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By C. W. Merrill

The price records of seven representative mineral commodities for the 68-year period 1890 through 1957 have been compiled and analyzed for significant trends. When these records are reduced to real prices in terms of dollars of constant purchasing power or to the purchasing power of industrial wages at average rates, a substantial overall fall in prices is revealed. This downtrend contradicts the widely held concept that heavy drafts on a mineral resource must lead to scarcity, reflected in rising prices. Three metals (aluminum, copper, and pig iron), two fuels (bituminous coal and petroleum), and two nonmetals (sulfur and cement) have been chosen because of their pre-eminence in their respective categories, their significance in an industrial economy, and the ready availability of their price records. It might be added that these seven commodities were selected before any price figures were compiled; none was selected or rejected to substantiate any preconceived notions as to price trends. The overall importance of the seven is demonstrated by the fact that, taken together, they composed over three-fourths of the value of all minerals produced in the U. S. in 1957. The first step in the analysis was to reduce the price records to a basis for significant comparisons. Two such comparisons have been made: 1) The quantities of each of the commodities that could have been purchased for an average hour's wage in each year, and 2) the unit price of each commodity through the years in terms of deflated dollars. These data are set forth in the accompanying table and two charts. The quantities of the mineral commodity purchasable with the average wage for one hour's work in all manufacturing industries through 1926 were based on annual average prices and on average annual wage rates determined by Paul H. Douglas and published in his "Real Wages in the United States, 1890-1926." The series was extended through 1957 by the Bureau of Labor Statistics, U. S. Department of Labor. Calculations based on these data show that the average worker could have purchased 1.28 lb of copper with his hourly wage in 1890, whereas his hourly wage would have purchased 8.11 lb in 1957, an increase of 633 pct in the 68-year period. An average hour's wage would have bought 10.85 gal of petroleum in 1890, compared with 33.04 gal in 1957. Even more spectacular is the increase in sulfur, of which 25.25 lb could have been purchased with the 1904 average hourly wage; 223.08 lb were purchasable with the wage in 1957—an increase of 883 pct. Comparable price data for sulfur are not available for years earlier than 1904. For every commodity, the calculations show an improvement in the wage earner's purchasing power in 1957 compared with the early years. Measuring purchasing power in terms of wages does not give an entirely fair picture of the availability of a commodity in an economy. When the efficiency of an economy changes and the balance shifts among such elements as raw-material production, manufacturing, and service trade, the economic significance of an hour's work changes. Partly to meet such criticism, but mostly to present another interesting measure of the response of minerals to changing market conditions, a second set of calculations has been made to deflate unit prices for the seven commodities into terms of 1954 dollars. To accomplish this adjustment to a common 1954 parity, the Gross National Product Price Deflator, developed by the Office of Business Economics, U. S. Department of Commerce, was used. Although the results of these calculations are not as striking as those based on labor's increasing purchasing power, nevertheless the declines outweigh the rises in the prices of the mineral commodities. In terms of these deflated prices, aluminum and sulfur are much cheaper today than in the early years; copper was substantially cheaper in 1957 than in 1890; pig iron and petroleum are little changed; and only bituminous coal and cement have increased substantially. Strangely, the two mineral commodities with the strongest reserve positions are the two to exhibit rising real prices. Now this apparent overall downtrend in prices has taken place during a period of almost fantastic increase in the demand for mineral products. The value of minerals consumed in the world during the period greatly exceeds all mineral consumption up to 1890. A stage has been reached in the U.S. in which 95 pct of the energy used is of mineral origin and in which machines, structures, roadways, communication facilities, and most other elements in the industrial economy are primarily of mineral origin. Even agricultural fertility is maintained, in large measure, by mineral fertilizers. A series published in Minerals Yearbook shows that the value of U. S. mineral products has risen from $615 million in 1890 to $18,000 million in 1957, a 29-fold increase. Even in deflated dollars, the increase has been eightfold, while population has expanded less than threefold. Not only are demands of the industrial nations— the U. S., countries of Western Europe, and Japan— increasing at rapid rates, but those countries with agrarian economies are calling themselves underdeveloped and clamoring to industrialize. The ever-expanding mineral requirements in the U. S. and throughout the world show no abatement. Mineral reserves frequently have been described as wasting assets. Much concern has been shown for future users, who have been pictured as finding themselves on a plundered planet. Conservationists have viewed the future with alarm and have demanded legislation and regulations to reduce the drain on mineral reserves.

Jan 1, 1960

By L. H. Duschak

Electrolytic zinc produced from sulfate solution and with pure lead anodes is always contaminated with a small and varying percentage of lead. The purpose of this investigation is to determine the characteristics of several lead alloys and their influence on the products of electrolysis and power consumption. The study of alloyed anodes has been a matter of interest for some years. Tainton, Taylor and Ehrlinger prepared a highly interesting paper' on this subject a year ago, in which the effects of silver-lead and some ternary alloys of lead-silver-tin were described, and the presentation of any paper on insoluble anodes will owe much to the inspirational results achieved by Dr. Colin G. Fink and Li Chi Pan in their work on insoluble anodes for the electrolysis of brine,2 and to other published papers by Dr. Fink and his coworkers embracing the development of the copper-silicon-manganese anode for the production of electrolytic copper and the general subject of anode development. The present paper describes a study of various combinations of 10 metals. The general plan of the work provides for the fabrication of the alloyed anode, its adequate conditioning by preparatory electrolytic operation, the production of cathode zinc and its analysis, the determination of the anode polarization, and other features. A list of the anodes tested, showing composition and polarization at various current densities together with the lead assay of the cathode zinc, is shown in Table 1. Determination of Anode Polarization In the determination of anode polarization under operating conditions it is essential that the anode area used be restricted to the side facing the cathode, in order that these measurements may be referred to a definite current per unit of area. It becomes necessary, therefore, to insulate the inactive face of the anode, to prevent the leakage of lines of force

Jan 1, 1930

By FREDERICW K. BRADLE

I HAVE been puzzled by two lines of thought'; one emanating from Washington, D. C., to the effect that we must all cheer up, that in a very short time, measured in terms of months, prices would begin to recover, business would become normal, and prosperity would continue on its way just as before the interruption of a year ago; and a second, coming from certain industrialists and economists, expressing fears that all commodity prices were in for a long downward trend, which would cause much unemployment, eventually drag down wages and so restrict purchasing power as to further aggravate the situation. One basis for the fear of a downward trend in commodity prices' is that ifter great wars a depression could last for something like 40 years-the downward trend to such a depression after our recent World War having been postponed for some reason or other; and the basis for another fear was that the production of gold was becoming less. I had 'also been trying for some time past to refresh my recollection as to how my ow11 particular lead interest climbed out of the depression of 1893; and as all the metals have had, and still have. relative values and prices, I can best express what I have in mind by talking principally about lead.

