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Iron Ores and Blast Furnace Practice Concentration of Iron Ores in the United States. By T. R. Counselman. (Metals Technolog), December 1943) Selection of Blast-furnace Refractories. By Hobart M. KrANer and E. B. Snyder. (Metals Technology, April 1944) The Washing of Pittsburgh Coking Coals and Results Obtained on Blast Furnaces. By C. 1). King. (Metals Technology, September 1943) Steelmaking The Role of Basic Slags in the Elimination of Phosphorus from Steel. By Richard L. BArrett and William J. McCaughey. (Metals Technology, April 1944) The Relative Deoxidizing Power of Boron In Liquid Steel and the Elimination of Boron in the Open-hearth Process. By B. W. Gurry. (Metals 'Technology, December 1943) Manufacture and Properties of Killed Bessemer Steel. By C. C. Wright. (Metals Technology, June 1944) Hardenability Effect of Sixteen Alloying Elements on Hardenability of Steel. By Irvin R. Kramer, Robert Hafner and Stewart L. Toleman. (Metals Technology, September 1943) Effect of Quenching Temperature on the Results of the End-quench Hardenability Test. By Clarence E. Jackson and Arthur L. Chrjstenson. (Metals Technology, December 1943) Effect of Some Elements on Hardenability. By Walter Crafts and John L. Lamont. (Metals Technology, January 1944) Effect of Several Variables on the Hardenability of High-carbon Steels. By I?. S. Rowland, J. Welchner and R. IS. Marshall. (Metals Technology, January 1944) Mechanical Properties Influence of Hydrogen on Mechanical Properties of Some Low-carbon Manganese-iron Alloys and on Hadfield Manganese Steel. By Herbert H. Uhlig. (Metals Technology, June 1944) Aging and the Yield Point in Steel. By J. R. LOW, Jr., and 14. Gensamer. (Metals Technology, December 1943) Tensile Properties of Medium-carbon Low-alloy Cast Steels. By H. A. Schwartz and W. Kenneth Bock. (Metals Technology, August 1944) Variables Affecting the Results of Notched-bar 1mpct Tests on Steels. By CLarence 15. Jackson, MYRon A. Pugancz and Frank S. McKenna. (Metals Technology, August 1944) The Notched-bar Lmpact Test. By John H. Hollomon. (Meta1s Technology, April 1944) Hardness Measurement as a Rapid Means for Determining Carbon Content of Carhon and Low- alloy Steels. By K. L. Clark and NIcHols Kowall. (Metals Technology, January 1944)

Jan 1, 1944

By William Phillips

THE possible sources of potash salts in the United States have been considered from many points of view during the last several years, but it is only within the last two or three months that the situation has become acute. We import from Germany, the only source of large supply, more than $10,000,000 worth of potash salts annually, and this business has been badly crippled by the European war. If there was ever a time in our industrial existence when the necessity of providing for our own needs was more acute than it is now, we are not aware of it. One has only to study the price, lists of chemicals sent out by the large supply houses to see the change wrought within a very short time. Whether or no these prices are to maintain for a considerable time, no one can say; but it appears to be probable that we shall not see prices materially lower for a period of uncomfortable length, to say the least. It is not my purpose at this time to discuss the various sources of supply of potash salts that have been suggested or recommended. Some of them might afford a pleasing relief but all of them combined would not affect the situation seriously. If we are to have our own sources of potash salts, they will have to compare, in some efficient manner, with the sources upon which we have drawn during the last 20 or 30 years; i.e., they must exist-in minable quantities. It seems to me to be quite idle to speculate upon our domestic sources of potash if those sources are not of a character similar to those upon which we have so long depended. A few thousand or, perhaps,, a few hundred thousand dollars' worth of chemically derived 'potash may be produced under the stress of present conditions, but when we consider that each year demands more than $10,000,000 worth, we must look to underground sources; we must look to mines similar to the famous Stassfurt and Halle deposits. If we cannot mine potash salts, we shall have to do without them for a while.

