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By George W. Maynard

IN the biographical notice of Thomas F. Witherbee, published in Bulletin No. 32, August, 1909 (p. xxv), it is said that ". he is believed to have been the first manager in America to use the chemical laboratory for the purpose of controlling the regular running of the blast-furnace." Since the year is not given, I cannot decide as. to Mr. Witherbee's priority; but the statement leads me to contribute a bit of history, showing an early departure from the "rule-of-thumb " blast-furnace work to the employment of a chemist. In the autumn of 1868 the department of mining and metallurgy was established at the Rensselaer Polytechnic Institute. In connection with the assay-department a laboratory was equipped for making general commercial analyses. In January, 1869, Alexander L. Holley, the manager and builder of the Bessemer plant at the Rensselaer Works of John A. Griswold & Co., the first plant erected in the United¬States under the Bessemer patents, began to send me samples of ore, pig-iron, and steel for analysis. Early in 1869 I was regularly retained as chemist for the Rensselaer Works; and while the laboratory was not located at the works, for all practical purposes it was the works-laboratory. The increase in work soon made it necessary for me to secure an assistant. I applied to Prof. Charles F. Chandler, who recommended Dr. August Wendel, who had been an assistant of Rammelsberg and had lately landed in New York. Dr. Wendel remained with me until 1873, when I left Troy. My leaving made necessary the erection of a laboratory at the Rensselaer Works, which, was done under my supervision, and Dr. Wendel was employed as chemist. During the period from 1868 to 1873 my work as consulting mining engineer frequently called me to the Lake Champlain

Nov 1, 1909

By E. F. Northrup

THESE brief notes respecting the properties of pure tin that make it useful as a pyrometric substance summarize information gathered by the writer In an extensive experimental investigation on the electrical properties of metals in the molten state. Tin in quantities sufficient for pyrometric purposes may be obtained at relatively low cost and in a state of high purity. The metal melts at 232° C. and, according to determinations made by Greenwood,. 1909, does not begin to boil until a temperature of 2270° C. is reached. The writer can assert, from personal observations carefully made, that tin shows no tendency to boil at a temperature of 1680° C. If Greenwood's observations are correct the temperature interval, 2038° C., in which tin exists as a liquid under atmospheric pressure, exceeds that of any other substance. It has never been observed, as far as the writer is aware, that tin forms any chemical union, as carbide, with carbon at the highest temperatures at which it can exist as a liquid. It is quite certain from the writer's personal observation that tin heated in Acheson graphite to 1680° C. remains chemically uncontaminated. Wires of pure tungsten do not dissolve in molten tin at temperatures at least as high as 1680° C. Tungsten wires or rods may, therefore, be used as electrodes dipping into molten tin when required for measuring the resistance of the molten metal at very high temperatures. When tin is raised to a high temperature in a covered graphite container, the CO atmosphere that exists above its surface has a reducing action, which maintains this surface of mirror brightness. Incidentally, tin maintained molten in a crucible of Acheson graphite makes a most excellent bath into which may be inserted several pyrometers that are to be intercompared at the same temperature.