Jan 1, 1930

By Nicholas J. Grant, Rolf Nordheim, Thomas B. King

Constant-load creep-rupture tests were conducted in an argon atmosphere at temperatures of 1600 to 2200°F on two heats of iron containing about 0.06 and 0.09 pct P in solid solution. The tests were conducted in the as-cast condition. Stresses were selected to give strain rates approaching those encountered in the hot working of steel, and within the limits of the creep-rupture test apparatus, namely. from about 0.001 to 50 pct per sec. FOR generations, rolling and forging practices have been developed largely by empirical methods, based on prior experience. While largely successful, difficulties are frequently encountered when new or different alloy compositions are tried for the first time. There is need to know the relationships which exist among temperature, strain rate, composition, and other variables on the deformation and fracture characteristics of steels. It has been shown for aluminum and several high-temperature alloys that the deformation and fracture characteristics follow rather well-defined laws and patterns which are closely related to the effects of strain rate, temperature, and composition.1"3 As the melting temperature of aluminum or its alloys was approached, it was possible to study the interplay of work-hardening factors and recovery or recrystal-lization, the latter resulting in improved ductility and increased resistance to intercrystalline fracture. In particular, the effects of composition are very poorly known. Within the meaning of "composition" should be included impurity elements, such as sulfur, phosphorous, lead, copper, and many others, as well as those elements which are added for alloying purposes in iron. The role of multiphase structures, in contrast to solid solutions, should also be studied in much greater detail. high strain rate creep-rupture tests would provide information regarding the deformation and fracture characteristics of metals at hot-working temperatures. It was also desired to establish the stresses which are necessary to accomplish the desired deformation, and to relate these to the strain rate and temperature. Secondly, it was the purpose of this particular study to determine the effects of phosphorus, within solid solution limits, on the deformation and fracture characteristics of iron at hot-working temperatures. EXPERIMENTAL PROCEDURE Two phosphorus levels were selected, one corresponding to the upper limit normally found for commercial steels, and one substantially higher than this, but within the region of solid solubility at the test temperatures chosen for this investigation. Twenty-pound heats were prepared by induction melting electrolytic iron in air in a magnesia lined furnace. After deoxidation with about 0.2 pct Al, ferro-phosphorus was added, and the heats were then poured into prefired silica molds. The purpose of using silica molds was to obtain a slow cooling rate during solidification to produce a relatively coarse grain size, producing a structure subject to some segregation and therefore more nearly characteristic of ingot structures. The major part of the casting assembly provided a large shrinkage head in order to produce sound castings and to promote slow cooling of the specimens. The primary austenitic grain size varied from ASTM No. 2 to No. 00. The composition of the heats, including a low phorphorus melt, used for comparison purposes, is shown in Table I. It will be noted that the oxygen content of the phosphorus containing heats is relatively high, in spite of the deoxidation practice, a condition which is difficult to control in small melts. Creep-rupture tests were nevertheless undertaken when it was noted that this quantity of oxygen did not appear to give results any different from those from a heat containing 0.01 pct 0, low phosphorus and comparable carbon Content;4 see Table 11.

Jan 1, 1961

By L. Hartsell Cash

INTRODUCTION Created in 1944 to help rebuild those economies, principally in Europe, which were seriously damaged or destroyed during the Second World War, the World Bank--or to use its correct name, the International Bank for Reconstruction and Development-began its operational phase by making a loan to the Government of France to accomplish two tasks: (i) to import coal for space heating purposes; and (ii) to buy new machinery and equipment to help rehabilitate its coal mines. Once the thrust of reconstruction in postwar Europe was largely accomplished, the World Bank Group (for today the World Bank has three separate lending windows) turned to mobilizing funds to improve living standards in developing countries, which remains its primary goal today. Over this period of time, the World Bank Group has continued to assist the world mining industry in various ways and, since 1955 the World Bank Group has financed mining or mineral processing projects with loans/credits totalling $1.5 billion. The World Bank Group consists of two institutions--the World Bank itself and the International Finance Corporation (IFC), which was founded as a separate institution in 1956 and three separate lending windows--the World Bank, the International Development Association (IDA), and IFC. The World Bank loans are provided at commercially-related interest rates but have grace periods usually of up to 3 to 5 years and repayment periods ranging from around 15 to 20 years. Since the World Bank raises its operating funds on the international capital markets in varying currencies and in varying interest rates, it relends a basket of currencies at floating interest rates which are fixed every six months to reflect the Bank's own borrowing cost. At the present time, the interest rate is just below 10% per year and in addition, a one-time front-end fee of 1/4 of 1% is charged. Also, a commitment fee of 3/4% per year is charged on the undisbursed amount of the loan itself. For loans to industrial and mining projects, it is normal to charge an additional guarantee fee of 1 to 1.5% in addition to the annual interest rate. This guarantee fee is payable to the government of the country in which the project is carried out since, by its charter, the World Bank is required to have the guarantee of the host government for each loan made in a specific country. By far the greatest source of lending funds within the World Bank Group is that of the World Bank itself and for the fiscal year ending June 30, 1984, the World Bank approved loans totalling $12 billion. The second lending window within the World Bank Group is IDA which performs the same functions as the Bank itself and has the same staff. Nevertheless, its loans (called credits) are made on much softer terms and are made to the poorest nations only. IDA funds are subscribed by the wealthier countries, usually as grants, and these are relent as credits to those countries with the lowest per capita income. IDA credits are made for 50 year periods, including 10 years of grace, to the government itself. The credits are interest free, but there is a service charge of 3/4% per year on the amount withdrawn and outstanding to defray the administrative costs of IDA. Credits approved during fiscal 1984 totalled $3.5 billion. The third lending window is IFC. While IFC is a separate corporation and operates quite separately from the World Bank and has its own staff and regulations, it works very closely with the World Bank on its overall approach to the mining sector and to a particular country. IFC's mission is essentially to supply venture capital and to stimulate development of the local private sector in capital markets as well as to promote the international flow of private capital to developing countries. Unlike the World Bank and IDA, the IFC does not lend directly to governments

