Search Documents

By Anthony Anable

The definite trend to stricter specifications with respect to hydraulic concrete has become increasingly manifest in the last six years or so; but it remained for the vast reclamation projects of the Bureau of Reclamation of the Department of the Interior of the last few years to focus attention on this trend, and to demonstrate how thousands of tons of concrete-making aggregates can be produced continuously and automatically with a control of fineness comparable with that obtained with small samples in well equipped private and governmental laboratories. Pioneer work in this direction was done, to be sure, by private companies, notably the Kaiser Paving Co. of San Francisco, prior to the present vast public works program. Then in 1931 came the first great aggregates-preparation plant of the Six Companies, Inc. to supply construction materials for Boulder Darn1 in Nevada, and now, in 1936, the aggregates plant of the Mason-Walsh-Atkinson-Kier Co., general contractors on the Grand Coulee darn in Washington. At Boulder dam and to an even greater degree at Grand Coulee dam, sand production is recognized as probably the most important single element affecting the physical characteristics of the concrete. For in the construction of dams accurate grading of the fine aggregate has considerable bearing on the attainment of a uniform and homogeneous concrete of a high degree of workability and placeability and, at the same time, combining high density and low cement content. Low cement content is of value not only from the standpoint of ceonomy but also because the use of an unnecessarily rich concrete causes certain undesirable characteristics to develop. This paper will relate how at Grand Coulee dam methods that are more advanced than ever before are producing four sizes of gravel and a sand having a fineness modulus of 2.5-3.0. The design capacity is 1000 tons an hour. Significantly, the methods and equipment employed arc broadly those that have been used for a generation in metallurgical mills for accurately sizing and grading both precious

Jan 1, 1938

By F. Julius Fohs

As an industry approaches stabilization, greater and greater stress must be laid on its technologic progress, which becomes a prime aid in improving its condition. The oil industry is tending toward this stage and hence its engineers must be pressed into greater service to prevent stabilization and stagnation from becoming synonymous, and to supply, either by improvements in processes or by new machinery, a means of obtaining savings in raw and finished products. Thus profits can be assured warranting continued investment. It may be repeated, technology must apply a slight improvement here, a change there, or a complete renovation, to eliminate inefficiencies and make each dollar invested yield greater results. The profits of ycstcrday were made of rich strikes, of monopolized patents or processes, of control of prices and of markets. Sixty-five years of growth, of large investment, of healthful competition, and of expanding markets, have put the oil industry in the foremost rank of world industries. .Just as the railroads passed a similar period of expansion and growth, and arc being stabilized with reasonable profits, so the oil industry must take advantage of the efforts of its engineers and experts to promote its healthful growth and a better service to the people. Herein is attempted a review of recent progress in which is presented the advances in exploration, production engineering, transportation, refining and greater efficiency in uses of petroleum, with a view not only to stressing important new processes and methods, but also the problems that press for solution. This review can only touch outstanding developments of recent years, but the several Petroleum Division symposiums of our program will present details worthy of attention. Exploration Geology offers directly little new in the technique of oil-finding— major stress being laid on improvement in subsurface correlation by means of foraminifera1 studies, additions to the knowledge of which are being made, slowly but surely, and by means of mineral, and especially heavy mineral, determinations in well samples. The general application

Jan 1, 1927

By A. W. Ross, William Marsh Baldwin, T. S. Howald

The related subjects of preferred orientation, directionality in physical properties, and earing tendencies of wrought metal strip have attracted the attention of metallurgists to such an extent that in the past 20 years hundreds of researches have been published on this one general problem. The anisotropy of tensile strength and elongation have been exhaustively studied in their relationship to the occurrence of ears in cups drawn from strip'-~O.~g and, to a lesser extent: yield strength7."-l7 and stress-strain curves'5 have been investigated. Despite the tremendous fund of knowledge thus accrued, no simple quantitative correlation of directionality and earing tendencies has yet been found. In a sense, this is not surprising. The formation of ears in a drawn cup clearly is a special phase of the general study of metal flow; in particular (as will be brought out in the course of this paper), ears are due to anistropy in the rates of deformation of the metal in the radial, circumferential, and "thickness" directions of the original blank. It would be difficult to effect a correlation between caring tendency and a property that may be completely independent of the flow of metal, or at best related to metal flow in an exceedingly complex fashion. Yet, it is this correlation that has been attempted; tensile strength and elongation are attributes of metal rupture. a phenomenon that has quite admirably been shown to be distinct from the phenomenon of metal flow,21 while yield strength and stress-strain

