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By A. M. Gaudin

A GREAT number of hypotheses has been advanced to explain the complex phenomena that are encountered in flotation. In the days of bulk-oil flotation, when a large quantity of oil was employed, it was observed that the oil-mineral aggregate floated above the ore-pulp because of its lesser density. With the advent of froth-flotation this phase of the theory had to be modified to take into account the presence of air bubbles. The reason why the mineral-bearing froth of today rises to the top of flotation cells is, of course, because the air-mineral aggregate, with whatever reagent may be associated with it, is lighter than the pulp. In an attempt to explain froth-flotation the fact has been emphasized that certain minerals are wetted and therefore remain in water; while others are not wetted and therefore become associated in preference with air. Such an "explanation" does not explain facts, it merely states them; for instance, it does not explain why minerals are wetted under some circumstances and not wetted under others. Going somewhat further, the wetting or nonwetting of minerals by water has been ascribed' to differences in the angles of contact between oil droplets and mineral surface at the surface of the minerals. This explanation, however, was abandoned when soluble flotation reagents came to replace the so-called "insoluble" reagents. Another theory, sponsored about 10 years ago by Ralston,2 involves the effects of electric charges at the surface of the minerals particles and air bubbles. This theory, unfortunately, was not developed as fully as it seems desirable.

Jan 1, 1927

By John Jermain Porter

PAGE. I. INtroduction............ 191 I1. Derivation of Formula foR Fuel-RequiRements.... 192 1. Heat Available in the Hearth........193 a. Method of Calculation..193 b. Data for the Determination of Critical Temperature.. 195 2. Heat Necessary in the Hearth ...... 197 a. To Care for Slag..197 b. To Care for Pig-Iron...198 c. To Reduce Silicon........198 d. For Other Items.........199 3. The Effects of Rate of Driving ..... 199 4. Loss of Carbon Between Throat and Hearth.....201 a. Solubility of Coke..201 b. Carbon-Loss Due to Flux....201 c. Effects of Reducibility of Ore..202 5. The Formula as Used........203 III. The LImitations of the Formula........ 204 1. Through Effects of Irregular Furnace-Work.....204 2. Through Ratio Between Heat-Requirements in Shaft and Hearth. 20.5 IV. The Formula Applied to Actual Furnace-Records,.. 209 1. Description of Furnace-Stock........ 209 2. Furnace Dam..........210 3. Application of Formula..211 4. Average Furnace-Practice..213 V. Sources of Error........... 214 VI. SuggesTions for Practical Methods of Fuel-Economy... 215 VII. Efficiency as a Factor in Furnace-Management.... 219 1. The Efficiency Principle........ 219 2. The Application to the Blast-Furnace..220 I. Introduction. The heat-balance of the blast-furnace has been a favorite subject for discussion for many years. and its study has contributed much to our knowledge. and still possesses a certain academic interest. As a means of accounting for differences in fuel-consumption, however. it has failed utterly. and it is evident that we must look elsewhere for the means of accomplishing this end.

Jan 1, 1912

By Thomas A. Edison

We have not yet begun. to realize the possibilities of automatic machinery, in part because we have not developed the designing brains, and in part because we have not sufficiently simplified industry to make possible the economical use of such machinery. The principle of the Jacquard loom, has scarcely been utilized except in weaving silk and in the player piano. It is the principle of bringing into action the various parts of a machine in accordance with a pattern traced on a steel card by perforations or as on the paper roll of a player piano. This principle gives us a control which can be applied to any kind of machine. It is a' great reserve principle for the future. But even now, with the machinery that we have at command, anyone can cut the number of employees in two, at the same time doubling his output, by installing semi-automatic or automatic machinery. And no one knows how far this process can go on. Cutting down the number of men is not just putting some poor fellows out of a job. It is increasing the number of good jobs by increasing the production per capita to a point where really satisfactory wages can be paid out of it, and this in turn- increases the amount of work required to be done and creates new jobs. Thus, cheapening in- creases the demand.

