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By D. W. Gentry, H. E. Sherer

Determining the age at which to replace a specific piece of mining equipment, and choice of the best possible replacement, is a problem common to nearly all mining operations. This paper examines the data required for intelligent equipment replacement decisions and discusses how to predict future repair cost from historic data, determine the total cost of various replacement alternatives, and evaluate the different replacement alternatives. Various operations research and computer methods were used to develop this easily-used, practical equipment replacement method.

Jan 1, 1984

Dimitri Konstantinovitch Tschernoff, was horn in Petrograd, Russia, on Nov. 1, 1839, and died in Yalta (Crimea) in the south of Russia, on Jan. 2, 1921. He obtained his early education in the Russian Gymnasium, corresponding to the American high school, and in the Technologic Institute. On graduation from this Institute in 1858, he was engaged as a professor of geometry and algebra and later became a librarian and superintendent of the museum in the same Institute. He also attended lectures in the mathematical physics section at the Univrrsity of Petrograd from 1859 to 1862. In 1866, Professor Tschernoff left the Technologic Institute and entered the employ of the Obouchoff steel plant, founded in 1863 for the manufacture of guns. Here he did his most important work on the heat treatment of steel, its crystallization and metallography. In 1880, he left the Obouchoff plant and went to the south of European Russia, where he discovered and developed some rock-salt mines. This enterprise brought him a rather large fortune. In 1884, he returned to Petrograd and during the next four years held several prominent positions in government departments. In 1899, he became professor of metallurgy in the Michael Artillery Academy, and retained that position until the time of the Russian Revolution. In 1902, Professor Tschernoff was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. In September, 1917, Professor Tschernoff was sponding his vacation, as usual, in the city of Yalta (Crimea) in the south of Russia, with his wife and one of his daughters. The revolution progressed so rapidly that they were unable to return to Petrograd, and were compelled to stay in Yalta without provision for the winter season. Suffering from hunger. and lack of sufficient clothing, and deprived of his books, Tschernoff nevertheless continued his studies and gave a number of lectures on steel at the Polytechnic Institute. At the same time he worked hard on some. mathematical problems. His health broke down through long-continued under-nourishment. His works in the metallurgical field are well known to the students of metallurgy; good abstracts of his most important papers were published in Revue de Metallurgie (1915, pp. 829-882) in commemoration of his 75th birthday.

Jan 1, 1922

By Northcutt Ely

A year ago the petroleum code was in effect, and Congress had before it bills with powerful backing designed to extend and put on a permanent basis the Federal authority impliedly recognized in the petroleum code. Those men in the industry who were convinced of the unconstitutionality of Federal regulation, who believed in conservation, and who were seeking accomplishment of a conservation compact among the oil-producing states, were at that time encountering difficulties in bringing about such an agreement. Since then there has been a shift in the center of gravity. Today, by virtue of the Supreme Court's Schechter case decision, the petroleum code is not in existence, the industry is not operating under an oil administrator, and the Federal-control bills are not on Congress' calendar. In view of what the Supreme Court has said in the Schechter case and the Hoosac Mills case about the local character of mining and manufacturing, the problem today is not whether the Federal Government or the State Governments ought to regulate oil production, but how effective we can make the devices that are available to us under the constitution for the conservation of the nation's oil resources. The interstate oil conservation compact ratified during the past year by Texas, Oklahoma, Kansas, New Mexico, Colorado and Illinois, approved by Congress, but not yet in effect in California, is the mechanism now at work. Interstate Oil Conservation Compact What is this interstate compact? The basic theory is simple and logical. It has four elements to it. The first point is that in order to effect the maximum recovery of our oil arid gas reserves it is necessary for some governmental authority to regulate the way in which those resources are taken out of the ground, so that the reservoir energy is efficiently used, and used equitably by the various owners of the pool. Second, that the state, as distinguished from the national government, possesses the police power necessary to protect the public interest and to protect the correlative rights of the common owners of the oil pool. Third, that the state governments ought to cooperate with each other through an interstate advisory commission so that orderly production in one state is

