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By James Gayley

The paper presented to the Institute in 1910, by H. O. Hof-man, on Recent Progress in Blast Roasting,' has called the attention of the iron industry to the adaptability of these processes to the reclamation of by-products such as flue-dust and blue billy, and the better preparation of concentrates and fine ores for use in blast-furnaces. The waste of valuable iron-ore through the production of flue-dust has increased at an enormous rate, and much of it has in

Jan 1, 1912

By J. Gross

G. H. Clevenger, Chairman of the Milling Methods Committee of the Institute, made the following introductory remarks: "Several years ago, a number of us felt that the time was ripe for a fundamental investigation of crushing and grinding. At the outset, it appeared that the first thing we needed was a yardstick whereby grinding efficiency could be measured. "The U. S. Bureau of Mines has been most generous in cooperating with the Milling Methods Committee in getting this work well under way. John Gross, who served the committee for a year as secretary, was placed in charge of the investigation and has been ably assisted by S. R. Zimmerley. "Messrs. Gross and Zimmerley will now present the Progress Report covering their work to date." PROGRESS REPORT J. Gross, Salt Lake City, Utah. -This has not been a simple problem, and when I tell you that we can give you a verbal report of what we have done during three years in five or ten minutes you will realize that we have necessarily done a great deal of work that does not appear in the final results. We have been in a virtually new field. Therefore, we have had to feel our way at each step so as to be fairly sure we were correct. The first thing that was realized in this problem was that unless we had some method of measuring what happened when we crushed an ore, we might as well quit and not go further. We realized that if we tried to measure the results of crushing or grinding by the ordinary sizing test we would not get anywhere. We could sieve down to say 200 mesh fairly accurately; we could even go one sieve size further with a little less accuracy, and then we were absolutely lost, unless we went into microscopic measurement. Even this latter method would not have been satisfactory. The question was: what were we going to measure? If we were going to measure size, we might measure one particular dimension of a particle and be off 200 per cent. or more. If we tried to measure surface, we would have something tangible; the surface of a particle, no matter how irregular, is something definite, far more definite than any linear dimension would be. Moreover, if we could measure surface, we would immediately have a method of checking the Rittinger law as to whether it was or was not correct. So the first thing that we sought was a method whereby we could measure surface on crushed particles or, we will say, on particles; it would not make any difference whether crushed or not. It then became a question of what kind of particles we were going to use in obtaining a method for surface measurement. We realized that it would be rather a com-

Jan 1, 1928

By F. C. Blickensderfer

DURING 1914 and 1915 extensive experiments were conducted at the concentrator of The Detroit Copper Mining Co. of Arizona, at Morenci, Ariz., in order to test the relative grinding efficiencies of the Marathon, the Chilean and the Hardinge Mills. The Marathon mill used in the experiments was the first one ever built by the manufacturers; and since this was the first time that it was given a thorough tryout, with such remarkable results, the data have been, assembled in the following paper and submitted in the interests of the milling profession.

Jan 8, 1916

There were present eleven Directors, the Institute's Legal Counsel, the Secretary, the Assistant Secretary, and twenty-three guests. The Report of the Committee on Nominations (listed elsewhere) was presented and ordered to take the statutory course. The appointment of a Committee on Mine Taxation was approved. An Advertising Manager was appointed. E. G. Spilsbury and A. S. Dwight were appointed as representatives of this Institute on the Franco-American Engineering Committee. The Transactions were presented to the University of Louvain, and the monthly Bulletin to the French Technical Index. Permission was given to publish in full the argument of William H. Shockley on simplified spelling. A committee was appointed to have charge of the publication of the Raymond Memorial Volume. There were elected 70 members, 15 associates, and 1 junior associate. Three members were reinstated and the resignations of two were ac-cepted. The clues of 10 members who had been in active service with the allied armies were remitted. An extension of time for the payment of dues was granted to the 11 members.

Jan 12, 1919

C. W. Kempton, Oro Blanco, Ariz.: In his interesting paper, Mr. Ingalls refers to reports of tin-deposits near Sain Alto, Zacatecas, Mexico. During 1891 I made some personal examinations of these deposits. They are, for the most part, located from 10 to 30 miles west of the town, in the Sierra del Fraile.