Jan 2, 1915

Total U.S. mineral production reached an estimated $17.8 billion for 1960, 4 pct above 1959 and second only to the record high of $18.1 billion established in 1957. As a group, metals achieved a rise from $1.6 billion in 1959 to $2.0 billion this year, an increase of 28 pct. Similarly the value of nonmetallic production including fuels (i.e., natural gas, petroleum, natural-gas liquids, asphalt and related bitumens, carbon dioxide. anthracite. bituminous and lignite coal, peat, and helium) rose from $15.5 billion in 1959 to approximately $15.8 billion in 1960. However, this 2 pct increase in the total value of non-metallic production was due to an increase in the value of the fuels ($11.8 billion in 1959 to $12.2 billion in 1960) which offset a drop in value of the other nonmetallic minerals ($3.7 billion in 1959 to $3.6 billion in 1960).

Jan 2, 1961

By D. W. Fuerstenau

Locked-cycle grinding experiments on mineral mixtures provide a means to study circuit performance in simulated continuous grinding systems. Such experiments with calcite/quartz mixtures revealed that approximately twenty-five 2-minute cycles are required before the composition of the circuit product and the recycle material attain steady state. The circulating load, after steadily increasing during the first 15 cycles, continued to fluctuate over a narrow range. Previous batch ball mill grinding of mineral mixtures has shown that breakage rate functions of minerals are time- independent but composition-dependent. In the closed-circuit grinding of ores with constituents having different grindabilities, the grinding rate parameters for the components also would therefore change during the transient period. With fluctuations in feed composition occurring randomly every half to one hour in processing plants, it is quite likely that the grinding circuit can be in unsteady state perpetually. The significance of these observations is discussed in this paper in the con- text of the models used in control schemes for the grinding circuits

Jan 1, 1984

By A. H. Geisler, J. H. Keeler

Preferred orientations in unalloyed zirconium were determined by the Geiger-counter spectrometer X-ray diffraction technique. With increasing P-annealing temperature the following textures were obtained: l—a retained a-annealing texture, 2—additional orientations predictable from the a-p (Burgers) relationship, and 3—a texture derived from a cube texture in the p phase. Earlier work on cold-worked and a-annealed zirconium was reappraised to show a quantitative dependence of rotations on temperature and to identify spurious areas of some of the pole figures. IN a previous paper,' the preferred orientations of high purity zirconium sheet were described for cold-rolled and annealed samples. Annealing temperatures up to 900°C, which is slightly above the allotropic transformation temperature, were explored. Of interest was the observation that the orientation of the hexagonal-close-packed material after annealing in the temperature range of the stable body-centered-cubic phase was similar to that of the material which had been annealed in the a temperature region, although a change in texture would be expected because of the many new orientations based on an orientation relationship between the two forms of zirconium. The reversion to an original orientation after an allotropic transformation cycle is not unusual. It has been found for titanium,"* for thallium," and for cobaltB among the hexagonal metals. Burgers found in his original work7 that, when zirconium was cooled through the allotropic transformation and then reheated, the body-centered-cubic phase reverted to the original orientation. Additional experimental work has been carried out to further explore the textures of zirconium after annealing in the temperature range above the allotropic transformation. In addition, a reappraisal was made of the earlier results for zirconium' in light of recent work on titanium4 which has shown that the texture type depends quantitatively on the temperature of annealing and that spurious areas may be encountered in the pole figures of hexagonal metals determined by the X-ray spectrogoniometer technique of analysis. Experimental Procedure Crystal-bar zirconium prepared by the iodide process was the material used in this investigation. The major impurity was hafnium which was less than 0.3 pct. The composition obtained by spectro-graphic analysis is given in Table I. Cold-rolled specimens were prepared from crystal bar by a series of reductions of approximately 0.010 in. until the sheet reached a thickness of 0.010 in., after which it was cold rolled to 0.001 in. thickness between sheets of alloy steel. The total cold reduction amounted to about 99.8 pct. Specimens were annealed for % hr at 1000" to 1100" to 1200°C or 1 hr at 1400°C in an evacuated Vycor or quartz tube. The transmission pole figures were obtained by

