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By W. P. Shinn

In a paper contributed by W. A. Goodyear, M.E., on "Water Gas as Fuel," read at the Boston Meeting, February, 1883,* the following statenlent was made: "The latest experiments on a scale of some magnitude in our citier, in the way of heating buildings and furnishing power for manufacturing purposes, have been by the distribution of high-presslire steam through pipes laid in the streets. Hilt these experiments (1) have not hitherto been very successful; and when we consider the high cost and (2) the great and unavoidable loss of heat and power, which always accompany the conveyance of high-pressnre steam to any considerable distance in pipes, to say nothing of (3) certain practical difficulties in the management of the pipes themselves, (4) it is evident that all such methods must eventually disappear before a system which can furnish a cheap gas of great heating power, easily distributed wherever wanted, without requiring pipes to stand pressures of 50 to 75 pounds per square inch, and (5) without keeping the whole mass of ground in the streets through which it passes hot, gratis, for a distance of ten or fifteen feet, in all directions around the pipes!' For the purpose of controverting Mr. Goodyear's statements in regard to steam-distribution in cities, I hare numbered the points made in his indictment, my principal object being, not a professional discussion of the technical and theoretical merits of steam vs. watergas, but a simple statement of facts, in regard to the present state of the street system of steam distribntion. Taking Mr. Goodyear's points in their order: 1. Concerning what he terms " These experiments," saying that they " have not hitherto been very successful," I propose to show, that the problem of stearn-distribution has passed beyond the experimental stage, and that its practical solution is highly successful. This will be shown by the facts hereinafter fully set forth. 2. "The great and unavoidable loss of heat and power whicn always accompany the conveyance of high-pressure steam to any con-

Jan 1, 1884

THE CHAIRMAN ( F. K. COPELAND, * Chicago, ,Ill.).-This is an interest-ing and very troublesome proposition to all of us. Ten or fifteen years ago, when the old-fashioned idea prevailed that a man was responsible for his own health and safety, that if anything happened to him it was his own lookout; we got along without this problem; but with the advent of accident compensation, with the agitation that there is all the time for pensions, sick benefits, and the responsibility of a company for the health of its employees, whenever you take a man on, that phase is becoming more and more important. One cannot afford to hire a man who is blind in one eye, even though he may have perfect sight in the other eye; if he loses that one eye, if lie becomes a total disability, the company is liable for the man's complete sight. Another thing that should make us particularly interested in this problem is the fact that the unions are very much opposed to it. One of the requirements of this steel unpleasantness is that the companies abandon their physical examination of employees. It is a very difficult problem to examine 400 or 500 men as intelligently as possible and decide whether a man on this or that side of the line is accepted. T. T. READ, Washington, D. C.-The United States. Bureau of Mines has in progress at the present time a study of the effect of underground atmospheric conditions on the safety and health of the workers. Im-proved methods have been employed and it is an excellent and ex-tremely valuable piece of research work.

Jan 12, 1919

By John Griffen

This paper records over twenty years' experience with the use of the Rheolaveur system in the United States, showing its ability to meet changing conditions caused by the dirtier mine output of present-day mechanical mining methods. Data are given on size ranges handled, number and capacity of units installed, maintenance experience, and operating results on two-product and three-product separations. IT is not the purpose of this paper to discuss the principles employed in the Rheolaveur system of fine-coal cleaning as these have been fully covered in the technical literature of the Institute."2 Rather, our purpose will be to record the highlights of over 20 years' experience in the United States with Rheolaveur fine-coal launders, which will indicate their capabilities and costs of cleaning and their adaptability to meet the changing conditions caused by present-day mechanical mining methods. Rheolaveur fine-coal launders are used in the United States to treat a wide variety of size ranges of fine coal, the coarsest being 1/2 in. to 0 and the finest about 1/8 in. to 0. In Europe feeds as coarse as 5/8 in. and as small as 1/2 mm (28-mesh) to 0 are being cleaned. The size ranges usually handled in this country are 3/8 to 1/4-in. round to 0. Thirty five units with a combined hourly feed capacity of 3200 tph have been installed in the United States. Individual units are cleaning as little as 25 tph, while others are cleaning as much as 200 tph. Rheolaveur fine-coal launders offer cleaning units of high capacity and are outstanding in requiring a minimum of building space per ton of input. Experience has shown that maintenance costs are low. Several installations were made in the Pittsburgh district from 1928 to 1930, and since that time operation has been largely two shifts per day. Minor repairs to liner plates and Rheo boxes have been required during the intervening years, but no major replacement of launders was required until 1947 and 1948. At one of these plants, launders operated for 17 years before they were replaced and during that period over 26,000,000 tons of —5/16-in. coal were cleaned. The effect of the much dirtier raw coal produced by mechanical loading of the Pittsburgh seam is shown by the following tests. The data in table I summarize the performance of a Rheo fine-coal unit when cleaning hand-loaded raw coal. The —4-in. raw coal fed to the cleaning plant analyzed only 8.16 pct ash and 1.31 pct sulphur and contained 4.6 pct sink, 1.55 sp gr. Two years later, in 1945, mechanically-loaded coal from the same mine was cleaned in the same plant. The feed, —4 in., then analyzed 20.10 pct ash and 1.53 pct sulphur and contained 20.2 pct sink, 1.55 sp gr. The performance of the Rheo fine-coal unit when cleaning this coal is given in table 11. It will be noted that the +48-mesh coal is cleaned almost as thoroughly as in table I. The large amount of high-ash slimes produced from the dirtier feed are responsible for the higher ash of —--48-mesh washed coal in table 11. In this plant the Rheo fine-coal unit did not get the full load of refuse resulting from mechanical