Jan 8, 1919

By R. E. Zinkham

An investigation has been conducted to compare short transverse and longitudinal fatigue and fracture properties in 4.25-in.-thick, high strength aluminum alloy plates. One plate was produced using standard rolling techniques while the other was pre.forged before rolling. Little difference was shown in fatigue strength of longitudinal specimens taken from mid-thickness of the plate. Howeuer, in the short transverse orientation fatigue strengths at 107 cycles were about 25 and 50 pct less, respectively, for the preforged and standard rolled plate. Differences in fatigue strengths were attributed to grain size and shape as well US orientation of constituents. Fatigue crack propagation rates and fracture toughness were compared at three different stress intensity (K) levels, using a constant compliance, double cantilever, wedge-shaped specimen. In a given plate, comparable fatigue crack Propagation rates were observed in the longitudinal (i9W) and short transverse (TW) orientations. Somezuhat gveater rates were observed in the short transzerse (TR) orientation. The preforged plute gave a lower rate for all three directions. Considerable secondary cracking developed, at times, over portions of the fatigue crack in both plates, particularly at the lower stress intensity levels in the short transverse specimens. Micro structure revealed constituent stringers as possible causes of the crack branching. Fracture toughness was considerably less in both plates in the short transuerse orientation. It is concluded that preforging not only improved directional tensile properties but also the fatigue and fracture properties in general. On occasion, aluminum plates have been milled away for hinges or bolted connections and stressed through the thickness or short transverse direction. Little or no information is available concerning fatigue characteristics or fracture toughness in this loading orientation in aluminum plate, or of the effect of fabrication on these properties. It was the intent of this project to examine, develop, and apply a unique specimen that has been advocated by others to study the fatigue characteristics and fracture toughness of two differently fabricated high strength aluminum plates. Linear elastic fracture mechanics criteria may be applied to the specimen so that the fatigue crack propagation rate and fracture toughness data may be of use for design or inspection applications. Fatigue characteristics are generally measured in the longtudinal or long transverse direction, where fairly large specimens such as center notched panels,' are usually employed. Limitations are evident due to plate thickness, however, in the type and size of specimen that may be tested in the short transverse direction without extensions. Therefore, a specimen that is to be loaded in this direction should, for convenience, be compact. The general type of fatigue crack propagation specimens discussed and employed herein meet this requirement. These specimens are commonly called double cantilever beam specimens and lately "crackline-loaded edge-crack specimens".2 They may vary from a slope of zero (parallel-sides) to a wedge shape, the type employed herein. In general for most specimens the stress intensity KI at the tip of a crack is a function of the load, P and crack length, a. Some varieties of the wedge shaped specimen, however, give essentially a constant stress intensity KI over a considerable range of crack length.' This feature can be a valuable asset in fatigue crack propagation experiments because the stress-intensity can be controlled simply by controlling the load without regard to crack length. MATERIAL AND METHODS Material. A standard rolled (light pass reduction) and a ~reforged and rolled (heavy pass reduction) plate of 7179-T651 material were used for the evaluation. The chemistry, processing history and average tensile properties are shown in Table I. Specimen Selection and Preparation. The specimen selected for the generation of fatigue initiation or S-N data was an axial tension type and is shown in Fig. 1. Specimens were taken from mid-thickness in the longitudinal and short transverse directions from both plates. Specimens were polished with 500 grit paper in a direction parallel to the loading axis. For the fatigue crack propagation tests, the specimen shown in Fig. 2 was used. This is similar to a specimen that has been employed by Mostovoy3 for fracture toughness studies on 7075-T6 aluminum alloy. It also fortuitiously agrees quite well with the dimensions of a specimen for which Srawley and Gross2

Jan 1, 1970

By A. G. Raine

For the technological age in which we live, with the constant goal of further improvement in the efficiency of mechanized systems, the need for a replacement of the antiquated drill and blast method of shaft construction has been recognized. For over a decade now; the trend in shaft construction has been toward large diameter bored shafts using either raise boring methods or more flexible, rodless "down the hole" boring machine. The limits of conventional shaft sinking have been reached, the mining regulations are more stringent, and the environmental agencies more aggressive, all contributing to the growing need for development of the rodless shaft boring machine. In the last three years in the United States, world shaft construction records have been achieved using a V-Mole machine, designed by Mirth GmbH of West Germany, using American electrics and hydraulics. Shafts of 7.0 meters (23 feet) diameter, totaling 2,255 meters (7,400 feet) in depth have been constructed at high advance rates, yet with unusually low accident rates. Bearing in mind the high cost of today's mining labor and the inherent danger associated with conventional shaft sinking, this alternative method of shaft construction achieves a fast, competitive, low manpower requirement, whilst enhancing a safer environment for the labor force. Recent results have proven that program time savings of 50 percent over conventional shaft sinking can be achieved which can be directly translated into improved client cash flow projections and more accurate project budgeting.

