Search Documents

Jan 1, 1914

By H. Sherman

The general curtailment of activities, so marked in 1931, was continued and intensified in 1932 and although production was maintained at approximately the level of the previous year, 1932 was chiefly characterized by the virtual cessation of drilling in many of the proven fields, a further decline in wildcatting activities, particularly in the Maracaibo Basin, and the relinquishment of large blocks of unfavorably located acreage. A total of only 60 wells was completed during the year of which six were wildcats, while at the same time concessions aggregating approximately. 3,222,000 acres were renounced and reverted to the National Government. The maintenance of production at the previously established level was made possible through the large potential built up by drilling in previous years and by a gradual increase in pumping and gas-lift installations. Towards the end of the year there was a slight but perceptible tendency towards increased drilling in certain of the proven fields. Total production for the year came to 118,076,000 as compared to 118,418,000 bbl. for 1931, while exports amounted to 114,758,000 as against 116,683,000 bbl. in 1931. Table 1 shows production and exports and the average rate per day for the first half of 1932 as compared to the second half. Table 1.—Petroleum Production and Exports in 1932, Venezuela (Barrels of 42 Gallons) Production Rate per Day Export Rate per Day I January-June............ 61,943,000 1 390, 347 July-December.......... 56,133,000 305,071 50,788,000 276,022 Total.........,....... 118,076,000 322,612 114,758,000 313,546 During 1932 the number of active vessels comprising the Lake Maracaibo fleet of shallow-draft tankers was still further reduced, some being temporarily laid up and some transferred to service in other coun-

Jan 1, 1933

ENGINEERS AVAILABLE. (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons.) Member, graduate of College of Mines of University of California, with 12 years' operating experience in mining and milling in California, Canada, and Mexico, is open for engagement. Speaks Spanish fluently. No. 17. Mining engineer and metallurgist open for engagement Jan. 1 as superintendent of mines or constructing engineer. Technically educated, with 14 years' experience in United States and Latin America in concentration, amalgamation, cyaniding, constructing. At present building large modern .all-sliming cyanide mill in Central America. No. 18. Member, mining and metallurgical engineer, is open to engagement. Specialty, the treatment of copper ores. Nine years' experience in the operation and also in the design and erection of copper smelteries. Four years true pyrite smelting. Able to organize the administration, accounting, etc., of a large plant. Speaks a fair amount of Spanish, Russian, German, and French. Qualified to take charge of a large smeltery, or to act as assistant to manager of a combined mining and smelting concern. No. 19. Member, technical graduate, 33 years old, 11 years' experience as chemist, metallurgist, and superintendent of lixiviation plant and in charge of construction of cyanide mill, is open for engagement. Speaks Spanish. No. 21. Member, lately with the Bishop Creek Milling Co., California, is now open for engagement as mine superintendent or superintendent of construction of mine and mill structures. No. 25.

Jan 12, 1913

By Edmund Newton

THE steel industry of the United States has depended in the past almost wholly upon imports for its supplies of manganese. Many of the important domestic sources yield ores leaner in their natural condition than the foreign ores the steel industry has been accustomed to use. To make them available, therefore, either' the ores must be concentrated or the practice of the steel industry modified. Roughly 25,000 T. annually of high-grade manganese ores are used for dry batteries, for chemical purposes, and in other ways; while approximately 750,000 T. are required for making steel. By present practice, every ton of steel takes an average of about 14 lb. (1.8 kg.) of metallic manganese. This is generally added to the steel in the form of an alloy, the standard alloys being the 80-per cent. ferro-manganese and the 20-per cent. spiegeleisen. During the year 1917 286,000 T. of ferromanganese and 193,291 T. of spiegeleisen were made in this country, the former largely from imported ores; and 45,381 T.

Jan 2, 1919

ON Coal's Horizon one development rises above all others. That is the swift expansion of output to make Soviet Russia the largest coal producer on earth next to the United States. Few Americans are aware of the speed and extent of that expansion nor of the accompanying creation of a strong, resourceful mining machinery industry, nor of the extent and character of the mechanization of Soviet coal mining. Two initial clarifications are necessary for better understanding. First, we must keep in mind the sharp distinction between the Russian people and the communist Soviet dictators who rule them. The great mass of the Russian people are not members of the Communist Party as people here are Republicans or Democrats. They are not permitted to be members. There are, by various estimates, only 2 to 4 million members of that party in all Soviet Russia. The other 196 to 198 million are the victims of their tyranny and their terror. It is the activity of the Soviet rulers that concerns us here.