Jan 1, 1896

By R. M. Brick

A PREVIOUS publication 1§ has described the effect of quenching stresses on the lattice parameter values of high-purity aluminum-copper alloys particularly with reference to the solution and precipitation of CuAl2. A similar study has been made of the aluminum-rich aluminum-mag-nesium alloys. Attention has been directed in the present investigation to the magnitude of the quenching stresses as affected by the specimen size and shape, the number of solute atoms and the quenching rate. The effect of cooling stresses in causing plastic deformation or cracking has been considered in relation to the physical properties of the alloy. On reheating alloys in the two-phase field, the time required for pre-cipitation to occur has been observed in connection with the degree of supersaturation, the rate of diffusion of the solute atoms as a function of the comparative atomic radii, degree of strain, temperature of reheating and grain size. A few qualitative comparisons on the relative effect of these factors have been drawn between the aluminum-copper alloys and the aluminum-magnesium alloys.

Jan 1, 1935

By James T. Kemp

Some interesting and, to American eyes, rather unusual processes for refining impure aluminum derived from scraps were found by American and British investigators who went into Germany in 1945 for the Technical Industrial Intelligence Committee of the Joint Chiefs of Staff. What was found was recorded in a series of reports (see page ), many of which have been released for general reading. This paper gathers under one title and summarizes the German work in refining light metal scrap. Reference must be made to the original reports for greater detail. Basically, the occasion and stimulus for the German developments in treating light metal scrap were hard necessity. Germany needed the metal for a rapacious war industry. Adequate supplies of new aluminum from reduction works were not assured. Great quantities of airplane and other light metal war scraps were forecast. It was evident that the scrap metal would have to be reabsorbed by the producing industry and would have to be kept of good quality. The normal current production of manufacturing scrap was being and could be consumed as generated. It offered no technical problem. The mixed scraps, especially those arising from crashed and decommissioned airplanes, however, presented problems of another kind. Airplane Scrap The recovery of usable aluminum alloy from the mixed assemblies that made up the piles of airplane scrap was attacked in different ways by different groups and with differing degrees of success. Three procedures actually were used on a commercial scale, one was in pilot-plant stage and another had come to a halt in the laboratory a year before Germany collapsed. Four of these five processes actually involved "refining"; that is, some measure of purification of the metal after melting. Sorting and Separation on a Sloping Hearth The simplest procedure for utilizing airplane scrap involved no refining in the strict sense of the word. This was the practice adopted by two representative plants visited by the author, the Leipziger Leichtmetalle Werke, Rackwitz, Saxony, and the Vereinigte Leichtmetalle Werke, Hanover. These firms did essentially the same thing that was done in England but not with equal success, to judge by their shorter experience, the smaller tonnage handled and by the number and quality of alloys produced. The two German firms named rough-sorted scraps by their easily recognizable alloys, essentially by part and shape. They used hand labor to chop and hack and tear apart. The easily separated heavy metal and nonmetallic scraps were discarded as they were found. Steel and the higher-melting-point metal parts riveted to aluminum or built into

Jan 1, 1947

By James T. Kemp

Some interesting and, to American eyes, rather unusual processes for refining impure aluminum derived from scraps were found by American and British investigators who went into Germany in 1945 for the Technical Industrial Intelligence Committee of the Joint Chiefs of Staff. What was found was recorded in a series of reports (see page ), many of which have been released for general reading. This paper gathers under one title and summarizes the German work in refining light metal scrap. Reference must be made to the original reports for greater detail. Basically, the occasion and stimulus for the German developments in treating light metal scrap were hard necessity. Germany needed the metal for a rapacious war industry. Adequate supplies of new aluminum from reduction works were not assured. Great quantities of airplane and other light metal war scraps were forecast. It was evident that the scrap metal would have to be reabsorbed by the producing industry and would have to be kept of good quality. The normal current production of manufacturing scrap was being and could be consumed as generated. It offered no technical problem. The mixed scraps, especially those arising from crashed and decommissioned airplanes, however, presented problems of another kind. Airplane Scrap The recovery of usable aluminum alloy from the mixed assemblies that made up the piles of airplane scrap was attacked in different ways by different groups and with differing degrees of success. Three procedures actually were used on a commercial scale, one was in pilot-plant stage and another had come to a halt in the laboratory a year before Germany collapsed. Four of these five processes actually involved "refining"; that is, some measure of purification of the metal after melting. Sorting and Separation on a Sloping Hearth The simplest procedure for utilizing airplane scrap involved no refining in the strict sense of the word. This was the practice adopted by two representative plants visited by the author, the Leipziger Leichtmetalle Werke, Rackwitz, Saxony, and the Vereinigte Leichtmetalle Werke, Hanover. These firms did essentially the same thing that was done in England but not with equal success, to judge by their shorter experience, the smaller tonnage handled and by the number and quality of alloys produced. The two German firms named rough-sorted scraps by their easily recognizable alloys, essentially by part and shape. They used hand labor to chop and hack and tear apart. The easily separated heavy metal and nonmetallic scraps were discarded as they were found. Steel and the higher-melting-point metal parts riveted to aluminum or built into