Jan 1, 1946

By William Marsh Baldwin, T. S. Howald, A. W. Ross

The related subjects of preferred orientation, directionality in physical properties, and earing tendencies of wrought metal strip have attracted the attention of metallurgists to such an extent that in the past 20 years hundreds of researches have been published on this one general problem. The anisotropy of tensile strength and elongation have been exhaustively studied in their relationship to the occurrence of ears in cups drawn from strip'-~O.~g and, to a lesser extent: yield strength7."-l7 and stress-strain curves'5 have been investigated. Despite the tremendous fund of knowledge thus accrued, no simple quantitative correlation of directionality and earing tendencies has yet been found. In a sense, this is not surprising. The formation of ears in a drawn cup clearly is a special phase of the general study of metal flow; in particular (as will be brought out in the course of this paper), ears are due to anistropy in the rates of deformation of the metal in the radial, circumferential, and "thickness" directions of the original blank. It would be difficult to effect a correlation between caring tendency and a property that may be completely independent of the flow of metal, or at best related to metal flow in an exceedingly complex fashion. Yet, it is this correlation that has been attempted; tensile strength and elongation are attributes of metal rupture. a phenomenon that has quite admirably been shown to be distinct from the phenomenon of metal flow,21 while yield strength and stress-strain

Jan 1, 1946

TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen -The following report covers briefly some of the more important activities of the Institute during the year 1923 In my report for the year 1922, I drew attention to the falling off in membership of the Institute due to the depressed condition of the mining industry in several lines and the inability of many of our members to find profitable employment in mining or its associated branches. A number who were unemployed during 1922 established connections during 1923, but a still greater number have been forced to resign or drop their membership during 1923. Fortunately, the number dropped is not so great as in the previous year. The Employment Service conducted by the four Founder Societies bears witness to the trend in business For the young men just out of college, there are plenty of opportunities at small salaries, there are plenty of opportunities for them as laborers, but for the mature members, those of experience, there are few calls. During the last eighteen months, our Employment Service has been able to place only six of our members out of every hundred engineers for whom it has found work. Another loss which this Society has suffered, but which is not felt so keenly by our sister societies, is in its foreign members The A. I M E has always had a large foreign membership, but of recent years exchange has been so heavily against many European and South American coun¬tries that a large number of members residing abroad have been compelled to relinquish their membership. Almost invariably these members express keen regret because of the necessity that confronts them, and almost invariably the writers express hope that present conditions will not last long and that they will soon be able to ask for reinstatement. Having stated the darkest side of the picture first, it may now be drawn to your attention that in spite of these losses the number of persons applying for membership was decidedly encouraging. From the quality point of view, the membership has not gone back¬ward. The Membership Committee has declined to recommend many

