Search Documents

By Claus G. Goetzel

SOME of the reactions and procedures upon which modern techniques in the production of metal powders are based were used for 2000 years by the ancients to reduce iron and other metals from their ores. Despite this, however, the art of powder metallurgy is relatively new and probably stems from the introduction of incandescent electric lamp filaments. Attempts to improve upon Edison's carbon filaments led to the production, in order. of metallic filaments of osmium. tantalum.. and finally of tungsten, which ha, replaced the others and is the commercial product of today. These metallic filaments were originally manufactured by the extrusion and sintering of a mixture of the metal or its oxide with a reducing agent which also served as a binder. Further progress in this direction was in the pressing of a small percentage of nickel with the tungsten. The sintering operation was carried out in an atmosphere of hydrogen, at a tem-

Jan 1, 1944

Jan 1, 1966

By Bieniawski, Z. T.

The importance of understanding the phenomena associated with rock fracture has long been fully appreciated in rock mechanics. This is clearly apparent from the special attention paid to rock fracture in the comprehensive papers published within the past four years. These papers present a picture of how the knowledge of brittle fracture of rock was gradually enriched and also show that what was often taken for granted three or four years ago is no longer considered as valid today.

Jan 1, 1972

By W. A. Hockings, D. W. Fuerstenau, A. L. Mular

This paper briefly describes a simple air pycno-meter and its use for rapid determination of the composition of mixtures of solid particles. Research on such problems as the pelletizing of solids, the mixing of solid particles, and the comminution of mixtures can be simplified by means of this analytical tool. THEORY OF OPERATION Liquid pycnometers1 are commonly employed to measure volumes. These devices are time consuming and sometimes give inconsistent results. The liquid used in the pycnometer may have an undesired influence on the material to be measured; moreover, complete displacement of air by the liquid is seldom

Jan 1, 1963

By T. K. Smith

The comments contained in the discussion of the paper concerning the prediction of fracture gradients are of considerable interest, since the subject is of a very controversial and timely nature. It is regrettable and Fairhurst2 contradicts the author's statement in the third paragraph of Other Applications. These references create significant doubt that Eaton's Eq. 1 predicts fracture pressure during the injection of fluid into old wells. 3. No evidence is presented in this paper to support the author's Conclusions 2 and 3. While an empirical coefficient related to back-calculated field data is correlated with depth (Eaton's Fig. 4), there is no reason to suspect that this coefficient might be the Poisson's ratio of the various formations involved. 4. Until the field data supporting the empirical approach proposed by the author are presented and evaluated, the accuracy claimed in Conclusion 5 is without substantiation. References 1. Geertsma, J.: "Problems of Rock Mechanics in Petroleum Production Engineering", Proc., First Intl. Symposium on Rock Mechanics, Lisbon (1966) 585. 2. Haimson, B. and Fairhurst, C.: "Hydraulic Fracturing in Porous-Permeable Materials", I. Pet Tech. (July, 1969) 811-817. that the comments are those of a critic and do not offer an alternative and better method for the prediction of fracture gradients. Nevertheless, a reply is in order.

Jan 1, 1970

By Ray W. Ballmer

"For his leadership in developing and managing large, complex, and technically innovative mines, particularly the outstanding and successful Bougainville mine and for his lecture, 'The Moving Targets of Mine Development '. " Recipient of the 1981 D. C. Jackling Award

Jan 1, 1982

By Richard A. Hawkins

O the American coal man, Australian coal mining most appear to have little, if any, influence on American coal-mining practice and to bear little relation to it. Actually, the relationship has been close, for Australian operators have carefully studied American practice by reading American technical publications, by consulting American engineers, and by visits to Ameriean operations. They have leaned heavily on America for their supply of mechanization equipment and many American mining-machinery manufacturers are active in that country, supplying its needs and furnishing technical assistance. Australia's influence on American coal mining has been obscure and probably negligible. However, it seems reasonable to assume that this influence will increase. The wartime development of air transportation will inevitably bring these two countries into much more intimate contact than existed in recent years. American servicemen. many of them former miners and coal-mining technicians, have visited Australian operation, while stationed in that country, have talked with operators and men over there, and undoubt-