Jan 1, 1954

By W. C. Schroeder

PRACTICAL experience has shown that at elevated temperatures solu-tions containing sodium hydroxide may attack stressed steel in a manner that cannot be explained in terms of ordinary corrosion. Because the ductility of the metal has been greatly reduced during the reaction, the entire phenomenon is usually called "embrittlement." Thus, after several years of operation caustic evaporators have been so badly embrittled that rivets could be cracked off with the blow of a hammer. Since fine intergranular cracks are almost always present in the zone of fracture, it has often been assumed that a process of selective corrosion in grain boundaries was responsible for the failure, although this has not been clearly proved experimentally. Concentrations of sodium hydroxide below those necessary for the uniform, rapid attack of the steel surface are reported to be most effective in producing embrittlement2,3. In the operation of steam boilers a similar type of failure has been found, mainly in riveted seams or other capillary spaces where the solu-tion may concentrate and where high stresses may also exist. It is believed that in such localized areas the dissolved solids may reach a value many times the few hundred parts per million prevalent in the body of the boiler. While this type of boiler failure has been the subject of investigation for a period of 20 years', an understanding of its mecha-

Jan 1, 1936

The Institute makes liberal provision for inclusion of engineering students through individual Student Associate membership. Such members pay $2 per year, receive MINING AND METALLURGY, may purchase Technical Publications at reduced rates, have the privilege of attending all meetings and are furnished a distinctive badge in the form of a watch fob. Provision is also made for the affiliation of organized student societies in recognized schools of engineering, chemistry, geology and related sciences. In order to qualify for affiliation it is not necessary that all members of the society become Student Associates since the individual members of the society are not listed as members of the Institute. However, a large majority of the members of many of the societies are also Student Associate Members of the Institute. Among the things that the Institute does for the affiliated societies are the following: (a) A copy of each issue of MINING AND METALLURGY is furnished to the society; (b) Reports of the meetings and activities of the society are reported in MINING AND METALLURGY; (c) Assistance is given by the Institute in obtaining speakers for the meetings of the society; (d) The name of the society and of its officers is listed in the annual Directory and other publications of the Institute; and (e) Members of the society are given the use of the Engineering Societies Employment Service. Student organizations, desiring to be recognized as affiliated student societies of the Institute, should make application to the Secretary, giving particulars as to the nature of their organization, of their membership, and their officers. The accompanying list on page 21 gives the names of the affiliated student societies, their presidents and their secretaries, as of April 16, 1933.

Jan 1, 1932

By N. F. Foster

The use of piezoelectric semiconducting materials for the fahrication of ultrasonic transducers has raised the upper fundamental frequency limit for transducers from about 200 mc to above 10 kmc, Several types of semiconductor transducer configurations have been proposed and examined experimentally. Depletion-layer transducers have been made and operated at frequencies below 1 kmc hut they appear to he better suited for operation at considerably higher frequencies around 10 knzc. Diffusion-layer transducers have been made and operated in the range 50 to 1000 mc and have exhihited considerably improved conversion losses and bandwidths compared with other transducers available in the frequency range. A variety of novel structures are possible using these new types of transducers, some of which could lead to substantial advances both in research and in the fabrication of ultrasonic delay lines and memory elements. THE field of ultrasonics today spans some five decades of the frequency spectrum from the audible to the kmc range and finds applications ranging from fundamental research into the atomic structure of matter to the degreasing of machine parts. To cover this wide range it has been necessary to develop a great many types of ultrasonic trandsucers utilizing a variety of materials and physical phenomena. The first ultrasonic transducers were made during World War I for a submarine-detection system. They consisted of plates of single-crystal quartz bonded between metal plates and were one of the first applications of the phenomenon of piezoelectricity discovered nearly 30 years previously. Despite the many advances which have been made in transducer technology, piezoelectric transducers using single-crystal quartz are still used almost exclusively for application above about 30 mc. Transducers at these frequencies are normally made in the form of thin quartz plates which are then bonded onto the medium in which the ultrasonic wave is to be propagated. The crystallographic orientation and geometry of these plates determines the type of wave generated and the way in which the efficiency of the electromechanical conversion varies with frequency. Analysis of the design parameters shows1 that the frequency of maximum efficiency (the fundamental or resonant frequency) is that frequency at which the transducer is approximately half the wavelength of the ultrasonic wave in the material. As the frequency increases, the ultrasonic wavelength, and therefore the optimum transducer thickness, decreases and in practice the fabrication of quartz transducers with fundamental freauencies above 100 mc becomes extremely difficult due to the extreme thinness required. For frequencies above 100 mc quartz transducers can be used in overtone-mode operation, and for very high frequencies (500 to 24,000 me) a technique using a quartz rod inserted in a high-Q microwave cavity4 is available. These techniques, however, exhibit comparatively low fractional bandwidths and rather poor conversion efficiencies. The present trend in ultrasonics is towards high frequencies and greater bandwidth to allow the use of shorter pulses which can give increased discrimination in radar-system delay lines and greater storage capacity in computer applications. The increasing demand for more efficient transducers with greater bandwidth