Jan 1, 1923

By Robert Bell

The Tar-Sands" is the name which has been given to the extensive horizontal deposit of fine Cretaceous sand, blackened by tarry petroleum, which forms the banks of the last or lowest 130 miles of' the Athabasca river before it terminates in Athabasca lake. The Cretaceous strata, to which these sands belong, extend northwesterly from Dakota all the way to this lake and for 500 miles beyond it. The Athabasca river forms the uppermost section of the Athabasca-Mackenzie, one of the great rivers of the world. It rises on the Pacific side of the Rocky mountains, westward of Edmonton, and flows north of east to a point called Atha-basca Landing, 100 miles north of Edmonton, where it turns northward and runs about 280 miles before it falls into the west end of Athabasca lake. The section of this river-system which discharges the lake just named into Great Slave lake, is called Slave river, and below the latter lake it becomes the Mackenzie river. Along the section of 280 miles of the Athabasca river above mentioned, the Cretaceous strata consist of bluish-gray and drab-gray marls, on top, from Athabasca Landing to Drowned rapid, 110 miles down stream; then heavily bedded gray sandstones, 225 ft. in greatest thickness, underlying these, form the banks for about 40 miles further. The strata appear to be horizontal, but they really dip very slightly to the southward. At Drowned rapid, we see the first of the tar-sands resting on almost horizontal beds of bluish-gray limestone of Devonian age. In some places the limestone is associated with shaly or marly bands. Notwithstanding the great hiatus between the two series, the horizontal tar-sands lie conformably upon the almost level upper beds of the limestone wherever the two formations are seen together, all along the river, throughout a

Jan 1, 1908

By Will Coghill

As the title indicates, this paper treats of the degree of liberation of minerals after grinding. To obtain the supporting data a "tool" not commonly used by metallurgists has been employed. It is the "heavy solution." The advantages gained through its use are shown. Actual ores were employed in order to make the study concrete. The selection was somewhat incidental and happened to embrace the red iron ores of Alabama. So, any reader interested in these ores will find some of their properties described. The red ores constituted the material examined and a somewhat new adaptation of heavy solutions was the tool of examination. If either the ores or the tool interest the reader these notes may be of some value. The writer's chief interest was in the rate of liberation of locked grains. Ores are generally ground preparatory to concentration and as long as the concentrators make suitable products the effectiveness of the grinding is likely to be unquestioned. But when suitable products are difficult to make, an investigation becomes imperative. In such a case a dissection of the ore might be made to find the cause of the trouble. Such a condition of unsuitable products exists in the low-grade red iron ores of Alabama. They are difficult to concentrate. To be sure it might be said that the concentration of iron ores is a new thing and that the ore-dressing methods are undeveloped, but a glance at the industry reveals an abundance of methods and devices for almost all imaginable conditions. Concentrating machinery has not taken a part in this investigation; the use of it would have been only machinery testing, and should never precede the ore testing which consists of such methods as herein outlined. When the properties of the ores have been gleaned the machinery may be used more effectively.

Jan 12, 1926

By A. L. Holley

THERE are regularly manufactured in the eleven Bessemer steel rail mills of the United States, 119 patterns* of steel rails, of 27 different weights per yard. This list does not include patterns which, although still largely inn use, are regarded by experts as obsolete, and which would swell the number to nearly 300; nor does it include all, the patterns for which rolls are kept on hand to fill a possible demand; nor does it include extra pattern,- rolled in one finishing groove by opening or closing the rolls so as to get different weights with the same contours. The list embraces only those separate patterns which are subject to current orders. How thoroughly modern these patterns are, is shown by the fact that of the whole 119, there are but five patterns of conspicuously bad shape; all the rest more or less completely illustrate the standard features,-a heavy bead,. light web and flanges, and a good angle :to hold the fish-plate. Sixty-two per cent. of the patterns have the "Chanute" head, which was not designed until 1874.† Sixty-four per cent. of the 119 patterns are embraced under five weights per yard,; three only of these vary from standard type; there am thus 76 patterns, all of them modern and standard, to represent five different weights, for which five patterns would perfectly answer. Of the 60-lb. rails, there is only one of the pear-head type, while a dozen of the bevelled head templets cannot be distinguished from each other * From all the works 188 patterns were sent to me as standard. Of these I found 119 different shapes and 69 duplicates. † Since this paper was read I have seen at the Bethlehem Iron. Works the templet of a 68-pound Lehigh Valley rail, with the bevelled head, usually called the "Chanute" head, and marked "Templet of 1872." This is shown on Plate II. I learn that iron rails, with bevelled heads, were rolled at Bethlehem prior to 1870.

