The crushing will be done in three stages: (I) Run-of-mine ore is reduced to —2 1/2-in. in a gyratory crusher; (2) the 3-in. ore is reduced to 1/2-in. in 72 by 24 in. rolls; (3) the 1/2-in. ore is reduced to — 6-mesh size in 54 by 24 in. rolls. The 54-in. rolls will operate in closed circuit with electrically vibrated screens, "Hum-mer" type, a conveyor circuit being used to carry the roll product to the screens. Sufficient screens will be installed to pass 1.5 tons undersize per hour per square foot. Fine-ore bin chutes will be piped for compressed air, which will be used intermittently to keep the ore feed in motion if it tends to arch or pipe in the bins. The Concentrator The concentration of the copper and iron sulfides in the ore will be effected in three stages: I. By direct treatment of the —6-mesh crushing-plant product on primary tables, which will recover about 35 per cent. of the original copper content of the ore in a clean granular concentrate. The table middling will be dewatered in Dorr rake classifiers and ground to — 48-mesh in ball mills operating in closed circuit with circulating classifiers.

Jan 1, 1923

By Arthur Crowfoot

As a result of work done, on an operating scale, in its experimental mill during 1920 and 1921, the plan here given was proposed for crushing, grinding, and concentrating low-grade sulfide ores at the Morenci Branch of the Phelps Dodge Corpn. The flow sheet is designed to recover 85 per cent. of the total copper and 95 per cent. of the sulfide copper from ore assaying 2.0 per cent. total copper and 0.3 per cent. acid soluble copper. At present, 1400 tons are treated daily under the conditions of this flow sheet, two 700-ton units having been installed in the 4000-ton concentrator. The run-of-mine ore will be reduced, in the dry-crushing plant, to —6 mesh and then delivered to the concentrator feed bins. The crushing will be done in three stages: (I) Run-of-mine ore is reduced to —2 1/2-in. in a gyratory crusher; (2) the 3-in. ore is reduced to 1/2-in. in 72 by 24 in. rolls; (3) the 1/2-in. ore is reduced to — 6-mesh size in 54 by 24 in. rolls. The 54-in. rolls will operate in closed circuit with electrically vibrated screens, "Hum-mer" type, a conveyor circuit being used to carry the roll product to the screens. Sufficient screens will be installed to pass 1.5 tons undersize per hour per square foot. Fine-ore bin chutes will be piped for compressed air, which will be used intermittently to keep the ore feed in motion if it tends to arch or pipe in the bins. The Concentrator The concentration of the copper and iron sulfides in the ore will be effected in three stages: I. By direct treatment of the —6-mesh crushing-plant product on primary tables, which will recover about 35 per cent. of the original copper content of the ore in a clean granular concentrate. The table middling will be dewatered in Dorr rake classifiers and ground to — 48-mesh in ball mills operating in closed circuit with circulating classifiers.

Jan 1, 1923

Discussion of the paper of O. P. Hood, presented at the Pittsburgh meeting, October, 1914, and printed in Bulletin No. 94, October, 1914, pp. 2607 to 2611. R. V. Norris, Wilkes-Barre, Pa.-I have had a little experience with gasoline locomotives and I want to indorse very strongly Mr. Hood's point with regard to the danger of carbon monoxide poisoning. I think .the terrible danger is not fully realized. I was foolish enough some time ago, in investigating a gasoline locomotive, to attempt to walk out of the mine entry behind it, and for several days I felt very seriously the carbon monoxide effects. The use of gasoline locomotives ought to be confined to mine entries where there is a very large amount of air. One of the grave dangers is their great convenience and the temptation to run them into chambers for just a few moments to get a car or two. GEORGE S. RICE, Pittsburgh, Pa.-Apparently one of the great dangers is in the style of the gasoline engine. When my attention was. first directed to the type of gasoline locomotives which I saw in the foreign mines-France, Belgium, and Germany, I was most favorably impressed with them, and they have given no trouble on account of fumes, so far as I could learn. Large numbers of them were being used, but all were of small capacity, and of a kind in which the speed control is by a governor of the hit-or-miss type, the engine running continuously. Their power capacity was very low, if I remember correctly it was not over 4 or 5 h.p., but they were used under favorable conditions where the grades in the mines were slight, since the entries or tunnels bad a slight grade in favor of-the load, making about the same pull for the empties against the grade as for the load with the grade. I understand the hit-or-miss valve arrangement enables a setting that will give more perfect combustion than can be insured with the valve controlled by the operating man, as in the automobile type of valve and engine used in this country. Apparently the European type of locomotive does not have the capacity to permit use under the conditions existing in this country, where most of our entries or tunnels have variable grades and long heavy trips of mine cars are used.

