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By Zay Jeffries

THIS paper will include a brief discussion of Prof. Howe's paper on The Supposed Reversal of Inheritance of Ferrite Grain Size from that of Austenite.1 The general subject of grain refining in steel and iron will also be treated. The conclusions reached are stated in the following hypotheses which are discussed more in detail below. 1. The ferrite grain size in pure iron, the ferrite and pearlite grain size in hypoeutectoid steel, the pearlite grain size in eutectoid steel and the cementite and pearlite grain size of hypereutectoid steel are not inherited from the grain size of the mother austenite. 2. The only structural feature that is generally inherited from the austenite of hypo- and hypereutectoid steels on cooling through their transformation ranges is the position of the excess ferrite or cementite at the austenite grain boundaries, sometimes causing complete and sometimes incomplete networks which outline the old austenite grain boundaries. Rapid cooling through the transformation range will cause the non-inheritance of this structural (network) feature. 3. The austenite grain boundaries themselves are nearly always effaced in all steels and also in pure iron during the Ar transformations. 4. The grain-size refining of steel and iron is brought about by the combined. effect of non-inheritance of the transformation products on either heating or cooling, i.e., the austenite transformation .products do not inherit their grain size from the austenite on cooling through the transformation range for does austenite inherit its grain size from the products which form austenite on heating. 5. In general, in both iron and carbon steel the larger the austenite ,grain size, the larger will be the grain size of the transformation products on cooling. This, of course, assumes all other conditions constant except the austenite grain size. An exception is found to this general rule in very pure iron such as electrolytic iron. 1n this instance small austenite grains may form very large ferrite grains on cooling through Ar3.

Jan 11, 1917

By H. LeRoy Scharon, A. B. Cleaves

THE application of geophysical techniques in the A engineering surveys of the Philadelphia and Western Extensions of the Pennsylvania Turnpike System is unique inasmuch as this is the first time, (to the authors' knowledge), that such studies have been employed on a large scale on a major highway system. These investigations were confined to specific areas along the center line of the proposed Philadelphia Extension between Carlisle and King of Prussia, and the Western Extension between Irwin and the State line near Youngstown, Ohio, as shown in Fig. 1. Along the 100 miles of the philadelphia Extension, the geophysical surveys were confined to 137 individual cuts and comprised a total length of 37.4 miles of line. The Western Extension, 66 miles in length, has 108 individual cuts. The accumulated length covered by electrical resistivity studies was 17.3 miles. The depth of the cuts varied from a minimum of 10 ft to a maximum of 62 ft. The geophysical investigations were made for the purpose of determining depths to bedrock in the 245 proposed cuts and at the sites of various structures. The 'data also served as a basis for geological interpretations of the condition of bedrock, contact zones, rock types, water table, and other factors significant in highway construction. The geophysical method of investigation employed the use of the electrical resistivity principle using the Gish-Rooney type electrical resistivity meter and the Wenner electrode configuration.* Apparent resistiv- ities were determined for constant intervals to various depths and were correlated with surface geological observations and subsurface geological conditions revealed by key diamond drill holes situated within a given cut interval. From these correlations, depths to bedrock were postulated with notations on other geological features that might be pertinent to modern highway construction. Geology The bedrock underlying the areas of the extensions of the Turnpike afford an excellent academic study of the electrical resistivity depth method as well as a practical application to modern highway engineering. The rocks encountered on the Philadelphia Extension vary in age from pre-Cambrian to Triassic and Quaternary, whereas in the Western Extension, bedrock is confined to relatively flat-lying strata in the Allegheny, Conemaugh, and Monongahela formations of the Upper Paleozoic, Pennsylvanian. Glacial and Recent stream, valley, and terrace deposits are common. Philadelphia Extension The oldest bedrock encountered in this extension are igneous and metamorphic. These, encountered chiefly in Chester County, consist of the strongly

