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By Paul M. Tyler

FOR the same reason that water is not missed until the well runs dry, the roles of many industrial minerals in wartime are often overlooked. In contrast to the growing shortages of many metals, our supplies of most nonmetallic minerals are limited only by our machinery for taking them from the ground and by our processing facilities. With few exceptions, the demand for increased supplies has been met without fanfare or delay. Only Brazilian quartz crystals, certain kinds of mica, and, latterly, industrial diamonds are on the so-called strategic list, although asbestos, beryl, corundum, cryolite, fluorspar, crucible-grade graphite, ilmenite, iodine, kyanite, monazite, nitrates, rutile, and zircon have caused more concern among those responsible for procurement and are included in our preclusive buying programs. Such specialties are needed urgently, but they are far less important in the over-all picture than the more abundant minerals.

Jan 1, 1942

By William L. Fink, H. R. Freche

The constitution of the aluminum-cobalt alloys has been the subject of relatively few investigations. Brunckl analyzed the residue which remained after treating the 17 per cent cobalt alloy with dilute hydrochloric acid. The results of the analyses indicated the existence of a compound Co3Al13. Guillet2 published a liquidus for the aluminum-cobalt system which contained two maxima corresponding to CoA16 and CoAl2 and two eutectic points at 30 and 74 per cent Co. The most extensive investigation of the system was carried out by Gwyer13 whose results are summarized in Fig. 1. It will be noted that at the aluminum end there is a suppressed eutectic at 644' C. By extrapolation of the duration of the eutectic arrest to zero, the composition of the compound was placed at Co3Al13. Another thermal arrest was noted at 550" C., which Gwyer attributed to a peritectic reaction. The present investigation of the aluminum end of the aluminum-cobalt system is the eleventh of a series dealing with the constitution of aluminum-rich alloys prepared from electrolytically refined a1uminum.l Preparation of Alloys.—The alloys used in this work were all prepared from electrolytically refined aluminum, the analysis of which is shown in Table 1. In preparing some of the alloys, metallic cobalt (98 to 99 per cent) was used either directly or in the form of an intermediate alloy, the composition of which is given in Table 1. In order to obtain alloys of higher purity, cobalt was introduced into some of the alloys by means of chemically pure cobaltous chloride which was readily reduced by the aluminum. A small electric furnace with nickel-chromium heating elements was used in the preparation of the alloys. Chemical Analysis.—An analysis sample from each melt was chill-cast in the form of a plate 3/16 in. thick. In all cases the casting temperature was well above the liquidus. Cobalt was determined electrolytically in all alloys containing more than 0.05 per cent cobalt and by the nitroso-

Jan 1, 1932

By P. A. Beck, L. J. Demer

As reported in a previous publication,' isothermal grain growth in high purity aluminum and in an aluminum alloy with 2 pct magnesium can be adequately described by means of the empirical relation: Here, D is the average gain size after an annealing period 1. The annealing period includes the time for complete recrystal-lization R, and the time for gain growth 1,. D, is the pain size as recrystallized, n is a parameter depending on the temperature and on the material. The effect of 2 pet magnesium in solid solution was to decrease D, and to increase R, A and n at a given temperature. The present work was undertaken in order to investigate the above listed-effects of magnesium in solid solution, as functions of the magnesium content. The work also includes the study of certain anomalous effects observed in the recrystal-lization and grain growth of the 2 pct magnesium alloy at 350°C. Experimental Procedure The method of producing the ingots used in this work was described in detail1 and need not be reproduced here. The materials used were high purity aluminum, furnished by the Aluminum Co. of America, of lot analysis shown in Table r and magnesium from a high purity distilled stock of magnesium crystals. Table i—Lot Analysis of High Purity Aluminum Per CeNt Si.................................... 0.00~ Fe.................................... 0.002 Cu................................... 0.002 Mg................................... 0.003 Mn................................... o. oox Ingots were prepared for a series of binary aluminum-magnesium alloys of increasing alloy content. The numbers used to designate these ingots and their magnesium contents by chemical analysis are given in Table 2. Table 2—Ingot Numbers and Magnesium Contents Ingot Number Pct oa Magnesium aI 2.05 22 1.80 24 0.12 26 0 02s The analyses showed no difference in composition between the top and the bottom of the ingots. Spectrographic analysis of the ingots for elements other than magnesium showed, within the limits of accuracy of the method, no increase in impurities over the amounts given in the lot analysis for the high purity aluminum in Table I. Careful microscopic study of ingot 21 in the as-cast condition, at magnifications up to I 500X, revealed a cer-