Jan 1, 1964

By W. W. Gorr, R. Smith, E. H. Wyche

THE combination of high strength and corrosion resistance of cold-worked 18 Cr, 8 Ni steel has been advantageously utilized for some time, particularly in aircraft and rail car structures. There are, however, certain limitations on the use of such materials because the high strengths can be obtained only by cold-working, limiting the available products to sheets, strip, wire and tubes. The authors sought to overcome these limitations by resorting to precipitation-hardening, which has been used so successfully in nonferrous metallurgy but only to a limited extent in iron-base alloys. Accomplishment of this objective not only overcame the limitations, but also effected certain improvements in mechanical and other properties. This paper is an account of the development by Carnegie-Illinois Steel Corporation of a precipitation-hardening 18-8 stainless steel (called Stainless W? and tentatively identified as type 322). A description is given of its composition and metallurgical characteristics, heat-treatment, physical and mechanical properties and corrosion resistance. DEVELOPMENT OF THE NEW STEEL For a considerable length of time the authors were unable to determine the mechanism of the precipitation-hardening process that had been noted by Ffield 18,19 in 18-8 Ti or 18-8 Cb after cold-working and reheating to moderately elevated temperatures. All known variables were exhaustively studied, but with little success. However, results began to indicate that chemical composition was the most important variable, particularly the ratio of austenite-forming to ferrite-forming elements. The investigators 'then focused their attention upon the composition, and, in particular, upon the element titanium and its mode of alloying in the presence of other elements. A heat was obtained that could not be brought to the softness level of annealed 18-8. The response to cold-straining and aging* was very marked by previous standards, and, more important, cold-straining was found to be entirely unnecessary to produce the precipitation-hardening effect. The chemical composition of this heat was: C, 0.06 per cent; Mn, 0.54; P, 0.016; S, 0.016; Si, o.58; Ni, 7.28; Cr, 17.6o; Ti, 0.90; Al, 0.17. For some time the development work, particularly on composition, was carried

Jan 1, 1946

By Wm. Reuben Webster

THE greatly enlarged demand for small sizes of seamless copper tube which has recently occurred, due particularly to the rapid growth of the electric household-refrigerator industry, has emphasized the superiority of phosphorized to tough pitch copper for the purpose of producing this commodity. In the manufacture of this material exceedingly heavy reductions by cold drawing are employed, customary practice involving as much as 90 per cent. reduction of cross-sectional area in four runs without intermediate annealing. Although this superiority has long been recognized by tube makers, no quantitative expression of it has heretofore been published. It is believed that the data herewith presented will serve this purpose. Recent investigators are not in agreement as to the relative mechanical properties of copper containing small amounts of oxygen as compared with copper containing sufficient oxygen to produce that condition known as tough pitch. Hanson, Marryat and Ford' found that "oxygen has a relatively small effect on the properties of copper." Johnson,2 on the contrary, states "it cannot be denied that it (tough pitch copper) is inferior, to deoxidized copper where severe mechanical manipulation is concerned." These authorities in the reports of their investigations, as might be expected from their conclusions, do not present data of a character requisite to a conclusive determination of the question.