Jan 1, 1929

By Albert Sauveur

As THE years go by, names of distinguished metallurgists will be added to the list of Henry Marion Howe lecturers, and now and then an illustrious one, for to be chosen to deliver the Howe lecture will be, I do not hesitate to predict, a highly coveted honor. I pray, therefore, your indulgence, if I confess to a feeling of gratification in having been appointed the first of these lecturers. It does not follow, however, that I am losing all sense of proportion and that I have an exaggerated idea of the little I have been able to contribute to our knowledge of iron and steel. Indeed, I fully realize how small were my claims to so great a distinction. I realize, also, that those entrusted with the task of selecting a lecturer were actuated, in coming to a decision, by their knowledge of the long and intimate friendship that had existed between the leader we have lost and myself. For their generous impulse, I thank them from the bottom of my heart; and with becoming modesty, I take up my task as the first Henry Marion Howe lecturer. It would be pleasant and indeed most appropriate to devote this entire lecture to a eulogy of Henry Marion Howe and his work, but how short the time for so large an undertaking and how inadequate my qualifications! On Aug. 28, Sept. 4, 11, and 18, 1875, a series of articles appeared in the Engineering & Mining Journal entitled "What is Steel?" With one exception, these constitute the first professional paper of Henry Marion Howe. That was nearly fifty years ago, three years after graduating from Harvard University. He was then but twenty-seven years old and already his keenly inquisitive mind was actively at work. There is a touch of romance in this young metallurgist who, on entering his. scientific career, destined to be so brilliant and so fruitful, on the very threshold of it, seems to have selected as his motto "What is Steel?" Like a knight-errant of science, he started on his quest for an answer to that question, a quest which was to last forty-seven years and which death only brought to an end. And while thus engaged how many wonderful messages we received from him, each one bringing us nearer to the goal! How illuminating, inspiring and encouraging were those messages! How well-equipped he was to wrench from nature some of the secrets she so jealously guards! How broad his learning and how clear his

Jan 5, 1924

By O. U. Bradley

THE extent of losses, due to evaporation, sediment, and water, in crude oil stored in steel tanks, is a very interesting question, and particularly so at this time, when every reasonable measure should be employed to eliminate all possible losses of this important natural product. Available information on this subject is incomplete; e.g., during the development of the Cushing Field, considerable surplus oil was stored in steel tanks, but from time to time, owing to changes in weather, somelosses by evaporation and short storage room on the leases, these tanks were topped out, thus rendering inaccurate any system designed to determine the average rate of evaporation or other losses of the oil over a given period. , Furthermore, the losses, as shown by the records at the time, as a result of hasty gages, failed to take into account the temperature and gravity of the oil. Losses may be classified roughly as occurring from evaporation, presence of sediment and water, and leakage. The coefficient of expansion and contraction of crude oil, in relation to temperature conditions, is of material importance; also, the rate of evaporation is dependent upon the gravity of the oil, as the escape of the lighter hydrocarbons in fresh Cushing oil, of from 40 to 42 gravity, on a warm day is considerable, and from available records of temporary storage, it is safe to assume that a loss of 1 to 13 per cent. in volume will easily occur in light crude oil of Cushing grade over a period of. 6 months, including the summer season. The presence of sediment, water, and other impurities, in the oil will also cause, more or less deterioration in quality, particularly when the fresh production is run direct from the. gage tanks, or from the wells on the lease to steel storage, as is often the case when an oil field is being rapidly developed. The bad oil will settle to the bottom of the tanks and may be determined by thiefing and running a centrifuge test on the sample. The amount of water in the oil depends entirely on the conditions under which it is produced. Sometimes in large producing wells, with heavy gas pressure, some water may come in with the oil, particularly if the well has been drilled to the top of a water sand. Under these conditions, cut oil is often produced, which, if not settled out, is carried over into the steel tanks.

Jan 7, 1918

By AIME AIME

The Bulletin. The Bulletin of the Institute will be issued hereafter monthly instead of bi-monthly as heretofore. Among other reasons for this change, it is desired to effect thereby the earlier transmission to members of important papers, lists of candidates tin? membership, and other items of timely information. The New Haven Meeting. As already announced in special circular, the XCVIth meeting of the institute for the reading and discussion of papers will be held at New Haven, Conn., beginning Feb. 23, 1909. The Secretary of the Local Committee is Prof. J. D. Irving, Box D, Yale Station, New Haven. The program embraces visits to many interesting works in New Haven, Ansonia, Bridgeport, etc. The leading topics for discussion at the sessions will lie: The Conservation of Natural Resources; A Sea-Level Canal at Panama; and The Technical Education of Mining Engineers. But papers on other subjects also are announced. Lt is probable that a supplementary session of this meeting, will be held in New York City, at some time during March, 1909, as a joint session with other national engineering societies, for the farther discussion of the subject of The Conservation of Natural Resources. A Pacific Coast Meeting. It is now reasonably certain that the XCVIIth meeting will be held oil the Pacific Coast, including a. visit to the Exposition at Seattle, and various other points en. route going or coming, depending upon the route and program finally adopted. (lore definite information will be announced at the New Haven Meeting, or at the earliest possible date thereafter.