Jan 1, 1951

By John Griffen

This paper records over twenty years' experience with the use of the Rheolaveur system in the United States, showing its ability to meet changing conditions caused by the dirtier mine output of present-day mechanical mining methods. Data are given on size ranges handled, number and capacity of units installed, maintenance experience, and operating results on two-product and three-product separations. IT is not the purpose of this paper to discuss the principles employed in the Rheolaveur system of fine-coal cleaning as these have been fully covered in the technical literature of the Institute."2 Rather, our purpose will be to record the highlights of over 20 years' experience in the United States with Rheolaveur fine-coal launders, which will indicate their capabilities and costs of cleaning and their adaptability to meet the changing conditions caused by present-day mechanical mining methods. Rheolaveur fine-coal launders are used in the United States to treat a wide variety of size ranges of fine coal, the coarsest being 1/2 in. to 0 and the finest about 1/8 in. to 0. In Europe feeds as coarse as 5/8 in. and as small as 1/2 mm (28-mesh) to 0 are being cleaned. The size ranges usually handled in this country are 3/8 to 1/4-in. round to 0. Thirty five units with a combined hourly feed capacity of 3200 tph have been installed in the United States. Individual units are cleaning as little as 25 tph, while others are cleaning as much as 200 tph. Rheolaveur fine-coal launders offer cleaning units of high capacity and are outstanding in requiring a minimum of building space per ton of input. Experience has shown that maintenance costs are low. Several installations were made in the Pittsburgh district from 1928 to 1930, and since that time operation has been largely two shifts per day. Minor repairs to liner plates and Rheo boxes have been required during the intervening years, but no major replacement of launders was required until 1947 and 1948. At one of these plants, launders operated for 17 years before they were replaced and during that period over 26,000,000 tons of —5/16-in. coal were cleaned. The effect of the much dirtier raw coal produced by mechanical loading of the Pittsburgh seam is shown by the following tests. The data in table I summarize the performance of a Rheo fine-coal unit when cleaning hand-loaded raw coal. The —4-in. raw coal fed to the cleaning plant analyzed only 8.16 pct ash and 1.31 pct sulphur and contained 4.6 pct sink, 1.55 sp gr. Two years later, in 1945, mechanically-loaded coal from the same mine was cleaned in the same plant. The feed, —4 in., then analyzed 20.10 pct ash and 1.53 pct sulphur and contained 20.2 pct sink, 1.55 sp gr. The performance of the Rheo fine-coal unit when cleaning this coal is given in table 11. It will be noted that the +48-mesh coal is cleaned almost as thoroughly as in table I. The large amount of high-ash slimes produced from the dirtier feed are responsible for the higher ash of —--48-mesh washed coal in table 11. In this plant the Rheo fine-coal unit did not get the full load of refuse resulting from mechanical

Jan 1, 1951

By Alden H. Emery, J. J. Forbes

The data contained in this paper were collected during the course of an investigation which covered 15 representative coal mines in six coalmining states. The purpose of the investigation was to determine by atmospheric sampling how much dust was raised into the air during the various operations of coal mining, such as undercutting with machines, loading coal by hand and transporting it from the working face to the surface. The data thus obtained were considered from two angles; namely, the possible physiological effect of inhalation and the explosion hazard of the dust. No attempt will be made to discuss the former factor in this paper. ConDitions of Mining The mines in which this investigation was conducted were considered representative, and it is believed that the results obtained will suffice for the average dustiness encountered in most coal mines. All of the coal mined was bituminous, from beds 30 to 120 in. thick. Only the ordinary room-and-pillar system of mining was employed. Daily production ranged from approximately 700 to 1500 tons and the men employed from 150 to 450. Coal was undercut by shortwall mining machines in all mines, with the exception of one in which pick mining was employed. Loading at the face wets done by miners; none of the mines used mechanical loaders. Electric drills, both for brushing roof and for shooting coal were commonly used, although some roof work was done with jack-hammers and a little of both with augers. Coal was hauled by motor, mule, or rope power in end-gate cars with capacities ranging from 1800 to 3600lb. With few exceptions, coal was won at the face by dry methods, that is to say, no water was employed for wetting down the dust either during undercutting, loading or transportation. Observations of Sources of Dust The common sources of coal dust as observed, arranged by decreasing amounts, were as follows: (1) Undercutting with mining machines; (2)

