Search Documents

By G. T. Swanby

Members of AIME, I read to you now a portion of a very fine business letter which we received several years ago. This letter originated in Rangoon, Burma, and reads in part: "Rest assured, if your goodselves see with us eye to eye, sure as certain we should get the business". I don't plan to give anybody "the business" today, but you can rest assured that if some of "you goodselves see with me eye to eye" on what I am about to discuss, I would be most pleased. My talk with you today will discuss the Federal Corporate income tax and its effect on our lives as engineers. In the-engineering-construction business we are faced with all the usual form of taxation which includes such items as sales tax, use tax, school tax, contractor; gross receipt tax, import duties and excise taxes, severance taxes, etc, adinfinutum.

Jan 1, 1965

By H. E. Biber

DURING the production of tin plate a thin layer of FeSn2, is formed at the interface between the steel sheet and the protective tin coating. Because excessive amounts of this alloy layer are undesirable, the kinetics of its formation is a subject of interest in the tin-plate industry. A recent study of this subject at our laboratory uncovered a relationship which should be of general interest to anyone studying kinetics of reactions in metallic systems. It had been previously concluded that, at any given temperature in the range 175" to 330°C, the Fe-Sn alloy layer would have a parabolic growth rate.1,2 However, our studies showed that this rule apparently holds only when the tin plate is heated very slowly to the "reaction" temperature; when the tin plate is rapidly heated, considerably different growth rates occur. An example of this effect of heating rate on growth behavior is contained in the accompanying results of alloy-layer growth measurements at 240°C in oil baths stirred at 10,500, 1800, and 0 rpm. The heating curves for these three conditions are given in Fig. 1, and the growth data are presented in Fig. 2. With the rapid heating rate, provided by the stirring at 10,500 rpm, the alloy layer had three distinct stages of growth. In the initial stage, which persisted well beyond the time required to heat the tin plate to bath temperature, the alloy layer formed very rapidly. The growth followed a rate law of the form w = ktn where n > 1. This initial stage was followed by a growth-retardation stage of about 50-sec duration in which little additional alloy was formed. In the third stage the growth again followed a rate law of the form w = ktn, but here « =0.3. With the intermediate heating rate provided by stirring at 1800 rpm, the three-stage nature was less pronounced and the slope of the third stage increased (i.e., n > 0.3). With the slow heating rate provided by the unstirred oil bath, the alloy layer grew in two stages. The initial rapid-growth stage persisted only until the specimen was heated to bath temperature, no growth retardation was observed, and the slope of the main portion of the plotted data was greater than in the stirred baths, having a value of almost 0.5. Similar results were obtained for other bath temperatures in the range 200" to 300°C. This effect of heating rate on growth behavior may be due to changes in the rate of nucleation of FeSn, crystallites. The iron and tin are in contact from the onset of heating. Thus the initial formation of FeSn, occurs not at the "reaction" temperature but rather while the tin plate is being heated to that temperature. Because nucleation is in general temperature-dependent, different heating rates could cause different over-all nucleation rates, which in turn could cause different growth behaviors. A more detailed discussion of the growth of Fe-Sn alloy layer and the effect of heating rate will be published shortly.

Jan 1, 1965

By William H. Lehr

In recent years, we have witnessed many innovations in the equipment used in handling bulk materials. Not too long ago, any sizeable stockpile of coal or iron ore was attended by one or more material handling bridges. More recently, large stockpiles have been built with mobile equipment of' the earth moving type with bulldozers and front end Loaders being utilized in reclaiming operations. The most recent stocking and reclaiming device is the rotary bucket wheel machine. The early bucket wheel machines built in the United States were developed for the strip mining of coal. We understand that the first American machine was built in the Midwest in 1944. This type of unit was developed in an effort to reduce the cost of removing overburden and to provide satisfactory spoil disposal. As the available coal reserves under shallow cover were exhausted, the cost of removing the deeper overburden with conventional equipment became too great for these operations to continue profitably. The first machine has now been followed by six or seven additional units, the largest of which can handle material at a rate of more than 7000 cubic yards per hour.