Jan 1, 1952

By Francis S. Peabody

This paper will not be a technical paper, because, although I have been in the business of mining and selling coal for 30 odd years, I am neither a mining engineer nor a practical miner. If I digress from time to time from my thesis, I must be forgiven by the expert engineers and highly technical gentlemen for whose proceedings this article is written. Waste of the wonderful store of power that the Creator placed at our disposal appears to have been the theory and the basis of our methods of extracting this power—waste from the time the coal is mined to the time it is consumed. Let us consider the prime causes of this wastage which has been the heritage of the coal mining industry. In the early days—about 150 years after " Stone Cole" was discovered in Illinois by Joliet and Marquette, and Father Hennepin noted a "cole" mine on his map—the mode of mining prevalent among farmer landowners, on whose property coal was discovered near the surface or outcropping on the hillsides, was to enter the seam by a shallow shaft or drift into the hillside and remove the coal by wedging it down until a large room was left. The roof without support would fall and our primitive coal operator would then sink another shaft or drive another drift. In these early operations only the large lumps were taken and all small pieces and screenings were left to be covered by the fall of the roof—in fact this condition prevailed in Illinois up to about 1885. Gradually the method of mining changed from the open chamber, to a single entry with rooms turned to the right and left. Later, as the demand for coal increased and the necessity for larger mines became evident, the "room and pillar" system grew to be regular practice. The room and pillar system of mining consisted of starting away from the shaft bottom or drift mouth, with a pair of entries usually 12 to 15 ft. wide and about 30 ft. center to center, one entry being used for the air intake and the other for the return air and haulage; from each entry rooms or chambers were turned, narrow at the mouth and widening

Jan 1, 1918

By W. H. Bassett, C. H. Davis

In the commercial annealing of cartridge brass there are four points regarding which definite data are essential. They have to do with the correct interpretation of grain count in its relation to annealing temperature and, incidentally, to Brinell hardness. These points are: 1. The comparison of the grain sizes of two cartridge-brass mixtures: 69 copper, 31 zinc, 0.376-in. (9.5-mm.) gage; and 68 copper, 32 zinc, 0.130-in. (3.3-mm.) gage 2. The comparison of the grain sizes of annealed metal that had previously been reduced by rolling varying amounts; for instance, 20.0, 36.6, 50.9, and 59.1 per cent. 3. The determination of standards for grain sizes on annealed brass of the composition 68 per cent. copper, 32 per cent. zinc and 69 copper, 31 zinc. 4. The comparison of grain size with Brinell hardness on identical samples of annealed metal. In their comprehensive and thorough investigation of the recrystal-lization of cold-worked alpha brass on annealing,l Mathewson and Phillips have discussed the relations between temperature of anneal, degree of deformation, and structural alteration in alpha brass. They have also shown certain comparisons between the ordinary physical properties and the grain size of annealed brass. The purpose of the present investigation is mainly concerned with the grain size of cartridge brass, its relation to Brinell hardness, and the publication of sufficient data to enable those engaged in the inspection of such material to have a correct foundation upon which to work. The first alloy was taken from regular mill stock that had been rolled from 0.580 in. to 0.376 in. (14.7 mm. to 9.5 mm.) gage, a reduction of 35.1 per cent. This bar (No. 1) had the following composition: Copper, 69.20 per cent.; zinc, 30.76 per cent.; lead, 0.02 per cent.; iron, 0.02 per cent. The second alloy was also taken from mill stock of 0.325 in. (8.25 mm.) gage and was rolled as shown in Table 1, in order to get four bars reduced two, four, six, and eight B. & 5. numbers respectively. This second alloy

Jan 1, 1919

EDWARD HART*, Easton, Pa. (written discussion?) .-In 1895 I visited the chemical plant of the Messrs. Chance at Oldbury, England, under the guidance of Mr. France, the manager. In the stock house I saw a pile of coal brasses with adhering coal and said to Mr. France, "I should think you would get dark acid." "Yes," he replied, "our acid has always been rather black. and our customers have grown used to it. Some time ago we ran out of brasses and could get only Spanish pyrite. Our product became white and the customers began to complain, so I put a little sugar in each carboy." E. A. HOLBROOK,* Pittsburgh, Pa. (written discussion?).-Mr. Davis says, "A very large tonnage of pyrite is annually being thrown in the waste in the coal mines of this country." This quantity is much larger than is generally realized by people not intimately associated with coal mining. At the beginning of the war this country seemed threatened with a short-age of pyrite. The U. S. Bureau of Mines conducted a general investiga-tion of the pyrite resources of the country in order to ascertain what material was commercially available. The general pyrite investigation was in charge of H. A. Buehler, with the subsection on coal pyrite in charge of E. A. Holbrook.