Jan 1, 1909

By M. G. Benz, J. F. Elliott

Otto Schaaber (Institut für Harterei-Technik, Bremen -Schönebeck, Germany)— Langenberg, Pestel, and Honeycutt gave an interesting example of the grain refining effect nonstationary magnetic fields may execute on a solidifying metal. Probably some additional comments, based on more than a decade of experience with this method of influencing crystallization, may be useful. They refer to an attempt to explain the mechanism of grain refinement by such fields, and to recent European developments which have not been mentioned in the paper. I. During studies of the temperature distribution in a metal body near the phase boundary solid/liquid, an anomaly was observed under certain special conditions: a) direction of heat transfer as horizontal as possible, b) steady state (equilibrium, i.e,, solidification resp. melting rate exactly zero). In the liquid phase, immediately adjacent to the phase boundary, the temperature was found to be constant over an appreciable distance in spite of a high value of heat transfer (40.000 to 70.000 keal/ m2h).3 Convection, which might explain this phenomenon, could not be observed. Therefore another explanation had to be sought. The assumption that a metallic melt, especially at temperatures near the point of solidification, contains some sort of atomic arrangement with a higher degree of order than the surrounding liquid, now is generally accepted. Considering the differences in energy between such an arrangement and its environs, a transport of heat even in absence of any temperature gradient is conceivable by continued formation and redissolution of regions with a higher degree of order, i.e., with lower energy level.3 At this stage, it was not necessary to postulate any special condition as to the form or size of these regions or the distance between arrangements to be newly formed and those to be redissolved. However, a simple consideration shows that an energy transfer from one region to another will only be possible without loss of energy, if the distance between will be equal to the lattice parameters, and if, secondly, crystallographic axis or planes will be parallel.4 By the way, this assumption might give a reasonable explanation of the well known orientation effect of the heat flow during solidification. Any measures to prevent columnar crystallization should act upon this ordering mechanism: a) the regions with a lower energy (higher order) should not be allowed to arrange themselves parallel to the direction of heat flow, and their growth should be disturbed; b) all conditions leading to an appreciable heat flow of uniform direction should be avoided or removed. Condition a) may be satisfied by a physical force preferably under 90 deg to the main axis of the columnar crystals (i.e., parallel to the solidification front) acting on the ordered regions; condition b) by equalizing any differences in

Jan 1, 1962

By C. Richard Honeycutt, Frederick C. Langenberg, Guenter Pestel

Otto Schaaber (Institut für Harterei-Technik, Bremen-Schönebeck, Germany)— Langenberg, Pestel, and Honeycutt gave an interesting example of the grain refining effect nonstationary magnetic fields may execute on a solidifying metal. Probably some additional comments, based on more than a decade of experience with this method of influencing crystallization, may be useful. They refer to an attempt to explain the mechanism of grain refinement by such fields, and to recent European developments which have not been mentioned in the paper. I. During studies of the temperature distribution in a metal body near the phase boundary solid/liquid, an anomaly was observed under certain special conditions: a) direction of heat transfer as horizontal as possible, b) steady state (equilibrium, i.e,, solidification resp. melting rate exactly zero). In the liquid phase, immediately adjacent to the phase boundary, the temperature was found to be constant over an appreciable distance in spite of a high value of heat transfer (40.000 to 70.000 keal/ m2h).3 Convection, which might explain this phenomenon, could not be observed. Therefore another explanation had to be sought. The assumption that a metallic melt, especially at temperatures near the point of solidification, contains some sort of atomic arrangement with a higher degree of order than the surrounding liquid, now is generally accepted. Considering the differences in energy between such an arrangement and its environs, a transport of heat even in absence of any temperature gradient is conceivable by continued formation and redissolution of regions with a higher degree of order, i.e., with lower energy level.3 At this stage, it was not necessary to postulate any special condition as to the form or size of these regions or the distance between arrangements to be newly formed and those to be redissolved. However, a simple consideration shows that an energy transfer from one region to another will only be possible without loss of energy, if the distance between will be equal to the lattice parameters, and if, secondly, crystallographic axis or planes will be parallel.4 By the way, this assumption might give a reasonable explanation of the well known orientation effect of the heat flow during solidification. Any measures to prevent columnar crystallization should act upon this ordering mechanism: a) the regions with a lower energy (higher order) should not be allowed to arrange themselves parallel to the direction of heat flow, and their growth should be disturbed; b) all conditions leading to an appreciable heat flow of uniform direction should be avoided or removed. Condition a) may be satisfied by a physical force preferably under 90 deg to the main axis of the columnar crystals (i.e., parallel to the solidification front) acting on the ordered regions; condition b) by equalizing any differences in