Jan 1, 1936

Dimitri Konstantinovitch Tschernoff, was horn in Petrograd, Russia, on Nov. 1, 1839, and died in Yalta (Crimea) in the south of Russia, on Jan. 2, 1921. He obtained his early education in the Russian Gymnasium, corresponding to the American high school, and in the Technologic Institute. On graduation from this Institute in 1858, he was engaged as a professor of geometry and algebra and later became a librarian and superintendent of the museum in the same Institute. He also attended lectures in the mathematical physics section at the Univrrsity of Petrograd from 1859 to 1862. In 1866, Professor Tschernoff left the Technologic Institute and entered the employ of the Obouchoff steel plant, founded in 1863 for the manufacture of guns. Here he did his most important work on the heat treatment of steel, its crystallization and metallography. In 1880, he left the Obouchoff plant and went to the south of European Russia, where he discovered and developed some rock-salt mines. This enterprise brought him a rather large fortune. In 1884, he returned to Petrograd and during the next four years held several prominent positions in government departments. In 1899, he became professor of metallurgy in the Michael Artillery Academy, and retained that position until the time of the Russian Revolution. In 1902, Professor Tschernoff was elected an honorary member of the American Institute of Mining and Metallurgical Engineers. In September, 1917, Professor Tschernoff was sponding his vacation, as usual, in the city of Yalta (Crimea) in the south of Russia, with his wife and one of his daughters. The revolution progressed so rapidly that they were unable to return to Petrograd, and were compelled to stay in Yalta without provision for the winter season. Suffering from hunger. and lack of sufficient clothing, and deprived of his books, Tschernoff nevertheless continued his studies and gave a number of lectures on steel at the Polytechnic Institute. At the same time he worked hard on some. mathematical problems. His health broke down through long-continued under-nourishment. His works in the metallurgical field are well known to the students of metallurgy; good abstracts of his most important papers were published in Revue de Metallurgie (1915, pp. 829-882) in commemoration of his 75th birthday.

Jan 1, 1922

By Northcutt Ely

A year ago the petroleum code was in effect, and Congress had before it bills with powerful backing designed to extend and put on a permanent basis the Federal authority impliedly recognized in the petroleum code. Those men in the industry who were convinced of the unconstitutionality of Federal regulation, who believed in conservation, and who were seeking accomplishment of a conservation compact among the oil-producing states, were at that time encountering difficulties in bringing about such an agreement. Since then there has been a shift in the center of gravity. Today, by virtue of the Supreme Court's Schechter case decision, the petroleum code is not in existence, the industry is not operating under an oil administrator, and the Federal-control bills are not on Congress' calendar. In view of what the Supreme Court has said in the Schechter case and the Hoosac Mills case about the local character of mining and manufacturing, the problem today is not whether the Federal Government or the State Governments ought to regulate oil production, but how effective we can make the devices that are available to us under the constitution for the conservation of the nation's oil resources. The interstate oil conservation compact ratified during the past year by Texas, Oklahoma, Kansas, New Mexico, Colorado and Illinois, approved by Congress, but not yet in effect in California, is the mechanism now at work. Interstate Oil Conservation Compact What is this interstate compact? The basic theory is simple and logical. It has four elements to it. The first point is that in order to effect the maximum recovery of our oil arid gas reserves it is necessary for some governmental authority to regulate the way in which those resources are taken out of the ground, so that the reservoir energy is efficiently used, and used equitably by the various owners of the pool. Second, that the state, as distinguished from the national government, possesses the police power necessary to protect the public interest and to protect the correlative rights of the common owners of the oil pool. Third, that the state governments ought to cooperate with each other through an interstate advisory commission so that orderly production in one state is