Jan 1, 1985

By F. W. Jessen, C. A. Johnson

The effect of treatment with ferrochrome lignosul-fonate on both sodium and calcium bentonites has been examined. In the early stages of treatment it appears that some base exchange of iron and chromium for sodium may occur with the sodium bentonite. Such exchange appears specific for exchange of sodium ions when the calcium ion concentration represents 40-5.5 per cent of the total exchangeable cations, and when additions of lignosulfonate are less than 1 lb per bbl. Adsorption appears entirely physical above 1 lb per bbl treatment level for all concentrations of calcium studied. Gel strength and plastic viscosity of both calcium and sodium bentonite systems were reduced with treatments of ferrochrome lignosulfonate up to 2 Ib per bbl, the greatest reduction occurring within a range of calcium concentration of 40-5.5 per cent of the total exchange capacity of the clay. INTRODUCTION The problem of control of viscosity and gel strength of drilling fluids by the action of thinners or dispersants has been studied by many investigators.1-7 In addition, much work has been done on formation of gel structure in clay suspensions. However, gel formation and structure still are incompletely understood, and the use of the various dispersing chemicals is based, to a large extent, on data almost entirely empirical in nature. In recent years the lignosulfonates have become increasingly important in the treatment and control of drilling fluids. More specifically, ferrochrome lignosulfonate has found rather wide acceptance, particularly in calcium systems.5-7 Lignosulfonates are refined lignin products made from spent sulfite liquor from which the fermentable sugars have been removed.15 The exact structure of lignin is not known; however, it is believed to be a phenolic propane type polymer which may exist as a branched chain or cross linked structure. The molecular weights of lignosulfonates probably range from 300 to 100,000 or more.15 A better understanding of the mechanism of adsorption of dispersants is essential before improvement and development of characteristics of drilling fluids and drilling fluid control is possible. This investigation was undertaken to determine the action of ferrochrome lignosulfonate on sodium and calcium montmOrillonite' LABORATORY INVESTIGATION A Stormer viscosimeter and Fann V-G meter were used to measure viscosity and gel strength. A Zeiss spectrophotometer was used for analysis of Fe and Cr and the flame attachment was employed in the analysis of Na, Ca and Mg. A General Electric X-ray diffraction unit utilizing Copper Ka radiation and a Ni-filter was utilized in the X-ray studies. PROCEDURE Two systems were studied. Predominately sodium clay, obtained from Wyoming, and a predominately calcium clay from Texas were used. These particular samples were chosen because of the extensive work of characterization completed by Mungan. Ionic base exchange capacity determined by flame photometry and total exchange capacity by the Kjehldahl method were obtained experimentally. A 7-per cent suspension of the sodium clay and a 20-per cent suspension of the calcium clay in distilled water were prepared by mixing with a high-speed mixer. The suspensions were allowed to stand for two weeks for complete hydration. Calcium chloride was added to portions of the sodium and calcium cla suspensions to obtain suspensions varying in Ca++ concentration as shown in Table I. A series of treatments was run with 500-ml portions of the original suspensions using a ferrochrome lignosulfonate. Treatment was carried out in the same way with each of the suspensions of varying Ca concentration. Viscosity and gel strength were measured and a filtrate obtained at each treatment level. Ten ml of filtrate were diluted to 50 ml, and aliquot portions of the 50 ml were taken for the Na, Ca, and Mg analysis by the flame photometer. The pH of these filtrates ranged from 7 to 7.3. Standard

By W. A. Gibson, A. D. Trujillo

The Santa Rita copper deposit first served as a source of native copper for Indian implements and weapons. In 1801 Santa Rita copper, trans- ported by mule train to Chihuahua, began to be used commercially for making coins. It was a small- scale operation made difficult by Indian raids, transportation costs and depletion of the higher grade ores. There was, moreover, no known method for economically extracting copper from the under- lying low grade sulfide ores. Originally, copper and copper oxide ores were mined by underground methods, but there was virtually no development of the deposit-which became United States territory after the Treaty of Guadalupe Hidalgo in 1848-for almost a hundred years. A number of small underground mines had been started during that time, but it was not until 1873 that all the principal claims were consolidated under one control.

Jan 1, 1966

By E. T. Hayes, A. H. Roberson, M. H. Davies

ZIRCONIUM has been produced on a pilot-plant scale for only a few years, but the potential uses have led a large number of research establishments to engage in a thorough study of the metal and its alloys. The work described in this paper is part of a cooperative project between the Bureau of Mines and the Air Materiel Command. The Zr-Cr system was one of the first investigated because of the possibilities of improving the properties at elevated temperatures, the chemical corrosion resistance, and the mechanical properties of zirconium in a manner similar to the enhancement of the properties of titanium by additions of chromium. There is no published work on the Zr-Cr system but from the similarity of the metals involved it was expected that it would be similar to the Zr-Fe' and Ti-Cr' systems. The materials used in this investigation were prepared in the Bureau of Mines laboratory at Albany, Ore. Zirconium was produced by magnesium reduction of zirconium tetrachloride, and a typical analysis is as follows: Fe, 0.06 pct; Ox, 0.08; N?, 0.01; C, 0.02; and other impurities such as Al, Pb, Ni, Ti, and Si less than 0.01 pct each. High purity chromium was prepared by treating crushed electrolytic chromium in a stream of dried and purified hydrogen." The resulting powder contained about 0.01 pct 0 and about 0.1 pct total metallic impurities. All alloys were prepared by arc-melting 50 g briquetted compacts of the desired composition in a Kroll-type" arc furnace using an inert atmosphere. The furnace was evacuated twice and backfilled with helium, which was gettered by melting a center zirconium button immediately before the alloys were melted. Alloys were remelted at least once to insure greater uniformity of composition and subsequently were annealed in vacuum at 1250°C for 48 hr. Fairly homogeneous alloys were obtained by this means; a slight loss of chromium from the surface by evaporation during the high temperature homogenization was noted. All alloys were analyzed for chromium and gave results in good agreement with the nominal composition. Spot checks on tungsten and nitrogen showed pick-up of these elements to be negligible. Over 70 alloys were prepared for use in this investigation; only the critical ones are shown in Table I. Alloys containing up to 10 pct Cr were amenable to hot working at 850°C and a number of these were sheath rolled to 1/16 in. thickness. Specimens were cut from the sheet for use as metallographic samples. For the thermal analysis a differential couple was used in conjunction with an X-Y recorder, the temperature of the specimen and the difference in ternperature between it and the standard nickel body were recorded simultaneously. Heating and cooling rates of 5°C per min were used. The sensitivity of the instrument was such that a difference in temperature between the specimen and standard equivalent to 0.1 mv produced a deflection of 1 in. on the recording chart. The chromel-alumel thermocouples were checked against a Bureau of Standards calibrated thermocouple. Melting-point determinations were made in a high vacuum induction furnace using an optical pyrometer. The pyrometer, calibrated against nickel, copper, and zirconium (iodide process) under near black body conditions, was focused on the base of a hole drilled in cylindrical samples. A North American Philips Geiger counter X-ray spectrometer was used for all diffraction studies. This instrument, in addition to supplying precise intensity measurements of planar reflections, has an added advantage in that metallographic specimens mounted in bakelite can be used directly, and this