Jan 1, 1965

By B. E. Warren

Jan 1, 1965

Experimental results are presented for the anode overvoltage as a function of current density for different alumina concentrations in an alumina reduction cell. Voltage changes due to the electrolyte resistance and also the decomposition voltage, have been evaluated as a function of alumina concentration and anode current density. From these values of voltage, changes in the total cell voltage have been derived for changes in alumina concentration for different anode current densities. The results show that for each operating current density there exists a discrete alumina concentration that defines a minimum reduction cell voltage. Discussion is made about potential savings in power consumption when the alumina concentration is controlled.INTRODUCTIONThe standard procedure in the aluminium industry when analysing the cell-voltage required for the Hall-Heroult process for reduction of alumina, is to subdivide the total voltage into the following components (e.g. Pearson, 1955; Maritell, 1960).1. ohmic drop through busbars and joints2. ohmic drop through cathode lining3. ohmic drop through anode4. ohmic drop through electrolyte5. overvoltage at anode6. electrolytic decomposition voltage.(Overvoltages ,at the cathode are of negligible magnitude at all practical current densities.)It is understandable that the voltages assigned for each factor invariably differ for different workers...

Jan 1, 1965

The structure of the Bulli coal seam at Appin Colliery was detailed by the seismic reflection method. This unusual application of the seismic method was possible because there is a reflector near the seam as was revealed during exploration for petroleum in an area north-west of Appin. The reflector, which was at a depth of 1,500 ft, was shallow by normal reflection survey standards. Measurement of the seismic velocity at two ventilation shafts showed that the reflector was probably the Bulli coal seam. Accurate depth control was established from previous drilling results.INTRODUCTIONAppin Colliery, situated on the Southern Coalfield of N.S.W. (Fig. 1), is being developed to supply coking coal to the Port Kembla steelworks of Australian Iron and Steel Pty. Ltd. The colliery is mechanized and a detailed knowledge of structure, particularly faulting, is important in planning the workings.The Bulli seam, which is approximately 9 ft thick, and between 1,500 ft and 1,800 ft below the surface, is worked in the colliery. It is the uppermost member of the Permian Coal Measures and is overlain by Triassic rocks, which consist of thick sandstone beds containing beds of coloured shales, and which are subdivided into the Narrabeen Group, the Hawkesbury Sandstone, and the Wianamatta Group.In the early stages of development of the colliery, surface geological mapping and diamond drilling provided information on structure. Generalized results of the mapping are shown on Fig. 2. Drilling indicated that the physical and chemical properties of the Bulli seam are relatively constant, and that the seam is nearly horizontal, the average dipbeing about 1 in 25 to the west.

Jan 1, 1965

The Cowarra gold mine is at latitude 36°O'S. and longitude 149°19'E. which is roughly 20 miles north-north-east of Cooma.The deposit was· originally worked towards the end of the last century, but the presence of sulphides associated with the gold in the primary zone caused cessation of work when that zone was reached.GEOLOGY AND MINERALIZATIONThe principal country rocks are sandstones and shales of Silurian and Ordovician age, both very strongly folded with structural pitches ranging from a few degrees to almost vertical. The mine proper is within Silurian rocks and the main orebody (there are several minor parallel bodies) is developed within a shear striking approximately north, dipping approximately 70° east, and ranging in width from 2 ft to 15 ft but averaging about 4 ft.This shear is impregnated with quartz and sulphides with which the gold is associated. The predominant sulphide is pyrite though pyrrhotite is commonly present in quantity.Arsenopyrite and bornite are present in smaller amounts.Stillwell (1936, 1937a, 1937b, 1938, 1941) has published five mineragraphic reports on the ore.The various levels have been mapped in detail (Figs. 1-3) and the No. 2 level plan (Fig. 1) shows the general relationship of shearing, as now indicated by mineralization, and faulting. There is no apparent connection between the fold structures and mineralization.Fig. 3 is a longitudinal projection showing the distribution of gold expressed as inch-ounces. The estimation of...

