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Adolph Greiner, Seraing, Belgium:—I have nothing special to add to Professor Hubert's paper except to say that there are some little things that it would be well to have corrected when the paper comes to be published. In dealing with the thermal efficiency of the engine, you will find that the 29.84 per cent. was a very high one. Professor Hubert has forgotten those engines built under the Cockerill type, but he has referred to them in Appendix 11. At our works at Cockerill we have built 63 engines, giving 63,000 h.p., and the other companies who have received licenses have built 113 engines, making 103,000 h.p., and aggregating 176 engines and 166,000 h.p. Eight years ago I had the pleasure of giving to the Institute the results obtained up to that time. Since then a good many engines have been constructed. In 1898 I thought a blast-furnace producing 100 tons of pig iron would allow 3,000 h.p. Professor Witz and Professor Hubert show that with the same production of pig the new engines take 3,800 h.p. out of the gas. At present at Cockerill we make 700 to 800 tons of pig iron per day, and we hope to have 26,000 h.p. in a few years. At present we have only half of that in gas-engines, but we hope to have in five or six years all the gas out of these furnaces to the number of 25,000 or 26,000 h.p. Tom WEstGarth, Middlesbrough, England :—My contribution is not a paper in the ordinary sense of the word, because I am sure you will agree with me that what I have written is only supplementary to the other two papers. The notes are schedules of the larger-size gas-engines built by British engine-makers, of 500 h.p. and upwards. If you look at the schedules you will find that in England gas-engines have become quite ordinary motors for a good many purposes. It was at first thought that gas-engines were troublesome, and ill-

Jan 1, 1907

By G. S. Rice

IT is evident from Professor Louis' remarks that he holds a different opinion on certain phenomena connected with a specific type of surface subsidence from mining than is held by many engineers in the United States. The question which appears to be at issue is whether or not the line or plane of "draw" produced in ground movement resulting from extraction of pillars may, under certain conditions, be vertical or even inclined toward the workings rather than inclined for- ward over the unworked mineral, as it is universally agreed occurs in mining by the longwall advancing method. In discussing this case it is well to take the simplest condition, such as specified by Professor Louis, of a flat bed, whether it be coal, iron or other mineral, where the overburden is stratified rock and where there is no overlying quicksand. Professor Louis says in effect that his experience is that the ultimate angle of draw is always positive and inclined 5" to 15" from the perpendicular over the unwrought mineral. My experience under Illinois coal-mining conditions is that .'where longwall advancing is used the draw is always positive as Professor Louis describes it, but that in extracting of panels by withdrawal of pillars, the ground movement is manifested, after the first roof' beam break, by the forming of an unstable dome over the goave. Then subsequently, by the falling of individual slabs from the under side, the dome gets larger and higher until it breaks through to the surface of the rock., Up to this time, arch stresses buttress the rocks above the solid coal or mineral. When, however, after. the dome breaks through and the central hole - #enlarges so the arch is no longer sufficiently supported -the stratified rocks cantilever out .from over the solid unworked mineral and tend to break off in masses triangular in vertical cross-section, until the broken loose material, sliding down against the solid rock, .has such a thrust that it balances the tendency ,for the solid stratified rock to break away and slide toward the excavation.