Jan 1, 1953

By C. H. Li, S. H. Bendel, J. A. Sartell

Small additions of Mg to a 62 Cu-38 Ni alloy reduce the oxidation yates drastically between 500° and 850°C. Metallographic examination of the oxide scale disclosed a continuous network, identified by X-ray diffraction as (Ni, Mg)O solid solutions, located along the former alloy grain boundaries. This network acts as a barrier to diffusion. It is thought to result from the segregation of mg to the alloy grain boundaries. Oxidation occurs preferentially in these regions because of the presence of this more active element. To substantiate these ideas, homogenized alloys ulere oxidized. No oxide network was produced and oxidation rates were the same as for the parent 62 Cu-38 Ni alloy. An interesting aspect of the oxidation of the 62 Cu-38 Ni alloy previously described by the present authors, is the relationship between oxidation kinetics and changes in the microstructure of the oxide.' The oxide scale on these alloys consists of two layers: a thin layer of CuO outside a much thicker layer of Cu20 in which particles of NiO are dispersed. In addition, immediately beneath the oxide-metal interface there is an internally oxidized zone in which NiO particles are dispersed in a copper-rich alloy matrix. Experimental observations on the growth of the individual layers under isothermal conditions have led to the conclusion that the rate-determining step in the oxidation of this alloy is the diffusion of anions through the Cu20 layer. It has been found that this diffusion rate is increased by the recrystallization of the outer CuO layer. Willardson and Gorton have reported that the addition of magnesium to the 62 Cu-38 Ni alloy causes a decrease in the oxidation rate.2 The present investigation was undertaken in order to determine the mechanism by which magnesium additions improve the oxidation resistance of the 62 Cu-38 Ni alloy. EXPERIMENTAL PROCEDURE Fifty-gram ingots of Cu-Ni alloys were prepared by vacuum melting materials of 99.999+ pct purity. These ingots were then remelted in a He atmos- phere and magnesium added in the form of a previously prepared and analyzed Cu-Mg master alloy. This procedure was necessitated by the high reactivity of pure magnesium at high temperatures. The proportion of the alloying elements was adjusted so as to obtain alloys with the desired magnesium content while maintaining a Cu-Ni ratio of 62 :38 by weight. (All alloy compositions will be given in weight percent.) Since it was considered desirable to study the oxidation of only single-phase, solid-solution alloys, it was necessary first to determine the approximate limit of solid solubility of magnesium in the 62 Cu-38 Ni alloy. A series of melts with various magnesium contents was made, homogenized by annealing for 48 hr at 975OC, then cooled in the furnace. Metallographic samples were prepared, etched in a potassium dichromate solution and examined at XI500 for the presence of a second phase. The alloys were then chemically analyzed and it was found that the approximate limit of solid solubility of magnesium in the 62 Cu-38 Ni alloy was 1 pct Mg. The ingots containing less than 1 pct Mg (0.19, 0.29, 0.58, and 0.87 pct Mg) were cold-rolled down to thicknesses suitable for oxidation experiments and specimens for gravimetric studies were cut to dimensions of 3.0 by 1.5 by 0.05 cm, specimens for inert marker studies, 0.6 by 0.6 by 0.17 cm. These were heat-treated in a protective atmosphere at a temperature (975" C) well above the oxidation temperatures and furnace-cooled to insure structural stability of the alloy during oxidation. Immediately prior to oxidation, the specimens were chemically cleaned by immersion for 1 min in a solution of 2 parts nitric acid, 1 part acetic

Jan 1, 1961

By A. D. Schwope, L. R. Jackson, K. F. Smith

Burghoff and Blank1 have pointed out that the creep properties of hard-drawn coppers are closely associated with their individual softening characteristics and have further shown that the creep resistance of various types of copper is improved, under certain circumstances, by cold stretching. In the design of certain types of electrical machinery, it is important to have the creep resistance as high as possible; furthermore, short-time creep strength is important since in many cases stresses are large only during warming-up and cooling-down periods. In this paper, data are presented showing the effect of cold work on the short time creep strengths of various types of commercial copper under several conditions. It is shown that trends from short-time creep tests are evident at longer times. Materials Used in the Investigation The coppers used in this investigation were commercial grade and of two basic types, oxygen free high conductivity (OFHC) and tough pitch. Additions of silver in amounts of 15 and 25 oz per ton were added to each of the two coppers. The analyses of these six coppers are given in Table 1. Originally, they started as wire bars 4 X 4 X 54 in. A. square rod was made by hot rolling the wire bars to 9/16-in. rod in 8 passes. This rod was then cold drawn to 0.445-in.-diam rod and annealed for 3 1/2 hr at 1000°F. It was then cold drawn to 0.325-in. rod and again annealed at 1000°F for 3 1/2 hr. Hard square rods were then made by cold rolling to 0.257 X 0.257-in. rod. Soft wire was made from the hard- drawn material by annealing at 650°F for 3 hr. The final rolling was performed using a set of 9-in. grooved rolls revolving at 30 rpm, which produced square wires. Reductions of approximately 5, 20, 30, and 40 pct were obtained using several passes in the same direction for the large reductions. The 5 pct reduction by drawing was accomplished using a steel die having 2 parallel bearing surfaces. The die angle was 7 1/2 degrees and the wires were lubricated with a paste of ceresin wax dissolved in carbon tetrachloride. The speed of drawing was 13 fpm. Since work was done on only two sides of the wire simultaneously, it was necessary to rotate it 90 degrees each pass to insure uniform deformation. The room-temperature tensile properties of the various tempers are given in Table 2. The grain size of the an- nealed 0.257-in. wires was uniform and averaged about 0.035-0.045 mm. Experimental Procedures for Short-time Creep Tests Standard creep-test frames (Fig 1) were used for the testing. Special fixtures were designed to apply axial compressive and tensile loads to the copper wires. The compression specimens were 1 in. long and the ends were ground flat and parallel. The creep in compression was indicated by the movement of reference marks s-ratched on intersliding platinum strips attached to the moving heads of the fixture. The movement was measured with an optical micrometer fitted with a filar eyepiece on which the smallest division was 0.00005 in. The tensile creep specirriens were 4 in. long which provided ample gripping surface for the jaw-type grips. The platinum strips were attached to a one-inch gauge length of the wire and the creep measured as previously described. The single-specimen furnaces were connected to individual power and control sources. The controlling equipment consisted of Foxboro controllers