Jan 1, 1927

By R. E. Hathaway

INTRODUCTION For a number of reasons, the mineral processing industry has been slow to adopt significant automation of its processes. Most ore grinding operations can be operated manually so the pressure for automation to run the process has not been there. Furthermore, many plants had proven over years of operation that manual operation would produce a profit, so why automate? Until recently, the instrumentation necessary for automation of the grinding process was not available. All this has now changed, however. Increasing costs for labor, fuel, power, grinding media, reagants, and capital equipment have not been matched by the market price of the finished product. This cost-price squeeze has made it mandatory to reduce operating costs and improve the efficiency of the process to remain profitable. A number of other factors have added to the direct operating cost to make the problem even worse. These include environmental pressures to conserve natural resources and reduce smelter stack emissions; increased competition--especially from developing countries, varying economic conditions, stockpiling, governmental controls, and to top it all off, lower grade ore bodies. Although many of these other influences are good overall, they take their toll in cost per ton of delivered product. Fortunately, many operators are finding the solution to the cost-price squeeze in instrumentation and process control. Automated processes yield tighter spec. products, require less operating labor, produce more product from a given plant, and reduce unit cost by increasing process efficiency. The plant manager has a "handle" on the plant through process control so that he can change operating modes as economics dictate by changing the set point of some process controllers. He can even respond to economic conditions by switching control strategies from one that maximizes production to one that maximizes recovery, or minimizes unit cost, etc. This has all been made possible by the advent of on-line analytical instruments and practical process control computers. On-stream particle size (1), x-ray, and silica analyzers are now available and in use in many plants. Digital computer hardware and software has become practical so operators can use it without trying to become computer experts. This chapter describes the approach toward design and implementation of automatic grinding circuit control that has proven to be the most cost effective, based upon results from a number of

Jan 1, 1982

By Karl S. Hughes

ANY one of the mining engineers who spent three years under the benevolent and protective custody of the military forces of His Imperial Nipponese Majesty will admit that he has survived a most disagreeable experience, but our friends here in the States all demand that we tell them something about our thrilling adventure. Many of the younger men who were on Luzon in December 1941 joined up with the Army, either as civilian technical employees or through their reserve officer status. They served through the Bataan and Corregidor defense and had five months of thrills and hardship, if that is what constitutes adventure. Unfortunately, too many of them are not alive to tell their stories. But for most of us, our internment as alien civilians was just one long, drawn-out pain in the neck. Yes, we starved; yes, we contracted beriberi, dysentery, typhus, dengue, and for a while had no quinine to fight the ever-present malaria; but these things are not exciting, neither is the account of them interesting. Our contingent from Mindanao, 250 .in number including 25 mining men, went through one period of starvation at Davao. When the activity of the Allied fleet interfered with the importation of staple foodstuffs, and the natives stopped bringing fruit and vegetables into the market, the food situation became acute, and in December 1943, with stocks in sight and in prospect insufficient to provision their own soldiers, our custodians decided that we must be moved to Manila. The story of that ten-day voyage in an antiquated Jap freighter is too disgusting to tell, but hardly more adventurous than the account of a game of solitaire.