Jan 1, 1929

Marius R. Campbell, Washington, D. C. (Communication to the Secretary): Having spent considerable time in a systematic study of this field,'both as regards the details of its structure and stratigraphy and the broader question of its relation to the Appalachian basin, I wish to add a word concerning the correlations made by Mr. Hodge in his paper. From A commercial standpoint, the question of correlation, even along the strike, is of little or no importance, for the variability is such that each opening should be tested individually, regardless of the horizon at which it appears; but these correlations assume an entirely different aspect when their scientific bearing is considered; they then become of vital importance, and, before being accepted, should be subjected to the most rigid scrutiny and severe tests. Mr. Hedge states positively that the Imboden seam of coal is equivalent to the Elkhorn coal of Pike and Letcher counties, Kentucky. In the writer's opinion, such equivalency is, at the utmost, only a possibility. This correlation has been generally adopted by the geologists of the Kentucky Geological Survey, but the writer has been unable to find on what grounds they base the statement. The evidence of identity seems to be in the character of the coal, as both seams furnish fine coking coal; also, in the similarity of the interval between them aid the " Bee Rock," or top of the great conglomerate. It is probably an easy matter to determine the thickness of this interval on Elkhorn creek, and we will assume that the measure of 300 to 350 feet is correct. In the Big Stone Gap field, the question of measuring the interval between the Imboden and the " Bee Rock " is exceedingly difficult. The line of outcrop of this mass of strata is along the northern base of Stone mountain, and, in the uprising of the great arch, the strata on its flanks have been thrown into many minor folds, and, in places, have been broken by local faults. This complicated structure, together with the absence of ally well-marked stratum, renders it exceedingly difficult to obtain a correct measure of the intervening sandstones and shales. The interval of 300 to 350 feet, assigned by Mr. Hodge, is mani-

Jan 1, 1893

LINN BRADLEY, H.' D. EGBERT and W. W. STRONG (communication to the Secretary*).--In the discussion of the paper, a request was made for a further explanation of the curves given on Chart I. In preparing the curves given on this chart, a typical blast-furnace top gas having the following composition by weight was assumed: Per Cent. C02 21.00 CO 24.00 Hz 0.25 CH4 0:25 N2 54.50 For any given top-gas temperature, Curves A, B, C, D, and E indicate in British thermal units the sensible heat lost in cooling the top gas to 60° F. by wet-cleaning methods. Top-gas temperatures are plotted as abscissae, sensible heats above 60° F. in British thermal units are plotted as ordinates, and separate curves are drawn for top gases carrying various amounts of moisture. For any given stove exit-gas temperature, curves A1,-B1, C1, D1, and E1, indicate in British thermal units the sensible heat carried out of the stoves by the moisture which is left in the top gas when it is dry-cleaned and enters the stoves hot. This moisture is removed when the gases are wet-cleaned and the sensible heat which it carries out of the stoves is therefore saved. As before, separate curves are drawn for top gases carrying various amounts of moisture. The curves in Fig. 1, therefore, indicate graphically how much more sensible heat is conserved by cleaning the top gases by the dry-hot method than is conserved by cleaning the top. gases by a cold-wet method and thus removing the greater part of the moisture carried by them. They also show of how little moment it is from a heat conservation standpoint whether or not the moisture carried by the top gases is removed before they enter the stoves. That wet cleaning secures the removal of this moisture and is thus to be recommended from a heat conservation standpoint is an argument often advanced by advocates of wet cleaning. The curves of Fig. 1 show how fallacious such an argument is.

Jan 6, 1917

By P. H. Dudley

The present paper was suggested by the paper read by Mr. R. W. Hunt at the New York Meeting, in February last, on rail-sections (Trans., xvii., p. 778)) in the discussion of which I brought forward some of the facts and observations here stated. Professional duties having prevented me from writing out my part of that discussion in time for its publication in the volume containing Mr. Hunt's paper, I take the opportunity to present it in separate form and greater fulness. The striking features of the series of rail-sections submitted by Mr. Hunt are their shallow heads and heavy bases. In these respects they are quite similar to the section of the 80-1b. rail, which I designed in 1883 to meet the requirements of the traffic of the New York Central and Hudson River Railroad. Before the adoption of the 80-1b. rail, this road had modified its 65-1b. section from a shallow head with rounding sides and quite heavy base to one having a deep head and thin base. All the leading railroads had changed from the earlier sections of steel rails to those having deep heads and thin bases, conforming to the recommendations of the Committee on Rails of the American Society of Civil Engineers. It is but proper to say that the committee's investigations upon the wear of rails were made upon the rails manufactured under a practice quite different from that which obtained after the committee's recommendations were carried into effect. The results in actual service have been contrary to what was expected. Fig. 1 shows my 80-1b. section of 1883. Before designing this rail I had taken, at different times, a series of diagrams of the condition of tracks, with my car, on the New York Central and Hudson River Railroad, all of the New England railroads, and all but one of the trunk lines. My diagrams gave me an opportunity which could not otherwise have been obtained to see the wear of great numbers of sections of rails under widely varying conditions of traffic.