Jan 1, 1956

By C. W. Allen, B. D. Cullity, H. S. Choi

The torsional deformation of aluminum and magnesium crystals is investigated, with particular reference to the dependence of proportional limit on crystal orientation. The proportional limit is found to be governed by the average value of the resolved shear stress on the most highly stressed slip systems, but the proportional limit does not strictly obey a critical-resolved-shear-stress law. The behavior of a cylindrical single crystal stressed in tension is well known: plastic flow begins when the resolved shear stress on the most highly stressed slip system reaches a critical value. There is much less understanding of the effect of torsion on such a crystal and on the way in which the critical-resolved-shear-stress law should be applied to torsional deformation. In the present paper particular attention is paid to the dependence of plastic yielding on crystal orientation and lesser attention to the mechanism of flow after yielding has occurred. New work on aluminum and magnesium crystals is presented, and previous results obtained in this laboratory on magnesium1 are re-examined. STRESS DISTRIBUTION The problems involved in torsional deformation of single crystals are due entirely to the complexity of the stress distribution. In tension, if loading conditions are perfect, the shear stress on any particular slip plane is completely uniform over the entire area of that plane. In torsion, on the other hand, the stress on any selected plane in a particular direction varies not only from center to edge of the specimen but also around its perimeter. It is convenient to express the stress at any point in terms of t0, which is the shear stress acting at the surface of a cylindrical specimen on a plane normal to the axis and in a direction tangential to the cylinder. At point P of Fig. 1 this stress acts in the direction of axis 2 and is given by To = 2T/pr3 [1] where T is the applied torque and r the specimen radius. This stress can be resolved on any chosen slip system, and details are given in the Appendix. Let P be the point on the specimen surface where the stress is to be evaluated; P is defined by its angular distance A from an arbitrary reference line through 0 normal to the axis. his line is usually taken as the direction of incidence of the X-ray beam used to determine the crystal orientation.) Then the shear stress t, acting at P in direction Dona plane whose normal is N is given by Ts/TO = sin ? 0, cos ?d sin (?0, - ?) + cos ?, sin ?d sin (?d - ?) [2] where 0, and Od are the angles between N and D, respectively, and the axis, ?0 and ?d are the angles between the projections of N and D, respectively, on the transverse plane and the reference line through 0. By means of Eq. [2], the stress 7, acting in any given slip direction can be computed. In the previous work on magnesium1 only gross slip tangential to the specimen surface was considered, and this

Jan 1, 1963

By M. O. Holowaty, C. M. Squarcy

Bituminous coal furnaces give way to coke, and by 1880, the American iron and steel industry was growing at a tremendous rate. In the twentieth century, the number of operating blast furnaces was cut in half while pig iron capacity more than doubled. Bituminous coal furnaces Attempts to relieve the shortage of charcoal by the use of bituminous coal in American furnaces began quite early. Use of bituminous coal in the blast furnace was restricted to areas lacking anthracite deposits but rich in deposits of bituminous coaL The largest concentration of bituminous coal furnaces was in Western Pennsylvania, West Virginia and Western New York state. Other areas included Kentucky and southern portions of the states of Indiana and Illinois. The first trials were made in Pennsylvania around 1780. Gradually several more furnaces began charging coal with their burdens as a partial substitution for charcoal. These so called cheaters were numerous, especially in Western Pennsylvania, which around 1810 began to expand its ironmaking capacity to catch up with the Lehigh Valley and the Schuylkill According to the existing references, complete bituminous coal burdens began to be used in this area only around 1840 when the ironmakers hastily adopted the hot blast apparatus introduced from England. The majority of these furnaces were built, however, after 1844 when an extensive experimental program, carried out at the Shenango Steam and Water Hot Blast Charcoal, Coke and Raw-Coal Furnace produced favorable results, with coal containing up to 35 pct volatile matter. The furnace was located near the Shenango River on the Lackawannok Run, five miles northwest of Mercer, Pennsylvania. It was built, owned, and operated by David Hogeland of Mercer. The first furnace was built in 1836 or 1837 as a charcoal furnace. Soon, however,