Jan 1, 1962

By W. D. Robertson, E. G. Grenier, V. F. Nole

The electrical, mechanical, and corrosion cracking properties of an age-hardenable Cu-Ni-Si alloy have been studied over a range of time, temperature, and deformation states for the purpose of determining the relationship between the properties and the structural state. The precifitate has been identi3ed as and the sites of preferred precipitation have been located by electron microscope studies of the structures developed by various combinations of heat treatment and plastic deformation. An extreme form of deformation banding has been observed in the aged alloy that results in high strain concentration in bands lying parallel to {111} planes. These bands are the structural paths along which transcrys-talline cracks propagate in the deformed alloy. The observations provide a basis for a general mechanism of transgranu-lar corrosion cracking of face-centered cubic alloys in terms of stacking fault probability. AMONG the age-hardening copper alloys the copper-nickel-silicon (Silnic Bronze) type is outstanding in exhibiting a high strength combined with a considerable capacity for cold working, a relatively high conductivity, and a low to negligible susceptibility to stress corrosion cracking. It is not a new alloy and it has been the subject of a number of investigations,1-5 which were made primarily to establish practical composition and heat treatment limits. The structural characteristics of the aging processes in this alloy have not previously been studied in detail. This particular investigation was undertaken to explore, in detail, and over a wide range of conditions, the properties obtainable by various combinations of working and heat treatment and to correlate structural changes with the observed mechanical, electrical and corrosion properties. MATERIAL AND PROCESSING Eight different commercial heats of the alloy were made and used in the investigation. The range of composition among the eight heats is shown in Table I. Billets, 8 by 24 in., were cast into water-cooled molds, extruded to 1.687-in. rod, and quenched in water after extrusion. Extruded material was rod rolled to 0.750 in., annealed at 1450° F for 2.5 hr, and quenched in water. Subsequent working operations were performed by tandem rolling to various sizes depending on the degree of reduction required. Final cold-working operations were performed by drawing to a uniform size of 0.187 in. diam and straightening by a roller straightening machine (Lewis). The combinations of heat treatment, working and aging that were investigated are summarized in Table 11; the various treatments were performed in the order given in each row of the table, and they will be subsequently identified by the symbols shown in the first column. SOLUTION TREATMENT All material investigated in the cold-worked condition, or cold worked prior to aging, was solution

Jan 1, 1962

By Heinrich 0. Hofman

A T THE meeting of the Board of Directors on June 24, Prof. Heinrich O. Hofman was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. Professor Hofman is best known to the world at large for his publications, and in this respect he is to this generation what Schnabel was to the previous one. The first edition of Professor Hofman's "Metallurgy of Lead and Desilverization of Base Bullion"; was published in 1893; the fifth edition in 1898. In 1913, he published his work on "General Metallurgy;" this was followed by "Metallurgy of Copper" in 1914, and a revised and enlarged edition of the "Metallurgy of Lead" in 1918. "Metallurgy of Zinc and Cadmium" is now in press. He also published, through the Massachusetts Institute of Technology, "An Outline of the Metallurgy of Iron and Steel" for students' use. Since the founding of "Mineral Industry" in 1892, he has been continuously the annual contributor on the metallurgy of lead, and all Institute members know that his contributions to the TRANSACTIONS have been liberal in the extreme. It is through this medium that the results of the extensive research work, which he has always carried on in connection with his work at the Massachusetts Institute of Technology, have been published. Of the greatest importance are his papers dealing with the formation temperatures of slags, but many other metallurgical subjects have been covered.