Jan 1, 1949

By Donald H. McLaughlin

THE activity and enthusiasm of pioneers still prevail among workers in applied geophysics1.- Within the year, new devices have .been tried out, instruments and technique have been improved and the methods of application to commercial problems have been increased in many ingenious ways. There is still great need for more skillful interpretation of results in terms of geology, but oil the whole geophysical prospecting is making encouraging progress toward finding its proper place and function in engineering and geological practice. Spectacular successes continue to be reported, particularly .from the Gulf Coast, where the race for salt domes has not slackened, and encouraging results have been giined elsewhere in the mapping of structures in the search for oil. In the mining field, however, it can hardly be claimed that the same measure of success has been obtained, for brilliant efforts worthy of wide recognition have been overshadowed to some eatent by the unfortunate outcome of surveys undertaken unwisely without recognition of the limitations of the work. Consequently, hopes were aroused that could not be fulfilled, and it must be admitted in an impartial survey that there are a few regions, chiefly in the far north, where the standing of geophysical prospecting is somewhat doubtful and where the course of public opinion regarding it shows a certain similarity to the history of the market during the past few months. Reliable work, however, is steadily going 011 and it can confidently be expected that the methods will eventually be regarded in many regions as an essential part of the technique of securing geologic data needed for intelligent exploration.

Jan 1, 1930

By John R. Freeman

THIS paper relates entirely to the casting of brass under fluid pressure in steel dies Die castings of metals and alloys of low melting point have been available for many years but the development of brass die castings has been relatively recent, occurring within the past five years The successful development of brass die castings has resulted from the availability of alloy steels that would give satisfactory life as dies and the development of suitable die-casting machines The melting point of copper is 1084° C (1983° F ) and of a high brass about 900° C (1652° F ), as compared to 327 5° C (6215 °F) for lead, 419 4° C (786 7° F) for zinc and 658 7° C (1217 7° F) for aluminum, temperatures that ale indicative of the casting temperatures required for the various types of alloys, of which the melting points are somewhat lower than those of the pure metals TYPE OF DIE-CASTING MACHINE In the well-known plunger and gooseneck types of die-casting machines used for casting the alloys of relatively lower melting point, much of the working mechanism is immersed in the molten alloy For alloys having the relatively high melting point of brass, this obviously is impossible Machines with a separate melting chamber are essential Two rather distinct types are in extensive use at the present time, the Pack and Polak machines, the former designed by Charles Pack and developed at the American Brass Co , the latter developed by Zoseph Polak, of Prague, Czechoslovakia The principles of operation of these machines have been described in articles by Pack1,2,3 and by Sieg 4

Jan 1, 1935

By John R. Freeman

This paper relates entirely to the casting of brass under fluid pressure in steel dies. Die castings of metals and alloys of low melting point have been available for many years but the development of brass die castings has been relatively recent, occurring within the past five years. The successful developnlent of brass die castings has resulted from the availability of alloy steels that would give satisfactory life as dies and the development of suitablc die-casting machines. The melting point of copper is 1084" C. (1983" F.) and of a high brass about 900" C. (1652" F.), as compared to 327.5" C. (621.5" F.) for lead, 419.4' C. (786.7" F.) for zinc and 658.7" C. (1217.7" F.) for aluminum, temperatures that are indicative of the casting temperatures required for the various types of alloys, of which the melting points are somewhat lower than those of the pure metals. Type of Die-casting Machine In the well-known plunger and gooseneck types of die-casting machines used for casting the alloys of relatively lower melting point, much of the working mechanism is immersed in the molten alloy. For alloys having the relatively high melting point of brass, this obviously is impossible. Machines with a separate melting chamber are essential. Two rather distinct types are in extensive use at the present time, the Pack and Polak machines, the former designed by Charles Pack and developed at the American Brass Co., the latter developed by Joseph Polak, of Prague, Czeclioslovakia. The principles of operation of these machines have been described in articles by Pack1,2,3 and by Sieg.4