Jan 1, 1947

By F. C. Miller

The metallurgical fuel of Colorado, Utah, and New Mexico has been a Veiny tardy member in the caravan of western industrial progress. The history of western coke has naturally been closely related to the development of the metallurgy of iron and steel and the precious metals, in the State of Colorado. It was at Leadville, with a population of 300 in 1877, that the Sentinel was published by Richard S. Allen. The Sentinel gave very full accounts of the various mineral discoveries at the new town of Leadville, which found their way to the more widely circulated journals of the East, and attracted the attention of many people. At the close of 1878, a census slowed a total of 5040 persons. The first smelter was established in 1877, at Malta, two miles from Leadville, by A. R. Meyer, but was not successful. It was succeeded by the Harrison Reduction Works, in 1878. The La Plata began with one furnace in June, 1878, and in 1879 had four furnaces in active operation. These furnaces used charcoal for fuel, and, because of hot tops, suffered a tremendous loss in lead and silver. This difficulty was overcome by the erection of 50 single-bank 10-ft. beehive ovens at Crested Butte, Colo., in 1880. The slack coal sent to these ovens was very pure, and yielded a coke carrying as little as 4.5 per cent. ash. Among the pioneers in the Leadville district were Grant, Eddy, James, Billings, Eiler, and Dickson. To these men the West owes the present expansion of its mining industry, and the erection of metallurgical processes for the treatment of precious metals. On Mar. 1, 1876, Pueblo was connected to the Atchison, Topeka & Sank Fe by the Pueblo & Arkansas Valley branch. The first smelter was erected in Pueblo by Mather and Geist. This modest plant grew into the immense Pueblo Smelting and Refining Co., now a part of the American Smelting and Refining Co. Coke for these small furnaces was made from unwashed Engleville coal, in 186 single-bank 12-ft. ovens at El Moro, in the Trinidad district, and it was not uncommon for the percentage of ash to exceed the percentage of fixed carbon in the coke. On Jan. 23, 1880, the Colorado Improvement Co. consolidated

Jan 1, 1920

By M. E. Kukura, L. G. Stevens

As described in a previous presentation and in various patents, the Minerals Sciences Div. of UOP, Inc., has developed a modified reduction roast ammonia leach process for nickel laterites. This process gave considerable improvement in extraction over the conventional Caron approach as practiced in Cuba, Australia, and the Philippines. This greatly improved response was obtained with a wide variety of ores. This paper describes the pilot plant flowsheet and reviews the design features unique to the UOP process. Operating results from pilot plant campaigns are compared with bench scale results. Operating problems and their solutions are also discussed.

Jan 1, 1976

By Evert Hoek

SYNOPSIS It can be shown that the properties of intact rock are relatively unimportant in rock slope stability and that failures are controlled by structural discontinuities such as bedding planes, joints and faults in the rock mass. The frequency, orientation and inclination of these discontinuities as well as their strength characteristics are important factors to be considered in any rock slope analysis and their influence will be demonstrated by means of a number of practical examples. Methods for determining the mechanical properties of discontinuities will be reviewed and the interpretation of the strength test results for use in stability computations will be discussed.

Jan 1, 1971

By Reed S. C. Rogers, Robin P. Gardner, Kuruvilla Verghese

The development and use of short-lived radioactive tracer methods for the onstream determination of residence time distributions in large-scale ball mills is described. Tests are reported on a pilot-plant ball mill with 0.43 m diameter and 0.86 m length and on an industrial mill with 1.83 m diameter and 2.74 m length. Tests with different tracer feed sizes indicate that the residence time distributions on both mills are independent of charge particle size. Similar tests are planned for a large ball mill of 4.57 m diameter and 9.30 m length. No safety problems were encountered in these tests and none are anticipated in tests of the larger mill.