Jan 1, 1921

MARCH 15-Industry is rapidly snapping back from another coal crisis, other business news is in general favorable and the outlook through the Spring is by most observers considered quite promising. Most industries report comfortable backlogs of unfilled orders, department store sales in recent weeks have equalled in dollars those of the corresponding period last year, retail sales of automobiles show again over the same period a year ago, and new orders for machine tools are at the highest figures since August 1946. Orders for railway freight cars have shown a very encouraging pickup, with a total of 9385 cars in January and the N. Y. Central alone ordering 4500 in February. Construction continues very active. In January new housing starts totaled 80,000 against 50,000 a year ago and the daily average contract awards, according to the Dodge reports, were 57 pct larger. In the first 22 days of February the increase in awards was 27 pct. Lumber orders since Jan. 1 have run 22 pct above last year. All of these favorable factors bolster the opinion that the upturn in industrial output and employment which began last summer has not yet spent itself and that the setback caused by the strikes will be made up when people get back to work. Only in a few lines are there indications that primary production may be outrunning the consumption of finished goods, although inventory build-up would seem to be rather modest as the National Association of Purchasing Agents reported in February that 78 pct of its members were buying for 60 days or less. Industrial prices as a whole show no significant trend despite the continued alarm over both the immediate and the long-term possibility of inflation caused primarily by the government's increasing expenditure and its inability to balance the budget. A recent advance of 1.9 pct in primary market prices is viewed by some people as the surface symptom of renewed inflation, but even so it is more than two years since the alltime high was reached by the daily index of sensitive commodities in November 1947. Over two years have passed since prices received by farmers hit their peak and about a year and a half since all wholesale prices and the consumer price index touched their highest points in August 1948. The decline in the wholesale price index has been almost continuous, interrupted only twice by slight advances in the monthly figures from February to March 1949, and, later in the year, from August to September. Of course, this continued decline in the last half of 1949 largely reflects a downward movement in farm and food prices. Wholesale prices for commodities other than farm and food leveled out after June and now stand only slightly under the June level. Farm products are down by 22 pct from January and by 18.6 pct from August 1948. Food prices are down only slightly less. Consequently, the farm price support program is in serious trouble and has imposed a heavy financial burden on the Treasury. In those commodities other than farm products only building materials, chemicals and textiles have come down as much as the average, while housefurnishings and metals and their products have fallen hardly at all. Glancing away from the domestic front, the results of the British general election indicated a highly inconvenient situation, that public opinion there is so exactly deadlocked as to divest the victors of much ability to make forceful decisions or create significant policy. It is generally considered that another election in the near future would give substantially the same result. The British people are equally divided and the politicians are not likely to precipitate another appeal to the country until there is manifest reason to believe that external and internal circumstances have changed sufficiently to permit one party or the other to obtain a decisive verdict. Because of the lack of a clear mandate steel nationalization will likely lag in Britain. In the meantime there is considerable discussion going on as to whether the European steel industries as a whole are at a disadvantage in world competition with the American industry. An article in the "Statistical Bulletin" for January of the British Iron and Steel Federation takes issue on this point with the authors of the Geneva report, observing that they wrote before devaluation, and this particular conclusion "has been overtaken by events." The "Bulletin" also contends that the statement was in any case incorrect so far as Britain was concerned, and that it was based on scanty and insufficient evidence. To support the rebuttal a detailed and extensive comparison is made of the home prices of certain steel products in Britain and in other countries of the world. The accompanying table gives a selection of the prices published. It sets out the changed position since devaluation and since the recent increases in American steel prices. These are home market prices; no doubt in competitive export business some of the price levels could be brought closer together at need.

Jan 4, 1950

By Bradley Stoughton

PROMINENCE has been given lately in engineering circles to the question whether an organisation with manifold interests can be as effective as one with a single aim, especially if that single aim be the furtherance of affairs of moment and the welfare of engineers in general. In its earlier days, the A. I. M. E. was forbidden by its constitution to engage in non-technical public affairs, but the members altered the constitution in this respect, in the year 1912, in response to the growing demand that engineers be more human in their interests and that the engineering societies represent them in this respect. Since that time, the activity of mining engineers in public affairs has been growing rapidly, and we are happy that the Institute has been able to render very valuable economic services. Doubtless the greatest public service rendered by engineers in a recent great emergency was the work of the Naval Consulting Board, without which the U. S. Navy would never have been able to enter promptly into service upon our entrance into the war, ,and both Navy and Army would have been a long time without the munitions that came at an early date. We can never forget that this Board was established through the direct activity of the then President of the A. I. M. E., with the hearty cooperation of other national organizations.