Jan 1, 1936

By F. W. Rols-Hausen, F. W. Jessen

It is the purpose of this paper to present data on brines occurring in the Frio formation of the Texas Gulf Coast, and to show how their composition varies, (1) with depth below the surface, (2) with depth below the top of the formation, and (3) along the approximate strike. The brines vary in chloride content from 3,180 to 73,000 p.p.m., though the average salinity of the salt waters is shown to vary with total depth; the concentration being 35,000 to 40,000 p.p.m. at 3500 to 5500 ft., slightly less than 50,000 p.p.m. chloride at 5500 to 6500 ft. and average 38,000 to 40,000 below 6500 feet. From the analyses available, it appears that the highest concentration of salts occurs in the upper 300 ft. of the formation, while lower salinity is found with increasing depth below this point. The salt waters from wells in Starr County show less concentration of dissolved salts than in any other group of wells farther north along the strike. In all, 116 analyses from 63 fields and 14 wildcats, from depths ranging from 1300 to 11,400 ft. below the surface and from z to 3240 ft. below the top of the Frio, are recorded. Introduction Brines have been studied for many Years in an attempt to solve some of the geologic and production problems associated with the production of oil and gas. One practical application of study of . water analyses is the correlation of waters occurring above, in, or below the producing sand in the same field or throughout the same formation. The Frio formation, the series of sands and shales occurring below the Marginulina zone and above the Vicksburg, is one of the major oil and gas-producing formations in the Texas Gulf Coast. Fossils are rare or absent in the upper Frio throughout most of the area. When available, cuttings and cores, and electric logs were used to determine the top of the Frio. A change in lithology was used to determine this point in most of the wells, and fossils were used in some of the deep wells. It is realized that a change in lithology is not perfect for correlation purposes over long distances and some of the trends may be influenced by the inability to differentiate between the nonfossiliferous Marginulina zone and the Frio. It underlies virtually all the area shown on the accompanying map (Fig. I). Although it is not productive in the updip facies, it has been explored to a limited degree below I2,000 ft. Further more, toward the coast line future drilling to deeper depths should encounter this formation. Although thousands of wells have penetrated or drilled entirely through the formation, very few water samples have been secured from the many sands occurring in this formation and analyzed. Previous Investigation No previous published study has been made of the chemical composition and concentration of waters from the Frio formation. However, one water analysis

Jan 1, 1944

By F. W. Jessen, F. W. Rols-Hausen

It is the purpose of this paper to present data on brines occurring in the Frio formation of the Texas Gulf Coast, and to show how their composition varies, (1) with depth below the surface, (2) with depth below the top of the formation, and (3) along the approximate strike. The brines vary in chloride content from 3,180 to 73,000 p.p.m., though the average salinity of the salt waters is shown to vary with total depth; the concentration being 35,000 to 40,000 p.p.m. at 3500 to 5500 ft., slightly less than 50,000 p.p.m. chloride at 5500 to 6500 ft. and average 38,000 to 40,000 below 6500 feet. From the analyses available, it appears that the highest concentration of salts occurs in the upper 300 ft. of the formation, while lower salinity is found with increasing depth below this point. The salt waters from wells in Starr County show less concentration of dissolved salts than in any other group of wells farther north along the strike. In all, 116 analyses from 63 fields and 14 wildcats, from depths ranging from 1300 to 11,400 ft. below the surface and from z to 3240 ft. below the top of the Frio, are recorded. Introduction Brines have been studied for many Years in an attempt to solve some of the geologic and production problems associated with the production of oil and gas. One practical application of study of . water analyses is the correlation of waters occurring above, in, or below the producing sand in the same field or throughout the same formation. The Frio formation, the series of sands and shales occurring below the Marginulina zone and above the Vicksburg, is one of the major oil and gas-producing formations in the Texas Gulf Coast. Fossils are rare or absent in the upper Frio throughout most of the area. When available, cuttings and cores, and electric logs were used to determine the top of the Frio. A change in lithology was used to determine this point in most of the wells, and fossils were used in some of the deep wells. It is realized that a change in lithology is not perfect for correlation purposes over long distances and some of the trends may be influenced by the inability to differentiate between the nonfossiliferous Marginulina zone and the Frio. It underlies virtually all the area shown on the accompanying map (Fig. I). Although it is not productive in the updip facies, it has been explored to a limited degree below I2,000 ft. Further more, toward the coast line future drilling to deeper depths should encounter this formation. Although thousands of wells have penetrated or drilled entirely through the formation, very few water samples have been secured from the many sands occurring in this formation and analyzed. Previous Investigation No previous published study has been made of the chemical composition and concentration of waters from the Frio formation. However, one water analysis