Jan 1, 1881

By A. L. Holley

THE application of scientific methods to the investigation of natural laws and to the conduct of the useful arts which are founded upon them, is year by year mitigating the asperity and enlarging the outcome of human endeavor. More notably, perhaps, are these the facts in that system of productive and constructive arts of, which engineering is the general name. In metallurgical engineering especially, within the period of our own recollection, how rapid has been the rate and how wide the scope of progress: the scientific discovery and mining of metalliferous veins; the economical separation and reduction of ores of every grade; the production and regulation of high temperatures; the varied improvements in the manufacture of iron, in saved heat and work, in uniformity and range of products ; and, most important of all, the creation and the utilization, to be counted by the million tons a year, of the cheap constructive steels. Wonderful as this range and degree of development may appear to the public eye, the close and thoughtful observer must, nevertheless, conclude that neither the profession nor the craft of engineering may congratulate themselves too complaisantly, but that they should rather acknowledge to each other the embarrassing incompleteness of the union between engineering science and art. There is a small school of philosophers whom we may designate as original investigators, men who come close to nature, who search into first principles, and who follow that scientific and therefore fruitful method by which the relations of matter and force are discovered, classified, and brought within the reach of practice. These wonderful - men do not indeed create the laws of nature, as they sometimes almost seem to, but they go up into the trembling mountain and the thick darkness and bring down the tables upon which they are written. * President's Opening Address. The discussion following this paper, and also the Joint Discussion of the Institute and the American Society of Civil Engineers, on the subject of Technical Education., are published in a separate volume.

Jan 1, 1876

By E. J. Bartosh

In the brief period from November 1936 to September 1937, the Wilmington oil field developed far beyond all expectations. Decline in some wells appears very rapid, but it is too early to draw definite conclusions, as the majority of wells are maintaining very large and steady output. Heavy curtailment in the central area, which has developed the largest wells, makes it impossible to arrive at a satisfactory estimate of decline. The field is producing oil from the Repetto (lower Pliocene) and Puente (upper Miocene) formations, which are of the same age as formations producing at Torrance, El Segundo, del Rey or the marginal fields of the Los Angeles Basin. All of these fields are underlain by schist. The Long Beach field, northeast of Wilmington, is productive throughout 3000 ft. of Repetto-Pliocene series and also approximately 3000 ft. of Miocene formations, whereas at Wilmington only 700 to 800 ft. of Repetto and 2500 ft. of Miocene formations contain oil and gas. This paper gives a brief summary of the history and development of the field to Sept. 15, 1937, showing the subsurface conditions as they exist with the field only partly developed. History of Development The Wilmington oil field, 20 miles due south of Los Angeles, adjacent to Los Angeles harbor and about midway between the cities of San Pedro and Long Beach (Fig. 7), was producing oil as early as 1932 and only came into prominence as a major oil field of Southern California in the fall of 1936, when the General Petroleum Corporation of California completed Terminal well No. 1 from the upper Miocene, at a depth of 3625 ft., for a daily production of 1500 bbl., 20" gravity A.P.I., thereby establishing discovery of the Terminal zone. As early as 1925, or during the close of the development of Torrance oil field, a number of wells were drilled in the Main Street area looking for

Jan 1, 1938

By R. V. Norris

The removal of mine-water by hoisting in tanks instead of pumping, while somewhat a reversion to the methods of the ancients, has come very rapidly into favor in the anthracite region of Pennsylvania during the past few years. In fact, so much so, that at the present time there are at least eight large collieries at which all the water is hoisted, and six more plants are in preparation. The particulars of the plants in operation and under construction, as far as decided on, are given in the tables on pages 107 and 108. Besides these, the Delaware, Lackawanna and Western R.R. Co. is constructing a hoist of large capacity for a depth approximating 500 feet, to be located in the Keyser Valley, near Scranton. The hoists will be driven by electric motors, geared directly to the sheaves. The Lehigh Valley Coal Company is planning a large hoist for the Packer collieries in the Shenandoah district, but no work has been done on this as yet. The earliest regular hoisting, I believe, mas done by means of semi-cylindrical tanks (Fig. 1) at the Nanticoke collieries of the Susquehanna Coal Company. These tanks were attached under the regular shaft-carriages, taking in water through six large clack-valves in the bottom, and discharging through an endgate opened by a lever which was operated by a guide-piece on the shaft head-frame. These tanks were designed July, 1880, by the late J. H. Bowden, one of the very early members of the Institute. Similar tanks are still used in emergencies at the Nos. 1, 2, 3 and 6 shafts of the company. The objections to. their use were: that water could only be hoisted during the night-shift, or when the shafts were not in use for hoisting coal, thus requiring a very large sump, and greatly limiting the water capacity of the plants; that the alternate wetting and drying