Jan 1, 1981

By Edwin A. Sperry

In 1892 I tested an ore, which was peculiarly difficult to treat, on several concentrators then in general use, including t,he Frue-vanner, the Luhrig table and the Cornish buddle. Owing to the character of the ore it had to be crushed- to a very fine state of division, and the results obtained were far from satisfactory; a large proportion of the values was lost in the slimes, which indicated the necessity of a very careful sizing before dressing. Even after reworking some of the slime-tailings, the results, in my opinion, were not as good aa those which might be obtained on a table designed more especially for the handling of slime. Although the subject of slime-concentration has occupied the attention of many engineers who have threshed the field quite thoroughly, the results obtained in my work led to a careful

Jan 1, 1904

By W. Randolph Van Lewis

In determilling the relative rate and in fi~lding the point where different inlpurities containecl in copper-matte are eliminated during the process of a converter-blow, the follo~ving results were obtainecl : A converter was selected which was starting on its sccolld charge. The first charge after lining had finished its copper " hot," and conseqaently no copper was adhering to the sides of the lining. All the copper and granulated slag from the previous charpc mcrc dumped, thus removing ally possibility of " salting " the matte to be tested. The coliverter worked fast and well during the entire test. Periods of ten minutes were selected. The converter mas brought from the stack to secure each sanlple of matte to be

Jan 1, 1904

By K. C. Mills, E. T. Turkdogan

The results on the rates of vaporization of Fe-Ni alloys, levitated by an electromagnetic field in a stagnant atmosphere of helium, are shown to be in close agreement with those predicted theoretically. AS shown in Part I of this series of papers, the rates of vaporization of metals enhanced by convection currents are increased further by the process of condensation of metal vapor when there is a steep temperature gradient in the boundary layer. At the time this theoretical work was completed one of the authors (K. C. Mills) had already carried out some experimental work on the rates of vaporization of molten Fe-Ni alloys. The experimental work was done under conditions which make it possible to compare the experimental rate data with those predicted on theoretical grounds. EXPERIMENTAL The object of the experiments was to evaluate the activities in a number of binary metal systems. The details of the experimental technique are given in another paper by Mills, Kinoshita, and Grieveson,2 and, for the present purpose, a brief mention of the relevant features of the experimental method will be adequate. Using an induction coil, the metal weighing about 1 to 1.5 g was levitated by the electromagnetic field in a stagnant atmosphere of pure helium. The helium was freed from oxygen and water vapor in the usual manner, and its pressure in the vaporization chamber was maintained at 1 atm through a bleeder device. The vaporization chamber consisted of a pyrex tube, 2.8 cm diam, with a side arm connected to the helium bleeder. The bottom of the tube, shaped conical, was surrounded by the induction coil, and the top was sealed with an optical flat for the purpose of measuring the melt temperature with a two-color optical pyrometer. By suitable adjustment of the high-frequency power input, the metal was brought to the desired temperature in about 30 sec of levitation. After a specified vaporization time, e.g., 3 to 4 min, the alloy was quenched by switching off the power. The amount of metal vaporized was determined from the difference between the initial and final weights of the sample. During the vaporization time, temperature fluctuations of about ±10°C were observed. COMPARISON OF EXPERIMENTAL DATA WITH THEORETICAL VALUES The experimental results are given in Table I. As already mentioned, the attainment of the vaporization temperature took about 30 sec from the moment of levitation. Therefore, the times recorded in Table I are 30 sec less than the total time; this is considered to be a reasonable estimate of actual vaporization times.

Jan 1, 1964

By D. W. Peaceman

In previous papers by this author on numerical calculations of multidimensional miscible displacement, some simplifying assumptions were made in writing the dispersion term of the differential equation. It was assumed that the flow vectors were essentially parallel to the x-axis. However, in most multidimensional miscible displacements, the flow vectors are not so simply oriented with respect to the coordinate axes. This paper derives the correct dispersion term /or the more general case; gives a difference approximation /or the dispersion tern; and derives the stability criterion for the corresponding explicit difference eguation.

Jan 1, 1967

By H. W. Knott, M. H. Mueller, P. A. Beck, W. P. Chernock

PREFERRED orientation studies by Harris of rolled uranium rods indicated that hot rolling to a small reduction of area caused the (010) planes to become strongly oriented and the (110) planes weakly oriented perpendicular to the rolling direc- tion. The relative intensities of these two fiber texture components were reversed upon rolling to higher reductions of area. Cold rolling caused the (010) planes to become strongly aligned and the (130) planes weakly aligned perpendicularly to the rolling direction. The present investigation was undertaken to explore in more detail the effect on the rolling texture of variables, such as the penultimate condition, the final rolling temperature and reduction of area. In addition, the recrystallization texture of rolled uranium rods was also investigated.