Jan 1, 1944

By Raphael D. Schilz, Michael F. Dunn, Edward D. Thimons, Francis S. Kendorski

During a mine fire or other emergency, it may be desirable to reverse the air flow in order to provide an escapeway or to control a fire. Also, in colder areas, the air flow may be reversed to prevent ice build-ups. When reversing main mine fans, the operator usually does not know what operating characteristics of flow and pressure to expect. Laboratory testing of vane axial main mine fans has been completed in order to establish forward and reverse performance characteristics under controlled conditions, with the results presented here. Preliminary tests under field conditions have also been conducted. The data obtained suggest that reverse performance characteristics are dependent upon the blade angle and the hub to tip ratio. There is also evidence that reverse performance can he predicted for a family of blade angles in a given hub to tip ratio. In general, the air quantity delivered by the fan is 30% to 60% less in reverse than when operating in the normal forward mode.

Jan 1, 1982

Scraper With over 40 pet more struck capacity than previous models, the new Caterpillar No. 90 scraper is designed to increase earthmoving production when used with D8 tractor power. This scraper moves dirt with the aid of a hard surfaced, reversible cutting edge. Material is carried in a flat, doublebottom bowl of high tensile steel. Operation is by means [ ] of a cable-control unit, which can be mounted on the rear of the tractor to provide for positive loading and ejection. Tapered roller bearings are installed at each axle. The scraper uses two 24.00 to 29 front tires and two 27.00 to 33 rear tires, all four of 24-ply rating. When loaded, the scraper distributes 60 pet of the weight on the rear tires. Circle No. 1

Jan 1, 1952

By Kiyoshi Sugasawa

At Sumitomo Metal Industries, technologies for manufacturing metallurgical coke have been developed, under the names of Sumicoal System and DKS formed coke processes. Sumicoal System is the process utilizing approximately 70% conventional fine coal, 30% briquettes charge, and 2-3% caking substance. This technology was industrialized in 1975, and now the blending ratio of non-coking coal has reached up to 20%. On the other hand, a large scale demonstration plant using the DKS process was constructed and operated over one year. As the result of that test, it is thought that the DKS process has also reached the stage of industrialization. This paper will describe these new coking technologies.

Jan 1, 1977

By Malcolm F. Hawkes, Robert F. Mehl

THE rate of isothermal transformation of austenite to pearlite depends upon the rate of nucleation, N, and the rate of growth, G, of pearlite in austenite.1.2 Values of N are given in terms of the number of nuclei forming in unit time per unit grain boundary area of unreacted austenite; values of G are given in terms of the linear rate of radial growth. Variations in the isothermal rate with temperature result from variation of -N and G with temperature. Depth of hardening of a steel depends fundamentally upon values of N and G; changes in carbon and alloy content effect changes in N and G and thus affect depth of hardening. Quantitative studies are available on N and G for the formation of pearlite in plain carbon eutectoid steels.3 Systematic studies in this field are necessary if the phenomena are to be well enough known to furnish. a proper basis for full rationalization and for theory. Accordingly, the studies are continuing, both with respect to the effect of alloying elements upon the values of N and G in the formation of pearlite, and to the values of N and G for the formation of ferrite in hypoeutectoid steels. The present paper is the first relating to the effect of alloying elements upon the values of N and G for pearlite. It offers special interest since cobalt is known to have an anomalous effect upon the rate of formation of pearlite, accelerating it, whereas all other elements retard it.' It will be shown that cobalt increases both N and G for pearlite and that this effect is inherent in the Fe-Co-C system and not dependent upon factors relating to austenite heterogeneity nor upon any recognizable adventitious factor. Inasmuch as the rate of diffusion of carbon in austenite and the interlamellar spacing of pearlite are variables related to G and possibly to N (in a manner not yet certain), measurements of the "effect of cobalt upon them are also reported here. In the course of the work, measurements were made on the effect of cobalt upon the martensite temperature and these are given. COBALT AS AN ALLOYING ELEMENT IN STEEL PROPERTIES OF COBALT Cobalt resembles iron more closely than does any other chemical element. Its atomic number is 27, hence it is the element immediately following iron in the periodic system. The two differ in atomic structure only in the fact that cobalt contains seven electrons instead of six in the third, or transition, level of the third shell. The next shell, which is the