Jan 1, 1904

By Charles Behre

UNDER the caption "fault," geologists intend to include all mass movements of solid rocks over adjacent rock masses. When these are studied long after their origin, however, circumstances make it possible to recognize as "fault" only formations showing clear evidence of actual movement of one side with' respect to the other. Necessarily the chief evidence consists of the offset of a vein, bed, or other key structure. Planes of movement parallel to the bedding; or nearly so, are recognized with difficulty or are overlooked and hence many important faults are wholly unrecorded. Indeed, among standard American references on structural geology, one alone emphasizes the importance of bedding-plane movements and that' one only briefly1. For some time the writer, cognizant of this difficulty, has paid special attention to such movements, both as observed in the field and as recorded in the literature. It is believed that enough data are now at hand to justify a short-discussion. Its purposes are fivefold. It is desired first to briefly classify and describe at least the more common kinds of bedding-plane faults, and second, to examine the causes and manner of their formation, at least in instances where the subject has not yet been well covered by other investigators. Third, certain by-products of bedding-plane movements are of such conspicuous importance to the economic geologist and mining engineer as to merit mention. Fourth, concrete illustrations should be placed before the reader in order to lend reality and to furnish a basis of comparison with his experience; such illustrations will necessarily be scattered through the text of this paper. They' are only in part from the writer's own field observations. The fifth and prime objective of this paper is to direct attention to the great importance of movements on the bedding planes, in the hope that the recognition of such movements and their significance may simplify mining problems.

Jan 1, 1937

By Charles H. Behre

UNDER the caption "fault," geologists intend to include all mass movements of solid rocks over adjacent rock masses. When these are studied long after their origin, however, circumstances make it possible to recognize as "fault" only formations showing clear evidence of actual movement of one side with respect to the other. Necessarily the chief evidence consists of the offset of a vein, bed, or other key structure. Planes of movement parallel to the bedding, or nearly so, are recognized with difficulty or are overlooked and hence many important faults are wholly unrecorded. Indeed, among standard American references on structural geology, one alone emphasizes the importance of bedding-plane movements and that one only briefly1. For some time the writer, cognizant of this difficulty, has paid special attention to such movements, both as observed in the field and as recorded in the literature. It is believed that enough data are now at hand to justify a short discussion. Its purposes are fivefold. It is desired first to briefly classify and describe at least the more common kinds of bedding-plane faults, and second, to examine the causes and manner of their formation, at least in instances where the subject has not yet been well covered by other investigators. Third, certain by-products of bedding- lane movements are of such conspicuous importance to the economic geologist and mining engineer as to merit mention. Fourth, concrete illustrations should be placed before the reader in order to lend reality and to furnish a basis of comparison with his experience; such illustrations will necessarily be scattered through the text of this paper. They are only in part from the writer's own field observations. The fifth and prime objective of this paper is to direct attention to the great importance of movements on the bedding planes, in the hope that the recognition of such movements and their significance may simplify mining problems.