Jan 1, 1890

By George Harrington

THIS paper is a brief description of the design and equipment of a new coal mine in southern Illinois, which has many features not common practice in shaft coal mining and which is laid out and equipped for such unusually large capacity that it promises soon to become one of the largest mining operations of its kind. Shaft sinking for the mine, New Orient, was commenced in May, 1921, by the Chicago, Wilmington & Franklin Coal Co. In October, 1924, the plant was practically completed and was producing over 6000 tons of coal per day. There is good prospect that within a few years, when the mine is fully developed and manned, the output will attain a daily rate of 12,000 tons. The coal seam at New Orient lies approximately horizontal, about 500 ft. below the surface, and may be said to run from 9 to 12 ft. in thickness. The tendency in Franklin County has been toward large mining units (5000 to 6000 tons per day) with great care being given to protection against fire and explosion hazards, and usually with quite elaborate surface plants permitting careful preparation of the coal into graded sizes comparable with those made in the anthracite region. The field is unionized, with uniform conditions of wages for various classes of work, hours, etc., and the Illinois mining laws are quite specific with regard to fireproofing and safety measures. These conditions make it difficult for any but well-equipped and well-operated mines to meet the competition of the numerous fine properties of which this county can justly be proud. The coal company's property was already developed on the western side by the Orient. mine-a much visited and written about operation (with which many of you are possibly familiar through the Department of Mines' film "The Story of Coal ") which until recently held the 8-hr. production record with 8218 tons and usually ran quite consistently with production of slightly over 6000 tons per day. Experience at Orient was naturally one of the greatest influences in determining the location and character of the New Orient.

Jan 2, 1925

By Charles E. Wait

It is said by some that the occurrence of a deposit of sulphide of antimony in Southwestern Arkansas has been known for fifteen or twenty years. Whether or not such is the case I am not prepared to say, but I am not able to find any record of such a discovery, or any analysis of antimony ore obtained from that section, published at so early a period. The present discoveries, that seem to be attracting some attention, date back to the winter of 1873-74. At that time a vein of ore was found by Mr. Robert Wolf, in honor of whom the vein was named, and still is called, "the Wolf lode." At the time of the discovery the ore was unknown to the prospector, and its composition was not thoroughly understood in that locality until samples were sent to several analytical chemists, who pronounced it sulphide of antimony—stibnite. Since the discovery of this ore there have been three mines opened, and a number of interesting minerals of the antimonial series have been found. I have had an unusually good opportunity to collect specimens from these mines; and it is owing to the constant inquiry concerning the character of these ores that I have collected for publication the results of quite a number of analyses, sufficient I trust to clearly point out their composition. This is one of the few localities in the United States where antimony ore is found in workable quantities ; I say workable quantities, because two different shipments of ore have been made to English reduction works, and in both cases excellent returns were made. The discovery of these deposits will, it is hoped, give rise to a prosperous and remunerative industry at no distant day, and when fully developed they may yield ore in sufficient quantity to supply the regulus for the home demand, thus adding wealth not only to those interested, but also to the State of Arkansas. The three mines are situated in the northern part of Sevier County, and may be reached by the St. Louis, Iron Mountain and Southern Railway to Fulton, thence by wagon-road to Columbus, Nashville, Centre Point, and to the mines. During most seasons of the year the