Jan 1, 1945

By K. Heindlhofer

Estimates of the "plasticity" of a metal are commonly deduced from three types of test—tensile, torsion and impact. The several results have been more or less at variance, though this disparity has attracted little notice, largely perhaps because they have been expressed in different terms. The discrepancy between the results of the three tests becomes obvious when each is made at a series of low temperatures, for the temperature range within which the "plasticity" of iron largely disappears proves to be very different in the three types of test. The rather abrupt disappearance of "plasticity" of iron within a narrow temperature range cannot be due to any physicochemical change (such as a precipitation) taking place in the material at that time, because the original plasticity is immediately regained when the temperature of the material is brought above the sensitive range. Accordingly this difference in behavior shows that the "plasticity" of a metal depends upon the mode of action of the stresses which produce the deformation, and therefore upon the method of test. Analysis of the stresses leads to the conclusion that the observed plasticity of a metal is determined by the relation between its resistance to rupture by separation and its resistance to shear (slip), on the one hand, and between the effective normal and shearing stresses on the other; and that the relation between the two resistances does not in general remain constant with change of temperature, and may somehow be altered to some extent by the previous treatment of the specimen. This suggests the view that the results of none of the usual mechanical tests are directly comparable even for a single metal tested at a series of temperatures, or for a series of metals at one temperature, because the proportion of the total resistance of the metal to the test contributed by the

Jan 1, 1935

By K. Heindlhofer

Estimates of the "plasticity" of a metal are commonly deduced from three types of test—tensile, torsion and impact. The several results have been more or less at variance, though this disparity has attracted little notice, largely perhaps because they have been expressed in different terms. The discrepancy between the results of the three tests becomes obvious when each is made at a series of low temperatures, for the temperature range within which the "plasticity" of iron largely disappears proves to be very different in the three types of test. The rather abrupt disappearance of "plasticity" of iron within a narrow temperature range cannot be due to any physicochemical change (such as a precipitation) taking place in the material at that time, because the original plasticity is immediately regained when the temperature of the material is brought above the sensitive range. Accordingly this difference in behavior shows that the "plasticity" of a metal depends upon the mode of action of the stresses which produce the deformation, and therefore upon the method of test. Analysis of the stresses leads to the conclusion that the observed plasticity of a metal is determined by the relation between its resistance to rupture by separation and its resistance to shear (slip), on the one hand, and between the effective normal and shearing stresses on the other; and that the relation between the two resistances does not in general remain constant with change of temperature, and may somehow be altered to some extent by the previous treatment of the specimen. This suggests the view that the results of none of the usual mechanical tests are directly comparable even for a single metal tested at a series of temperatures, or for a series of metals at one temperature, because the proportion of the total resistance of the metal to the test contributed by the

Jan 1, 1935

By A. M. Gaudin

This year the American Institute of Mining, Metallurgical and Petroleum Engineers has chosen to give me its Robert H. Richards Award, a distinction which is widely regarded as the highest honor in the field of mineral engineering. I am deeply moved by this tribute, which suggests not only regard for my service to the profession but also the affectionate esteem of my fellow mineral engineers. You have made me happy at the prospect of the permanent association of my name with that of Robert Hallowell Richards and of the distinguished recipients of the award, Arthur Fay Taggart, Frank R. Milliken, John F. Myers, Edward William Englemann, C. Harry Benedict, Edward W. Davis and Arthur W. Fahrenwald. I wish to thank you all for an honor so generously bestowed. Professor Richards is known to us all as a legendary figure, and we can read about him in the Richards Memorial Volume of our Transactions. Some of us have even had the good fortune of knowing him. I count myself among those lucky few. In its intangible attributes the Award recalls those things for which Professor Richards stood: for Science in Art, for thoroughness, for meticulous accuracy, for bold imaginativeness, most of all for professional integrity. Now, as in his day, these attributes are central to an engineer's creed. They are appropriately needed in a formulation of a definition of the mineral engineering profession.

Jan 6, 1957

By Scott Tzcrner

WITHIN recent years people have begun to realize the importance and significance of the mining and allied industries. The leading part the engineer plays in civilization is becoming recognized. However accurate quantitative knowledge of the industrial importance of mining is still seldom possessed except by those close to this business. It is true that there are a few who go to the extreme and represent the whole progress of civilization as a reflection of man's gradual mastery of mineral utilization, but on the whole, the magnitude of the-industry is underestimated. In this paper I shall call attention briefly to the importance of mining in the United States, in Canada, and in the world. Ordinarily, the annual primary mineral production of the United States is about $5,500,000,000. The average for the last 5 years has been a little over that, but last year, sadly enough, it was less than 31/4 billion. Just now, we are on the decline, and have been for the last two years. In Canada, the 5-year average was about $268,000,000, and last year it was 227 million. Due in part to gold mines (in 1930, for the first time, Canada's gold production exceeded that of the United States), the Canadian average is holding up better than ours. Average world mineral production over the last -5 years has been estimated at about $12,000,000;000 whereas in 1931 it was less than than 8 billion.