Jan 1, 1961

By C. P. Besse, N. F. LeBlanc

Described in this paper are oceanographic data which should be considered by an offshore design engineer and methods for developing a design wave height from the oceanographic data. The selection of a design wave is predicated on contemplated waves which might affect the site throughout the life of the structure. Selection of a design wave height may be based on (1) arbitrarily established recurrence Frequencies of hurricanes affecting the structure (predicted wave heights are associated with the expected variations of forces resulting from these waves) and (2) a risk-type evaluation wherein all possible storms affecting the area are considered (anticipated wave heights are associated with both investment plus risk costs and expected variations of forces). It is shown how the following oceanographic predictions are integrated into design considerations: (1) a classification of storm intensity which considers all recorded storms which affected the design area, (2) the recurrence interval of storms of a given- intensity (this interval is dependent on the extent of the geographical area considered in the design problem) and (3) a forecast of all wave heights which might affect the area (geometry of a structure often necessitates consideration of waves from a multiplicity of directions). The authors believe that the described techniques can result in selecting an adequate and reasonable design wave. INTRODUCTION Since the inception of offshore operations in the Gulf of Mexico, engineers engaged in designing suuctural facilities have been plagued with the problem of selecting an adequate and reasonable design wave. In the development of any offshore structure it is mandatory that the engineer evaluate the ability of the structure to withstand the ocean waves to which it will be subjected. Selecting such design waves quite naturally necessitates a coalition of the oceanographer and the design engineer. The oceanographer must provide a detailed knowledge of scientific principles which govern the behavior of waters in the Gulf of Mexico. He should also have an adequate knowledge of the manner in which design waves are utilized by the engineer. Although the design engineer's primary responsibility is applying the oceanographer's specialized knowledge in the creation of real structures, it is important that he possess some knowledge of related oceanographic principles to reasonably evaluate and apply the recommendations of the oceanographer. In the Gulf of Mexico it is the hurricane wind waves which generally govern the design of an offshore facility. The oceanographer must therefore develop techniques for predicting the heights, periods and frequency of all hurricane waves which might affect a particular structure. From this mass of oceanographic data, the design engineer must select the design waves which will apply to his particular design. PAST STUDIES ON FREQUENCY AND AMPLITUDE OF HURRICANE WIND WAVES Past oceanographic studies on the frequency of hurricane wave heights in the Gulf of Mexico have been devoted largely to predicting the recurrence interval of hurricanes which will generate maximum significant waves of given heights. The maximum significant wave height is the average height of the highest one third of the waves in that portion of the storm producing maximum wave heights. Since these waves occur over a relatively small portion of the storm (Fig. 1) and since the paths of hurricanes vary considerably (Fig. 2), the recurrence frequency of such heights is largely a function of the extent of the geographical area considered. In establishing the frequency of maximum significant waves for the entire American Gulf coast, the major fully developed hurricanes which affected the coastline from BrOwnsville, Tex., to Key West, Fla., were considered (Fig. 2). These Storms were selected and described by C. L-

By B. J. Nelson, F. N. Rhines

STUDIES upon the rates of oxidation of copper alloys containing small quantities of the alloying elements1,2 have shown that steady growth of the scales at predictable rates is limited to a small concentration range and to oxidation at temperatures above 600°C., whereas unpredictable and erratic oxidation behavior is found with alloys containing larger additions and at low temperatures. The latter effect appears to be associated with modifications in the geometric disposition of the oxides. At low concentrations of the baser elements in copper, simple oxidation behavior is typified by the formation of two distinguishable zones of oxidation: (I) a subscale composed of discrete particles of the oxide of the alloying element embedded in substantially pure copper and (2) an external scale composed of cuprous oxide (with a very thin layer of cupric oxide on the outside) containing particles of the alloying element distributed throughout, but most profusely near the metal surface (see Fig. 2, top). Where this type of structure obtains, the process of oxidation is believed to be implemented, and its rate controlled, by the diffusion of the reacting elements through a continuous matrix phase; i.e., through the alpha (metallic) phase of the subscale and alloy and through the cuprous oxide of the external scale. Copper is presumed to diffuse outward through the cuprous oxide layer to the external surface, where it reacts to form more cuprous oxide.3 Oxygen is delivered at the oxide-metal interface in the form of cuprous oxide, which may either react with the alloying element to deposit its oxide at the inner limit of the external scale or dissolve in the pure copper that remains at the surface of the metal after it has become depleted in its oxidizable alloying elements. Both oxygen and the alloying element are pictured as diffusing through the metal, the oxygen inward and the alloying element outward. Where the two diffusion streams meet in sufficient concentration the oxide of the subscale is precipitated. If the oxygen pressure in the surrounding atmosphere is just below the pressure necessary to maintain cuprous oxide undecomposed, no cuprous oxide can be formed; some of the oxide of the alloying element may form upon the external surface, if its decomposition pressure is below that of cuprous oxide, and a normal subscale appears. This condition is achieved experimentally by enclosing the alloy with cuprous oxide together with an excess of copper. At temperatures from 600°C. downward, the precipitated oxides tend to accumulate at the grain boundaries of the alpha phase where a relatively small volume establishes a partial barrier to the diffusion of the reactants. Similarly, large volumes of precipitated oxides tend to deposit in various patterns that may be expected to hinder the diffusion of the reactants in the