Jan 1, 1920

POSITIONS VACANT The National Bureau of Standards needs men to fill metallurgical positions with salaries varying from $1200 to $2000, depending upon the training and experience of the candidate. Experience either in ferrous. or, non-ferrous metallurgy. Duties will be almost entirely of an investigational nature, in connection with problems of military importance. Qualified men are urged to send to the Bureau of Standards at once a statement of training and experience, names of references, acid minimum salary that would be accepted, so that they may he advised of appropriate civil service examination for which to file papers. Until further notice, such papers are received by the Civil Service Commission at any time and ratted promptly.

Jan 10, 1917

By Alan Kissock

MOLYBDENUM is thought of as one of the rarer elements, for though it occurs in almost every country of the world it is seldom found in commercial quantities. In this country, however, there is one deposit which makes the term "rare" a misnomer. There are two commercially mined molybdenum minerals: molybdenite, the sulfide, and wulfenite, a lead molybdate. Of these two only the former is of any con- sequence but wulfenite is of mineralogical interest. It is frequently associated with oxidized lead ores and particularly in arid sections. Deposits, however, are usually quite superficial. It is highly oxidized and yet it does not appear to be an alteration product for it apparently disappears below water level and I know of no case where primary molybdenite, or in fact any molybdenum whatever has been identified below these surface wulfenite occurrences. The genesis of wulfenite would make an !- interesting study.

Jan 1, 1933

By SAMUEL GOMPERS

THE name engineer makes a very strong appeal to one who appreciates the mechanism underlying the fabric of our civilization. Engineers are scouts of civilization. We send them ahead into the lone 'places-the wilderness, the jungles, the great watery expanses, to build the highways necessary for civilized man. The engineers must deal with Nature, with that mysterious dynamic thing we call "force," with materials. It is their function to direct the human activity necessary to coordinate these forces and material in order to make them serve the needs and aspirations of men. Because of my high conception of the engineering profession I was glad to accept the invitation to address The American Society of Mechanical Engineers to voice my understanding of the possibilities of your work as engineers of industry, and to suggest what seems to me the responsibility of the-engineer to the whole modern industrial system.

Jan 1, 1921

By J. McD. Porter

IN many of the old placer-mining districts are still to be found large tracts of gold-bearing gravel not suitable to be worked with a dredge, because the bed is too shallow- or the gulch too narrow. Frequently there is not enough grade to handle the gravel successfully by ground-sluicing or a bedrock flume, or it contains too many boulders to be worked successfully with the ordinary pipe or tube hydraulic elevator. In southwestern Oregon, two practical placer-miners named Ruble, after working for years trying to make money out of placer-ground containing many large boulders, invented and patented a hydraulic elevator of an entirely new type, and one . that has been found to work very successfully in flat' ground and in gravel containing many large boulders. It is a very simple contrivance. A few years ago I acquired the property near Pierce City, Idaho, known as the American placer-mine. Various attempts .bad been made to work this ground. A bed-rock flume had been installed by one company, an Evans elevator by another, and still other methods were tried on a smaller scale. All were unsuccessful. I installed a Ruble elevator, and it has proved very satisfactory. Working under 100-ft. (pipe) head, the 'ground has been handled at a cost of a little less than 8 cents per cubic yard. The conditions at the American mine are exceptionally hard, the boulders being large, heavy, and numerous. Basalt-boulders, up to a size of 16 by 18 by 32 in., have been elevated to a height of 16 or 17 ft., with a 4-in. nozzle-stream, under 100-ft. head. Boulders larger than this size are blasted. At the American mine, a foreman, two pipemen, and two laborers are-required per day of 24 hr. to operate the elevator. Several sizes of this elevator are in use, the one at the American mine being the 25-ft. size, having 25 ft. of grizzly

Oct 1, 1909

By Tilden Cummings

The extractive mineral industries share a number of common characteristics and basic problems which are completely different from those associated with manufacturing and mercantile operations. These industries now supply about 95% of the inanimate energy consumed in this country, and share with agriculture in providing virtually all of our basic raw materials. Mineral producers, like farmers, are subject to the economic hazards of fluctuating markets and prices. Unlike farmers, however, they cannot renew the productivity of the earth, but must seek continually for new sources of supply. The necessity for exploration and development of new reserves, to replace those used up by production, introduces additional factors of economic risk. These operations require the expenditure of large amounts of capital, often well in advance of any assurance of profitability. Commercial banks that understand these special problems can provide a variety of constructive financial services to the mineral industries. The history of cooperation between banks and mining enterprises has yet to be written, but there is every indication that it would encompass a period of hundreds of years. Records refer to depository and lending services by the early European private bankers involving precious metals and jewels. Many of the exploratory voyages to the Far East and the New World were organized with the financial backing of wealthy syndicates, some of which also provided banking services, in the hope of finding new sources of gold and other precious minerals. In the United States many large banks are closely identified with the development of some of the larger mineral deposits such as the Mesabi Range and the gold fields of California.