Jan 1, 1932

By J. Jones-Parra, R. S. Reytor

The porosities of fractured limestone reservoirs can be divided into two broad types in accordance with their effects on fluid distribution and fluid flow. In the coarse porosity, gravity segregation lakes place freely and the resistance to fluid flow is very small. In the fine porosity there is no segregation and a high resistance to flow, and it has relative permeability characteristics similar to tight sandstones. By analyzing the affect of the two porosities it is concluded that in some cases to recover the maximum amount of oil it is necessary to remove large quantities of gas from the reservoir by producing at high gas-oil ratios. In this manner the fine porosity is drained of its oil and the gas-oil contact drops slowly permitting higher production rates from the oil leg. Since this conclusion is contrary to widely accepted principles of conservation, a mathematical model (Fig. I) was constructed to duplicate the conditions desired. The behavior of the model indicates that under certain conditions it is possible to recover more oil by producing at high gas-oil ratios than by production at low gas-oil ratios, and that the rate of production is affected more by gas shut-offs than by the decrease in pressure (Figs. 2, 3, 4 and 5). INTRODUCTION It has been noted that certain limestone reservoirs behave in such a way as to indicate that there are two distinct types of porous spaces available for fluid storage and fluid flow. Regardless of the nature of these porous spaces the distinguishing characteristic is that in one type of porous space there is definite gravity segregation between the oil and the gas; while in the other, the gas evolved tends to remain distributed equally throughout the reservoir. For the sake of simplicity the porosity in which gravity segregation takes place at a fast enough rate to affect the behavior will be called "coarse po- rosity", while that in which this is not so will be termed "fine porosity". The behavior of a reservoir of this type would be different than that of a sandstone reservoir, especially if most of the oil is in the fine porosity. It has been observed that fluid flow to the wells takes place mostly through the coarse porosity. The large fractures which

By Cleland N. Conwell

Coals are found in all parts of Alaska, ranging in geologic age from Carboniferous to Tertiary, and grading from lignite through anthracite. Only the Matanuska and Nenana coal fields have been extensively developed. Nenana Field Today roughly 94% of the coal mined in Alaska comes from the Nenana field near Healy. The coal-bearing horizons in the Nenana field are found in a sedimentary sequence of Tertiary age approximately 2800 ft in thickness. The sediments rest directly on schists of possible Precambrian age. Individual coal beds in the field have been designated by both letters and numbers, starting with the alphabetical designations from A to G, and the numbers 1 to 6. Of these coals, the principal beds that are mined are F, 1, 2, and 3. These vary greatly in thickness, e.g., bed 1 ranges to over 50 ft, and beds 2 and 3 to 30-40 ft.

Jan 10, 1972

By F. H. McDowell

The increasing interest in the subject of electrical separation warrants the addition to what has already been written of a few lines covering the practical workings of the Tilly Foster mill under the direction of Mr. E. S. Moffat, General Manager. Since my last paper was presented to the Institute, Mr. S. P. Tomkins, the superintendent, has had thrust upon him for solution several problems complicated by the introduction of new conditions. 1. The richer portion of the lean ore dump, and that nearest the railroad track, having been worked up in 1890, the handling of the balance, including a largely increased amount of rock, could only be accomplished at an increased cost. 2. The tailings had accumulated close about the mill to such an extent that arrangements had to be perfected to move them further away.

Jan 1, 1893

By Paul M. Tyler

THE winning of metals from Nature has been advanced to a degree of efficiency that commands admiration even in this Machine Age. Economy of human effort underground, in surface plants, and in treatment works, and better means of performing all manner of operations have cut costs and im¬proved products to an extent that seems far beyond the wildest imagin¬ings of those that labored in the days of hand mining and muscular metallurgy. Principles and methods borrowed from other professions and sciences - mechanical engineering, chemistry, and physics-all have con¬tributed to the rapid development of ore production and treatment, but no small part of the achievements must be credited to the free exchange of ideas within the industry itself and mass attack upon problems of mutual concern. The esprit de corps or class consciousness that has contributed so effectively to the progress of the metal industries has been less apparent among nonmetallic mineral producers. As a class they have been handicapped by inadequate contact with the metal-mining fraternity as well as among themselves.