Jan 10, 1919

By Hermsdorf, Richard P. E.

AMONG the newer lead smelting and refining plants of the country is that of the United States Metals Refining Co., at Carteret, N. J. Not only is the technical practice here modern and efficient, but exceptional care is taken to assure healthful operating conditions for the employees. One large building houses the entire department, which includes, as its chief units, one reverberatory smelting furnace, one blast furnace, two softening furnaces, one utility reverberatory furnace, two Faber du Faur retorts, five 120-ton kettles, three 60-ton antimouial lead kettles, and one 5-ton kettle for experimental purposes. There is a 10-ton overhead crane in the kettle aisle, which is also used for shipping lead. Other auxiliary equipment is referred to in the outline of operations. A general plan of the plant is shown in Fig. 2, and a general view in Fig. 1. Primary smelting operations are conducted in a 30 by 11-ft. reverberatory furnace with bottom, roof, and upper walls of clay brick, magnesite

Jan 1, 1934

By C. S. Samis, D. P. Seraphim

In the presence of oxygen, galena is oxidized in an aqueous medium containing ammonium acetate in accordance with the following reaction: PbS + 1/2 0, + 2 NH~Ac -» PbAc, + So + 2 NH: + H2O. This reaction was studied in an autoclave under oxygen pressure by polarographic measurement of the concentration of lead ion in solution. Oxidation rate is parabolic. The reaction products are lead acetote and elemental sulfur, the latter forming a film on the galena crystal. Reaction kinetics appear to be determined by the diffusion of lead from the galena phase to the solution interface through the film of sulfur. RECENT applications of pressure leaching on a commercial scale have emphasized the metallurgical importance of the oxidation of sulfide minerals in aqueous media by oxygen under pressure. Research experience has shown that sulfates, thio-nates, and metal oxides are the products of humid oxidation of sulfide minerals in basic solutions. The metal oxides may be solubilized in the presence of a complexing ion.' Certain oxide minerals are also amenable to treatment by this type of oxidation.' Several kinetic studies have been made of reactions of this type. Stenhouse' found that pyrite (FeS?) oxidized in a sodium hydroxide solution to produce a soluble sulfate and an insoluble layer of iron oxide and that the kinetics of the reaction were controlled by oxygen diffusion through the oxide layer. Andersen' studied the oxidation of galena (PbS) in a sodium hydroxide solution under oxygen pressure. He found the lead and sulfur to be simultaneously oxidized to produce plum bite ions and sulfate ions, and that the reaction rate was proportional to the surface area of the galena. The kinetics appeared to be determined by the reaction of oxygen and water with the galena surface. In each of the above reactions the metal and sulfur components of the mineral were oxidized simultaneously and at equal rates. In the present study the alkaline medium has been replaced by an approximately neutral solution of ammonium acetate in which lead sulfate is soluble. Under the conditions no sulfate was produced and no sulfur could be detected in the solution. The metal component of the mineral was solubilized and the liberated sulfur remained as a film of elemental sulfur on the surface of the galena crystal. A kinetic study of this reaction was undertaken to establish the kinetic mechanism and to determine the rate controlling step. Specific reaction rates were determined by oxidizing crystals of galena of measured surface areas in an autoclave maintained at the desired temperature and oxygen pressure. The rate of reaction was followed by measuring the concentration of lead in the ammonium acetate solution with a cathode ray polarograph, employing stationary platinum electrodes incorporated in the autoclave. Experimental Materials and Equipment Crystals of galena obtained from Violamac Mines, Retallack, B. C., were selected for oxidation because

Jan 1, 1957

By D. W. Fuerstenau

Recently R. J. Charles1 showed that comminution of brittle or semi-brittle materials in batch operations is described more appropriately by a variable energy relationship than by the specific relation- ships proposed by Rittinger,2 Kick,3 and Bond.4 That is, the value of n in the empirical differential operation which applies to crushing and grinding (Eq. 1) is variable. Independently, Holmes6 developed an identical generalized equaton for size reduction. The experimental data of Charles and Holmes show that the value of n is determined by the material and the comminuting machine and is constant for a given combination of these two conditions. The general objective of the present article is to extend the Charles-Holmes concepts to continuous ball milling. The specific objective is to analyze the operation of a vibratory ball mill dry-grinding chromite in a continuous open circuit and to develop an equation for the comminution of chromite in this mill.

