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By Roland Kammel

For electrolytic recovery of silver from dilute aqueous solutions improved mass transfer is necessary to achieve favourable current efficiencies and high space-time yields. The many cell designs proposed for this application can be divided into two different groups: cells from which the silver must be redissolved and cells from which the deposit can be reclaimed as a metal. Introduction Electrolytic silver recovery methods have proven advantageous under technical and economic aspects for the treatment of rinse water, still rinses and spent silver solutions in the electroplating and surface finishing industry, of exhausted fixing baths from photographic processing, bleed electrolytes from silver refining processes and leach liquors. Examples of the compositions of typical dilute silver solutions are listed in Table I.

Jan 1, 1984

Born, March 28, 1853 Died July 23, 1916 On July 25, 1916, the Board of Directors adopted the following minute and directed that it be entered upon the records of the Board & published in the Bulletin of the Institute, and thereof be sent to the family of Mr. Kirchhoff: Charles Kirchhoff was one of the oldest, most widely known and most highly esteerned members of the American Institute of Mining Engineers. On his return in 1875 from a European course of study, to begin a highly successful professional career, he joined the Institute, then just commencing to acquire both national and international recognition. He became at once, and-for more than 40 years continued to be, its earnest , and active supporter, serving it as Manager, Councilor or Director for terms aggregating 9 years,-as Vice-President for 2 years, and twice as President for a year. During the critical period of the erection of the United Engineering Society's building, and the transfer of the Institute to permanent head-quarters therein, Mr. Kirchhoff was its efficient representative in the United Engineering Society, and on the Building Committee. In 1910, amid the congratulations of colleagues, employees, and innumerable friends, Mr. Kirchhoff retired from active business as Vice- President and General Manager of a great technical publishing company. Yet he sacrificed of his well-earned leisure yet one more year, to serve the Institute as President through 1911.

Jan 9, 1916

By J. H. Brophy, M. H. Kamdar, J. Wulff

A constitutional diagram for the Ta-W-Re alloy system is presented. Rhenium dissolves in the complete range of solid solutions between tungsten and tantalum up to 48 wt pct in tantalum 'to about 30 wt pct in tungsten. Intermediate x and u phases only are found. X-ray diffraction and fluorescence, metallography and melting-point measurements were employed. THE constitution diagram of ternary alloys of tungsten, tantalum, and rhenium for temperatures above 1000°C is reported in this paper. Alloys in this system rich in tantalum and tungsten are of interest for high-temperature applications, and those rich in rhenium for electronic applications. No ternary phase diagram appears to be available in the literature. The three-component binary diagrams have been previously established1-3 and the present ternary data are consistent with these. EXPERIMENTAL TECHNIQUES Commercially pure tantalum (99.7 pct), rhenium (99.99 pet), and tungsten (99.9 or 99.95 pct) powders were purchased from Fansteel Metallurgical Corp., Chase Brass and Copper Co., and Fansteel or Westinghouse Electric Corp., respectively. These powders were pressed without binder and arc-melted under helium. The preparatory and analytical techniques employed were identical to those used for the Ta-Re system investigation carried out in this laboratory.324 These included X-ray diffraction and metallographic phase identification, X-ray fluorescent and wet chemical analyses, solidus determinations and heat treatments in a resistance-heated tantalum-filament vacuum furnace. For microstructural examinations standard mechanical polishing techniques were used through diamond laps. Polished speciments of all compositions were etched by swabbing with 4 parts HI?, 4 parts HNO3, and 1 part H20. Since the microstruc-tures of alloys containing one or two phases closely resembled their counterparts in the respective binary systems, typical examples are omitted in this presentation. In all the alloys examined, it was possible to observe the number of phases present. Particularly when there were small amounts of one phase involved, it was possible to identify it only by a combined conclusion based on X-ray diffraction, position of an alloy in a composition series, and the phase rule. A total of 100 different alloy compositions was arc-melted and studied in the as-cast condition metallographically and by X-ray diffraction. Specimens of each of these compositions were heat-treated at 2680, 2530, and 2020°C for 1, 2, and 4 hr, respectively. Those which were treated at 2020 were given a preliminary homogenization treatment at 2500°C for 1 hr. Specimens of 25 alloys were heat-treated at 1200o C for 168 hr. Solidus temperature measurements were made by the detection of incipient melting in eighteen alloy compositions. The metallographic and X-ray diffraction results are summarized in Table I. Graphically, this information appears in the isothermal plots of Figs. 2 and 3. Within the accuracy of the experimental methods, two such plots are sufficient to locate these data, since the results for 1200°C were similar to 2020 and those at 2530 resembled 2680

Jan 1, 1962

Carlisle: An old friend and good friend, Alan Bateman, is the Silliman Professor of Geology Emeritus at Yale and editor of the Journal of Economic Geology. Now, Alan, let's start off by telling us something about how you became interested in copper. Bateman: Well, after I left Yale in 1913, I was appointed one of the field members of the Secondary Enrichment Investigation. We spent three years in the field studying all the copper deposits of North America, trying to find out how secondary copper enrichment took place. As part of this investigation, I went up to Kennecott, Alaska, in 1916. After the trip I was asked by the president of the company to become consulting geologist to them. I accepted his offer, and to this day I'm still consulting geologist to the Kennecott Copper Corp. Up at Kennecott, there were both Henry Krumb and my good friend Henry DeWitt Smith, who was general superintendent. He and I had been together at Yale, and I had ushered at his wedding. Interestingly enough, Henry took his bride to Alaska and I took mine there two months later. My assistant was Don McLaughlin, and I think that was his first experience in a mining camp. We published a paper on Kennecott together and cemented a friendship lasting to this day.