Jan 1, 1945

By J. W. Hickman, E. A. Gulbransen

In a previous paper' the authors have investigated the structure of the oxide films formed on most of the metals that make up the alloys of this study. The metals were studied in order to provide basic information on the structures, both physical and chemical, of the oxide films and to determine how these structures are effected by the temperature, time of oxidation, and surface preparation. It was felt that an understanding of the physical and chemical structure as well as the stability of the oxide film might furnish clues as to the nature of the reaction process and the protective quality of the film. The oxidation of the metals was studied over the temperature range 300' to 7o0°C. except for copper, wherc the range selected was 100' to 500°C. The results of these studies were presented in graphical form as existence diagrams of the oxides on a time-temperature scale. For some of the metals the existence diagrams were simple and showed few chemical transitions, but there were numerous cases where the physical state of the oxide surface was a function of time and temperature. In general the physical state of the oxide surface changed with increasing temperature so as to increase the sharpness of the diffraction patterns and to cause orientation effects to be more pronounced. Deviatiois in lattice Darameters from X-ray values were noted. In general these deviations were of positive nature and may be due to solid solution of the metal in the oxide lattice. This effect might be expected in thin oxide films. In a study of the oxidation of alloys containing two or more metals, there may arise the complicating factor of identification of the oxides formed. A thorough understanding of the oxides formed on the pure metals, therefore, was, essential before investigation of the oxidation of alloys. In this paper it is our purpose to present a study of the following problems: 1. The existence diagrams of various alloys. 2. The effect of the structure of the alloying metal on the existence diagram of iron. 3. The effect of the percentage of chromium on the oxides formed on Fe-Cr alloys. 4. The relationships, if any, between the oxides formed and the protective quality of the oxides. The following alloys are included in this study: alloys of iron with body-centered cubic, face-centered cubic and other metals, 13 Cr-Fe, 18-8 stainless steel, K4²B, Nichrome V, Hipernik, Inconel, Stellite "²I," Refractaloy, Kovar, mild steel, a series of Cr-Fe alloys and a series of Co-Fe alloys. Since many of the commercial alloys in this list contain more than two metals, various complicating factors in the identification of the oxides formed may arise.

Jan 1, 1947

By E. A. Gulbransen, J. W. Hickman

In a previous paper' the authors have investigated the structure of the oxide films formed on most of the metals that make up the alloys of this study. The metals were studied in order to provide basic information on the structures, both physical and chemical, of the oxide films and to determine how these structures are effected by the temperature, time of oxidation, and surface preparation. It was felt that an understanding of the physical and chemical structure as well as the stability of the oxide film might furnish clues as to the nature of the reaction process and the protective quality of the film. The oxidation of the metals was studied over the temperature range 300' to 7o0°C. except for copper, wherc the range selected was 100' to 500°C. The results of these studies were presented in graphical form as existence diagrams of the oxides on a time-temperature scale. For some of the metals the existence diagrams were simple and showed few chemical transitions, but there were numerous cases where the physical state of the oxide surface was a function of time and temperature. In general the physical state of the oxide surface changed with increasing temperature so as to increase the sharpness of the diffraction patterns and to cause orientation effects to be more pronounced. Deviatiois in lattice Darameters from X-ray values were noted. In general these deviations were of positive nature and may be due to solid solution of the metal in the oxide lattice. This effect might be expected in thin oxide films. In a study of the oxidation of alloys containing two or more metals, there may arise the complicating factor of identification of the oxides formed. A thorough understanding of the oxides formed on the pure metals, therefore, was, essential before investigation of the oxidation of alloys. In this paper it is our purpose to present a study of the following problems: 1. The existence diagrams of various alloys. 2. The effect of the structure of the alloying metal on the existence diagram of iron. 3. The effect of the percentage of chromium on the oxides formed on Fe-Cr alloys. 4. The relationships, if any, between the oxides formed and the protective quality of the oxides. The following alloys are included in this study: alloys of iron with body-centered cubic, face-centered cubic and other metals, 13 Cr-Fe, 18-8 stainless steel, K4²B, Nichrome V, Hipernik, Inconel, Stellite "²I," Refractaloy, Kovar, mild steel, a series of Cr-Fe alloys and a series of Co-Fe alloys. Since many of the commercial alloys in this list contain more than two metals, various complicating factors in the identification of the oxides formed may arise.

Jan 1, 1947

By Harold Earle Cook

The purpose of this paper is to state briefly the inspection requirements of the Bureau of Ordnance, the specifications governing the inspection, and the physical and chemical properties of the steel used in the construction of ordnance for our Navy. It would be of interest to evoke discussion on points in these specifications which do not tend to insure the production of the very best material for the purpose intended. In other words, what requirements of our specifications are useless and also in what manner are our specifications deficient? It might be well at the start to answer the first criticism of this paper which will probably be made, and that is that the title does not agree with the subject matter. Considering metallographic work as covering only the macroscopic and microscopic examination of metals, this paper will have gone beyond the subject; but it is believed that a broader definition of metallography is that it is the study of the relation of the internal structure of metals and alloys to their composition and to their physical and other properties. The internal structure of steel is dependent on its physical and its chemical properties. These physical properties are dependent on the chemical composition and the mechanical and thermal treatment of the steel. So it seems that this subtitle would not be entirely necessary and that the title " Metallography of Steel for Ordnance Purposes" would cover a study, not only of what we can learn of macroscopic and microscopic examination, but broadly of the whole subject of the specifications, the fulfillment of the requirements of which produce the structural conditions revealed by macroscopic and microscopic examination. I will refer but briefly at the beginning to the microscope and its uses in our inspection. It is only very recently that the Bureau of Ordnancc has furnished certain of its inspection offices with a portable Tassin outfit for the microscopic examination of steel. Since that