Jan 1, 1927

By W. R. Bean

Probably few, if any, of the many serious problems confronting malleable foundries have been more difficult of solution than the question as to why malleable that is ductile, black in fracture, and normal in all respects before galvanizing should, by that process, be rendered brittle, brilliantly crystalline or "white" in fracture, and of low resistance to shock. So far as we are aware, the technical literature contains no data or discussions on this subject, except two referencesl,2 of a general character. It is apparently a question that every one concerned, producer and consumer alike, has been willing to evade as far as possible. Various theories as to the cause of the deterioration have been given but such checking of these theories as we have done indicates that there was no sound basis for most of them. This work on the galvanizing of malleable was first undertaken in 1916, and has continued until the present time. We now feel that for all practical purposes we have reached a solution and are glad to be able to offer it in a form that can be readily applied to production processes. It is impossible to give here a detailed account of the early work done on this problem. A great number of tests were instituted and an enor-

Jan 1, 1923

By W. R. Bean

Probably few, if any, of the many serious problems confronting malleable foundries have been more difficult of solution than the question as to why malleable that is ductile, black in fracture, and normal in all respects before galvanizing should, by that process, be rendered brittle, brilliantly crystalline or "white" in fracture, and of low resistance to shock. So far as we are aware, the technical literature contains no data or discussions on this subject, except two referencesl,2 of a general character. It is apparently a question that every one concerned, producer and consumer alike, has been willing to evade as far as possible. Various theories as to the cause of the deterioration have been given but such checking of these theories as we have done indicates that there was no sound basis for most of them. This work on the galvanizing of malleable was first undertaken in 1916, and has continued until the present time. We now feel that for all practical purposes we have reached a solution and are glad to be able to offer it in a form that can be readily applied to production processes. It is impossible to give here a detailed account of the early work done on this problem. A great number of tests were instituted and an enor-

Jan 1, 1923

By Henry Rawdon

ONE of the most vital problems in the manufacture of steel at present is the occurrence of the defects that have been popularly termed "snow flakes," "flakes," or "scabs." Particularly is this the problem of many manufacturers who during the past 2 yr. have undertaken large-scale production for the first time. A study of the microstructure of such defective material throws considerable light upon the nature of these defects and is essential before measures may be taken for the elimination of the defects. Flakes do not appear to be found in the plain carbon steels; they have been found, however, in abundance in some of the simple alloy steels that are being used in such vast quantities; viz., nickel steel of the approximate composition, 0.40 carbon and 3.5 per cent. nickel, and in the chrome-nickel type. The present article summarizes the characteristic features of defective steel of the flaky type as they have been found by laboratory study of numerous specimens, and it aims to show the conditions within the metal that are favorable to the occurrence of this type of defect without entering into the details of mill practice (size of ingot, design of molds, rate of cooling, distribution of cooling stresses, etc.), all of which conditions appear to play a role in the production of these defects.

Jan 2, 1919

By James E. Harding

The usual method of sampling mineral deposits is to drill holes and assay the sludge or core. Though the results thus obtained may not represent the true average value of the deposit, it is on these results that estimates of practically all large orebodies are made. In a large number of cases, the results of exploitation fall far short of the estimated value of the orebody. The standard method of making these estimates is to find the cubic contents of triangular prisms, in the apexes of which the drill holes are placed, by. multiplying the surface area by the average depth of the ore in the three drill holes and then multiplying the cubic contents by the specific gravity of the ore or rock to find the tonnage. The assay value is found by dividing the sum of the products of the depth of ore in each hole and the corresponding assay value by the sum of the depths of the ore in the three holes. As the latter part of this method is subject to many mathematical errors, it should not be depended on. Some engineers, therefore, use a discount factor, but as this factor is either arbitrarily selected or is obtained by obscure methods, the results are no better than guesswork. The standard method is correct when the drill holes are so laid out that the triangular prisms are equilateral in cross-section. But as ore deposits cannot always be drilled into at regular intervals and because of the human factor, if many holes are drilled, triangular prisms of all degrees of angularity are produced. In such cases it is necessary to assume that the influence of the different holes is not the same in all directions, which assumption of course is absurd. The area of the triangular prism is usually found by scaling; an ore-body of sufficient size to justify churn drilling is too large to be handled conveniently on maps having a scale larger than from 1000 to 1 to 1,500 to 1 and maps of such scales cannot be accurately measured. A variable is thus introduced in the first operation. In addition, the scaling is frequently done from blueprints, which sometimes shrink as much as 4 per cent. between printing, washing, and drying. The error due to scaling may be eliminated by surveying the location of each hole and

Jan 1, 1922

By R. N. Woody, S. J. Work

Crushing development at Duval Corp.'s Sierrita concentrator in Sahuarita, Ariz., has been a continuing effort since plant startup in January 1970. The original crushing system was designed to produce 65 000 t/d (72,000 stpd) of ore. However, in the summer of 1970 the Sierrita plant was averaging only 43 000 t/d (47,000 stpd) due to coarser than expected secondary crushing plant feed, lower than design crusher operating availability, and inability to achieve design tertiary crusher power draught at an acceptable hydraulic support pressure.