Jan 1, 1965

Recently discovered Carboniferous bentonites are variable in charadeI and thickness, but being altered aeolian, ash-fall tuffs, they are probably extensive. Most are the Ca-montmorillonite type without the natural swelling characteristics of the Wyoming deposits, but their situation, thickness, and response to beneficiation through cation exchange may give them some potential as sources of future economic deposits.INTRODUCTIONLoughnan and See (1959) gave an account of bentonites and fuller's earth deposits of New South Wales. The most likely potential industrial sources were those occurring in the uppermost formations of the Newcastle and Singleton Coal Measures (Permian) in the Hunter Valley and deposited during epochs not marked by strong contemporary vulcanicity.One feature of the record of known occurrences at that time was the absence of bentonites from the thick volcanic sequences of the Carboniferous, but since this paper appeared, many bentonite beds have been discovered by the writer in the Carboniferous facies formerly known as the "Kuttung Series".The purpose of this contribution is to report briefly on the occurrence, genesis, mineralogy, and economic potential of these deposits which augment possible sources of bentonite near major industrial centres on the eastern seaboard.The potential world demand for bentonite would increase markedly with the trend to pelletization in the steel industry, if its use in this field became more general. More detailed mineralogical studies will be presented in later publications.STRATIGRAPHIC DISTRIBUTIONBentonite occurs at irregular intervals throughout a thick sequence of dominantly continental, plant bearing strata...

Jan 1, 1965

By Paul Soros

A major share of the increase in the energy demands of Ontario province in the next decade will be supplied by bituminous coal mined in the U,S, To be competitive with alternative sources of energy, it is essential that the delivered cost of coal, inclusive of all transportation charges, be kept at a minimum. The Bessemer aid Lake Erie Railroad Company and the Pittsburgh and Conneaut Dock Company are currently building a shiploading terminal at Conneaut, Ohio, to service this tonnage, together with expected increases in coal consumption in the Eastern Lake Erie - Lake Ontario area, (see Fig, 1).

Jan 1, 1965

By Belcher C. B

A procedure was required for the rapid determination of silicon in low-alloy irons and a suitable method used the formation and reduction of silicomolybdic acid at 50°C. The procedure gives results for elemental silicon and this enables the correct computation of oxidation requirements in basic oxygen steelmaking. The method could be useful in iron foundries which have not installed direct reading spectrometers.INTRODUCTIONOxygen steelmaking experiments required rapid determinations of 0,5-1,6 per cent silicon in iron (3-4 per cent C) within 10 min of sampling; a reproducibility better than ±0.03 per cent Si was desired. Only elemental silicon (Si°) is of interest as a fuel in basic oxygen steelmaking technology, and the proposed procedure determines exclusively this form of silicon. The method is described as it may prove useful to other workers although the interference study would be incomplete for some applications.The analysis of silicon in iron is frequently obtained using direct reading spectrometers, but for the proposed experiments the spectrometers could not be used because of the prohibitive distance from the furnace. It should be noted that spectrometers determine both the elemental silicon and that present as silicon dioxide in occluded slag and inclusions.The silicon content of iron and steel is determined in this laboratory by spectrophotometric measurement of a "molybdenum blue" colour. The reactions involved have been extensively investigated; Strickland (1952) showed that a...