Jan 1, 1959

James W. Neill, Pasadena, Cal. (communication to the Secretary*):—Professor Hofnlan's paper brings the art up to date. As I was one of the pioneers in this business, I beg to give the following incomplete data regarding my efforts in this line. In the year 1883, while I was in charge of the smelting-operations at Mine La Motte, Mo., there mas at the concentrator an unusually large protluction of a middle product, locally called " iron," which carried considerable values in nickel and cobalt, and which it was desirable, for this reason, to treat by itself. The works could not spare a furnace for the purpose; and to handle this product I improvised a " roast-hearth " from an old " lead-hearth." This was a small cast-iron furnace of the uslial construction, about 2 by 4 ft. in dimensions, with a hollon- cast-iron back, through which the wind circulated before entering the tuyeres. I had a cast-iron grate made to fit this hearth, and placed it tlush with the lip, or apron, and above the tuybres. On this grate, which had round holes about 0.25 in. in diameter, and a total surface of about 20 by 40 in., I roasted the nickeliferous pyrite product; starting the fire with kindling, then adding charcoal, and then gradually feeding the sulphides with a shovel, so as to cover the fire, choke down blow-holes, and get an even bed. Blast at a pressure of 3 or 4 oz. was supplied by a Can-blower. When a cake of roasted material had formed, it was removed with a steel bar, or fork, to the lip of the furnace, and thence into a wheel-barrow. The fine material which had renlained unmelted, but very hot, on top of the cake would promptly ignite when the cake was broken up and removed. The fire would then be covered with fresh material and

Jan 1, 1911

By Harrison Schmitt

During the past decade the writer has studied and mapped certain ore deposits and their structural associations in the states of Chihuahua, Durango, New Mexico and Arizona, and he believes that these deposits, with the exception of the manto-chimney, are representative of the principal types in the area of the states named. In this paper the deposits are described; then generalizations are drawn so far as seems appropriate. Hanover, New Mexico The Hanover, New Mexico, zinc deposits were briefly described by Lindgren and others,' Paige2 and recently in more detail by Schmitt. These, the kind ordinarily called contact metamorphic, border the southern end of an oval area of granodiorite intrusive ¾ mile wide and 2 miles long (Fig. I). The granodiorite has intruded, folded, and metamorphosed sedimentary and igneous rocks, which range in age from pre-Cambrian to Upper Cretaceous. About 90 per cent of the ore has replaced coarse, recrystallized, pure, fossiliferous, lower Mississippian, nonmagnesian limestone (Hanover limestone) 110 ft. thick;4 about 75 per cent of it occurs in the upper 50 ft. of this horizon just below an 18-ft. lower Pennsylvanian shale bed, which lies on a locally inconspicuous unconformity representing upper Mississippian time. The orebodies show five shapes or attitudes, each dependent on a special structural situation: 1. Most of the ore occurs as podlike, thick lenslike or other "three-dimensional" shoots extending from top to bottom of the Hanover limestone and lying adjacent to the outer contact of a silicate zone largely of andradite, which follows the intrusive contact (Figs. 1 and 2).

Jan 1, 1935

By Harrison Schmitt

During the past decade the writer has studied and mapped certain ore deposits and their structural associations in the states of Chihuahua, Durango, New Mexico and Arizona, and he believes that these deposits, with the exception of the manto-chimney, are representative of the principal types in the area of the states named. In this paper the deposits are described; then generalizations are drawn so far as seems appropriate. Hanover, New Mexico The Hanover, New Mexico, zinc deposits were briefly described by Lindgren and others,' Paige2 and recently in more detail by Schmitt. These, the kind ordinarily called contact metamorphic, border the southern end of an oval area of granodiorite intrusive ¾ mile wide and 2 miles long (Fig. I). The granodiorite has intruded, folded, and metamorphosed sedimentary and igneous rocks, which range in age from pre-Cambrian to Upper Cretaceous. About 90 per cent of the ore has replaced coarse, recrystallized, pure, fossiliferous, lower Mississippian, nonmagnesian limestone (Hanover limestone) 110 ft. thick;4 about 75 per cent of it occurs in the upper 50 ft. of this horizon just below an 18-ft. lower Pennsylvanian shale bed, which lies on a locally inconspicuous unconformity representing upper Mississippian time. The orebodies show five shapes or attitudes, each dependent on a special structural situation: 1. Most of the ore occurs as podlike, thick lenslike or other "three-dimensional" shoots extending from top to bottom of the Hanover limestone and lying adjacent to the outer contact of a silicate zone largely of andradite, which follows the intrusive contact (Figs. 1 and 2).

Jan 1, 1935