Jan 11, 1964

By A. G. Worthing

Black: Bodies.-In the ordinary conception, a black object is an opaque object that reflects but little of the light that is incident on it. This means naturally that such an object is a good absorber of luminous radiation. The black body; which is so closely connected with high-temperature measurements, represents the limit in blackness of all black objects. It is a body that not only absorbs all visible radiations but also all other radiations in the infra-red and the ultra-violet regions of the spectrum which are incident on it. No substance is known that is completely black; platinum black, one of the nearest if not the nearest representative of the ideal, reflects 1 per cent. or so of ordinary visible radiation. The closest approach to the ideal is a small opening in the wall of a relatively large opaque cavity. Any radiation incident on this black body will be almost completely absorbed if the relative dimensions are properly chosen no matter what the material may be. The great difference between the blackness of such a cavity and of lampblack, for instance, will be apparent to one who makes the simple test. Non-black Bodies.-The field of non-black bodies covers all real bodies. Their characteristics are extremely varied. So far as absorption of radiation-is concerned, these bodies range practically from the almost completely black, platinum-black, and lampblack, which absorb all but a fractional part of 1 per cent. or so of the incident radiation, by an infinite variety of steps to freshly polished silver, which ordinarily absorbs only a few per cent. The exact percentage absorbed depends not only on the nature of the incident radiation, but also on the temperature of the body, the condition of its surface, the angle of incidence, the nature of the surrounding medium, and on certain other less important conditions. As consequences of these varied characteristics, we have not only the differences of color of ordinary objects, but also the changes of color that any one object undergoes on heating or when lighted front various directions. This complexity of the phenomena, in a way, is responsible for the meagerness of knowledge, regarding materials at elevated temperatures. Measurement of High Temperatures.-Excepting in cases where the thermocouple or the gas thermometer are applicable, in which case the temperatures obtained are true temperatures regardless of-the material" studied, high, temperatures are almost always, if not always, determined from measurements of radiation. In fact, determinations of temperature from this latter point of view are often so much more convenient than the thermocouple and especially the gas-thermometer determinations that, in the region where all of these types of measurements may be made, the radiation measurements are often preferred. This is true even though the temperatures usually thus directly determined are not the actual temperatures, a consequence of the sources of the radiation being non-black bodies; in other words, a consequence of being concerned with iron, or glass, or tungsten instead of small openings leading to relatively large-cavities uniformly heated. Coordination of Experimental Results.-In order that data on iron, glass, tungsten, or other non-black bodies obtained in one laboratory, may be, correlated with similar data obtained elsewhere, temperatures must be expressed on a common scale. The true temperature scale is the natural scale for this purpose it is ordinarily the scale to which all other temperatures can be most directly reduced. When the measurements depend on the radiation, a knowledge of emissive powers repre-

Jan 9, 1919

By Peter N. Calder, Alan Bauer

INTRODUCTION One of the most important decisions involved in the design of an open pit mine is the selection of a slope angle. Despite this fact, engineering procedures have developed slowly in this field. Only recently have the instruments and know-how become available to undertake a design based on sound engineering principles. The effect of blasting on open pit slope stability is one aspect in which the state of the art has not developed fully. These effects include: a) the effects of the ground motion associated with blast waves on slope stability, and b) the fracturing of rock in the vicinity of slopes caused by blast waves. Natural rock jointing plays an important role in both of these. SUMMARY OF BLASTING EFFECTS In recent years there has been a trend to larger sizes of blast holes in open pits to the extent that today 9% in. and 12% in. diam. holes are the most common. The reasons for this have been economic. Larger machines are more efficient and produce at a lower overall cost per ton. As the size of blast holes have increased, so have the other factors associated with blasting. Bench heights have increased, the tons/ft. of hole yield has risen significantly and the explosive load per hole has increased. Quite naturally the rupture radius for a single blast hole has increased along with the vibration level produced per blast hole. Open pit blasting operations can result in two types of unwanted damage: 1. Damage to structures, such as buildings, dams and slopes by ground vibrations initiated by the blast. 2. Fracturing of ground beyond the planned excavation limits. Let us first consider item one. Vibration effects are determined by the type of blast which is fired and the type of medium through which the blast wave is being transmitted. They are strongly influenced by the weight of charge per hole, the number of holes per delay, the distance from the shot point, the mode of initiation, the point of interest relative to the blast, etc.