Jan 1, 1935

ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Member, technical graduate, aged 36. Experienced copper metallurgist and mining geologist. Familiar also, through 15 years' broad practical experience, with mining, cyanidation, concentration (including oil flotation), metallurgical accounting, and mine and plant management. Best references. No. 237. Member, graduate engineer with 10 years' experience in malleable, gray -Iron, and steel, as chemist., metallographist, and metallurgist. Researches and investigations by laboratory methods and under works conditions. No objection to some routine. No. 243. Member, technical graduate, broad experience in coal, oil, and clay. Will go anywhere as mining geologist after Sept. 1, 1915. No. 244. Member, technical graduate, aged 30, married, with over 10 years' experience as chemist, engineer on construction, superintendent and general superintendent of bituminous coal and coke plants. SpeaksSpanish. References. No. 245. Member, open for engagement as mine safety inspector or as superintendent of bituminous coal mine. No. 246. Member, graduate mining engineer, with five years' experience in coal mining as mining engineer, construction engineer, pit boss, and superintendent, open for engagement. Best references. No. 247.

Jan 9, 1915

By G. Reinberg, C. D. Clarke

Most underground mining operations are dependent on pumping installations to keep the mine unwatered. The reliability of such installations is obviously of paramount importance. The volume of water to be handled is often considerable, and the total head is relatively high. In these cases, both capital cost and operating expense of the pumping installations will become significant factors in overall mining costs. To insure reliability and to keep efficiencies, and hence operating costs, within acceptable limits it goes without saying that mechanical maintenance of a mine pumping installation must receive scrupulous attention at all times. Large mine pumping installations today almost invariably use multistage centrifugal pumps, since positive-displacement units would not be economically competitive except under very unusual conditions of small volume combined with extremely high heads. Centrifugal pump maintenance, under ideal circumstances, would be confined to parts subject to normal running water, i.e., bearing surfaces, stuffing box packing, and shaft sleeves. Under adverse conditions, however, metal may be lost from the wetted surfaces of a pump by erosive or corrosive action of the pumped fluid, and maintenance costs can easily attain enormous proportions.

Aug 1, 1956

By T. C. M. Pillay, John Chipman

The Si-0 equilibrium in liquid iron was investigated in some detail by Gokcen and Chipman1 who reported equilibrium constants of the following reactions: In each case the thermodynamic equilibrium constant K was obtained by extrapolating K' to infinite dilution. Their results on reaction [I] were consistent with those of earlier observers, and there seems to be little doubt as to the approximate validity of the equilibrium product determined. On the other hand, the results on reactions [2] and [3] indicated unusual curvilinear relationships between the activity coefficients of silicon and of oxygen and the silicon concentration. Since a linear relation is observed in all other similar instances, it was concluded that some source of error had affected the gas-metal equilibrium relationships. Recently the authors undertook a restudy of these equilibria with the view especially to establishing the equilibrium constant of reaction [2]. Their experiments, however, were discontinued before a tbroughly satisfactory answer had been obtained and consequently have remained unpublished until the present time. Quite recently Matoba, Gunji, and Kuwana2 published the results of a very thorough study of these equilibria. It is the purpose of the present note to Compare these three sets of experimental data, a comparison which leads to Confirmation of the results of Matoba and coworkers. The experimental arrangements described by Dutilloy and Chipman were employed. A controlled mixture of Hz, H,0, and argon was led into the induction furnace over the surface of the Fe-Si melt contained in a silica crucible. On account of the slow approach to equilibrium, runs were continued for at least 8 hr and, in some cases, as much as 12 hr. Samples were taken by means of silica tubes at the start and during the final 4-hr period of each run. Out of twelve runs only seven appeared to have approached equilibrium with sufficient certainty to be reported here. The results of these experiments, all at 1600°c, are shown by the triangles in Fig. 1. Equilibrium was approached from both oxidizing and reducing conditions and the direction of approach is indicated by the shape of the triangle. Attempts to extend the study to higher silicon concentrations were unsuccessful on account of the transfer of silica from the metal bath to the upper portions of the crucible by means of a silicon-monoxide mechanism. Matoba, Gunji, and Kuwana used similar methods and approached equilibrium from both sides. Their results at three temperatures are shown by the solid lines of Fig. 1. A line corresponding to 1600 deg is interpolated from their equations and is shown by the dotted line. The results of Gokcen and Chipman at 1600 deg in the range 0.02 to 2.0 pct Si are also shown. At concentrations up to about 0.6 pct Si, these investigators approached equilibrium from both directions, and their results in this range appear to be trustworthy. Above 1 pct Si, however, all of their experiments involved oxidation only, as shown by a decrease in the silicon content of the bath. It now seems certain that they failed to reach equilibrium at these higher silicon concentrations and that the curvilinear relation shown by their results is incorrect. It is evident that their results in the lower silicon range are in good agreement with those of Matoba and coworkers. In fact, a straight line drawn through their results would parallel the dotted line and would differ from it by only 0.05 in log K. The new data also lie close to that line. It may thus be concluded that the three sets of data are in good agreement and that the equations proposed by Matoba and coworkers for reaction [2] are satisfactory . They take the limiting value of log K', at 0 pct Si as log K ,. The slope of each line gives the value