Jan 5, 1965

By Donald L. Katz

FIFTEEN years ago Dr. Manning published a paper in "Petroleum Development and Technology" on '.Fundamental Research Relating to Petroleum." He tabulated for several industries "the proportion of their present success which can be fairly attributed to the application of information and processes obtained by scientific research," giving petroleum a score of 7 compared to 100 for the electrical and coal-tar industries. Today the petroleum industry as a whole and the producing groups both have raised their score beyond the majority and are climbing toward the top. Present practices are being developed both by fundamental research and the application of the research method in field operation.

Jan 1, 1941

By L. T. Stanley

A method is described whereby the behavior of the front is approximated when gas is injected into a thick reservoir having reasonably homogeneous properties. The method is applied to the Abqaiq field of Saudi Arabia. The producing member is the Arab-D, a high-permeability calcarenite which has no continuous betlding planes. Field performance indicates the injected gas to be partially miscible with the reservoir oil because gas volume factors experienced are lower than those predicted by the gas law. Eqlrilibril~m calculations confirnz ihis and also show that the volume factor may vary appreciably, depending on the relative quantities of oil and gas in contact in the reservoir; consequently, volutnetric balances are made for the purpose of determining the behavior of the gas volume factor during injection history. The effect of gravity segregation on position and shape of the gas front is approximated by dividing the producing section into three zones vertically and tracing the movement of the average interface in each zone, with counterflow of oil and gas taking place betweell zones behind the front. This results in a gas front that advances more rapidly along the top of [he formation than along the base, producing an "umbrella" effect in cross section that becomes more pronounced as the front progresses. The calculations cover the gas-injection period of Abqaiq field history through 1958, and the position of the gas front is plotted at one-year intervals. Finally, some comparisotls between the calcrlated fronial position and the gas-oil contact as Measured by neutron logs are made. INTRODUCTION Fig. 1 is a structure contour map of the Abqaiq field. For analytical purpcses, the field has been divided into two areas designated A and B, as shown on the map. Gas injection into Area A was begun in early 1954 into two wells located near the crest of the structure on the north-south axis of the anticline. During the period covered by this paper, the average injection rate has been 122 MMscf/D with a maximum sustained rate of 160 MMscf/D. The reservoir pressure has been maintained at 2,450 psig since start of gas injection. The reservoir originally was undersaturated but, prior to pressure maintenance, the pressure was drawn below the bubble point in most of the Area A section, creating an in-place free-gas saturation of 8 per cent at the crest of the structure. The average critical gas saturation is 13 per cent established by laboratcry core tests. That the entire reservoir remained below critical gas saturation prior to gas injection is borne out by the fact that none of the crestal wells have exhibited high gas-oil ratios during production history. The Area A reservoir is a carbonate section about 200-ft thick having average porosity and permeability of the order of 22 per cent and 500 md, respectively. The productive horizon is the Arab-D member of Jurassic age and is encountered at an average depth of

By Fred C., Bond

IN CYANIDE milling, little attention has been paid to the effect of the viscosity of the mill solution on the extraction speed. The viscosity of the solution varies with the amount of dissolved salts present as impurities. These salts build up to a maximum depending on the character of the ore, the grade of cyanide used, the lime and salts added, and the impurities originally in the water. The viscosity will change from month to month and week to week as these factors vary; and that this variation affects the extraction is unquestioned, although methods for calculating it are lacking. The character of the ore is probably the most important of the four factors, as the amount of minerals present that are soluble in cyanide solution will vary constantly, and each variation affects the viscosity of the mill solution. When the cyanide consumption increases as the character of the ore changes, the viscosity of the solution will increase and the extraction will decrease, for the cyanide consumption is usually a measure of the impurities dissolved from the ore. In other words, as the difference between the total and free cyanide increases the extraction will decrease, other factors remaining constant.

Jan 1, 1926