Jan 4, 1979

By Forbes Wilson

IN February 1952 Freeport Sulphur Company started exploration work on a group of lateritic deposits at Moa Bay, Cuba. As a result of successful exploration work and a vast amount of metallurgical research over the past five years, these deposits will soon become a new Free World source of nickel and cobalt. Moa Bay lies on the north coast of Oriente Province, the easternmost part of the island, about 600 miles east of Havana and about 40 miles east of the U. S. Government nickel plant at Nicaro.

Jan 5, 1958

By Dewey J. Sabin

THE Rio de Canada Honda placer property is situated at an altitude of 5500 ft. above sea level in the San Luis Mountains of the Province of San Luis, Argentina. The mine is reached by 70 km. of fair truck road, from the nearest railway station on the Ferrocarril Buenos Aires al Pacifico. The Pan-American airport at Villa Mercedes, 1.40 km. distant, serves as the most convenient point for shipment of gold. Placer mining in the Rio de Canada Honda dates from the time of the Incas and the present native population depends on the gold washed from this river and the adjacent arroyos as a means of livelihood as did the many generations before them. They dig pits to bedrock where they are not driven out by water, and mine the bedrock gravel by means of tunnels and caves. No timber is available and the ground is supported by rock cribs carefully built with the boulders encountered; or with angular blocks of slate rock taken from quarries on the surface.

Jan 1, 1936

By Hsun Hu

C. G. Dunn (Geneva1 Electvic Reseavclz Labo,vatory)-Dr. Hu16 has obtained a number of rolling and annealing texture results that partly agree with those of Dunn17 and Dunn and Kohl8 for experiments of a similar nature. I would like to discuss some of the points of agreement as well as some of disagreement and then present some unpublished data as a contribution to the work on textures. Firstly, there is agreement on the components produced during a 70 pct cold-rolling reduction of a (110) [001 ] single crystal; there is agreement on the forma- tion of a (110) [001] recrystallization texture provided recrystallization occurs at 800°C or higher; and there is agreement on the formation of (120) [001] components provided recrystallization occurs below 600°C. There is some disagreement on the low-temperature recrystallization since I also obtained a substantial amount of a (110) [001] component while the author obtained only (120) [001] components. I also discussed the differences between low- and high-temperature recrystallization (which included further annealing changes in the samples on long

Jan 1, 1962

By H. D. Dahl, Roger C. Parsons

In order to improve roof stability, Continental Oil Co.'s research program, initiated in 1969, was directed toward defining the geological parameters that affect the severity of roof conditions in any particular area of the mine. In addition, the program was seeking to define why roof falls in the Humphrey No. 7 mine (and in northern West Virginia-southwestern Pennsylvania coal mining areas) are oriented so that they occur primarily in north-south rooms or entries. Conclusions and recommendations from this study of roof fall orientation are given.

Jan 1, 1973

By P. D. Merica

ALUMINUM and its alloys have been the subject of much investigation, during recent years, in the course of which the principal features of the constitution of most of the binary alloy systems with aluminum have been determined. Except in the case of a few metals-silicon, bismuth, cadmium, lead, zinc, and tin-an aluminum-rich compound is formed in each binary system, which forms a eutectic with the aluminum or its solid solution with this compound. Thus such compounds as FeAl3, CuAl2, Mg4Al3, and NiAl3 are formed, which are found in aluminum-rich alloys of their respective series as eutectics with the aluminum solid solution. These compounds are, in all cases, hard and brittle and their presence affects profoundly the physical properties of the alloys in which they occur. Within the zinc-aluminum system a compound, Al2Zn3, is formed that decomposes at lower temperatures. Silicon and tin each form a simple eutectiferous series with aluminum; bismuth, lead, and cadmium are only partly miscible in the liquid state with it. The extent of the solubility in aluminum, in solid solution, of these compounds or of the elements themselves, in the case of those series

Jan 7, 1919