Jan 1, 1935

By John R. Freeman

This paper relates entirely to the casting of brass under fluid pressure in steel dies. Die castings of metals and alloys of low melting point have been available for many years but the development of brass die castings has been relatively recent, occurring within the past five years. The successful developnlent of brass die castings has resulted from the availability of alloy steels that would give satisfactory life as dies and the development of suitablc die-casting machines. The melting point of copper is 1084" C. (1983" F.) and of a high brass about 900" C. (1652" F.), as compared to 327.5" C. (621.5" F.) for lead, 419.4' C. (786.7" F.) for zinc and 658.7" C. (1217.7" F.) for aluminum, temperatures that are indicative of the casting temperatures required for the various types of alloys, of which the melting points are somewhat lower than those of the pure metals. Type of Die-casting Machine In the well-known plunger and gooseneck types of die-casting machines used for casting the alloys of relatively lower melting point, much of the working mechanism is immersed in the molten alloy. For alloys having the relatively high melting point of brass, this obviously is impossible. Machines with a separate melting chamber are essential. Two rather distinct types are in extensive use at the present time, the Pack and Polak machines, the former designed by Charles Pack and developed at the American Brass Co., the latter developed by Joseph Polak, of Prague, Czeclioslovakia. The principles of operation of these machines have been described in articles by Pack1,2,3 and by Sieg.4

Jan 1, 1935

By Zay Jeffries

A SURVEY of rare metals and minerals for the past year places uranium as one of two partners, the other being the neutron, in what historians will probably say is the greatest discovery in physics at least during the year and probably for a consider- ably longer period. The uranium atom has been made to divide into parts somewhat after the style of reproduction of the amoeba. When an amoeba divides into two parts, however, it produces two amoebae substantially alike and each substantially like the parent: furthermore, there is no considerable change of energy when this happens. When the uranium atom divides it yields other atoms such as barium and krypton with the complete destruction of the original uranium atom but with the liberation of a tremendous amount of energy. This will be discussed more at length later.

Jan 1, 1940

By J. E. Tobey, David R. Mitchell, J. H. Kerrick

DETAILED knowledge of purchase specifications established by coal consumers is essential to the successful design and operation of a coal-preparation plant. ANTHRACITE Specifications should be considered by both the consumer and the producer as guide posts outlining a certain path for both to follow. Plants differ, therefore specifications must differ to meet the varied requirements. Specifications are not of themselves a "cure all" or an assurance of complete satisfaction in fuel utilization. Specifications should not be regarded as a license to engage in an orgy of buying any and all coals that may happen to fall within their limits. This would lead to the indiscriminate mixing of coals which may vary in their burning characteristics. Different coals of equal grade tend to be individualistic in their burning characteristics. Rather, specifications should be used to help simplify coal selection, to reduce the actual number of coals used over a given period; in other words, to have a stabilizing influence on coal or customer turnover. In the final analysis, the use of too many coals per year in a plant is costly to both the consumer and the producer. Too many sources usually result in higher operating and maintenance costs for the consumer and higher sales costs for the producer. Finally, the statement included in the report accompanying the com¬prehensive Coal Selection Charts prepared by the Coal Committee of the National Association of Purchasing Agents, and released in 1938, is significant. This Committee worked diligently for a period of 15 years seeking to find a scientific and reliable method for selecting coals. The two following paragraphs are quoted from its report: More important is the fact that no ready-made classification or set of specifications can possibly replace the judgment and resourcefulness of an experienced combustion engineer or fuel technologist, nor the usual need for full scale plant tests under the exact conditions of use before a final decision is made ...