Jan 1, 1880

By Charles E. Wait

IT is said by some that the occurrence of a deposit of sulphide of antimony in Southwestern Arkansas has been known for fifteen or twenty years. Whether or not such is the case I am not prepared to say, but I am not able to find any record of such a discovery, or any analysis of antimony ore obtained from that section, published at so early a period. The present discoveries, that seem to be attracting some attention, date back to the winter of 1873-74. At that time a vein of ore was found by Mr. Robert Wolf, in honor of whom the vein was named, and still is called, "the Wolf lode." At the time of the discovery the ore was unknown to the prospector, and its composition was not thoroughly understood in that locality until samples were sent to several analytical chemists, who pronounced it sulphide of antimony-stibnite. Since the discovery of this ore there have been three mines opened, and a number of interesting minerals of the antimonial series have been found. I have had an unusually good opportunity to collect specimens from these mines; and it is owing to the constant inquiry concerning the character of these ores that I have collected for publication the results of quite a number of analyses, sufficient I trust to clearly point out their composition. This is one of the few localities in the United States where antimony ore is found in workable quantities; I say workable quantities, because two different shipments of ore have been made to English reduction works, and in both cases excellent returns were made. The discovery of these deposits will, it is hoped, give rise to a prosperous and remunerative industry at no distant day, and when fully developed they may yield ore in sufficient quantity to supply the regulus for the home demand, thus adding wealth not only to those interested, but also to the State of Arkansas. The three mines are situated in the northern part of Sevier County, and may be reached by the St. Louis, Iron Mountain and Southern Railway to Fulton, thence by wagon-road to Columbus, Nashville, Centre Point, and to the mines. During most seasons of the year the

Jan 1, 1880

By V. R. Garfias

With the exception of the United States and Russia, none of the leading world powers have within their boundaries the oil supplies needed to meet present peace-time requirements, and even in regard to the United States it is admitted by competent observers that the known oil reserves within the country are inadequate to meet demands for more than a comparatively few years. It follows, therefore, that the transportation of petroleum—almost entirely by tank steamers—from foreign fields to the main consuming centers is one of the most important factors affecting the present and future development of the oil industry. The world-wide distribution of petroleum is affected by numerous factors of which international politics is not the least important. The assurance of an ample supply of petroleum—one of the most essential munitions of war—is of paramount importance particularly to those countries subjected to the rivalries of powerful neighbors. And paralleling the importance of the control of an ample supply is that of its safe transportation from the fields to the consuming centers. To illustrate: France is dependent almost entirely on foreign sources for its petroleum requirements estimated at close to 100,000 bbl. daily, and in order to control such a supply after the World War it acquired an interest in the Iraq oil fields. Lately it has undertaken the construction of a pipe line from these fields to the Mediterranean seaboard in Syria with the expectation that late in 1934 these fields will supply between 30 and 40 per cent of the country's requirements. It should be noted, however, that the availability of this supply is entirely dependent on the safe operation in the Mediterranean at all times of an adequate fleet of tank steamers. Thus, in order to transport 40,000 bbl. daily, it will be necessary for one 10,000-ton tanker to leave Tripoli, the Syrian port, say for Marseille, every other day throughout the year while to meet the entire present peace requirements of France from the Iraq fields, a fleet of some 30 such tankers must be kept in continuous operation between Tripoli and Marseille.

Jan 1, 1934

By O. E. Kiessling

THE present system of competitive exploitation of oil pools results in losses, both of petroleum and of profits. Under a competitive system the owner produces or withholds his product according to the price, which reflects the demand, but in the pe-troleum industry the producer does not have complete control over the expansion and contraction of his out-put. Under a series of court decisions, reviewed in detail in the paper, petroleum is not covered by- the general theory of English common law that the owner of land owns everything from the center of the earth to the sky within the areal limits of his property, but is considered to be his only when he has reduced it. to possession, which he can only do by taking it out of the ground. If A can obtain possession of the petro-leum which is beneath the property of B without tres-passing on B's property he commits no legal wrong and B has no defense except to get it into his (surface) possession before A takes it. No one would expect an. owner under such a system to forego the possibility of securing some oil from his property in order to in-crease the ultimate production of the pool. The pe-troleum industry. should offer a constructive program, that will eliminate losses and protect the interests of individuals as far as possible. If improved methods of oil recovery can be applied the quantity of petroleum recovered might be double or even treble the amount recovered by ordinary procedure. But increased recovery is not the only benefit from pool development. In brief, the following advantages can be claimed for unit operation: 1. Saving in development and operating costs. 2. Less danger of damage to the fields by defective wells. 3. Development is better gaged to fit market demand and to effect the most efficient recovery of oil. 4. More oil, gas, and gasoline can be marketed. 5. By regulating pressures, recovery .of oil and gas will be greater and the wells will flow longer. Reagan County (Big Lake), Rainbow Bend and Cabin Creek are examples of longer life of pools thus obtained.