Jan 12, 1959

By Charles Mitke

EXCLUDING top-slicing, and sublevel caving, large production caving methods may be divided into two general classes, the branch raise, or undercut caving method, and the combined shrinkage and caving method, each of which has a number of variations, the result of continual efforts towards obtaining lower costs and better extraction, by the introduction and substitution of minor improvements and modifications. EARLY CAVING METHODS Present caving methods are the cumulative result of developments covering a period of many years, with the most rapid growth during the past 15 years. They originated, presumably, from early English stoping methods, and, as far as is generally known, were first introduced in the Michigan iron district. They have had their greatest expansion and application in the large low-grade porphyry coppers. In their present form, they are probably a development and combination of sublevel caving and shrinkage (back-stoping on ore) with gravity handling of broken material. Sublevel caving, as practiced in the Michigan district today, is a combination of drift, or crosscut, mining, with top-slicing, and caving, supplemented by later refinements in the shape of mechanized handling of broken ore. A height of anywhere from 16 to 20 ft. is generally taken, and the ore is drilled and blasted along the drift or crosscut for half this height (say 8 to 10 ft.), after which the upper 8 to 10 ft. caves and breaks of its own weight, with comparatively little assistance from drilling. This

Jan 1, 1928

By Charles A. Mitke

Excluding top-slicing and sublevel caving, large production caving methods may be divided into two general classes, the branch raise, or undercut caving method, and the combined shrinkage and caving method, each of which has a number of variations, the result of continual efforts towards obtaining lower costs and better extraction, by the introduction and substitution of minor improvements and modifications. Early Caving Methods Present caving methods are the cumulative result of developments covering a period of many years, with the most rapid growth during the past 15 years. They originated, presumably, from early English stoping methods, and, as far as is generally known, were first introduced in the Michigan iron district. They have had their greatest expansion and application in the large low-grade porphyry coppers. In their present form, they are probably a development and combination of sublevel caving and shrinkage (back stoping on ore) with gravity handling of broken material. Sublevel caving, as practiced in the Michigan district today, is a combination of drift, or crosscut, mining, with top-slicing, and caving, supplemented by later refinements in the shape of mechanized handling of broken ore. A height of anywhere from 16 to 20 ft. is generally taken, and the ore is drilled and blasted along the drift or crosscut for half this height (say 8 to 10 ft.), after which the upper 8 to 10 ft. caves and breaks of its own weight, with comparatively little assistance from drilling. This

Jan 1, 1928

Flexibility is the keynote in designing modern exploration drills that and mobility. Add to the flexibility of individual drills the wide range of models, and the man looking for a drill has ample choice today. Weight? Choose from models as light as 50 lb or as heavy as 10,000 lb. Hole capacity? From less than 1 in. for smallest core drills to 20 in. or more for auger types. Transportation? The lightest go by packsack (in fact, that is one trade name) ; others are designed to go by Jeep, truck, on skids or are built on light trailers. Power? Select air power, gasoline or diesel engine, electric motor, or use a power take-off from the vehicle on which the drill is mounted. Drill bits offer almost as much variety as the drilling machines themselves. Many drills are suitable for a variety of uses, and often adapt to several types of bits with ease. Some of the types available are: diamond core, diamond reaming, rotary, auger, shot, and special soil sampling tools.