Jan 1, 1962

By W. P. Haynes

ESTIMATED United States crude-oil production during 1943 established a new annual peak of 1,500,000,000 barrels, a daily average of 4,118,000 barrels. This would be an increase of 315,000 barrels per day, or 8 per cent over 1942 and 7 per cent over 1941, the previous peak. During the first ten months of the year, production jumped from 3,782,000 barrels per day in January to 4,400,000 in October. Available data for the last two months of the year indicate a leveling off of this trend, with daily rates slightly above 4,400,000 barrels.

Jan 1, 1944

By Dudley L. Davis, E. C. Peterson

INTRODUCTION THE Darwin District is 30 miles east of Olancha which is 220 miles north from Los Angeles via U. S. Highway No. 6. The ore deposits occur in the Darwin hills that have been elevated above the Darwin Plateau by typical basin and range-type faults. Some of these faults have been active quite recently as shown by the displacement of Quaternary (?) basalt flows and the rejuvenation of erosion in Darwin wash. The ore bodies occur as fissure fillings and replacement of favorable beddings in a thick series of Paleozoic limestones, dolomites, shales and quartzites. Rich oxidized lead-silver ores were discovered in the early seventies. By 1875, Darwin had a population of about 5000, and by 1880 several small mills and smelters had been built. Early exhaustion of surface ores, the isolated location of the district, and fluctuation of metal prices caused intermittent operations until World War II. The district production is estimated at about $3,000,000 prior to 1900 and perhaps $4,000,000 between 1900 and 1945 when Anaconda purchased the major producing mines. For the past two years, daily production has averaged 75 tons of direct shipping and 150 tons of milling-grade ore. At present, 300 tons of mixed oxide and sulphide ore are treated by flotation, the oxidized lead minerals being activated by addition of sodium sulphide after galena and sphalerite have been recovered from the circuit. Extraction averages 85 pct of the lead, 80 pct of the silver, and about 33 pct of the zinc in a bulk concentrate. The mill is designed so that minor changes permit selective flotation of pyritic lead-zinc ores encountered at depth. GENERAL GEOLOGY The oldest rocks in the Darwin hills are a series of Paleozoic limestones, dolomites, shales and quartzites probably Pennsylvanian in age. These rocks have been intruded on the west by the Coso granite batholith and on the east by a granodiorite stock. Numerous sills and dikes grading from orthoclase granite to gabbro are exposed in the underground workings. The sedimentary rocks have been considerably folded and faulted, the most prominent structure being a northwest pitching anticlinal fold, the crest of which lies just west of the ridge line of the Darwin hills. The east limb of this fold has been intruded by the granodiorite stock and east of the stock the sediments show several closely spaced anticlines and synclines. The minor flexures on the west flank of the major fold are structurally important in localizing the ore in the Defiance and Essex mines of the Darwin group. There are three principal systems of faulting and fissuring, most of which are post-intrusive and premineral in age, with minor amounts of postmineral movement. The Darwin tear fault is the largest, most persistent fault in the district. It strikes N 60 to 95°W, dips steeply south and is traceable for about 1o miles. It is a normal

Jan 1, 1947