Jan 11, 1927

By John D. Sullivan

Leaching of copper ores is a comparatively old art, probably dating back to medieval times. The leaching of mixed oxidized-sulfide ores, however, is modern. The first modern plant leaching mixed ores was at Ajo, Ariz., where commercial operations commenced in 1917. While the ore at Ajo was primarily oxidized there was always some sulfide present. The Inspiration leaching plant, which was put in operation in 1926, may be considered the first plant constructed for the extraction of both sulfide and oxidized copper. The pioneers in leaching mixed ores had a difficult task before them since they had very little fundamental data on the chemical and physical factors of leaching. For the very large amount of painstaking experimental work that was done before building the Ajo and Inspiration leaching plants the reader is referred to the original articles.' For a period of several years the writer worked on problems connected with the chemistry and physics of leaching mixed oxidized-sulfide ores. This paper summarizes the experimental work and discusses various factors involved in leaching ores. It also presents many data heretofore unpublished. Among the new data are those on chrysocolla, pages 518 to 519, inclusive; dioptase, page 519; covellite, page 529; virtually all those on chalcopyrite, pages 531 to 533, inclusive; enargite, page 533; and tetrahedrite and tennantite, pages 534 and 533. The oxidized copper minerals of commercial importance in American ores are azurite, Cu3(OH)2(CO3)2; malachite, Cu2(OH)2CO3; chrysocolla, CuSi03.2H2O; tenorite (or melaconite), CuO; and cuprite, Cu2O. Dioptase, CuSiO3.H2O is less common. Brochantite, CuSO4.3Cu(OH)2, while the chief mineral in the ore at Chuquicamata, is not of major importance in the United States. Metallic copper, while chemically not so, is frequently classed as an oxidized mineral of copper. The most important sulfide minerals are chalcocite, Cu2s; covellite, CuS; bornite, Cu5FeS4; and chalcopyrite, CuFeS2. Less important complex sulfides are enargite,

Jan 1, 1934

By W. E. D. Stokes

The application of aviation to mining and petroleum operations, on the basis of economy and attainment, has become a demonstrated fact. According to Dominion Government rccords, 30 Canadian companies engaged in air transportation with northland mining camps, carried 13,000 tons of freight in 1935, and in 1936 carried 16,000 tons. In addition, many mining companies used planes to transport prospectors with canoes, outboard motors, gasoline drums and supplies to remote locations, and one company maintained a plane to take radium-bearing ore from its mine on Great Bear Lake nearly 1000 miles south to the railway at Waterways, Alberta. Heavy pieces of mining machinery weighing 2 tons are being carried by Ford trimotor planes over the Andes, at an altitude of not less than 15,000 feet. At Bulolo, New Guinea, 17,500 tons of disassembled gold-dredging equipment has been flown over inaccessible terrain, while supplies and building materials for a community of 1000 whites have been transported by airplane. A 31/2-ton shaft was carried on one notable trip, while at another time an automobile, 2 tons of rice and a large safe went over the mountains in one plane. Fig. 1 shows an electric generator that was carried by plane to Bulolo. Many large American oil companies operated fleets of planes during 1936, ranging from fast, luxurious air liners for executives to elaborate geological prospecting units, ambulance planes, freight carriers and pipe-line repair crews. According to the U. S. Geological Survey, commercial firms photographed 16,291 square miles during 1935, while the Government compiled from aerial photographs by the Geological Survey in the United States 85,544 square miles. It was found that information could be determined in a fraction of the time required by surface methods. However, sounding a word of caution, a Commonwealth of Australia government report on aerial survey operations had this to say: It is necessary to repeat ad nauseam that aerial photographic survey is in no sense a substitute for geological investigation, though it is a very valuable adjunct thereto, and greatly facilitates and aceeleratcs geological mapping. There are many details