Jan 1, 1950

By C. A. WARNER

AN OIL and gas mining lease contract, as entered A into by and between 'the lessor and the lessee, contains certain express covenants stipulating, in part at least, the exact performance thereof; it also contains certain implied covenants, among which may be included that of protection of the leased premises against drainage by the drilling of necessary offset wells. In the drilling for, and production of, oil and gas, however, it not infrequently happens that the lessee, acting in good faith, does not deem it prudent to, drill a test thereon even though the location for such test is offset by a producing well on an adjoining lease. Such conclusion, on the part of the lessee, is generally construed by the lessor as constituting a breach of the implied covenant mentioned above, and he may take proper action to secure satisfaction therefor. The action against the lessee is generally for cancellation or relinquishment of the lease, together with, or apart from, claims for damages allegedly sustained through failure to properly protect against drainage of the leased premises.

Jan 1, 1931

By Juan Sodi, John F. Elliott

The standard free energy of ReS2 has been measured in the range of 1050° to 1250°K using H2/H2S mixtures and a slight variation of the method described by Hager and Elliott.1 The result is: The experimental method and apparatus were modified slightly for this study. Measurements on Cu2S were made to verify the application of the method to the work on ReS2. THE EXPERIMENTS AND RESULTS Briefly, the experimental method consisted of exposing a chip of copper or rhenium at a known temperature for 8 hr to a slowly flowing gas stream at the same temperature in which Ph2S and PH2 were known. The chip was withdrawn quickly from the hot furnace, and subsequently it was inspected for the presence of a sulfided surface. In the experiments described here, there was no ambiguity in any case as to the presence or the absence of the sulfide. At a given temperature, gas compositions for sulfidization were explored systematically until two compositions were found whose values of ?G°, Eqs. [I] and [2], were within approximately 100 cal of each other, one of which was sulfi-dizing and the other was not. These are termed the "straddle" compositions and it is assumed that the equilibrium composition lies between them. The chief modification to the apparatus, which is shown schematically in Fig. 1 of Ref. 1, was to support the metal specimen on a small alumina boat which could be moved along the reaction tube, 6 mm ID, by platinum wires. An appropriate seal at each end of the reaction tube permitted the sample to be moved from the cold end of the tube into the hot zone in 2 to 3 sec, and the sample could be withdrawn equally rapidly. Thus, it was possible essentially to quench the specimen from the reaction temperature with the reaction gas or helium flowing and without danger of breaking the reaction tube. The usual practice at the end of the experiment was to switch the gas system to the helium tank, flood the reaction chamber with helium, and pull the sample out of the hot zone. The purpose of the modification was to permit study of the sulfidization of copper without the complication of the back-reaction between the gas and the specimen as the latter cooled during slow withdrawal of it from the hot zone; this was a problem in the earlier work.&apos; A further improvement located the tip of the temperature-indieating thermocouple and the specimen precisely at the hottest part of the furnace. A carefully calibrated thermocouple, with its tip at the position of the specimen and with other conditions duplicating those of an actual experiment, showed that in the temperature range of 900° to 1122°C the temperature of the specimen differed from that of the tip of the indicating thermocouple by less than 0.5°C. The two positions were 0.5 cm apart. The reaction gas was prepared from ultrahigh-purity hydrogen (<l ppm O2, <0.5 ppm H2O) and CP grade hydrogen sulfide (99.5 pct H2S). High-purity helium (99.995 pct He) was used. All of these gases were purchased from the Matheson Co. All flow meters were recalibrated by the soap-bubble method with hydrogen, H2S, helium, and several gas compositions used during the study. These calibrations gave a linear relationship with a slope of 1.0 for the plot of log flow rate vs log pressure drop across the flow meter, in accordance with the Hagen-Poiseuille equation. The analysis of the gas was determined in the same manner as was reported previously. Good checks were obtained between the composition of the gas established by the flow-meter settings and by chemical analysis of the gas taken after the mixing bulb and ahead of the furnace. The pressures of H2S, H2, S2, and HS in the equilibrium gas at temperature were calculated from the following data :3 The pressures of the species S and S8 were negligible for the conditions of the experiments.3 There was no sign of vaporization of ReS2 either by weight loss or deposits in the reaction tube. Thus it is not possible to account for the apparent volatility of the compound reported by Juza and Biltz.2 The inlet gas composition and the calculated equilibrium ratio of PH2 S/PH2 for the "straddle" points of each experiment are shown in Table I. The specimens of metal for the experiment were small clippings of annealed copper (99.9+ pct) sheet 0.005 in. thick that was obtained from Baker and Adamson and of "high-purity" rhenium (99.9+ pct) sheet 0.005 in. thick that was purchased from Chase Brass and Copper Co. A specimen was removed from the apparatus; inspected for the presence of the sulfide, and then stored in a sealed vial. A fresh clipping was used in each measurement. The condition of the surface of each specimen after the experiment is noted in Table I.