Jan 1, 1916

By Edward H. Robie

SEPTEMBER usually being a fine month for motoring, we set out with our better half at the end of August in our Studebaker for points West. A combined business trip and vacation. The first night found us 392 miles away, at the Statler Hotel in Buffalo, and the next morning we revisited Niagara Falls for the first time in some forty years. The cataracts were as impressive as ever and certainly worth a day of any vacationist's time, instead of the half hour we could spare before going on to Chicago. The Centennial of Engineering, the hundredth anniversary of the founding of the ASCE, no doubt attracted the greatest gathering of engineers in history but still the attendance was disappointing to most of the forty or fifty societies that participated. Perhaps the time-the two weeks following Labor Day-was unfavorable. Few could afford to spend ten days away from home and business at that time of the year. Fall meetings of the AIME normally attract far more than the 300 that registered in Chicago. The technical program, however, was excellent, especially that arranged by the Minerals Beneficiation and Industrial Minerals Divs. The mineral industry papers of a more general nature that were presented as a part of the Centennial program on Monday and Tuesday of the following week were of high quality and offered by top names but had a meager audience. Undoubtedly the celebration brought engineers and engineering to the attention of millions of people. The pageant at the Museum of Science and Industry proved continuously interesting, showing the progress of engineering following the first use of fire. The show continued for many weeks. A special stamp was issued by the Government, which engineers might well use on their Christmas cards or other mail this year. After six days in Chicago we set out north, first visiting Fairbanks Morse in Beloit and Allis-Chalmers in Milwaukee. Will Mitchell's Basic Industries Research Laboratory is doing interesting work and being installed in more comfortable quarters. The next day at Ishpeming, C. W. Allen arranged for luncheon with a local group of AIME members and we then looked over the new surface plant of the Mather B mine, a model of modern functional design. Then on to a small dinner meeting at Calumet following cocktails at Endicott Lovell's attractive summer home on the lake at Point Mills. The new Memorial Union Bldg. at Houghton, where we were domiciled for the night through the courtesy of Roy Drier, is a beautiful modern addition to the college, a model of its kind.

Jan 1, 1952

By William G. [Peryam], Bishop Ottey M., Fred E. Johnson

THE Lepanto Consolidated Mining Company is the largest copper producer in the Philippines, and the only one that makes a concentrate valuable principally for its copper; also, it has the only productive copper mine situated at considerable distance from the sea, and is the only one in the islands operating its own smelter. The Lepanto mine is in the Municipal District of Mankayan, sub-province of Benguet, near the heart of the Mountain Province of Northern Luzon. It is 165 km. from its shipping point at San Fernando, Province of La Union, on the shore of the China Sea. Elevations at the property range from 3200 to 4500 ft. The climate is very mild; temperatures are seldom below 50° or above 80°F. Annual rainfall approaches 170 in. and is mainly confined to a rainy season lasting from May to October. The months from December to April, inclusive, are usually extremely dry. This climatic pecularity entails the problems of landslides on the roads during the rainy season and water shortage during the dry season. The Mountain Trail, an improved rock-surfaced toll road maintained by the Commonwealth Government, gives access to the property. The 105 km. over this road may be traveled in about 4 ½ hr. during the dry season. Very few sections of the road are straight for more than 100 meters, and about one third of it is a one-way road controlled by gates. All freight for the property is delivered by the Manila Railroad Company to Bauang, La Union, 45 km. west of Baguio and at sea level, where it is picked up by freight trucks and hauled via Baguio to Lepanto. Granulated matte is hauled in bulk from Lepanto in four-ton lots on freight trucks to the storage bins at San Fernando. Freight rates from Bauang to the property amount to P8.00 per ton, and from the property to San Fernando the rate is P16.00 per ton. The company pays the road toll, P1.00 per truck, each way. THE CAMP The company maintains a modern camp, well separated from the mine and reduction plant. Comfortable and sanitary living quarters, water, and light, as well as free medical service are provided all employees. A hospital staffed by a doctor and two nurses takes care of all medical treatment. Considering recreational facilities of great importance, the company has provided two tennis courts, two basketball courts, and badminton courts for employees. Bowling alleys and a motion picture theater are operated by the company, the profits being expended for other recreational purposes. A moderate sized recreation hall serves for barrio dances, meetings,