Jan 1, 1965

By Edwin M. Thomasson

HELIUM SHIPMENTS in 1964 exceeded the volume shipped during the previous year for the 15th successive time. Shipments from Bureau of Mines helium plants were 667.4 million cubic feet,2 about 6 percent more than in 1963. Production at Bureau of Mines plants totaled 784.5 million cubic feet. An additional 3,193.1 million cubic feet, which was produced by private companies participating in the helium conservation program, was purchased by the Bureau and stored underground for future use. The Bureau of Mines continued to sell helium at $35 a thousand cubic feet, the price established in 1961. Substantial railway freight rate reductions for tank car shipments of helium went into effect during the year, resulting in a lower delivered price for helium. As the Nation moved ahead in the space age, it became increasingly apparent that helium would continue to play an essential role in research, in technology, in defense, and in industry.

Jan 1, 1965

By James F. O?Neil

Brown iron ore deposits in Quitman County, Ga., were investigated by the Federal Bureau of Mines in cooperation with the State of Georgia, Department of Commerce, and the University of Alabama. Ninety-one holes were drilled, having an aggregate footage of 2,188 feet; seventy-one holes penetrated 248 feet of iron mineralization. Average thickness of the ore zone was 3.5 feet under an average thickness of 14.7 feet of overburden. The drilling developed inferred reserves containing nearly 30 million long tons of crude ore with an average analysis of 28 percent iron plus minor quantities of manganese. Test work done by the Bureau on the crude ore samples indicated that they would upgrade by current lug washer practice, with the use of a 1i8-inch screen, and yield 4.4 million dry long tons of concentrate with an average analysis of 52.1 percent iron plus manganese. The weight recovery obtained was 14.7 percent. Research studies made by the Bureau showed that the weight recovery would be increased by changing the screen size without any appreciable sacrifice of grade. The average weight recovery was increased to 18 percent with a 10-mesh screen and 22.8 percent with a 20-mesh screen. Screen tests studies indicated that there was no appreciable interlocking of the iron and manganese minerals and the clay and silica waste particles of the materials retained on a 200-mesh screen. Clay was prominent in micron-size slimes. Silica was deleterious in the minus 20-mesh size.

Jan 1, 1965

By Frank B. Fulkerson

Three of the five primary aluminum producers in the Pacific Northwest have facilities in the region to make aluminum mill products. Only one of the three, however, produces a variety of shapes and forms. The principal reason for the lag in development of an aluminum mill products industry was found to be transportation cost. The long range outlook is for expansion, based mainly on growth of the western market for aluminum used in construction, containers and packaging, electrical applications, diesel trucks, mobile homes, and irregation pipe. Consumption of western aluminum mill products in 1985 is projected at 1.1 million tons, compared with estimated consumption of 250,000 tons in 1961.

Jan 1, 1965

By R. Schuhmann

Jan 1, 1965

The 8 ft by 91/2 ft drive which joined No. 7 Shaft with Browne Shaft on the 1,480 ft level was extended from both ends and met at a point approximately 12,000 ft from No. 7 (2,000 ft from Browne).The surveying required for this 2 1/2 mile haulage drive called for greater accuracy than was obtainable from South Mine standard methods. Procedures and devices from published information were tried and modified as required to suit local conditions. Several new methods were applied and improved as the drive advanced. The control of angular, linear and level measurements was perhaps considerably in excess of the requirements, but this was offset by abnormally large discrepancies resulting from shaft plumbing. The accuracy of the final breakthrough, although not to the standard desired, was sufficient to complete the connection without inconvenience and added cost.INTRODUCTIONThe acquisition of the Browne Shaft leases in January 1962 presented the management of Broken Hill South Limited with the problem of transporting ore from these leases to its mill. It was eventually decided that diesel locomotivehaulage through a 2t mile drive on the 1,480 ft level between the two mines was the best solution. The drive was advanced from both ends after Browne Shaft was deepened by 80 ft to reach the 1,480 ft level horizon. Each end advancedabout 15 ft/day with the miners working three 7 hr shifts. Blasting was restricted to the end of the shift.The survey work involved five shaft plumbings and 78 theodolite stations in a traverse, underground and surface,of more than 5 miles. Because of the exceptional length of the drive, an unusually high degree of reliability was required.The aim was for a maximum error at breakthrough of 1 ft 1 in 30,000, and to secure this, precise methods of linear measurement were necessary. Shaft plumbing in particular posed special difficulties.