Jan 1, 1969

By L. E. Snow, L. F. Pett

AT the Utah Copper Pit of Kennecott Copper Corp. a versatile mobile drill unit has been developed and tested. Through increased drilling speed and additional available drilling time, an improvement of 233 pct in drill performance has been realized. Operators using drill power can quickly and easily convert the unit from a vertical to a toe hole drill. Drilling is done with the machine in line with the unit or at right angles to it. Table I covers the 1950 drill record at the mine, showing the types of machines used and the footage obtained. Development of the new units was prompted by a desire for solution of the following problems: 1—The ever-expanding operations within the Utah Pit, requiring some 65 miles of transmission pipe lines radiating from a central compressed air plant, have now taxed this compressor plant beyond capacity. While 100 lb per sq in. pressure is maintained at compressors, transmission losses from innumerable small leaks result in low terminal pressure at the drills. Fig. 1 illustrates that while terminal pressure varies according to size of air hose and fittings used, the average drill is operating on air pressures within the 60 to 70-lb range. The compressor plant is operated primarily for air rock drills. All drilling is done on day shift, but it is necessary to run two of the three 3720 cu ft capacity compressors during night shift in order to prevent drastic loss of pressure through leaks. On day shift all three compressor units are operated at capacity, so that there is no reserve safeguard available for extensive repairs to any compressor. The calculated volume of compressed air required for operation of 25 drills is but 33 pct of three day-shift compressors. While compressed air is being used to a minor extent for purposes other than drilling, it is felt that satisfactory substitute facilities could be pro- vided in the event that air lines were no longer available. 2—Drill performance has increased beyond the capacity of present 3-in. drifter machines. 3—The installation, maintenance, and moving of air lines in routine mining is a growing problem. The 2-in. level lines are placed outside electrification towers and must be moved to new location upon completion of each shovel cut. In addition to these moves it is often necessary to dismantle level lines so that excessive shovel spillage, or material covering track following a blast, can be pushed in the clear with bulldozers. Where level room is limited, it is often necessary to remove air lines in giving bulldozers room to prepare grades for wagon drills. In spite of precautions taken, many level lines become buried, twisted, and constricted, with excessive air loss resulting. Excessive back break in blasting often leaves several sections of air line suspended in mid-air. Occasionally air lines come in contact with defective electric transmission towers, so that holes are burned through pipe. 4—Rail-handling of drilling equipment such as wagon drills from one location to another requires considerable locomotive crane crew time. Any new unit developed should travel under its own power. 5—Present practice requires accessory material including hose, water pressure tanks, water barrels, drill steel, and bits to be transported by means of push cars when drill locations are changed on any level. 6—In order to supply numerous drill locations with material, many stock piles of new drill rods, drill bits, and other essentials must be left at strategic points, usually in the vicinity of powder magazines. This practice makes for poor housekeeping and contributes to the loss of supplies. Planning the Unit It was felt that a mobile drill unit which would rectify the foregoing problems should meet certain demands: 1—It must furnish compressed air to operate a 4-in. rock drill at a pressure of 90 to 100 lb.

Jan 1, 1953

By L. E. Snow, L. F. Pett

AT the Utah Copper Pit of Kennecott Copper Corp. a versatile mobile drill unit has been developed and tested. Through increased drilling speed and additional available drilling time, an improvement of 233 pct in drill performance has been realized. Operators using drill power can quickly and easily convert the unit from a vertical to a toe hole drill. Drilling is done with the machine in line with the unit or at right angles to it. Table I covers the 1950 drill record at the mine, showing the types of machines used and the footage obtained. Development of the new units was prompted by a desire for solution of the following problems: 1—The ever-expanding operations within the Utah Pit, requiring some 65 miles of transmission pipe lines radiating from a central compressed air plant, have now taxed this compressor plant beyond capacity. While 100 lb per sq in. pressure is maintained at compressors, transmission losses from innumerable small leaks result in low terminal pressure at the drills. Fig. 1 illustrates that while terminal pressure varies according to size of air hose and fittings used, the average drill is operating on air pressures within the 60 to 70-lb range. The compressor plant is operated primarily for air rock drills. All drilling is done on day shift, but it is necessary to run two of the three 3720 cu ft capacity compressors during night shift in order to prevent drastic loss of pressure through leaks. On day shift all three compressor units are operated at capacity, so that there is no reserve safeguard available for extensive repairs to any compressor. The calculated volume of compressed air required for operation of 25 drills is but 33 pct of three day-shift compressors. While compressed air is being used to a minor extent for purposes other than drilling, it is felt that satisfactory substitute facilities could be pro- vided in the event that air lines were no longer available. 2—Drill performance has increased beyond the capacity of present 3-in. drifter machines. 3—The installation, maintenance, and moving of air lines in routine mining is a growing problem. The 2-in. level lines are placed outside electrification towers and must be moved to new location upon completion of each shovel cut. In addition to these moves it is often necessary to dismantle level lines so that excessive shovel spillage, or material covering track following a blast, can be pushed in the clear with bulldozers. Where level room is limited, it is often necessary to remove air lines in giving bulldozers room to prepare grades for wagon drills. In spite of precautions taken, many level lines become buried, twisted, and constricted, with excessive air loss resulting. Excessive back break in blasting often leaves several sections of air line suspended in mid-air. Occasionally air lines come in contact with defective electric transmission towers, so that holes are burned through pipe. 4—Rail-handling of drilling equipment such as wagon drills from one location to another requires considerable locomotive crane crew time. Any new unit developed should travel under its own power. 5—Present practice requires accessory material including hose, water pressure tanks, water barrels, drill steel, and bits to be transported by means of push cars when drill locations are changed on any level. 6—In order to supply numerous drill locations with material, many stock piles of new drill rods, drill bits, and other essentials must be left at strategic points, usually in the vicinity of powder magazines. This practice makes for poor housekeeping and contributes to the loss of supplies. Planning the Unit It was felt that a mobile drill unit which would rectify the foregoing problems should meet certain demands: 1—It must furnish compressed air to operate a 4-in. rock drill at a pressure of 90 to 100 lb.