Jan 1, 1942

By G. R. Leverant, C. P. Sullivan

To evaluate the effect of a dispersion of nondeform-able, incoherent, second-phase particles on high-strain cyclic deformation and fracture, recrystallized TD-nickel (Ni-2ThO2) and a commercially pure nickel, Ni-200, were fatigued under strain control at total strain ranges varying from 0.009 to 0.036. Relative to the Ni-200, the slip at the surface of the TD-nickel was more wavy and discontinuous due to the presence of the thoria particles. This made crevice formation (incipient cracking) within slip bands more difficult in TD-nickel than in Ni-200. Both materials cyclically hardened to a constant (saturation) flow stress which increased with increasing plastic strain amplitude. Cellular substructures were developed in both materials during cycling. The cell size in TD-nickel was controlled by the thoria particle distribution and was independent of plastic strain amplitude over the range investigated. The cell size in Ni-ZOO was larger than that in TD-nickel at similar plastic strain amplitudes and was a function of plastic strain amplitude. These results, together with the cyclic stress-strain curves for both materials, are discussed in terms of a model for fatigue strain accommodation at saturation recently proposed by Feltner and Laird. NUMEROUS fatigue investigations have considered the interrelation of slip character, dislocation substructure, and cracking in pure metals and solid-solution alloys. However, except for the studies of the low-strain fatigue of internally oxidized copper alloys1 and cast, dispersion-strengthened lead,&apos; little is known about the effects which small, incoherent, nondeform-able, second-phase particles have on cyclic deformation and cracking processes. Effects due to the particles alone are often obscured by a dislocation substructure introduced during thermomechanical processing of dispersion-strengthened metals. In the present study, recrystallized TD-nickel and a commercially pure nickel, Ni-200, were employed to evaluate the effect of a thoria dispersion on high-strai fatigue deformation and cracking at room temperature. I) MATERIAL AND EXPERIMENTAL PROCEDURE The TD-nickel was supplied by DuPont as a 5/8-in.-thick stress-relieved plate which had been subjected to a proprietary schedule of thermomechanical treatments, and the Ni-200 as 3/4-in. bar which was subsequently annealed for 2 hr at 850°C in argon resulting in an average grain diameter of 0.05 mm. The compositions of these materials are given in Table I. The microstructure of the TD-nickel consisted of elongated grains parallel to the primary working direction with an average width of 0.16 mm, Fig. l(a). Many fine annealing twins were present indicating that the starting material was in a recrystallized condition; this supposition was confirmed by the absence of of any extensive dislocation substructure, Fig. l(b). Sheetlike stringers parallel to the rolling direction were occasionally seen both within grains and at grain boundaries. Some approximately spherical particles about 2 in diam, which may correspond to exceptionally large thoria particle aggregates, were also present. The average Young&apos;s modulus of the plate material in the rolling direction was 21.8 X 106 psi which is consistent with a {100}<001>recrystalliza-tion texture3&apos;* being prominent. In transmission microscopy, the 2.3 vol pct of thoria particles generally appeared to be uniformly distributed although some clusters, 0.1 to 0.3 in diam, of larger particles were observed as previously reported for TD-nickel sheet,5 and stringering of particles was present in some areas as welt. The average diameter of the thoria particles was 450A with a calculated mean planar center-to-center spacing of 2100A, as determined by quantitative metallographic analysis.= The 0.2 pct offset yield stress was 36,000 psi which agrees with the value predicted by the modified Orowan relation7 for edge dislocations bowing between thoria particles of the size and spacing observed in the present investigation. Fig. 2 illustrates the specimen design employed for the axial high-strain fatigue testing. Adapters were screwed onto the threaded portions of each specimen so that testing could be performed in the same manner as that reported for buttonhead specimens.8 Stressing was coincident with the working direction for both materials. The gage section of each specimen was electropolished and lightly etched prior to testing. The total strain was controlled, being varied between zero and a maximum tensile strain ranging from 0.009 to 0.036. In addition to these tests, a circum-ferentially notched TD-nickel specimen was cycled over a total strain range of 0.0075. The same strain

Jan 1, 1969

By James T. B. Ives

The map exhibited* as an example of my method of construct ing geological strata-maps is essentially an educational appliance. The method, however, is available for the production of maps of comparatively small areas, which, I am confident, will be found of great practical value to mining engineers. Before stating how the method may be so applied I will briefly describe the map exhibited, as the easiest way of making my meaning clear. Almost any region might be taken. This map represents the eastern half of the United States; and the geology is that of the map issued by the Geological Survey, and revised and extended subsequently by Professor Hitchcock for your Institute. I use ten cards, of the colors used in the geological map, each having the geog raphy of the area printed upon it; and I superimpose these in the order in which the colors occur in the index to the map. I next cut away a portion of each card, excepting the lowest, leaving only so much of each as represents the exposure of the formation of that color plus all those which overlie it. When that is done, the whole, looked at from a distance, appears to be an ordinary geological map. Looked at more closely, however, the formations are seen to overlie one another, as in nature. The cards are covered with glass in a frame, which, hinged at the bottom edge, can be let down. The cards are then found to be all hinged in the same manner, and they, too, may be lowered, one after the-other. I am told by teachers of geology of great experience and the highest reputation that by this appliance they will be assisted in im parting to students the first facts and principles of geological sci ence. Having let down the whole series of cards, until that repre senting the Archaean is seen underlying all the rest, the teacher will gradually rebuild it. The Cambrian will thus be laid down upon the Archaean before the eyes of the class, the Silurian upon that,