Jan 1, 1984

By Charles Stein

The effects of several different prior treatments an the creep behavior of 99.9995 pct aluminum at 260°C and 1000 psi canstant stress are compared with annealed specimens. Quenching from 538oC, irradiation with 2 mev electrons, and tension-compression room temperature fatigue damage were used to change the substructure of the specimens prior to their creep testing. The quenched and the irradiated specimens showed a larger primary and transient stage contribution to the creep curve than those specimens which were only annealed prim to creep testing. The specimen receiving prior fatigue damage at room temperature showed no first stage or transient creep when tested under identical conditions as the above specimens and had an average creep rate seven orders of magnitude lower than that of either the annealed, the quenched or the irradiated creep specimens. In a previous electron transmission microscopy investigationl of the substructure developed during the creep of pure aluminum at 0.57 Tm, it was noted that a large concentration of vacancy loops and dislocation loops were present in and near the subboundaries while the interior of the subgrains contained few of these defects and had a low dislocation density, see Fig. 1. Yim and Grant2 and Hazlett3 have shown that the presence in nickel of a substructure developed by prior cold work effectively reduces the primary and transient contributions to the creep curve. Hultgren,4 McLean,5 Gervais, Norton, and Grant,6 Chang and Grant,7 and others have shown the same effect with the higher stacking fault energy material, aluminum. However, the specific defect responsible for the change in the creep behavior developed by the prior cold work was not established. Specifically, what effectively interfered with dislocation motion in these materials at elevated temperatures? Was it jogs on dislocations produced by their interaction with other dislocations or with vacancy or dipole loops, see Fig. 1, or did the subgrain walls determine the mean free path for glissile dislocations? This would be a realistic possibility only if subgrain boundaries are effective barriers to dislocation motion. The ability of a subgrain boundary to act effectively against glissile dislocations depends on the number and the arrangement of dislocations in the subboundary,8 which in turn is a function of the creep strain.' This paper compares the creep rate of specimens possessing a large vacancy concentration to that of annealed specimens and with specimens having a stable subboundary wall containing Lomer locks produced by prior fatigue damage. EXPERIMENTAL PROCEDURE Vacancy Loops. Aluminum creep specimens, 99.9995 pct pure, were machined from zone refined rod to a 2-in. gage length and a cross-sectional area of 0.025 in. These specimens were annealed at 538oC, 1000°F, for 10 min and quenched into ice water. They were then reheated to the creep test temperature of 260°C, 500°F, and held at this temperature for 18 min to al-low for vacancy condensation and loop formation. The specimens were subsequently creep tested at 1000 psi constant stress at 260°C. The temperature along the gage length was monitored by three Pt-Pt, 13 pct Rh thermocouples, two embedded in the upper and lower shoulders of the specimen and one attached to the mid-point of the gage length- The temperature gradient was held to ± l°C or less throughout the Creep test. Elongations were measured by two LVDT's 'connected in an averaging 'On-figuration, with quartz extension arms placed against the specimen at the extremes of the 2-in. gage length. i K 3J?--' * *H - >^> - ' ^L r 77 . *y J OJL, J Fig. 1—Transmission electron micrograph of pure aluminum strained 8.2 pct at 260°C and 1000 psi constant stress. Note the presence of numerous loops near the light dislocation tangle

Jan 1, 1970

By Hallan Marsh

THE subject of this paper is apt to bring to mind wells ranging from 6000 to over 8000 ft. in depth. However, it is uncommon to pump wells at depths greater than about 5000 ft. Fig. 1 shows the number of wells being pumped at various depths by one company in Southern California. FIG. 1.-NUMBER OF WELLS BEING PUMPED BY ONE COMPANY FROM VARIOUS DEPTHS IN SOUTHERN CALIFORNIA. A few companies have a very few wells pumping at depths greater than this. This paper will deal with wells between 3000 and 5500 ft. in depth. Most California oils at these depths are between 25° and 35 gravity. The subject is so broad that it will be necessary to omit many interesting phases, and to treat others very briefly. Power, power transmission equipment, power efficiency, counterbalancing, sucker rods, pumps and volumetric efficiency will be discussed.