Oct 1, 1955

By R. G. Vardiman, M. R. Achter

Observations of dislocation structure in niobium are presented using two techniques. Triangular pits developed by electroetching are confined to orientations in the stereographic triangle between the (111) pole and planes of the (1ll) zone and require the presence of carbon. Some unusual electroetching phenomena at other orientations are noted. A chemical etch of dislocations decorated by the addition of carbon to 50 ppm reveals the complete dislocation line structure in a surface layer up to 30 p deep, with a resolution of less than 1 p. This effect is independent of surface orientation. The structure of subboundary nets may be resolved for misorientations up to about 1'. Dislocation structures found in strain anneal grown crystals, such as helices, prismatic loops, and high-density areas, are observed. The measurement of dislocation density is discussed and values obtained in different ways are compared. IN the course of some work on the response of refractory metals to thermal-mechanical treatments, it was desired to examine the defect structure of relatively low dislocation density crystals of niobium in bulk form. Surface and bulk methods for the observation of dislocations have been reviewed by ~melinckx,' and include etch pitting, decoration, and various X-ray techniques. The dislocation line structure has been developed by decoration in a few metals, although observations were limited to certain orientations, or by the coarseness and nonselectivity of the precipitate. The most commonly used technique is etch pitting. In niobium, etch pits have been developed chemically'0," in material of high impurity content and electrolyti-cally'' in relatively pure material. In this paper, etch pits developed electrolytically, and the dislocation line structure of a surface layer developed by decoration and chemical etching, are examined, and observations are presented from both techniques. EXPERIMENTAL METHODS Our starting material was electron-beam-melted niobium, swaged to 4 or -in.-diam rod. Chemical analysis is given in Table I. Single crystals were grown by a strain anneal technique using 1 to 2.5 pct of strain and growth temperatures of 1700" to 2300"~.'~ Some crystals grown by zone melting were also examined. The desired surface orientation was exposed either by spark machining or by sectioning with a cut-off wheel and prepared for etching by electro-polishing.

Jan 1, 1969

Canadian owned Lake are carriers will be used again this year in an attempt to make up the deficit caused by the two months steel-strike. Buffalo mills need between 5 million and 6 million tons of ore before the Lakes navigation season ends. Mutual Security Program aid will help reactivate Austria's largest iron ore mine. The Erzberg development is one of the moat important in Europe. MSA announced approval of $500,000 in supplemental financing of equipment. Following the war, the Russians stripped the Erzberg and Radmar deposits of equipment. The he Carborundum Corp. is going to build a $2.44 million plant at Akron, NO.. TOP near Niagara Falls for production of rare metals used by the Atomic Energy Commission. A subsidiary, the Carborundum Metals Co., Inc.,, will produce zirconium, hafnium sponge metals. The pyrochlore rich Sukulu Hills in Eastern Uganda will be mined under a pool arrangement including Tinto Mines, Monsanto Chemicals and Frobisher Mines. The combine will be known as the Uganda Development Corp., Pyrochlore is used in the manufacture of heat-resisting. alloys for Jet engines.

Jan 1, 1952

It is well to bring before you again the chief purpose of the National Research Council and of this its Division of Engineering, to stimulate others to make researches rather than to make them ourselves, because a given amount of our energy spent in inciting others will accomplish far more than if applied in executing them ourselves. This is because there are scattered through the numberless governmental, educational, and industrial laboratories of the country a very great number of investigators not only capable of being stimulated, but willing to aid in cooperative broadly planned research rather than to follow the haphazard methods of the past. Taken collectively, these laboratories and their personnel can produce an annual crop of knowledge the value of which is of the order rather of billions than of millions of dollars. I invite you to regard this potential product as a crop, to be planned, fertilized, harvested, and distributed with the sane order of statesmanship, the same breadth of view, with which we treat any other great human product or achievement, whether agricultural, industrial, or transportational.

Jan 1, 1919

By Ralph Arnold

PERHAPS the most striking feature in the three newly discovered fields in the Los Angeles basin is the enormous thickness of oil sand. The total thickness is not yet known in any of the fields, since no well has as yet been drilled deep enough to pass through it. In the Signal Hill area a maximum of 1500 ft. or more of productive sand has been penetrated. In the other fields the interbedding of considerable shale members renders the total sand thickness somewhat less, but in all cases the depth of sand strata is enormous when compared with other California fields. For instance, in the Coalinga field the total thickness of sand on the average has been less than 100 ft., while in the Midway and Sunset fields not more than 250 ft. of actual productive sand has been encountered in any one place. This condition has so upset all previous ideas regard-ing the possible future production that but few of the engineers who have had to deal with the situation feel