Jan 1, 1947

TENDENCIES toward nationalization grew noticeably stronger in some areas. Late last fall Bolivia took over the tin mines of four foreign operators and handed them a bill for a fabulous amount claimed for damages. In the same breath, the price Bolivia offered to pay for the mines appeared to many to be slightly ridiculous. Many engineers felt that the country would not be able to run the mines successfully. Even if they could, some thought that the Bolivian Government would gut the orebodies in an attempt to get at rich deposits for high profits, leaving the lean ores in unmineable condition.

Jan 2, 1953

By J. H. Frye, R. M. Treco, J. W. Caum

IT has been suggested that: "Insofar as the hardening due to a solute depends upon the increase of lattice parameter produced by it, it is reasonable to suppose that this hardening might be related to the resistance which the pure solvent would offer to increase in its parameter."1 It was further suggested that this hypothesis might be examined by comparing the hardnesses of analogous silver and copper alloys, since the stress necessary to produce a given lattice expansion is quite different in the two metals. Suitable data 2,3,4 are now available on these alloys, and we shall proceed to an examination of the hypothesis quoted above. HARDNESS, LATTICE PARAMETER AND IONIC OVERLAP Increase in ultimate Meyer hardness has been plotted against increase in lattice parameter in Figs. I and 2, It is believed that most of the values are accurate within the limits indicated by the rectangles, These data are also presented in Table I. Ultimate Meyer hardness, Pu, is defined by the equation: [P" - D2] where L = load, D = diameter of an impression having the same diameter as the testing ball, which in this case is 4 mm. Increase in lattice parameter is defined as the difference between the lattice parameter of the solid solution and that of the pure solvent. The curves in Figs. I and 2 are based on equal solute concentration and an equal degree of plastic deformation pro¬duced by the testing ball. Hardnesses are corrected to a constant grain size for copper and silver alloys, respectively, and these two grain sizes are approximately equal. Furthermore, all solutes are from the same period of the B subgroup of the periodic table as their solvent. [ ] The question arises as to whether or not lattice parameter is the only factor controlling the hardness of these alloys. There

Jan 1, 1943

By D. K. Grubbs, A. B. Moose

A brief overview of domestic sources of anorthosite in Oklahoma and Wyoming is presented, including drilling data on anorthosite and limestone exploration.

Jan 1, 1982

By J. Farkas

A techno-economic assessment for the recovery of several elements from seawater is presented. Gold recovery has been used as an illustration for the economic evaluation of several processes. Current technology does not present any economically viable alternative to recover gold from seawater because its concentration is several magnitudes too low. However, with the increasingly larger availability of concentrated seawater, mainly from desalination and other processes, coupled with advances in technology, especially genetically modified specific microorganisms, may make the recovery of gold and other desired elements from seawater a reality in the near future.

Jan 1, 1984

By K. B. McQuillin

The increasing volume of data produced by the Anglo American Corporation of South Africa, Limited, during the course of coal exploration prompted the establishment of a computer based processing system for coal data. This system, known as the Coal Mine Evaluation System, consists of geological, mine planning and financial evaluation sub-systems. This paper describes the use of the geological sub-system in assessing the surface mine potential of a portion of the Witbank Coalfield, South Africa, in which more than one thousand core boreholes have been drilled to date.