Jan 1, 1928

By J. D. Rice, H. H. Rachford, G. H. Bruce, D. W. Peaceman

The problem of unsteady-state gas flow through porous media leads to a second-order non-linear partial differential equation for which no analytical solution has been found. In this paper a stable numerical procedure is developed for solving the equation for production of gas at constant rate from linear and radial systems. An electronic digital computer is used to perform the numerical integration using an implicit form of an approximating difference equation. Solutions are presented in graphical form for various values of dimension-less parameters. The solutions are compared with the laboratory study of gas depletion in a linear system. INTRODUCTION Production of fluids from porous rock reservoirs is essentially a transient process. Transient gradients develop as soon as production begins, and further withdrawals continue to cause disturbances which propagate throughout the reservoir, each adding in some way to the prior ones. A correct mathematical analysis of this behavior is complicated by the fact that the transient or unsteady-state flow of compressible fluids must be described by difficult second-order partial differential equations. As a practical matter, three distinctly different cases arise: 1. Flow of single-phase liquid 2. Flow of gases 3. Multiphase flow The first of these has been found to give a linear second-order equation similar to the well-known heat flow equation. where 7 is fluid density, 8 is time, and a a constant for the system, provided d 7 = r cdp, where the compressibility, c, is constant over the range of pressure, p, considered. Solutions of Equation (1) for both linear and radial flow are available in several forms.2'3' On the other hand. the second case, which is the flow of gas, gives a non-linear second-order equation, the solution of which is not known. Although a number of approximate solutions have been proposed, each is limited in value by the associated simplifying assumptions. Inasmuch as the analysis of transient flow is limited to liquid systems, a solution of the second case is necessary if further progress is to be made in studying underground fluid movement. For this reason a solution of Equation (2) was undertaken by means of numerical integration of approximating difference equations. BASIC DIFFERENTIAL EQUATION Equation (2; is derived by combining the equation of continuity, the perfect gas law, and Darcy's law to give the basic differential equation Strictly speaking, the fluids present in a gas reservoir are not perfect gases. Furthermore, there are indications that over certain velocity ranges, Darcy's law is not applicable. It would not be practicable. however, to attempt to obtain numerical solutions which would take into account all the possible variations from these laws which could occur in actual systems. The

Jan 1, 1953

My predecessor in the office of President of the Institute started a custom of visiting the various local sections, thus obtaining their points . of view and their ideas as to how the Institute can best serve the interests of its members. Exceedingly valuable- exchange of ideas was thus brought about. I am following this custom as far as the limited amount of free time at my disposal will allow me, and I trust that my successor in office will appreciate the benefit to be derived from following the custom thus initiated and will continue the swing around the circle of the local sections. The activities of the Institute are increased by the prestige gained from large numbers and I trust that every member of this local section will consider himself a member of the committee on increase of membership and will see if he is not able during the coming year to gain at least one new member for the Institute. This is a perfectly possible proposition for, although the membership of the Institute is at present approximately seven thousand, I feel sure there are at least seven thousand more men in the United States who are interested in mining, metallurgy or geology from the metal-mining point of view who would make admirable members or associate members of the Institute. The first consideration of the Institute as a body, and of each member as an individual, is to win the war and defeat the Huns. In order to accomplish this, the Institute, as a body, has cooperated with the other national engineering societies and the great bureaus of the Department of the Interior, the United States Geological Survey and the Bureau of Mines in forming committees to study and advise the Government on pressing problems of vital importance.

Jan 5, 1918

By Willard S. Morse

The ores of the district are treated at this mill by the lixiviation process, consisting of drying, crushing, chloridizing-roasting and lixiviation by hyposulphite and Russell solutions. Gas is used as fuel for both drying and roasting, The gas-plant consists of two- Taylor revolving-bottom gas-producers, one 6 feet in diameter for the ore-dryers, the other 7 feet in diameter for the Stetefeldt furnace. The producers were made by Messrs. R. D. Wood & Co., Philadelphia, who also furnished the

Jan 1, 1893

By Bernard MacDonald

The writing of this paper was prompted by the discussion by H. M. Chance of the paper written by Thomas M. Chance,l and by the remarks of the editor in which he stated that while the matter contained in discussion did not refer to the original paper it " was presented as of interest to the operators of cyanide and other lixiviation processes dealing with fluid mixtures of varying specific gravity." For some years past the principle enunciated in the discussion referred to has been known to the writer and demonstrated by him to be an efficient and economical way of separating water or solution from solids in the cyanidation, lixiviation or acid leaching of ore pulps. In utilizing this principle in commercial practice he has invented a method whereby not only the separation of solution from solids may be effected in any given tank, but also the counter migration of the solids and solution may be effected continuously through a series of tanks in which the hydro-metallurgical treatment of ore pulps is being carried on. In effect this method is analogous to the counter-current system, but is different physically in that it is carried on throughout a series of tanks on practically the same level, continuously and automatically, by hydrostatic pressure and gravity-flow, without the aid of intervening pumps or elevators, at the same time that agitation is being carried on in the same tanks. In the Parral system, agitation is effected in tanks by a number of air lifts of comparatively small diameter through which the pulp is continuously transferred from the bottom of the tank and spouted horizontally on top of the charge. The spouting force of the several streams thus discharged maintains a rotary flow in the pulp charge which extends from top to bottom of the tank. This continuous transfer of pulp and the spiral flow from top to bottom of the tank maintains the pulp constituents in uniform proportions and meets the requirements of efficient treatment in a most economical manner. The quantity of compressed air required is very small, as the pulp is not lifted but simply transferred from the bottom to the top of the tank charge under hydrostatic balance. Fig. 1 gives a bird's-eye view of two adjoining tanks in any series equipped with the apparatus for producing the separation of