Jan 1, 1943

GEORGE F. BECKER Dr. George Ferdinand Becker, notice of- whose death appeared in the May Bulletin, was born in New York City Jan. 5, 1847, the son of Alexander Christian Becker, member of a Danish family, and Sarah Cary Tuckernian Becker of Boston. Dr. Becker was the last member of the group of distinguished geologists who, in 1879, were associated with Clarence King at the time of the organization of the United States Geological Survey. He was a leader in mining geology and geophysics, and for many years had been the chief of the Division of Chemical and Physical Research in the Geological Survey, and the investigations under his direction led to the establishment of the Geophysical Laboratory of the Carnegie Institution of Washington. Dr. Becker was a graduate of Harvard University and received the degree of Doctor of Philosophy at Heidelberg, and in 1871 passed the final examinations at the Royal School of Mines in Berlin. He was for four years an instructor of mining and metallurgy in the University of California, from which he went to the United States Geological Survey. In 1896 he examined the gold and diamond mines f South Africa and at the time of the Spanish-American War was detailed to serve as geologist on the staff of General Bell with the army in the Philippine Islands. He died at his hone in Washington, D. C., on Apr. 20'.1

Jan 6, 1919

By R. G. Whittemore, R. Derry

Nickel metal, in powder form, has been produced by pressure reduction, with hydrogen gas, of slurries of nickel hydroxide at temperatures up to 250°C. The nickel hydroxide was obtained by precipitation from nickel chloride and nickel sulphate solutions, using both magnesium oxide and calcium oxide. Rates of reduction and yields were determined as a function of temperature, hydrogen overpressure, seed addition, and the amount of alkali used. The mechanism of reduction of slurries obtained from the sulphate system was studied, and major differences between the sulphate system and the previously examined chloride system investigated. Specifically, in the sulphate system, contra the chloride system, no seeding was necessary, plating and densification were virtually absent and only short induction periods occurred. Grades of product are given and the use of this process in the recovery of nickel from laterites is discussed. The selective reduction of nickel from mixed hydroxide slurries and effluent treatment plant sludge has also been examined.

Jan 1, 1973

By B. J. Nelson, F. N. Rhinos

Studies upon the rates of oxidation of copper alloys containing small quantities of the alloying elementsl,2 have shown that steady growth of the scales at predictable rates is limited to a small concentration range and to oxidation at temperatures above 600°C., whereas unpredictable and erratic oxidation behavior is found with alloys containing larger additions and at low temperatures. The latter effect appears to be associated with modifications in the geometric disposition of the oxides. At low concentrations of the baser elements in copper, simple oxidation behavior is typified by the formation of two distinguishable zones of oxidation: (I) a subscale composed of discrete particles of the oxide of the alloying element embedded in substantially pure copper and (2) an external scale composed of cuprous oxide (with a very thin layer of cupric oxide on the outside) containing particles of the alloying element distributed throughout, but most profusely near the metal surface (see Fig. 2, top). Where this type of structure obtains, the process of oxidation is believed to be implemented, and its rate controlled, by the diffusion of the reacting elements through a' continuous matrix phase; i.e., through the alpha (metallic) phase of the subscale and alloy and through the cuprous oxide of the external scale. Copper is presumed to diffuse outward through the cuprous oxide layer to the external surface, where it reacts to form more cuprous oxide.3 Oxygen is delivered at the oxide-metal interface in the form of cuprous oxide, which may either react with the alloying element to deposit its oxide at the inner limit of the external scale or dissolve in the pure copper that remains at the surface of the metal after it has become depleted in its oxidiza-ble alloying elements. Both oxygen and the alloying element are pictured as diffusing through the metal, the oxygen inward and the alloying element outward. Where the two diffusion streams meet in sufficient concentration the oxide of the subscale is precipitated. If the oxygen pressure in the surrounding atmosphere is just below the pressure necessary to maintain cuprous oxide undecomposed, no cuprous oxide can be formed; some of the oxide of the alloying element may form upon the external surface, if its decomposition pressure is below that of cuprous oxide, and a normal sub-scale appears. This condition is achieved experimentally by enclosing the alloy with cuprous oxide together with an excess of copper. At temperatures from 600°C. downward, the precipitated oxides tend to accumulate at the grain boundaries of the alpha phase where a relatively small volume establishes a partial barrier to the diffusion of the reactants- Similarly, large volumes of Precipitated oxides tend to deposit in various patterns that may be expected to