Jan 1, 1977

By Clarence Zener

THEORETICAL considerations by one of the authors have led1 to the prediction that the dynamic internal friction of annealed metals has a broad maximum at a certain grain size. This prediction they have veri-fied2 for alpha brass. In the present paper the theory is extended to include the precise manner in which the internal friction varies with grain size on either side of the maximum. New experimental data are pre¬sented to test this extended theory. The physical basis for the type of internal friction that is being investi-gated lies in the interplay between stress and temperature. Just as local fluctuations in temperature give rise to local fluctuations in stress, so like-wise fluctuations in stress give rise to fluctuations in temperature. But temperature gradients give rise to necessarily irreversible thermal cur-rents, and hence to internal friction. The theory for this type of internal friction has been developed quantitatively,3 and has been experimentally verified,4,5 for the particularly simple case of the transverse thermal cur-rents accompanying transverse vibrations. Of more fundamental impor-tance are the intercrystalline thermal currents accompanying all types of vibration. The variation in stress across grain boundaries arises from the elastic anisotropy and at least partial random orientation of the individual crystallites. An exact quantitative treatment of the internal friction due to these thermal currents is of course out of the question. However, much information can be obtained from general arguments.1,6 Thus when the frequency of vibration f is low, or when the grain size d is small, adja-cent grains remain nearly in thermal equilibrium, and vibration proceeds isothermally with little internal friction. Again, when the frequency is high, or the grain size large, the heat flow per cycle is small, the vibration proceeds adiabatically with little internal friction. The internal friction will become a maximum in the transition region. The degree of adiabatic-

Jan 1, 1940

By S. K. Ghosh

This paper discusses how the information on ash composition, ash-fusion temperatures, and ash-slag viscosity can be used to predict slagging and fouling potentials of a particular coal. A review of several empirical parameters that are commonly used for determining such potentials is given. Also, some guideline values for interpreting the relative propensity of slagging and fouling of various types of coal are provided.

Jan 1, 1986

By A. G. Suydam

Ancient as is the art of producing copper, so ancient is one of its eternal problems: refractories. Looking backward, in the light of present knowledge, clouded though it be, one cannot avoid a sense of profound respect for the patience, acumen and courage of those who have wrought so successfully despite difficulties, a more accurate understanding of which seems merely to accentuate. The problem of refractories arises from the necessity for constructing containers in which to bring natural ores into thermal solution in order to effect reduction and separation of the valuable metal content and free it of undesirable contamination while producing a waste slag. The very forces known to produce thermal solution of sufficient liquidity are necessarily destructive of exposed refractory linings in proportions varying inversely with thermal conductivity, directly with the porosity and ease of fluxing of the refractories used, and directly with the temperatures employed. Beyond this, mechanical forces are set up within the refractory lining incident to rapid heating or cooling, shrinkage at high temperatures, and unequal or excessive loading, that frequently pass the elastic limit, causing spalling or distortion. The effects of these forces are often accentuated by the necessity of providing at the same time as hot a bath and as cool a container as are consistent with fuel economy. Evolution in the Use of Refractories Clay Brick.—Fireclay and clay refractories had to yield wherever they were in contact with slags rich in basic oxides, first because of the combining power of those oxides with free silica and secondly because of the tendency of alumina to form either aluminates or alumina-silicates of varying complexity. Of no less importance, the incipient fusion point was low as compared with good clay brick of today, while the brick lacked strength at high temperatures. Expansion was slight, therefore it was difficult to make and maintain tight walls, roof, or bottom. However, the spalling tendency was low because of some of these properties and clay brick have retained their place in roasting furnaces, boiler furnace linings, and in the upper walls of some of the reverberatory types such as some refining, anode and wire-bar furnaces. They have served often and most efficiently for hot patching.

Jan 1, 1934

By L. R. Flint, W. L. Freyberger, W. J. Howarth

W. L. Freyberger (Director, Institute of Mineral Research, Michigan Technological University, Houghton, Mich.)-The authors are to be complimented on their theoretical analysis of a column flotation process, and the comment I wish to make is not related to that analysis, but to the use of the word "countercurrent" to describe that process. Strictly speaking, the process the authors have described is countercurrent only in the sense of particle-bubble contact. That is, as solid particles and air bubbles pass through the column, the leanest flotation feed (the tailing) comes in contact with the greatest concentration of mineral-free bubbles. However, air bubbles alone do not comprise the complete extracting phase in a flotation system. A second component of this extracting phase is the collector, which is really the extractant inducing transfer of mat-

Jan 1, 1972