Jan 1, 1965

By Arnold M. Lansche

DOMESTIC OUTPUT of white arsenic, As2O3, was derived entirely as a byproduct of smelting arsenic-containing copper ores by The Anaconda Company at Anaconda, Mont., and American Smelting and Refining Company at Tacoma, Wash. Arsenic metal was not produced. Consumption, and Uses.-Most of the white arsenic produced in 1964 was consumed in manufacturing lead and calcium arsenate insecticides. In the 12 year period since 1951 the production of lead arsenate insecticide has varied between 7,800 tons and 4,900 tons, indicating that lead arsenate has maintained its position in competition with organic insecticides.

Jan 1, 1965

By R. L. Grunes, F. K. Kies, C. D&apos, Antonio

THE several studies concerned with the annealing of thin nickel films have largely been restricted to films of a single thickness.1-4 It is well-known, however, that both physical and mechanical properties depend upon film thickness.5, 6 The strength-thickness relations found in vapor-deposited nickel films in the annealed and as-deposited states, as an example, are at least partially due to the density and arrangement of imperfections within the films.7, 8 For these reasons, the annealing characteristics of thin nickel films as a function of thickness were investigated. Electrical resistance was chosen to monitor annealing behavior since resistance changes are partially dependent upon defect structure. In addition, the equations predicting film resistivity as a function of thickness are already available.9, 10 Further advantages afforded by electrical-resistance measurements are its adaption to continuous readings during annealing and its relative simplicity. Nickel films were vapor-deposited, at average rates of 60Å per sec, on Vycor substrates held at room temperature in vacuums of about 10-5 torr. Afterwards, deposition-thickness measurements were made using a multiple-beam interferometric technique. A more detailed description of deposition procedures and the interferometer appear elsewhere.7, 8 The four-probe method was employed in measuring electrical resistance since this technique measures film resistance without contributions from lead wires and contacts. Resistance measurements were made before, during, and after annealing to temperatures of 700°C under vacuums of approximately 10-4 torr. Measurements were made every 25°C or more often when necessitated by unusual resistance changes. Cooling and heating rates were maintained at approximately 5°C per min. Typical resistivity vs temperature curves are shown in Figs. 1 through 4. It is apparent from these

Jan 1, 1965

By Frank E. Woolley, Robert D. Pehlke

Jan 1, 1965

By Forrest T. Moyer

INJURY experience in the metal and nonmetal mineral industries during 1964 was better in rates of occurrence but worse in severity rates than in 1963. The frequency rate of injuries per million man-hours was improved at metal mills, nonmetal mines, and sand and gravel operations, and was virtually unchanged at metal mines; however" the rate of occurrence of work injuries at nonmetal mills, stone operations, nonferrous reduction and refining plants, and slag plants was higher than in 1963. The severity rate of injuries during 1964, data for which are presented for the first time in this chapter, was better at metal mills, nonmetal mines, stone operations, and slag plants. However, the severity rate was worse at metal mines, nonmetal mills, sand and gravel plants, and nonferrous smelters.

Jan 1, 1965

By Oliver Q. Leone

The effect of oxygen content in the anode metal on titanium electrorefining characteristics was studied. Increasing quantities of oxygen in the anode resulted in increased anode scale formation, decreased anode and cathode current efficiencies, lower titanium recovery efficiencies, and higher oxygen content of the cathode products. The titanium electrorefining process performed best when the anodes did not contain more than 0.5 percent oxygen, although anode dissolution was recorded for alloys containing up to 25 percent oxygen. Back emf affords a useful index of an alloy to electrorefining.

Jan 1, 1965