Jan 1, 1943

By Robert M. Dreyer

AGGREGATE With an annual domestic production of over 1.6 billion tons at a value of over $2 billion (see Table 15.1.1), the production of aggregate (crushed rock, sand, and gravel) is a basic industry of utmost economic importance. Because of the role of aggregate materials as essential ingredients of concrete, asphalt surfacing, and plaster, their delivered prices are major factors in determining the cost of construction. The annual domestic production comes from nearly 10,000 plants. About 15% of these plants account for over one-half the production. In a rapidly inflating economy, the average mine sales price of aggregate has remained relatively stable. The actual mine sales prices, however, vary greatly depending on quarrying costs in various parts of the country. Of much more importance in construction costs, however, is the delivered price of aggregate. This varies for each job, depending on the distance from the quarry and resulting transportation costs, as well as the initial cost at the mine. Because of a proliferation of regulations limiting new quarries in the vicinity of the encroaching urban sprawl, the average distance which aggregate must be transported has been increasing rapidly. Although it is impossible to derive an average delivered cost for aggregate, it should be noted that even an increase of only $1 per ton in average delivered cost over the last decade (probably a minimal assumption) would mean an annual cost $1.5 billion higher than ten years ago. In recent years, structural engineering considerations, as well as an increasing use of lightweight concrete blocks, have resulted in a rapidly increasing demand for lightweight concrete and plaster, the essential ingredient of which is lightweight aggregate. Principal lightweight aggregates are: pumice, slag, perlite (thermally expanded hydrous volcanic glass), vermiculite, and expanded shale, formed by the thermal expansion of shale and slate. The United States now has the capacity to expand, annually, over 13 million tons of shale and slate and to expand over 600,000 tons of perlite. In locating a site for aggregate production. the following factors must be considered: (1) tonnage available; (2) quality of aggregate (including local variations); (3) distance from major use areas; (4) transportation costs, including those resulting from present and possible future haulage restrictions; (5) zoning regulations; (6) operating costs, including the cost effects of compliance with local regulations governing blasting, air pollution, water pollution and drainage, noise levels, and operating periods. At one time, locating a suitable site for the production of crushed rock, sand, or gravel, in most areas, was regarded as an extremely simple task. In the past few years, however, finding a site for profitable production of aggregate has assumed ever-increasing com-

Jan 1, 1976

By H. P. Greenwald

THE Committee on Rock-Dusting was formed after the fall meeting of the Coal Division in Chicago in 1938. Its primary task was to study the recommended American practice for rock- dusting coal mines to prevent coal-dust explosions as approved by the American Engineering Standards Committee. After approximately two years' work he committee concluded that although certain portions of the recommended practice could well be revised, information needed for a logical revision was not at hand, and it was inadvisable, therefore, to make revisions

Jan 1, 1943

United Engineering Trustees, Inc. WILLIAM H. BASSETT H. G. MOULTON R. M. ROOSEVELT The Engineering Foundation GEORGE D. BARRON E. DEGOLYER R. M. ROOSEVELT Engineering Societies Library Board ROBERT PEELE H. K MASTERS A. B. PARSONS, Ex-officio F. F. SHARPLESS R. H. SWEETEST

Jan 1, 1934

By Robert Glass Cleland

[Clarence F. Birdseye 1885-1891 William E. Dodge 1885-1903 James Douglas 1885-1917 D. Willis James 1885-1907]