Jan 1, 1944

By F. N. Rhinos, B. J. Nelson

Studies upon the rates of oxidation of copper alloys containing small quantities of the alloying elementsl,2 have shown that steady growth of the scales at predictable rates is limited to a small concentration range and to oxidation at temperatures above 600°C., whereas unpredictable and erratic oxidation behavior is found with alloys containing larger additions and at low temperatures. The latter effect appears to be associated with modifications in the geometric disposition of the oxides. At low concentrations of the baser elements in copper, simple oxidation behavior is typified by the formation of two distinguishable zones of oxidation: (I) a subscale composed of discrete particles of the oxide of the alloying element embedded in substantially pure copper and (2) an external scale composed of cuprous oxide (with a very thin layer of cupric oxide on the outside) containing particles of the alloying element distributed throughout, but most profusely near the metal surface (see Fig. 2, top). Where this type of structure obtains, the process of oxidation is believed to be implemented, and its rate controlled, by the diffusion of the reacting elements through a' continuous matrix phase; i.e., through the alpha (metallic) phase of the subscale and alloy and through the cuprous oxide of the external scale. Copper is presumed to diffuse outward through the cuprous oxide layer to the external surface, where it reacts to form more cuprous oxide.3 Oxygen is delivered at the oxide-metal interface in the form of cuprous oxide, which may either react with the alloying element to deposit its oxide at the inner limit of the external scale or dissolve in the pure copper that remains at the surface of the metal after it has become depleted in its oxidiza-ble alloying elements. Both oxygen and the alloying element are pictured as diffusing through the metal, the oxygen inward and the alloying element outward. Where the two diffusion streams meet in sufficient concentration the oxide of the subscale is precipitated. If the oxygen pressure in the surrounding atmosphere is just below the pressure necessary to maintain cuprous oxide undecomposed, no cuprous oxide can be formed; some of the oxide of the alloying element may form upon the external surface, if its decomposition pressure is below that of cuprous oxide, and a normal sub-scale appears. This condition is achieved experimentally by enclosing the alloy with cuprous oxide together with an excess of copper. At temperatures from 600°C. downward, the precipitated oxides tend to accumulate at the grain boundaries of the alpha phase where a relatively small volume establishes a partial barrier to the diffusion of the reactants- Similarly, large volumes of Precipitated oxides tend to deposit in various patterns that may be expected to

Jan 1, 1944

After a three-year period characterized by inflation, recession, depressed metal prices, lack of demand, enormous world inventories, and rapidly escalating costs, the Canadian mining industry is showing welcome signs of recovery. A rise in world metal prices and particularly strong demand for gold, uranium, and coal have stimulated the industry in early 1979. In this atmosphere of growing optimism, over 3000 mineral industry executives, economists, geologists, and mining and metallurgical engineers convened in Montreal, April 26-29, for Canada's largest mining convention, the Annual General Meeting of the Canadian Institute of Mining and Metallurgy.

Jan 6, 1979

By William E. Messner

California’s Monterey Peninsula, noted for its beaches, resort hotels, and beautiful homes, also harbors a pioneering beneficiation operation. Here for more than 35 years the Del Monte Properties Co. has provided sand products from large dunes, some over 300 ft high, located in the Del Monte Forest. Raw material-the dunes derived by wave action from Santa Lucia granite of Jurassic age-has unusually consistent chemical and physical composition. Coarse crystalline feldspar is the principal constituent, followed in abundance by quartz, with some biotite, ilmenite, garnet, zircon, and monazite.