Jan 1, 1937

By Joe B. Alford

Founding of the Institute The advance of population and civilization in the U. S. moved through the woodlands of the East, and reached the edge of the great central plains about the middle of the nineteenth century. There the advance paused for almost a generation - ahead were vast reaches of prairie country, uncharted, forbidding, and populated by hostile tribes of the native Indians. The turmoil of the Civil War, and the readjustments following it, further delayed the advance. By about 1870, the Nation was becoming stabilized again, the conflict with the Indians was closing, and the pressure of growth was forcing population to resume its westward movement. In addition to geography, the Nation had another frontier: the development of its immense natural resources. Conditions of the time brought into sharp focus the need for coal, iron, steel, gold, silver, and other minerals. The application of engineering and science was necessary for the production of these minerals and their manufacture into products to meet the needs of a growing nation. The requirements of the time were eloquently expressed in a paper by AIME member Edmund C. Pechin in 1872 : We find, the world over, the most intense activity everywhere displayed in enterprises requiring prodigious quantities of iron. Railways of colossal magnitude are projected. . . . The growing scarcity of timber is compelling the use of iron in buildings; bridges of wonderful size and strength; huge ocean steamships; barges and boats for lake and river traffic; churches; cars, and thousands of minor articles of every shape and size. . . . The time has come when scientific research is to assume its true position - the day of "sheer force and blind stupidity," whose only protection is a high tariff, has gone forever . . . the physicist, the geologist and mineralogist; the chemist, the engineer, are as essential to success as the [blast] furnace itself. . . . There is no merely practical man, no matter how varied may have been his experience, or how long his practice, that will not benefit from the results of scientific investigation. That there is a growing sense of the importance of having thoroughly prepared scientific men in every department of business is evidenced by the institutions [of learning] that are springing up in different quarters, provided with

Jan 1, 1971

By C. O. Worden, C. A. Zapffe, F. K. Landgraf

SUMMARY FOLLOWING the discovery of Parke and Ham that deoxidation control of cast molybdenum can be predicated upon simple fractographic examination, a special study of that metal was undertaken to investigate those patterns ascribed to forgeability and nonforgeability. An elaborately developed system of cleavage patterns immediately rewarded the study; and they are reported here as a necessarily preliminary contribution calling attention to information which is both new in type and in origin. In general, the present observations confirm those of Parke and Ham, and Woodside; but they also disclose a wealth of detail and correlated phenomena which greatly expand the earlier information. For example, the oxide pattern of nonforgeability is found to be complex, perhaps involving as many as three distinctive patterns. And the nature of the carbide seems to be at least twofold. In addition, transgranular facets are here shown for the first time. Elaborately complex, but in a characteristic manner, these facets depict distortion in original crystal growth which provides truly extraordinary patterns. No carbide and oxide forms display themselves transgranularly, except in profile as exceedingly thin superficial films at the grain boundaries. Crystallographic features are also rare-a condition undoubtedly resulting from the great substructural distortion; but occasionally registrations are found of cleavage on {001}, and faulted areas believed to be Neumann-type deformation on {112}. INTRODUCTION Parke and Ham, 1 and again Woodside, 2 have reported that the forgeability of molybdenum cast by their vacuum-electric-arc process can be predicted with great dependability by a simple fractographic observation. They state that nonforgeability is the result of a grain boundary oxide which can be readily identified on the fracture facet at high magnification; and they convert the nonforgeable condition to a forgeable one by increasing the carbon content of the melt until the oxide structures subsequently observed in the fractograph become replaced by a second strongly marked pattern characteristic of carbide and coincidentally indicative of forgeability. Considerable importance immediately attaches to such observations: (I) because of their direct commercial application to one of metallurgy's inviting and relatively unexplored metals; (2) because of a general scientific curiosity regarding the nature of these characteristic markings; and (3) perhaps more important, because of