Jan 1, 1952

By John Birkinbine

(New Haven 'Meeting, February, 1909.) AWAKENED public interest in efforts to conserve natural resources will certainly be appreciated by the members of the American Institute of Mining Engineers, and a discussion upon conservation may well form a part of one of the Institute meetings, for the records of papers and discussions which appear in the 38 volumes of its Transactions are replete with evidence of effort's in this direction. Every process which reduces the fuel consumed or the power applied per unit of product; every utilization of waste material, or employment of that formerly rejected, to obtain something of value ; every feature of construction or operation which lessens the labor required or increases the output per employee, is an advance in the direction of true conservation. This may not appear from the records of late conferences or from published articles, in which the effort seems to be concentrated upon reducing the consumption and presenting to the people of the country estimates of exhaustion of natural resources. I rejoice in the awakening of public interest in a matter so important for the present and future welfare of our nation; I appreciate the possibility of much good following conferences of the Governors and delegates from various States and from national societies; and I recognize the interdependence, not only of different States, but of contiguous nations. In fact, the marvelous development of transportation by land and by water, and the decreasing rates at which commodities can be moved great distances, have in many cases practically obliterated geographical boundaries, and nearly every country on the globe can either market its product in other lands or draw upon them for raw or manufactured materials ; hence, conservation is an international subject.

Apr 1, 1909

By David R. Maneval, H. B. Charmbury

At the turn of the century, iron and coal were the keys to industrial prosperity. At that time, Pennsylvania was the leading mineral producer in the Country, producing 200,000,000 tons of coal in a typical post-World War I year. Close to 90% of the Nation's energy was generated by coal. Today, coal accounts for but 22% of the energy generated, leading to a drastic reduction in Pennsylvania coal output. In contrast with the post-World War I days, 1964 figures showed a drop in production to 93,846,480 net tons. This huge decrease has created a serious economic problem in a state so much dependent on the coal industry. Along with the reduction in coal production, employment has dropped considerably through these years (the number of miners alone has gone from 280,011 to 43,149), thus causing a heavy burden of supporting the unemployed on the taxpayers. As far back as 1939, coal operators and economists saw the problems on the horizon and the need for improvement. Realizing that research was a way to improve and stabilize the industry they demanded legislative action. The Legislature reciprocated with a small grant to The Pennsylvania State University with the provision that each State research dollar be backed with one from the industry. This initial grant laid the foundation for the further growth in coal research.

Jan 3, 1966

INTRODUCTION In the preceding chapters we have discussed the various elements of mineral economic analysis, their interrelationships, and the most accepted and advanced techniques by which these elements are manipulated to provide the decision maker quantitative measurements for judging alternate investment opportunities. Regardless of how carefully the economic evaluation is made, and how comprehensive the study of economic parameters has been, uncertainty still remains a significant factor in the outcome of the analysis. The investor or money manager is acutely aware of the uncertainty factor. Many of the economic parameters are functions of economic forecasts and value estimates that can- not be known with any degree of certainty. The postulated DCF-ROR is based upon certain estimates representing "best guess" values, and a single point parameter DCF-ROR analysis represents a combination of "best guesses." The wise decision maker looks at such an analysis and asks the "what if" questions. What if the production cost is 10% higher than the estimate? What if there is an overrun in construction costs? What if the mineral price falls lower than expected? What will be the effect of a higher royalty rate? Many more such questions may arise in trying to assess the total risk involved in funding a mineral project. Prior to the advent of the computer it was difficult to answer all such anticipated questions because of the many laborious calculations involved. Now, with the aid of the computer, most of these questions can be answered by the analyst at the same time the original computations are made by using the process of sensitivity analysis. Sensitivity analysis shows the effect of critical parameter changes upon the DCF-ROR or other profitability measure. When probability of occurrence can be associated with the various parameter value levels, sensitivity analysis becomes probabilistic analysis, and the risk factor can be quantitized in terms of total probability. SENSITIVITY ANALYSIS The determination of the sensitivity of the profitability index (usually the DCF-ROR) to changes in the various economic parameters, taking them one at a time, is called sensitivity analysis. The analysis may be performed for any number of parameters involved in the DCF-ROR computation. Generally, in mineral evaluations the most sensitive and most tested parameters are: the metal or mineral price, the operating cost, the annual production grade, and the initial capital invest-