Jan 1, 1888

By A. F. Baker, E. R. Palowitch, A. W. Deurbrouck

As air-pollution regulations become increasingly more stringent, increased significance is being placed on the amount of sulfur present in coals used for steam generation. These regulations are aimed at minimizing the pollution of the atmosphere with noxious gases such as the sulfur oxides that are formed and emitted when coal is burned. Two meet these future requirements, a definite need exists to reduce the sulfur content of some of the coals used for steam generation. Reducing pyritic sulfur involves liberating the pyrite from the coal and then removing it. The specific gravity of pyrite is high (5.0) compared to that of coal (about 1.2, mineral-free), and standard coal-washing devices, such as wet concentrating tables, will efficiently remove pyrite particles larger than about 100 mesh. Particles below this size will be entrained in the table water and will be carried into the clean coal product. Techniques such as froth flotation are of little benefit for pyrite reduction because the flotation characteristics of pyrite are similar to those of coal.

Jan 6, 1966

By Charles A. Ashburner

VERY little is known of the economical value of the cod-bells of the State of Texas. The first authentic statement in regard to their occurrence is that contained in the reports of the United States Exploratians for the Pacific Railroad, near the 32d parallel of latitude, published in 1863-55. Professor William P. Biake reports, "that a number of seams of bituininorls coal, varying in thickness from two to four feet, have been opened along the Brazos River, in Young County, about one hundred and fifty miles west of Fort Worth." Dr: Shurunrd also states, " that the claracteristic fossil fornis of the Carbeiferaas Era have been found with this coal, and considers the age of the formation established. Foesils obtained from the carboniteroas limestone remove all doubt of the age of these deposits."† In the spring of 1879, I was called upon by some Eastern capitalisets to make an examination of the Brazos coal-field, in order to obtain the thickness, extent., and value of the coal which could be mined and be&apos;made merchantable fir stearn, heating, and metallurgical purposes. The demand for coal in this section of the country is great, and a fuel which in our Eastern markets might be considered of inferior quality, would here find a ready sale. It must be remernbered that the market value of a coal does not depen&apos;d upon its absoltite purity, but upon its actual value in heat units which it is capable of prodwing. A poor coal which can be cheaply milled near the consuper, is infinitely more remunerative to a mining company than a superior coal whose cost to the consumer is greatly increased by high mining charges and railroad freights. The value of the Texan coals does not depend upon their purity but upon their low first cost and nearness to a market. A glance at a geological map of the United States, will show that the Brazos coal-field is the extreme southwestern extension of what may be called the Missourian, Fourth or Western, bituminous coal

Jan 1, 1881

By A. L., Bailey

All who are even generally aware of the tremendous rate of increase in coal washing operations must realize the growing importance of the float-and-sink test. I believe it is conservative to estimate that, in the past decade, the dollar volume of float-and-sink testing has increased tenfold. It is a simple matter of economy, then, to examine the factors that determine the cost of adequate float-and-sink testing. When the Coal Preparation Section of the Bureau of Mines entered upon a greatly expanded program of such work in connection with the synthetic liquid fuels investigations, it seemed advisable to examine these factors experimentally. The principal consideration that differentiates float-and-sink test sampling from general purpose sampling, is that the original particle size must be preserved. Therefore, the total cost of the test will be directly affected by any standard that might be proposed to limit sample bulk reduction at any given particle size. For this reason, the relationship of sample size to variability of results was the first factor to be studied experimentally.

Jan 1, 1949

By NORMA D. MACFADDEN

WHILE the library work of the Woman&apos;s Auxiliary to the A. I. M. E. was founded three years after the formation of the Auxiliary, its present policy of establishing permanent libraries in mining camps throughout the United States dates only from 1924. Since then sixteen libraries have been established and thousands of books have found their way to homes of far-away miners, bringing pleasure and knowledge to a multitude of Americans and future citizens. Library work was initiated under the presidency of Mrs. H. W. Hardinge in 1922 and firmly established with her aid as one of the main activities of the Auxiliary. The first chairman served but a short time and Mrs. A. O. Ihlseng then took over the work of chairman of the Library Committee. To place the surplus books of Auxiliary members and their friends in use in mining camps was the immediate work of the committee. This was accomplished by placing a traveling library in the Bureau of Mines&apos; cars and also by sending books for distribution to section chair- men in our larger mining camps.