Jan 2, 1955

By R. Stefanko, Y. J. Wang, H. R. Hardy, R. Y. Kim

Since 1964, the Dept. of Mining at The Pennsylvania State University has been carrying out extensive studies associated with the phenomena of microseismic activity and inelastic behavior in geologic materials. Briefly, the program to date has involved the following stages 1) Study of the microseismic noise and energy rates for selected geologic materials under incremental, uniaxial tension.1,2 2) Investigation of the frequency spectra of microseismic activity of selected geologic materials under incremental, uniaxial tension.3,4 3) Investigation of the time-dependent inelastic deformation of geologic materials and the analysis of such deformation in terms of mechanical models.5, 6 4) Simultaneous study of microseismic activity and time-dependent inelastic deformation in geologic materials under incremental, uniaxial compression.7,8 Details of the research involved in stage 4 of the program constitute the subject of this chapter. It should be noted that the majority of the experimental data quoted in this chapter forms part of a thesis to be presented by one of the authors (Kim) in partial fulfillment of the requirements for the Ph.D. degree in mining engineering at The Pennsylvania State University. During the last two or three years, a number of important papers have been published which deal primarily with the fundamental structure and mechanical behavior of geologic materials. Recent papers 9,10 have provided research workers in the rock mechanics field with a meaningful overall picture of rock as a structural material. The concept that many

Jan 1, 1970

Statistics compiled by the United States Geological Survey show that the iron ore mined in the United States in 1917 reached a total of 75,288,851 gross tons, exceeding the former record output of 1916 by 121,179 tons. The shipments from the mines in 1917 were 75, 573,181 gross tons, valued at $238,260,333, a decrease in quantity of 2,297,372 tons, or 2.95 per cent., and an increase in value of $56,358,056, or 30.98 per cent., over the shipments in 1916. The average value per ton at the mines for all grades of ore in 1917 was $3.15 as against $2.34 in 1916. Stocks of iron ore at mines, mainly in Minnesota and Michigan, amounted at the close of 1917 to 10,628,908 gross tons, compared with 10,876,352 gross tons in 1916. The quantity of pig iron, exclusive of ferro-alloys, sold or used in 1917, according to reports of producers to the United States Geological Survey, amounted to 38,612,546 gross tons, valued at $1,053,785,975; compared with 39,126,324 gross tons, valued at $663,478,118 in 1916, a decrease of 1.32 per cent. in quantity and an increase of 59 per cent. in value. The average price per ton at furnaces in 1917, as reported to the Survey, was $27.29, compared with $16.96 in 1916, an increase of 61 per cent. The production of pig iron, including ferro-alloys, was 38,647,397 gross tons in 1917, compared with 39,434,797 gross tons in 1916, a decrease of 4.5 per cent., according to figures published by the American Iron and Steel Institute, March 18, 1918.

Jan 12, 1918

By H. R. Joesting

Geophysical search for minerals is stepped up to meet requirements of expanded defense program - Seismic and electrical surveys become firmly established for ground-water and engineering investigations.

Jan 2, 1953

By Charles A. Lindberg

It will be generally agreed that the most important accessory to a rail haul operation is the railroad type locomotive crane. The oldest and still most common type is the steam crane, a self-contained steam power plant, coal fired, complete with boom and hoisting machinery and mechanical drive capable of propelling the unit on its own power at speeds up to 15 mph on the level, and hauling, if necessary, a car for transport of the objects being handled. Usually, for greater mobility and safety, this crane and flatcar are moved around the pit by a switcher locomotive. Crane capacities range from 25 to 40 tons, these loads being handled with the shortest radius of boom and with outrigger. Boom lengths are 55 to 60 ft long, usually with heavy lift main blocks at 40 ft boom lengths. Lifting capacities with booms at maximum radius are approximately 20 % of maximum rating. Free capacities, namely without outriggers, range from 65 (at minimum radius) to 55% (at maximum radius) of the above capacity values.

Jan 3, 1950

By M. Stuart, R. F. Down

The Copper flotation concentrate produced at Gortdrum mines contains about 1% Hg. This article deals with the treatment used to produce a substantially mercury-free copper concentrate. Metallic mercury is a byproduct. Nearly all the mercury in the Gortdrum concentrate is present in the copper mineral tennantite-tetrahedrite. This mineral is variably distributed throughout the ore body so that by selective mining it was possible to produce salable concentrate relatively low in mercury while the treatment plant was being built. Roasting was the only feasible method found for removing the mercury from the concentrate, and it was decided that this should be done in an atmosphere with limited oxygen. A multiple hearth furnace is used. Mercury soot is condensed from the gas stream and treated to produce prime virgin mercury. Problems were experienced at first with materials handling, oxygen control, cooling of the calcined concentrate, treatment of the mercury soot, and in the metallurgical accounting. Precautions were necessary to avoid health problems. The plant is now operating reasonably well. The value of the mercury produced does not warrant the cost of the plant but without it, the copper concentrate could not be sold.

Jan 1, 1975