Jan 1, 1919

By R. S. Shoemaker, F. W. McQuiston

MAGMA COPPER COMPANY San Manuel Division The San Manuel Division of Magma Copper Company is located about 40 miles north of Tucson. Tons of ore milled in 1973 .were approximately 19 million at a rate of 63,000 tons per day. From this, about 42,600 tons of copper concentrate was produced as saying approximately 1.070 MoS2 and 28.5% Cu. As with many copper ores, the San Manuel ore contains a small amount of gold, but in this particular case, much of the gold follows the molybdenite. Separation of the molybdenite from the bulk sulfide concentrate by flotation produces a moly concentrate containing 9170 MoS2, just under 1.070 Cu, and 0.44 oz Au per ton. Cyanidation of this material for gold recovery is the only practice of its kind known to the authors of this Monograph. After thickening, the final moly concentrate is filtered for subsequent repulping with cyanide and lime. Gold dissolution takes place in three agitators in series with the pulp from the agitators being filtered in two stages in disc filters. Between filtration stages, the cake is repulped with barren solution. Filtrate from both filters is the pregnant solution. The Merrill-Crowe recovery unit is comprised of two solution tanks and the usual clarifying filter, vacuum tower, zinc dust feeder and Merrill precipitate press. Because of the presence of finely divided sooty chalcocite in the molybdenum concentrate, the cyanide consumption of 55 pounds per ton is extremely high. A compensating factor, however, is the low copper, moly concentrate produced. Precipitation of the gold from the highly copper-contaminated solution requires 0.56 pounds of zinc dust and 0.28 pounds of lead acetate per ton, high figures when compared to normal cyanidation practice. The Merrill- Crowe precipitate assays approximately 28.5% Cu, 8% Zn, 156 oz Au and 197 oz Ag per ton. The San Manuel cyanidation plant is an outstanding and innovative development.

Jan 1, 1975

By George A. Bell

The mine and milling plant of Demonstration Gold Mines, Ltd., is near the city limits of Baguio, Mt. Province, P. I. The mine road connects with the main highway to Manila. The nearest railway point is near sea level, approximately 40 miles distant. The Baguio district is very mountainous and has one of the heaviest rainfalls in the world. It is therefore difficult to maintain roads or to impound tailings and mine dumps. All supplies are trucked into the district direct from Manila or the nearest railway point, which means uncertain deliveries and high freight rates. Installation of equipment is difficult and costly. The average elevation at the mine is 4000 ft. and the climatic conditions are ideal except for a three months rainy season. The company generates its own power for mining and milling operations with three 400-hp. Ruston Diesel engines direct connected to 250-kw. General Electric alternating current generators. Labor conditions have been excellent, although at present social security laws are causing some unrest. Labor receives a higher average wage rate in this district than other labor in the Islands. The company also furnishes free living quarters, hospitalization and workmen's compensation. Taxation has been reasonable up to the present time, but some of the new mining legislation may make it difficult to operate and pay dividends. The future depends largely upon the continuation of $35 gold and the political outcome in the Islands. History The Demonstration ore body was worked by the Igorots for many years, as evidenced by old stopes and fill encountered in present operations. Attention of Americans was first attracted soon after the Spanish-American war. During the building of the Benguet road to Baguio, the engineers and foreman became interested in the geology of the district.

Jan 1, 1939

By George A. Bell

THE mine and milling plant of Demonstration Gold Mines, Ltd., is near the city limits of Baguio, Mt. Province, P. I. The mine road connects with the main highway to Manila. The nearest railway point is near sea level, approximately 40 miles distant. The Baguio district is very mountainous and has one of the heaviest rainfalls in the world. It is therefore difficult to maintain roads or to impound tailings and mine dumps. All supplies are trucked into the district direct from Manila or the nearest railway point, which means uncertain deliveries and high freight rates. Installation of equipment is difficult and costly. The average elevation at the mine is 4000 ft. and the climatic conditions are ideal except for a three months rainy season. The company generates its own power for mining and milling operations with three 400-hp. Ruston Diesel engines direct connected to 250-kw. General Electric alternating current generators. Labor conditions have been excellent, although at present social security laws are causing some unrest. Labor receives a higher average wage rate in this district than other labor in the Islands. The company also furnishes free living quarters, hospitalization and work- men's compensation. Taxation has been reasonable up to the present time, but some of the new mining legislation may make it difficult to operate and pay dividends. The future depends largely upon the continuation of $35 gold and the political outcome in the Islands. HISTORY The Demonstration ore body was worked by the Igorots for many years, as evidenced by old stopes and fill encountered in present operations. Attention of Americans was first attracted soon after the Spanish- American war. During the building of the Benguet road to Baguio, the engineers and foreman became interested in the geology of the district.