Jan 1, 1953

By R. D. Saltsman

This paper deals with the evolution of a test procedure devised to totalize a coal&apos;s ignitibility, its degree of caking, and its coke reactivity and the development of a method for assigning proper combustion indices to stoker coals. The application of this type of work to stoker design is also discussed. It is believed that this work may be the prelude to understanding the effect of various petrographic constituents on the combustion characteristics of a coal or a blend of coals. The inadequacy of our knowledge of the coal combustion process has long been recognized. This was expressed very well by Spicer and Finney.1 "The control of combustion processes in industry and the design of the equipment necessary for efficient burning to take place have always been very much branches of an industrial art rather than of an exact science. This has been especially true of the utilization of coal, a substance so heterogeneous and complex in character that all too little is known about its chemical and physical composition." During the past several years one branch of coal utilization, that of high temperature carbonization, has made significant advances from being an art into being an exact science. This has been accomplished by the development of petrographic techniques for identifying, measuring, and determining the thermal properties of the organic materials which affect the carbonization of coal and the correlation of this information with a pre-existing standard of coke quality, the stability index. The success in using petrographic analysis for predicting the coking properties of coals and their blends suggested that petrographic techniques might be applied to the combustion process for predicting the combustion characteristics of coals. Certainly the different organic entities2 influence the combustion characteristics of a coal as they influence its coking properties. If it were possible to predict combustion characteristics from an analysis of a coal&apos;s petrographic composition, it would seem logical that an intelligent investigation could then be made into methods of altering stoker coals to improve their combustion characteristics. The successful application of petrographic analysis in the field of high temperature carbonization was made possible by the pre-existence of the stability index, which is a numerical value of coke quality. The quality of combustion is determined by the sum of the effects of the ignitibility, the caking, and the coke reactivity characteristics of a coal. While the literature is filled with papers reporting the correlation of various analyses to the ignitibility, or to the caking, or to the coke reactivity characteristics of coals, none of these earlier studies could be related to one index. The lack of a single index for combustion quality precluded the application of petrographic techniques for predicting combustion characteristics. SELECTION OF THE COMBUSTION TEST EQUIPMENT The primary prerequisite of any test developed to evaluate the relative performance of stoker coals must reflect the three characteristics of the coal burning process: 1) ignitibility, 2) degree of caking, and 3) coke reactivity. The widespread variations in these combustion characteristics of the available stoker coals are well known. The ignitibility, which has been defined as that characteristic which determines the ease with which the fuel may be brought to a condition of self-supporting active oxidation, varies from where a coal is deemed to be flashy to the opposite extreme of being fireproof. The ignitibility of a coal influences its ability to pick-up from hold fire, greatly affects the degree of bed stability during swing loads, and is a factor in determining the average burning rate obtainable on a given grate. The caking characteristic affects the degree of bed porosity during the devolatilization period, and coals are classified on a scale varying from free burning to highly caking. Caking is not synonymous with bed swelling since a bed may swell two to three times its normal depth during the period of devolatilization yet remain very porous, allowing an efficient and high rate of combustion to take place. Caking is melting

Jan 1, 1964

By L. E. Snow, L. F. Pett

AT the Utah Copper Pit of Kennecott Copper Corp. a versatile mobile drill unit has been developed and tested. Through increased drilling speed and additional available drilling time, an improvement of 233 pct in drill performance has been realized. Operators using drill power can quickly and easily convert the unit from a vertical to a toe hole drill. Drilling is done with the machine in line with the unit or at right angles to it. Table I covers the 1950 drill record at the mine, showing the types of machines used and the footage obtained. [ ] Development of the new units was prompted by a desire for solution of the following problems: 1-The ever-expanding operations within the Utah Pit, requiring some 65 miles of transmission pipe lines radiating from a central compressed air plant, have now taxed this compressor plant beyond capacity. While 100 lb per sq in. pressure is maintained at compressors, transmission losses from innumerable small leaks result in low terminal pressure at the drills. Fig. 1 illustrates that while terminal pressure varies according to size of air hose and fittings used, the average drill is operating on air pressures within the 60 to 70-lb range. The compressor plant is operated primarily for air rock drills. All drilling is done on day shift, but it is necessary to run two of the three 3720 cu ft capacity compressors during night shift in order to prevent drastic loss of pressure through leaks. On day shift all three compressor units are operated at capacity, so that there is no reserve safeguard available for extensive repairs to any compressor. The calculated volume of compressed air required for operation of 25 drills is but 33 pet of three day-shift compressors. While compressed air is being used to a minor extent for purposes other than drilling, it is felt that satisfactory substitute facilities could be provided in the event that air lines were no longer available. 2-Drill performance has increased beyond the capacity of present 3 ½ -in. drifter machines. 3-The installation, maintenance, and moving of air lines in routine mining is a growing problem. The 2-in. level lines are placed outside electrification towers and must be moved to new location upon completion of each shovel cut. In addition to these moves it is often necessary to dismantle level lines so that excessive shovel spillage, or material covering track following a blast, can be pushed in the clear with bulldozers. Where level room is limited, it is often necessary to remove air lines in giving bulldozers room to prepare grades for wagon drills. In spite of precautions taken, many level lines become buried, twisted, and constricted, with excessive air loss resulting. Excessive back break in blasting often leaves several sections of air line suspended in mid-air. Occasionally air lines come in contact with defective electric transmission towers, so that holes are burned through pipe. 4-Rail-handling of drilling equipment such as wagon drills from one location to another requires considerable locomotive crane crew time. Any new unit developed should travel under its own power. 5-Present practice requires accessory material including hose, water pressure tanks, water barrels, drill steel, and bits to be transported by means of push cars when drill locations are changed on any level. 6-In order to supply numerous drill locations with material, many stock piles of new drill rods, drill bits, and other essentials must be left at strategic points, usually in the vicinity of powder magazines. This practice makes for poor housekeeping and contributes to the loss of supplies. Planning the Unit It was felt that a mobile drill unit which would rectify the foregoing problems should meet certain demands: 1-It must furnish compressed air to operate a 4-in. rock drill at a pressure of 90 to 100 lb.