Jan 1, 1937

By Basil B. Zavoico

The developments in the Russian oil industry during 1935 marked a very definite turning point from the time when the industry was being educated to the modern methods of oil-field finding and development, refining, transportation and marketing, to the time when the industry has thoroughly assimilated the modern technique and is now firmly standing on its own feet, as is shown by the remarkable qualitative, if not quantitative, progress in 1935. The oil industry promises that 1936 will be a record year in every respect with both quantity and quality approaching the desired high levels and standards. More particularly the Soviet Government is beginning to be successful in the development of new fields and such new production in geographically strategical points of the country will be in the coming years a factor of great importance in the industrial life of the country. The most notable achievements of the last year have been: the very successful development of the Ishimbaevo oil field in the Lower Oural-Permian Basin; the discovery and development of several promising oil fields in the Puta district of Azerbaijan, while large flush production of Baku area was extended 50 miles due southwest into the Saliani-Aliat district, where a 3000-bbl. well was completed early in 1936 at Pirsagat. Also, an apparently important discovery was made at Zikh, on the Apsheron Peninsula proper. These discoveries, as well as several important strikes in the deeper producing sands in the older fields of the Apsheron Peninsula, have greatly augmented the proven reserves of Russia and made them available either at the points where transportation facilities were already present or at points not too far distant from major industrial centers of the country. Of course, not all objectives were achieved during the past year, and several major difficulties remain to be solved in the coming years, the more important of which are: (1) supply of equipment and of parts; (2) the unavailability of competent technical men in sufficient numbers, which more particularly affects the distant fields; and (3) the problem of distribution of oil products throughout the country, especially the question of handling the needs of small consuming areas, which, while individually unimportant, in the aggregate require huge distribution.

Jan 1, 1936

By Basil B. Zavoico

The developments in the Russian oil industry during 1935 marked a very definite turning point from the time when the industry was being educated to the modern methods of oil-field finding and development, refining, transportation and marketing, to the time when the industry has thoroughly assimilated the modern technique and is now firmly standing on its own feet, as is shown by the remarkable qualitative, if not quantitative, progress in 1935. The oil industry promises that 1936 will be a record year in every respect with both quantity and quality approaching the desired high levels and standards. More particularly the Soviet Government is beginning to be successful in the development of new fields and such new production in geographically strategical points of the country will be in the coming years a factor of great importance in the industrial life of the country. The most notable achievements of the last year have been: the very successful development of the Ishimbaevo oil field in the Lower Oural-Permian Basin; the discovery and development of several promising oil fields in the Puta district of Azerbaijan, while large flush production of Baku area was extended 50 miles due southwest into the Saliani-Aliat district, where a 3000-bbl. well was completed early in 1936 at Pirsagat. Also, an apparently important discovery was made at Zikh, on the Apsheron Peninsula proper. These discoveries, as well as several important strikes in the deeper producing sands in the older fields of the Apsheron Peninsula, have greatly augmented the proven reserves of Russia and made them available either at the points where transportation facilities were already present or at points not too far distant from major industrial centers of the country. Of course, not all objectives were achieved during the past year, and several major difficulties remain to be solved in the coming years, the more important of which are: (1) supply of equipment and of parts; (2) the unavailability of competent technical men in sufficient numbers, which more particularly affects the distant fields; and (3) the problem of distribution of oil products throughout the country, especially the question of handling the needs of small consuming areas, which, while individually unimportant, in the aggregate require huge distribution.