Jan 1, 1939

By George A. Bell

The mine and milling plant of Demonstration Gold Mines, Ltd., is near the city limits of Baguio, Mt. Province, P. I. The mine road connects with the main highway to Manila. The nearest railway point is near sea level, approximately 40 miles distant. The Baguio district is very mountainous and has one of the heaviest rainfalls in the world. It is therefore difficult to maintain roads or to impound tailings and mine dumps. All supplies are trucked into the district direct from Manila or the nearest railway point, which means uncertain deliveries and high freight rates. Installation of equipment is difficult and costly. The average elevation at the mine is 4000 ft. and the climatic conditions are ideal except for a three months rainy season. The company generates its own power for mining and milling operations with three 400-hp. Ruston Diesel engines direct connected to 250-kw. General Electric alternating current generators. Labor conditions have been excellent, although at present social security laws are causing some unrest. Labor receives a higher average wage rate in this district than other labor in the Islands. The company also furnishes free living quarters, hospitalization and workmen's compensation. Taxation has been reasonable up to the present time, but some of the new mining legislation may make it difficult to operate and pay dividends. The future depends largely upon the continuation of $35 gold and the political outcome in the Islands. History The Demonstration ore body was worked by the Igorots for many years, as evidenced by old stopes and fill encountered in present operations. Attention of Americans was first attracted soon after the Spanish-American war. During the building of the Benguet road to Baguio, the engineers and foreman became interested in the geology of the district.

Jan 1, 1939

By T. A. Klinefelter

Lightweight concrete aggregates are materials weighing less than the usual aggregates of sand, gravel, and crushed rock. Concretes made with sand and gravel or crushed rock weigh 145 to 150 lb per cu ft, compared with 50 to 90 lb per cu ft for concretes made with lightweight aggregate. The ultra-lightweight concretes weigh much less than 50 lb per cu ft. Lightweight aggregates may be natural or manufactured materials, or byproducts from other commercial operations. Natural materials include pumice and pumicite, tuffs, breccia, scoria, diatomite, and vegetable products, such as peat, straw, and sawdust. Manufactured materials include expanded perlite, vermiculite, slag, clay, shale, and slate. Byproducts include cinders, aircooled slags, and coke breeze. Concretes made with lightweight aggregate were used first in construction of commercial buildings, later in homes. Present usage is general in multistory and other building construction, such as bridge decks, barges, jet-plane runways, piers and other structures. The industry has grown remarkably in the last decade. General Considerations The particular use to which the concrete may be put determines the importance of the various properties of the aggregates employed. Any given type of aggregate, however, should be reasonably uniform in composition and properties. It should be suitably graded and maintain proper weights, insulation values, and adequate strength to prevent breakdowns in mixing. It should bond properly with the cement, be inert to chemical reactions with cement and steel, and resist weathering, moisture, insects, and fungi. Some properties of any given type of lightweight aggregate from different suppliers may vary considerably because of differences in the source of raw material and the method of treatment. This statement applies particularly to expanded clays, shales and slates. All lightweight concretes have higher absorption of moisture and lower thermal conductivity, lower compressive strength, as well as lower unit weight as compared with standard concretes made with sand, gravel or crushed rock. Excepting cinders, the cost of lightweight aggregates is usually higher. Grading and unit weight requirements are given in ASTM standards: C 330-53T, Lightweight Aggregates for Structural Concrete; C 331-53T, Lightweight Aggregates for Concrete Masonry Units; C 332-54T, Lightweight Aggregates for Insulating Concrete. The production of masonry units shows the growth of the use and types of lightweight aggregates. In 1947 the total number of lightweight block was 460,000,000 units in 8 by 8 by 16-in. equivalents. By 1954 this had increased to 950,000,000 units. Of the 1954 production, 27 pct was of manufactured types, 43 pct of cinders, and 30 pct of remaining types. Raw Materials Used as Lightweight Aggregates It was stated above that a variety of products both natural and manufactured are used as lightweight aggregates. It is easy to understand that a bulky material of low unit value cannot be transported far and still remain a low cost product. Hence the product used in a particular market depends upon the availability of the possible raw materials. Thus it is