Jan 4, 1915

By H. H. Rachford, and J. D. Rice

The effectiveness of digital computing machines in making technical calculations depends on how well the work is arranged to utilize the capability of the machines. This note presents a particularly useful way of calculating hydrocarbon vapor-li.quid equilibrium in the flash vaporization (or condensation) system. The method is well suited to sequence-controlled computing equipment. It is not limited to equilibrium calculations and may be used for solution of most implicit equations in one variable. INTRODUCTION There is increasing interest in the use of electronic digital computers in research and engineering calculations. This is a fortunate and inevitable trend in view of both the increasingly extensive numerical work which is becoming a routine part of many daily production operations and growing demand for the overwhelming amounts of calculations required by newly developed numerical methods for solving heretofore unsolved problems. Machines are in many ways ideally suited to the task but of necessity present certain difficulties. for a particular poblem to be solved must often be formulated quite differently from the way it would be arranged for manual solution. This is done in order to take advantage of the inherent speed and precision of electronic computers and at the same time to limit the need for number storage to the capacity of the machine. Therefore, this note is submitted to present a general and quite powerful method of finding solutions of the frequently encountered implicit equation: F(x,y1,y2,...ya)=0.......(1) where the root, x, is to be found for a given set of y1, ... yn.. The procedure is well suited for use with computing machines, for it usually requires but little storage or programming beyond that necessary to evaluate F. HYDROCARBON EQUILIBRIUM The method is described in terms of the problem it was designed to solve, i.e., the calculation of hydrocarbon vapor-liquid equilibrium in flash vaporization. Given the composition of a hydrocarbon mixture and appropriate values of the equilibrium ratios K, to find the phase ratio and compositions in a closed system: let z, be the mol fraction of the i-th component in the mixture. If K, is the ratio yl/xl, where y, and x,

Jan 1, 1952

By L. F. Mondolfo

R301 is a clad aluminum alloy, composed of a core of a duralumin-type alloy clad with a magnesium silicide alloy. It differs from other well-known clad alloys in that the cladding and the core respond to the same heat-treatments, and therefore the cladding contributes appreciably to the mechanical properties of the material. In Table 1 are reported the compositions of the core and cladding alloy for the material used for the experiments. [ ] In clad aluminum alloys where the core contains copper and the cladding does not, at elevated temperatures the copper tends to diffuse from the core through the cladding. This fact is well known and many investigations have been conducted to determine the features of this diffusion.1-7 Most of those investigations cover materials clad with pure aluminum; the present investigation covers a material clad with an alloy. Since the cladding thickness on R301 varies with the gauge, as shown in Table 2, several gauges were investigated. [ ] MATERIAL AND PROCEDURE The material used was sheet of the following gauges: 0.025, 0.040, 0.064, 0.102, 0.170. Cut in pieces approximately 3 by 5 in., it was in the cold-rolled state and was soaked for increasing times at the following temperatures: 910°F., 940°F., 970°F. A Lindberg cyclone furnace was used for the experiments. The procedure was as follows: The furnace was started empty with controlling pyrometer set at the determined temperature. After the furnace had reached that temperature, it was run for some 20 to 30 min. empty, in order to allow the temperature inside to become stabilized. Then the first samples were introduced. A load thermocouple, with recording pyrometer, was connected with the sample of the heaviest gauge. About 10 min. was required for the material to reach temperature and the soaking time was counted from that point. After 200 min. soaking, the second group of samples was introduced without stopping the furnace. After 200 min. more, the third group of samples was introduced, and so on, until the last sample had been introduced. Every time the furnace was opened and new samples were added, a drop of temperature was registered by the thermocouple connected with the material

Jan 1, 1945

ALABAMA Anniston. Carrington, F. G. Ashland.-Herr, I. Auburn.-Brown, R. L. Bessemer.-Abbott, C. E. Dobbs, G. G. Ferguson, V. Salmon, H. S. Schaber, C. F. Birmingham.-Adams, J. H. Aldrich, T. H. Aldrich, T. H., Jr. Allen, A. W. Ball, E. M. Bonnyman, J. Bowron, J. Bush, M. W. Crawford, G. G. Crockard, F. H.

Jan 1, 1917