Jan 1, 1929

By J. E. Neal, C. T. Naber, O&apos

Silicon thin films were deposited by electron beam evaporation in an ultrahigh vacuum onto (0001) and (1102) sapphire substrates. Attempts were made to correlate the structural properties of the deposited silicon films with the following: 1) substrate orientation, 2) substrate surface condition, 3) substrate temperature, and 4) deposition rate. The substrate temperatures were varied between 500° and 1000°C and the deposition rates were varied between approximately 50 and 700A per min. The following sapphire surface treatments were investigated: 1) annealing in the ultrahigh vacuum at 1200° C; 2) heating in a hydrogen atmosphere at about 1350°C; and 3) etching with silicon by evaporating silicon onto sapphire substrates heated to 1200° or 1300°C. Twinned silicon films were occasionally formed at substrate temperatures between the 800° and 1000°C on unprocessed mechanically polished substrates; however, the reproducibility and crystallinity of these films were generally poor. Single-crystal and twinned silicon films were formed at substrate temperatures between 700° and 1000°C on substrates which were silicon-etched at 1300°C prior to deposition. Fiber texture films were formed at substrate temperatures between 500° and 700°C. The (111) lattice plane of the silicon single-crystal films was parallel to the (0001) sapphire plane and the (100) silicon plane was parallel to the (1102) sapphire plane. TECHNIQUES are well-established for growing single-crystal silicon thin films on sapphire by chemical methods.&apos;-* Vacuum epitaxial techniques have a number of advantages over chemical epitaxial techniques in the fabrication of thin film microcircuits.5 One of the most significant is that vacuum techniques are compatible with well-established procedures for forming vacuum-deposited thin-film resistors, capacitors, and interconnections. Salatna, Tucker, and young6 recently reported the formation of relatively poor crystalline-quality silicon films on sapphire by electron beam evaporation in a vacuum of about 7 x 10-7 Torr. The purpose of the investigation described here is to determine the relationships between the structural properties of silicon thin films deposited on sapphire substrates by electron beam evaporation in an ultra-high vacuum and the following: 1) substrate orientation; 2) substrate surface condition; 3) substrate temperature; and 4) deposition rate. The substrate temperatures were varied between 500° and 1000° C and the deposition rates were varied between approximately 50 and 700A per min. Two orientations of sapphire were used: (0001) and (1102). The thick-nesses of the films were between 8000 and 16,000A. The morphology and crystallinity of the deposited films and substrate surfaces were investigated by optical microscopy, electron microscopy, and electron diffraction. APPARATUS AND PROCEDURE A cross section of the ultrahigh-vacuum thin-film evaporator is shown in Fig. 1. The bell jar is stainless steel and copper gaskets are utilized at all seals. High vacuum is attained by a 6001iter per sec ion pump and a titanium sublimation pump. Sorption pumps are used to rough the system to a pressure of about 10 µ prior to starting the ion pump. Vacuums in the 10- 10 Torr range were attained after baking the system at about 250°C for 8 hr. Vacuums in the 10-8 to 10-9 Torr range were maintained during silicon evaporation. The silicon charges, which were cut from p-type single-crystal boules which had resistivities between 2000 and 4500 ohm-cm, were placed in the water-cooled copper crucible of a 180 deg bent-beam 5-kw electron beam evaporator. During evaporation, a molten zone was formed in the top center of the silicon charge, and the portion of the silicon charge in contact with the water-cooled crucible remained solid. The substrate heater, which has been described

Jan 1, 1969

By R. E. Grant

THE Cerro de Pasco Railway Co., owned and operated by the Corporation, is a common carrier whose chief functions are transportation of ore and concentrates from the mines at Cerro de Pasco to the smelter in Oroya, and haulage of coal from the coal mines at Goyllarisquisga to the coal washery at Fundicion. Connecting with the Peruvian Central Railway at Oroya, the C. de P. Railway maintains joint, daily freight and passenger service from Lima and the port of Callao to Cerro de Pasco, terminal of the C. de P. main line and gateway to the Huanuco Valley. Extending from Oroya to Cerro de Pasco the main line is a standard-gauge roadbed of 70-lb. rail, 132 km. long with a maximum compensated grade of 2.25 per cent and a curvature of 16°, climbing from an elevation of 12,272 ft. above sea level at Oroya, lowest station on the line, to 14,208 ft. at Cerro de Pasco. The highest point reached by the C. de P. is on the coal branch at Alcacocha where the rails are 14,385 ft. above the sea.

Jan 1, 1945