Jan 5, 1923

By Robert A. Melton

Since many of the easily mined, continuous, thick coal seams in the Appalachian Region have been exhausted, new exploration and mining is being directed toward less continuous seams that are under more cover and are more difficult to mine. The direct results of this are that more money and time and more expertise and data are needed to plan and open new coal mines today. It is also becoming apparent that the old methods of assimilating and preparing information needed for mine planning are inadequate to meet the needs of today's modern mining engineer, especially in the areas of data gathering, storage, retrieval, preparation, and interpretation. The system described here allows assimilation of old and new core data in a relatively quick, accurate, and efficient manner. The system is a set of computer assisted procedures consisting of the following four basic steps: 1) raw data collection, computer input, storage, and graphic preparation, 2) geologic profile correlation and establishment of seam continuity, 3) computerized data posting of important seam parameters, 4) geologic and planimetric analysis for mine planning.

Jan 1, 1977

By Max Barber

PRESENT equipment and practices in open-pit mines of the Lake Superior iron ranges have been described recently in some detail by A. H. Hubbell.1 It is anticipated that any further improvements will be the result of gradual evolution of present methods and equipment, just as those now used have been gradually evolved from earlier methods. An exception to the process of gradual evolution during the last decade has been the adoption of electric power for operating shovels and trains in open-pit mines, but it is not expected that any such revolutionary changes will be made in the future. The use of Diesel, engine equipment will gain considerable headway, no doubt, and will find favor in certain lines of operation as improvements and adaptations are evolved to meet particular requirements. The question of installing belt conveyors for handling material from deep mines of restricted area, where haulage grades become a serious consideration, or even for transferring earth, rock, or ore material for distances of several miles, is now being studied and some very interesting data are being obtained.

Jan 1, 1932

By H. W. Morse

THE CHAIRMAN (H. W. MORSE).-Gentlemen, for the first time in the history of the American Institute of Mining Engineers, we have a full session on the subject of leaching-especially on the leaching of copper ores.. This branch of metallurgy is rather in its infancy. We have had one big plant running for a year or more, and pretty successfully; and another one which will be started in February or March, the New Cornelia. We have another one at Garfield for the Utah company, which is just designed and construction begun; and from several other points come reports of interesting test work. The first paper on the program this evening is one of some of the test work on the New Cornelia ore by myself and Mr. H. A. Tobelmann. LAWRENCE ADDICKS, New York, N. Y. (written discussion).-The Ajo proposition has had, as I understand it, two great advantages: it has not been obliged to measure leaching against flotation or some other metallurgical process, and it deals with a copper content high enough

Jan 12, 1916

By William G. Schultz

Sylvite of Canada, a division of Hudson Bay Mining and Smelting Co., operates a new 8500-tpd potash mine ten miles northeast of Rocanville, Sask. This mine, employing less than 60 men in its underground maintenance, engineering, and production operations probably ranks as one of the most highly mechanized and automated mining operations in the world. Access to the flat lying potash bed is through two 16-ft-diam concrete and steel lined shafts 3300 ft deep. The backbone of the operation is two 258-ton, 1500-hp continuous mining machines capable of mining in excess of 700 tph per machine while employing extensible conveyors for haulage. This production capability is complemented by a completely automated haulage, storage, and hoisting system. Of the other unique features of this operation, the principal ones are that the mine was designed and developed by the people that are currently operating it and from the time the shafts were commissioned, the mine was completely developed, equipped, and brought to full production in less than six months.

Jan 1, 1974

By John V. Beall

Many Americans will judge the energy crisis by the picture shrink on their TV screen. And they are right to make this assessment considering the large areas of the country with marginal generating capacity, (See Fig, 1). The Federal Power Commission (FPC) recommends 20-25% reserve generating capacity above peak summer loads and 15-20% as minimal. The New York metropolitan area is the most concentrated power service area in the United States, and a spot check with Consolidated Edison, serving this area, revealed that on Friday, August 18, the company was operating at 5% reserve.

Jan 10, 1972