Jan 1, 1936

By Basil B. Zavoico

During 1937 the Russian oil industry made very satisfactory progress in its exploration branch and added considerably to its proven reserves in the older producing districts, while several entirely new potential areas were opened for development by discovery wildcats. The exploitation of known fields, however, suffered greatly from internal political difficulties, referred to as "sabotage," and was also seriously handicapped by the requirements for national defense under the duress of a grave international situation. More particularly, the necessity for preparing for a major war resulted during 1937 in short-rationing of the oil industry in its iron, steel and rubber requirements, affecting quantitatively drill pipe, casing, tubing and the rubber equipment of automobiles, and qualitatively much of the oil-field machinery for which it was either impossible or difficult to obtain iron or steel of required specifications, which necessitated manufacture of heavier and unwieldy equipment and caused directly and indirectly an unavoidable major curtailment of drilling operations below the planned footage. War-preparation measures during 1937 also required accumulation of a large gasoline reserve in the Vladivostok area and inasmuch as shipments from California can be made much more cheaply than from Caucasian refineries, either by tank cars across Siberia or by tankers via Suez Canal and Indian Ocean, some 2,000,000 bbl. of gasoline was imported from the United States in the past year, resulting in a decline of 46.98 per cent in net exports of all petroleum products from Russia below the 1936 net export volume, which is the lowest level since 1925. Production of crude oil during 1937 is estimated at 212,742,000 bbl. as compared with 202,543,700 bbl. produced in 1936, an increase of 5.04 per cent, but 11 per cent below the planned output. There were no major readjustments as to the source of crude-oil production, Baku district still accounting for the largest share; that, is, 77.21 per cent of the total. Exploration operations were outstandingly successful during the past year, major discoveries having been made on the Apsheron Peninsula, in Grozny and Maikop-Kuban districts, in Ural-Permian Basin, in Middle Volga-Samara district and other areas.

Jan 1, 1938

By Donald L. King

This paper has been prepared with the objective of providing basic information on thickening equipment as applied to mineral processing plant design. Thus, by design, the content is elementary, yet sufficiently informative to advise the reader concerning the thickening and clarifying process, equipment configurations, installation and operation. Practical considerations are provided for slurry samples for testing, evaluation of testing, preliminary sizing, duty classification, and thickener selection to enhance operation, see icing and control. Illustrations are provided to both inform and demonstrate present state of the art features and capability.

Jan 1, 1978

By Carl Floe

THE possibility of separating the various constituents of mixed ores or metalliferous products by differentially producing their soluble sulfates has not received the consideration that it deserves. The production of the soluble sulfate may be accomplished by baking the ore with sulfuric acid or by treating it with gases containing oxides of sulfur. This paper is primarily concerned with the first method. The procedure used was to mix the material with a solution containing a definite weight of sulfuric acid, baking the mixture at various tempera-tures and then leaching out the soluble sulfate with water. The amount of acid used was calculated to produce certain desired soluble sulfates. The temperature of baking depended on the decomposition points of the sulfates involved. The object was to prevent the formation of or to decompose certain sulfates while leaving a maximum quantity of another sulfate in a water-soluble form. This procedure has two possible advantages over the ordinary method of leaching with an aqueous solution of sulfuric acid. First, a more selective leach may be obtained, and second, the higher temperatures and stronger acid concentrations involved will permit a better recovery of materials that are difficultly soluble in relatively dilute aqueous sulfuric acid solutions. The method of sulfuric acid baking followed by water leaching is not new, as it has been applied in the treatment of various metalliferous materials such as the recovery of cadmium from flue dust1, the re-treat-ment of zinc leach residues2 and the working up of electrolytic slimes3.

Jan 1, 1936

AN UNUSUAL OPPORTUNITY FOR INSTITUTE MEMBERS to increase or complete their sets of the Transactions. In order to encourage the custom of members increasing each year the number of Volumes of the Transactions in their private libraries until the sets are complete, the Board of Directors has authorized the sale of Transactions previous to the year 1913 at the following greatly reduced rates. This offer is made effective for sales made only during the year 1914, and applies only to members in good standing, and to libraries. The reduced price automatically ceases to apply to any volume when the total number of such volume left in stock is reduced to fifty (50).

Jan 12, 1913

Montreal, April 6-7. "Resilient" and "bullish" were the terms used by R. D. Mushlitz of Asarco and K. C. Hendrick of Noranda Sales Corp. respectively, to describe the near term prospects for lead and zinc. The two men delivered their predictions at a joint meeting of the Lead Industries Association and the Zinc Institute held here. In speaking before a packed audience, Mushlitz insisted that "the lead industry is far from the sedentary one which many would have us believe, and although it may be slow and tortuous at times, . . . it is a viable and progressive industry which won't give up easily to the various pressures. . . . and, in the long run, will prevail."

Jan 5, 1972