Jan 1, 1948

By Henry N. McCarl

[The Construction Materials section contains the following Chapters: Aggregates Cement and Cement Raw Materials Crushed Stone Dimension and Cut Stone Lightweight Aggregates Gypsum and Anhydrite Sand and Gravel Insulating Materials-Thermal and Sound Slag Roofing Granules] Mineral aggregates are those natural and manufactured industrial mineral and rock materials that provide bulk and strength in portland cement concrete, bituminous concrete mixes, and plaster or stucco surfaces. They may also provide special characteristics such as thermal and acoustical insulation, weight, surface textures, abrasion resistance, and impermeability to various concrete products and mixes. Most aggregates are relatively inexpensive materials, but despite their low unit value, the tonnages consumed each year in the United States and throughout the" world make mineral aggregates by far the leading industrial mineral and rock materials both in terms of volume (tonnage) produced and value consumed. The major use of mineral aggregates is in concrete. The low cost, high bulk aggregates tend to keep concrete construction costs at levels competitive with other building materials. Other major uses of aggregates include highway and railroad base or ballast materials, graded fill, and various industrial uses such as metallurgical and chemical fluxes and raw materials-these latter uses are often considered nonaggregate uses of mineral aggregate materials. The per-ton value of mineral aggregate materials at the production plant in 1980 and 1981 varied from $2 to $5 for most sand and gravel and crushed stone, $3 to $6 for air-cooled slag, $7 to $20 for expanded slag and expanded clay or shale aggregate, to as much as $165 to $320 for expanded perlite or vermiculite. The expanded lightweight aggregates have been dramatically affected by increasing fuel costs. It is ironic that the specialized aggregates used as insulating materials to conserve energy cost so much more to produce due to the high proportion of energy consumed in their production. The first four parts of "Construction Materials" deal with the utilization of four major mineral aggregate types: Crushed Stone, Lightweight Aggregates, Sand and Gravel, and Slag. While the focus will be on the use of these industrial minerals and rocks, there will also be some coverage of sources, mining and production, especially in those cases where they are not discussed in the Commodity section of this book.

Jan 1, 1983

THE relation of labor to the accident rate in mines is admirably epitomized by Thomas T. Read in his paper presented at the St. Louis meeting, in the sentence "Reliance for accident prevention must be upon the individual worker himself." In connection with the inspection of mines for the fixing of merit premium rates for insurance under workmen's compensation, it has been the practice of The Associated Companies to allow 60 per cent.of the credits for safeguarding of the physical hazards of the mine and 40 per cent. for the human element. By "human element" is meant. that inherent tendency of the industrial worker to be careless, negligent or disobedient, in respect to his own safety, and after that also f his fellow workman. This is a tendency not only of the laborer or of the skilled miner, but of all human beings, working or traveling, anywhere. This element of mine safety, sometimes called the moral hazard, has been admirably shown by statistics compiled from the records of the Department of Mines of the Union of South Africa to be clue in about equal measure to the carelessness of the miner and to that of the operator. These statistics show that about one-half the fatalities in mines are clue to the so-called hazard of the industry, or what is sometimes called the dangers inherent to work or misadventure. Of 2497 fatalities investigated, including over 200,000 employees, for a period of over 2 ½ years, it was found that 17.5 per cent. were due to faulty plant or material, fault of the foreman, or of the management-in short were-clue to the operator; 17.1 per cent. to disobedience of orders, carelessness or ignorance of injured persons; and 5.9 per cent. through fault of others, including fellow workmen. The fault of the operator is evidenced by failure to give proper warning, failure to inspect, failure to furnish proper equipment, and neglecting to comply with the recommendations of the inspector. That education and training of the mine operator as well as of the mine worker