Jan 1, 1980

By H. O. Hofman

(Canal Zone Meeting, November, 19]0.) THE sudden decease, April 1, 1910, in Chicago, of Dr. Franklin R. Carpenter was a shock to his- many friends. He died in his sixty-second year, of heart paralysis. To most fellow-members of the Institute who have followed the progress of the. last twenty-five years in the mining and treatment of non-ferrous ores, the work of Dr. Carpenter in that line is familiar ; but very few, even of those who knew him well in the later years, are acquainted with his earlier struggles to satisfy an inborn hunger for knowledge. The story of his life resembles that of the pioneer who opens up new country; overcoming hardships with indomitable courage, meeting doubts and difficulties with an alert and open mind, and exercising in the face of reverses an unconquerable perseverance. It seems appropriate to place on record in the Transactions a brief outline of the life and work of this eminent engineer. During the past 15 years of his life Dr. Carpenter was much interested in genealogy. In the pursuit of this study as an avocation, he traced his own ancestry to the time when ?Hugh," called "le Charpentier" on account of the dexterity with which he had swung his battle-axe as a crusader, settled in Sussex on lands received from William the Conqueror. The Carpenters came to this country with William Penn. A prominent member of the family was Joshua Carpenter, the founder of Christ Church, Philadelphia. Dr. Carpenter's branch of -the family moved from Pennsylvania into that part of Virginia which is now West Virginia, where his grandfather settled in Harrison county, while the grand-uncle went further west, and built the first iron-furnace at Hanging Rock, Lawrence county, Ohio. In fact, since early times, the Carpenters appear to have been iron-masters. Franklin R.. Carpenter was born, Nov. 5, 1848, in Parkers-

Aug 1, 1910

By John Freeman

THIS paper relates entirely to the casting of brass under fluid pressure in steel dies. Die castings of metals and alloys of low melting point have been available for many years but the development of brass die castings has been relatively recent, occurring within the past five years. The successful development of brass die castings has resulted from the availability of alloy steels that would give satisfactory life as dies and the development of suitable die-casting machines. The melting point of copper is 1084° C. (1983° F.) and of a high brass about 900° C. (1652° F.), as compared to 327.5° C. (621.5° F.) for lead, 419.4° C. (786.7° F.) for zinc and 658.7° C. (1217.7° F.) for aluminum, temperatures that are indicative of the casting temperatures required for the various types of alloys, of which the melting points are somewhat lower than those of the pure metals.

Jan 1, 1935

By A. E. Brugger

SOME 2,000 years ago Pliny is supposed to have said, "Out of Africa always something new." It may perhaps even now be news to a great many that the Belgian Congo has in recent years been producing approximately a quarter of a ton of diamonds annually. For that is what the 1 1/4 million carats, the recovery from 40-odd operating mines, and about 20 or 25 per cent of the world's normal consumption, amounts to. In 1915, first exploitation operations produced less than 50,000 carats from two mines. The rapid expansion of operations following the Euro¬pean war meant a most rapid development of a virgin land. The interior is now reached by air in one day from the mouth of the Congo River, where steamers unload mail and passengers from Antwerp. This trip formerly consumed 4 to 6 weeks by a narrow-gage, wood-burning, railroad around the rapids of the lower Congo and Livingston Falls; by river boat to the heads of navigation, Djoko Punda on the Kasai or Luebo on the Lulua; and thence by caravan of native porters over narrow-trails to head¬quarters on the Tshikapa. Hundreds of miles of automobile roads have been constructed over veldt and through forest, bridging streams and ferrying rivers. The railway from Capetown to the Katanga copper district to the East, once two months away by trail is now reached in 2 or 3 days over fair automobile highway. Native "boys" who a few short years ago wore little more than a smile and a string of beads and to whom a wheelbarrow was a complicated piece of machinery, are today driving Fords, tending boilers and engines and operating electrical equipment, or are capable mine workmen, machinists and artisans, and dressed in all manner of cast-off white man's clothing. Even as late as 1920, due to difficulties of securing and transporting machinery during and just after the war, the crudest hand operations were the rule for the excavation, sizing, and concentration of the diamondiferous gravel. All washing and concentration is now mechanized, using steam or electric power, and where operations are sufficiently large to permit competition with native labor costs, excavation and transportation are also accomplished by machinery.

Jan 1, 1932