Jan 1, 1960

By M. P. Nackowski, Armond H. Beers, W. T. Parry

Three hundred soil samples were collected on a one-mile grid in a 400-square mile area of the Oquirrh Mountains, Utah, including the Bingham-Lark, Ophir, Rush Valley, and Mercur mining districts. The soil samples were analyzed for copper, lead, zinc, silver, molybdenum, manganese, and iron by X-ray fluorescence using arsenic as an internal standard. Anomalies coincide in most cases with the mining districts. However, in the Mercur district no anomalies were detected. Also samples collected one mile from the Bingham mine barely reflect this major producer. No samples were collected within the Bingham mine area.

Jan 1, 1973

By Donald C. Branford

The place of geophysics in the curriculum of a college or an engineering school has been much discussed. There is uncertainty as to whether the graduate may be called a "geological geophysicist" or a "geophysical geologist." Some have used the term "geophysical engineer." The question of the specialized undergraduate curriculum versus a general undergraduate training in the parent sciences with the addition of cultural electives has been and is still being argued. The literature during the past Io years shows that there are two rather definite schools of thought on this subject. The prospective employer, engaged in active geophysical exploration, visualizes the graduate in terms of the routine work he will do in the field. The school administrator, grounded in many years of tradition in the cultural type of education, visualizes the graduate in terms of his position in a political and cultural society as well as in his work as a professional geophysicist. Both are right and both wrong. A third school of thought, that of the student himself, has been almost totally ignored. It would seem best, for the purpose of this paper, to treat these various points and allied material separately, and then to integrate the conclusions as a set of conditions that should be fulfilled as far as possible in the ideal curriculum. At the end the relationship of our findings to the curriculum that has been tentatively adopted at the University of Pittsburgh will be considered. Divisions in Definition or Field of Geophysics Geophysics is that field of science in which geological and earth problems are solved with the use of physical and chemical techniques. Altogether too much attention has been paid to the artificial separation in this science of the commercial applications from the so-called "pure" or academic geophysics. The only real difference in the two types of work is one of scale of operations. In the commercial field the scale is large in terms of fmancial backing, immediate economic importance, and speed of operations. In the academic field the scale is large in terms of breadth of interests, in eventual economic importance, and length of time allowable for theoretical investigations. In exploration work the scale is small in terms of dimensions, since the methods are applicable only to the outer 20,000 ft. or SO of the earth's crust. In academic work, the student is not pressed for results of immediate economic importance, and therefore can afford to spend more time on problems that seem unimportant at the time. In the sense of background knowledge of the parent sciences necessary to the geophysicist, no essential difference can be found. Physics, chemistry, geology, and mathematics together, and in their proper proportionate amounts, form the matrix from which geophysical ideas and methods may spring.

Jan 1, 1946

By Donald C. Bradford

THE place of geophysics in the curriculum of a college or an engineering school has been much discussed. There is uncertainty as to whether the graduate may be called a "geological geophysicist" or a "geophysical geologist." Some have used the term "geophysical engineer." The question of the specialized undergraduate curriculum versus a general undergraduate training in the parent sciences with the addition of cultural electives has been and is still being argued. The literature during the past 10 years shows that there are two rather definite schools of thought on this subject. The prospective employer, engaged in active geophysical exploration, visualizes the graduate in terms of the routine work he will do in the field. The school administrator, grounded in many years of tradition in the cultural type of education, visualizes the graduate in terms of his position in a political and cultural society as well as in his work as a professional geophysicist. Both are right and both wrong. A third school of thought, that of the student himself, has been almost totally ignored. It would seem best, for the purpose of this paper, to treat these various points and allied material separately, and then to integrate the conclusions as a set of conditions that should be fulfilled as far as possible in the ideal curriculum. At the end the relationship of our findings to the curriculum that has been tentatively adopted at the University of Pittsburgh will be considered. DIVISIONS IN DEFINITION OF FIELD OF GEOPHYSICS Geophysics is that field of science in which geological and earth problems are solved with the use of physical and chemical techniques. Altogether too much attention has been paid to the artificial separation in this science of the commercial applications from the so-called "pure" or academic geophysics. The only real difference in the two types of work is one of scale of operations. In the commercial field the scale is large in terms of financial backing, immediate economic importance, and speed of operations. In the academic field the scale is large in terms of breadth of interests, in eventual economic importance, and length of time allowable for theoretical investigations. In exploration work the scale is small in terms of dimensions, since the methods are applicable only to the outer 20,000 ft. or so of the earth's. crust. In academic work, the student is not pressed for results of immediate economic importance, and therefore can afford to spend more time on problems that seem unimportant at the time. In the sense of background knowledge of the parent sciences necessary to the geophysicist, no essential difference can be found. Physics, chemistry, geology, and mathematics together, and in their proper proportionate amounts, form the matrix from which geophysical ideas and methods may spring.