Jan 2, 1918

By R. L. Langenheim

Cooperative education for engineers is based on the premise that theory and practice are inseparable in training men for the engineering profession, and the two must be advanced simultaneously in order to train men most successfully and efficiently. The teaching of theory obviously should be done by the college but the practice must be obtained in the field where the application of the theory is made. The ideally trained engineer is one that knows theory, can apply the theory to practice, can direct, and work with, his fellow men. The old four-year plan of training engineers does a fair job of teaching the underlying theory of engineering but neglects entirely the training necessary for application of the theory, except through laboratory experiments, and the training in adjustments necessary to direct and work with men. An engineer, like a lawyer, doctor, dentist or other professionally trained man, cannot practice until he has had practical experiences that give him a knowledge of the other phases of his profession. The doctor serves as an interne, the lawyer reads law in the office of a practicing attorney, and the engineer must enter the profession as a laborer or as an apprentice, unless he has had the advantage of a cooperative education. Cooperative education provides the opportunity for the coordination of practical and theoretical training for the engineering profession throughout the period of training and thus eliminates many that are unfit to enter the profession, giving them an opportunity to seek other fields for which they may be better fitted, and reduces the overhead in industry that results from a large turnover of men not fitted for the profession. The Cooperative Plan Cooperative education in engineering is no longer an experiment. It was inaugurated at the University of Cincinnati in 1904 by Dean Herman Schneider, and has worked successfully ever since. Over twenty schools offer this type of education and many thousands of young men have had the opportunity to receive their technical training under this plan. Under the cooperative plan a student attends class for a period of eight weeks, then enters industry for eight weeks, maintaining this schedule

Jan 1, 1937

THE second operation in the art of casting, and one of the greatest importance, is that of melting and thoroughly liquefying the materials of which you wish to make your casting. On this operation depends the whole outcome of your intentions and the perfection of your work. Without it, even though you had a great abundance of moulds and vast quantities of bronze, your desires, labor, and expense would all be in vain. In this operation I find on consideration that, in addition to experience, there are three necessities-perhaps indeed four-that must be provided without fail. The first is the furnace or other agent which contains the fire and the metal brought together. The second is the wood or charcoal which is the necessary and proper nutriment of the fire, from whose virtues are derived the greater or lesser forces which, according to their kind, are ready to effect what is required. The third is to have the materials disposed to easy fusion by means of corruption, alloying, or by their own nature. The fourth, as the motivating cause of the whole, could perhaps be listed as the first-this is the ingenuity and good judgment of the worker, together with the bodily exertions not only of himself but also of his helpers in addition. For, besides a certain ordinary caution, it is necessary to pay particular attention, first, to see that the furnaces, machines, ladles, hearths, refineries, and other kinds of instruments or similar vessels be made so as to dispose the metals for melting, and, when melted, that they easily maintain them so. These should also be prepared in such a way that they cannot be injured by the fire, for if they should be damaged the operation would fail. In order to do this, it is first necessary that you arrange the instruments with forethought and action so that the power of the fire can operate. Fire operates on things only when brought together with them in long-continued operation, or when driven by a great force of wind. It burns many things and softens others, but it makes the metals as liquid as water.

Jan 1, 1942

By V 7. 0 / 300 dpi

THE cams at present universally used in stamp mills lift the tappets with an involute form of curve, to which the surface of the tappet is always tangent; moreover, the line of contact between tappet and cam, if produced, would pass through the center of the stem. This is no doubt a desirable feature, but the writer has long believed that it would be much more desirable if the cam were to pick up the stamp without shock, and gradually increase the upward velocity of the stamp throughout its upward movement. The involute form of cam attempts to impart instantly a considerable upward velocity to the stamp, starting it from a state of rest, and the result is a destructive blow, a great deal of noise, and much wear and vibration. The writer has developed a form of cam which will lift the stamp with a motion similar to that of the piston of an engine between the end and middle of its stroke; in other words, harmonic motion, from the point. of zero to maximum velocity. The curve will give this ideal motion only when the stamp is set for the exact drop for which the cam was designed, but the improved cam will not be as bad as the involute cam until the drop is reduced one-half. In other words, if a cam is designed for a 6-in. drop, it will be some improvement over the usual form of cam until the drop is only 3 in. Any cam, whatever its form, must of course lift the stamp in the same number of degrees of revolution; therefore, with this new form, since the stamp starts more slowly on its upward course, it must end up by going faster, the average speed being the same as with the involute cam. The stamp, after it is no longer in contact with the cam, keeps on going up a certain distance, which is easily calculated. It is therefore possible to hang up a stamp without a cam stick, if the fingers are not more than 1/8 in. longer than necessary to hold the tappet above the cam.

Jan 12, 1914

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