Jan 1, 1952

By S. F. Frederick, W. A. Bailey

The relationship between microstructure and mechanical properties of cast 356-type aluminum alloys was studied to determine the cause of the variations in properties resulting from differences in solidification rate. It was found that variations in strength are a consequence of variations in ductility and that ductility is inversely proportional to the dendrite cell size. A mechanism is proposed to account for this correlation based on the fracture strain of the inter-dendritic silicon particles and the differential strain across dendrite cell boundaries. IT has long been assumed that permanent mold castings of aluminum are superior to sand castings because of their finer grain structure and reduced porosity.&apos; A systematic variation of static properties was noted during unpublished studies of fatigue-strength variations with solidification rate of A356-T6. Of particular interest was the observation that for a given composition and heat-treatment, both ductility and the ultimate strength increased with higher solidification rate. Because the A1-Si system forms the basis of many alloys used for castings and welding wire, a study was initiated to determine the details of how higher cooling rates improved mechanical properties of these alloys. The results of this study are presented here. EXPERIMENTAL PROCEDURE Specimens were prepared from 356-T6 to supplement the A365-T6 alloy data from earlier studies. This allowed a comparison of behavior of alloys with substantially different strengths but with only small differences in alloy composition. The composition and heat treatment of both alloys are given in Table I. The specimens were cut from a chill plate casting,&apos; which is a 6 by 9-in. plate, 1 in. thick, which has one end heavily chilled, and a large riser at the other so that solidification is essentially unidirectional from the chill end to the riser. Although not measured here, solidification times measured on similar specimens by embedded thermocouples are a few seconds at the chill end and up to 5 min near the riser. Specimens were obtained by cutting slabs from the plate, parallel to the chill; these represented different cooling rates, with essentially the same composition. For the tests, either 0.125 or 0.250-in. thick slabs were cut for standard 2-in. gage length specimens. The thicker specimens were tested to failure at 2000 lb per min while the thinner specimens were tested in an Instron machine at a constant cross-head speed of 0.02 in. per min. These thin specimens were intended for trans- mission electron microscopy. Some thin specimens were tested to failure while the remainder were given various amounts of prestrain. Dendrite cell sizes were measured by the linear intercept method on photomicrographs at either X100 or X50, depending on the cell size. It was assumed that the dendrite cells were outlined by the silicon particles. Determinations were made on two mutually perpendicular planes and an rms average taken. Electron fractographs of representative tensile specimens were made in the conventional manner using the two-stage replica technique.3 Samples for transmission electron microscopy were prepared by chemical milling followed by electropolishing. RESULTS AND DISCUSSION The results of the tensile tests and the dendrite cell-size determinations are given in Figs. 1 and 2. All data show the same trends, namely, a decrease in ultimate strength and elongation with increasing distance from the chill (and solidification time), and a corresponding increase in dendrite cell size. The yield strength remains essentially constant. The constancy of the yield strength was particularly significant since it indicated that variation in the solidification rate does not affect the stress required to initiate plastic flow. By plotting true stress-true strain curves as in Fig. 3, it can be seen that both

Jan 1, 1969

By F. W. Lee

Historical-From the beginning of time, all ingenuity of mankind has been concentrated upon the methods of finding gold and unusual deposits in the earth. An illustration (Fig. 1) from the old treatise by Agricola, "De Re Metallica," published in 1580, will serve to show the im-plicit faith of that generation in divining methods. However, it was not until 1920 that real progress was made in prospecting by using the latest advances of the physical sciences. The public interest was stimulated by the successes of these methods on the part of commercial oper-ators, and governmental agencies received many requests for information concerning their relia-bility. There were also, in the late 1920&apos;s.high- pressure mine-promotion schemes which used geophysical methods in a very questionable manner, symbolized in Figure 2 as of 1928 by an elec-trified forked stick. Authoritative information concerning such practices for public protection was needed to curb such notorious undertakings. Dr. Scott Turner, then Director of the United States Bureau of Mines, thoroughly understood the situation and was first in the governmental de-partments to recognize the possible value of a study of modern prospecting methods. The Bureau of Mines began this investigation by employing Drs. A. S. Eve and D. A. Keys of McGill University for short periods in the summer in 1927. Their first publication [see 1 of "References" at end of paper] served to illustrate the fundamental scientific principles which underlie geophysical prospecting. This was followed by a second publication [21 giving the results of field-tests. In the light of the rapid improvements during the intervening ten years, these two papers take a historical position. Later a full-time position under Civil Service was planned by the Bureau of Mines for con-tinuous investigations and research concerning geophysics and its applications to prospecting. It was Turner&apos;s idea that. since the oil-industry had been making very rapid progress with good results, if mineral mining could also benefit to the same degree, it would be of great help to that industry.

Jan 1, 1940

By E. K. Olson

Eagle Mountain mine of Kaiser Steel Corp. began production in 1947 when the direct shipping ore contained 51-56% Fe. The high grade, wide ore face and low stripping ratio ores were rapidly depleted and Eagle Mountain required processing plants for upgrading and more efficient mining equipment. During 1970-71 total annual pit tonnage averaged 56 million tons of material ranking the Eagle Mountain Mine as the fourth largest in the country. Ore production averaged 12.5 million tons requiring a stripping ratio of 3.5: 1. During this period mining activities were scheduled for a three-shift, seven-day operation. The present mining rate is about 30 million tpy on a two-shift, five-day schedule.

Jan 12, 1972

By Arthur F. Hagner

The titaniferous magnetite deposit at Iron Mountain, Wyoming, is in Precambrian anorthosite. Individual ore bodies are lenses, commonly arranged en echelon, conformable to the platy crystal structure and compositional layering of the anorthosite; a few transect these features at various angles. The ore bodies are on the east flank of the principal anticline in the anorthosite mass. Magnetite and ilmenite, accompanied by spine!, are the ore minerals. The principal gangue minerals are olivine, which was introduced with the ore, and plagioclase, the chief constituent of the anorthosite. The anticlinal region appears to have been a structurally weak zone, and westward-bowing curves of the axis were especially favorable sites for localization of the two largest massive ore bodies. These bodies are synclinal and plunge southeast. The proportion of magnetite-ilmenite to olivine and to anorthosite appears to be related to structural features. Where magnetite-ilmenite is present with olivine, the magnetite-ilmenite is encountered along the most pronounced parts of a fold where anorthite content is highest, whereas olivine is associated principally with more gently folded portions. During granulation and recrystallization of the anorthosite mass, temperature and pressure changes furnished the energy required to release and mobilize iron and other elements that migrated to areas of low pressure, the ore zone. Some iron and magnesium may have combined with silica from partly dissociated plagioclase to form olivine. The ore formed by replacement of anorthosite as indicated by: (1) the marked changes in mineralogy along strike, dip, and plunge of an ore body; (2) the concentration of massive ore in folds and olivine on limbs; ( 3) the halo of low-grade mineralized rock that transects the structure of the anorthosite in the hanging wall; and ( 4) the layering in the large southern ore body, that strikes more easterly than the trend of the body.

Jan 1, 1968