Jan 1, 1942

By Donald C. Branford

The place of geophysics in the curriculum of a college or an engineering school has been much discussed. There is uncertainty as to whether the graduate may be called a "geological geophysicist" or a "geophysical geologist." Some have used the term "geophysical engineer." The question of the specialized undergraduate curriculum versus a general undergraduate training in the parent sciences with the addition of cultural electives has been and is still being argued. The literature during the past Io years shows that there are two rather definite schools of thought on this subject. The prospective employer, engaged in active geophysical exploration, visualizes the graduate in terms of the routine work he will do in the field. The school administrator, grounded in many years of tradition in the cultural type of education, visualizes the graduate in terms of his position in a political and cultural society as well as in his work as a professional geophysicist. Both are right and both wrong. A third school of thought, that of the student himself, has been almost totally ignored. It would seem best, for the purpose of this paper, to treat these various points and allied material separately, and then to integrate the conclusions as a set of conditions that should be fulfilled as far as possible in the ideal curriculum. At the end the relationship of our findings to the curriculum that has been tentatively adopted at the University of Pittsburgh will be considered. Divisions in Definition or Field of Geophysics Geophysics is that field of science in which geological and earth problems are solved with the use of physical and chemical techniques. Altogether too much attention has been paid to the artificial separation in this science of the commercial applications from the so-called "pure" or academic geophysics. The only real difference in the two types of work is one of scale of operations. In the commercial field the scale is large in terms of fmancial backing, immediate economic importance, and speed of operations. In the academic field the scale is large in terms of breadth of interests, in eventual economic importance, and length of time allowable for theoretical investigations. In exploration work the scale is small in terms of dimensions, since the methods are applicable only to the outer 20,000 ft. or SO of the earth's crust. In academic work, the student is not pressed for results of immediate economic importance, and therefore can afford to spend more time on problems that seem unimportant at the time. In the sense of background knowledge of the parent sciences necessary to the geophysicist, no essential difference can be found. Physics, chemistry, geology, and mathematics together, and in their proper proportionate amounts, form the matrix from which geophysical ideas and methods may spring.

Jan 1, 1946

By S. L. Hoyt

Some of the more important properties of finished materials are strength, ductility, toughness, resistance to alternating and repeated stresses, etc. Of these, the property that appears to have received the least consideration, at least in this country, is toughness, which is due, possibly, to our regarding toughness as a qualitative property or, at any rate, as one that parallels ductility. This arises out of our greater experience with the simple carbon steels in the rolled or forged (non-heat-treated) condition which, qualitatively, are tough if ductile and are not tough if brittle. In this way we have erroneously become accustomed to judging the toughness of a material from its behavior in the tensile or similar test. The point of view presented in the present paper is that toughness, like hardness or tensile strength, should be regarded as an independent property and of sufficient importance to require, in so far as that may be possible, quantitative determinations. If such be true, it becomes at once necessary to devise experimental means for measuring or valuating toughness, and the notched-bar impact test (the Charpy test) is advanced as the most logical test that has so far been developed for this purpose. It is further advanced, with particular emphasis, that we have two kinds of toughness to deal with and, accordingly, they will be dealt with independently. Classification of Materials According to Toughness Toughness has been defined somewhat as follows: Tough materials are those that offer considerable resistance to permanent deformation but which, once such resistance has been overcome, may be deformed plastically, but only by the expenditure of considerable energy. In other words, tough materials may be deformed plastically but they absorb a considerable amount of work in the process. This kind of toughness may be called "static" toughness when the rate of loading is reasonably slow or "dynamic" toughness when the rate of loading is comparatively rapid, as in impact testing, but in all cases the stress distribution is essentially uniform. However, static toughness does not

Jan 1, 1920