Jan 1, 1971

By Ezequiel Ordoñez

The two mining districts of Pachuca and Real del Monte, well known for their antiquity and the extraordinary richness of their veins, are situated, 3 miles apart, only 62 miles north of the City of Mexico—the first being on the western, and the second on the eastern slope of the Pachuca range of mountains which bounds the great valley of Mexico. Close to the celebrated mining region of Pachuca is located the city of the same name, capital of the State of Hidalgo, at 2460 meters above sea-level and 20° 07' 35" North latitude, with 35,000 inhabitants, the majority of whom work in the mines; the remainder being Government employees, merchants, and a small number engaged in less important industries. The city extends along both sides of the canada which carries the waters of the river called "Avenidas de Pachuca," the banks of which are united by four bridges at regular intervals. The attention of the traveler approaching the city is first attracted by the appearance of the mountains, barren of vegetation, bounding the city with rocky cliffs and steep declivities, the grades of which serve as foundations to the irregular and varied groups of houses. Above these are the dumps, and, close by them, the mouths of the shafts, covered with conical tile roofs. The smoke of the chimneys, the noise of the mills and the appearance of some of the constructions reveal at first glance the industrial character of the place. At the left of the entrance to the canada, the mountain of San Cristobal, celebrated for the famous vein of Xacal, one of the richest and earliest exploited in the district, rises 450 meters above the city.

Jan 1, 1902

The following is a report of the papers submitted to the Papers 'and Publications Committee during 1928: The Committee held nine regular meetings during the year 1928. During that period there were presented to the Institute 214 papers which were acted upon as follows: Accepted as Technical Pub1ications............................ 85 Declined for publication...................................... 16 Action pending, Dec. 31...................................... 25 Manuscripts held for annual volumes, Dec. 31................... 7 Withdrawn temporarily...................................... 1 Accepted as Preprints........................................ 20 Printed for first time in volumes.............................. 35 Published in Mining and Metallurgy........................ 12 Papers in Technical Publication No. 156 (Coal Classification) and not accounted for elsewhere in this table..................... 10 Mimeographed only*................................... 3 Total.................................................. 214 * A considerable number of papers were mimeographed for the annual meeting. Of the 85 papers accepted as Technical Publications 8 were reprinted in the Transactions, 7 in Proceedings of the Institute of Metals Division (1928), 7 in Iron and Steel Technology in 1928, 13 in Geophysical Prospecting, and 50 were in Technical Publication form on Dec. 31. Of the 20 papers accepted as Preprints 1 was reprinted in the Transactions, 13 in Petroleum Development and Technology in 1927, 2 in Geophysical Prospecting, and 4 were in Preprint form on Dec. 31. Of the 35 papers printed for the first time in the various volumes 8 were included in the Transactions, 2 in Proceedings of the Institute of Metals Division (1928), 1 in Iron and Steel Technology in 1928, and 24 in Petroleum Development and Technology in 1927. Of the 12 papers accepted for Mining and Metallurgy 1 was, accepted for Geophysical Prospecting and 1 for the Transactions. There were published in 1928 113 Technical Publications containing a total of 1928 pages, as against 88 in 1927, totaling 1528 pages. The Technical Publications published in 1928 were classified as follows: Group A, Metal Mining, 17 papers (361 pages); B, Milling and Concentration, 4 papers (39 pages); C, Iron and Steel, 15 papers (256 pages); D, Non-ferrous Metallurgy, 13 papers (191 pages); E, Institute of Metals, 36 papers (588 pages); F, Coal and Coke, 15 papers (392 pages); G, Petroleum and Gas, 10 papers (246 pages); H, Non-metallic Minerals, 3 papers (33 pages); I, Mining Geology, 18 papers (356 pages); K, Mining Administration, etc., 3 papers (47 pages); L, Geophysical Prospecting, 21 papers (430 pages).

Jan 1, 1929

By William B. Plank

NEVER before have so many men chosen the mineral technology field for their college training. In the college year 1936-'37, 7190 such students were enrolled in the 53 schools of the United States. My last study of the mineral technology schools of the United States and Canada was made for the year -1934-'35, and the current study, as the previous one was made for the A.I.M.E. under the auspices of the Division of Mineral Industry Education. Altogether, four studies of enrollment have been made. The first three were for successive college years beginning with 1932-'33. This present one covers a two-year period, for the purpose of these studies may he served satisfactorily if they are made biannually. The data on the schools were collected in the same way as for former studies, 'namely, by questionnaire, dated in this case Nov. 18, 1936. The figures reported are therefore comparable with those of former cars.

Jan 1, 1937

By J. W. Pugh

VANADIUM has only recently received consideration with respect to structural applications. It would appear likely to find service where its high electrical resistance and constact temperature

Jan 1, 1958

Curlisle: We're sitting in Don McLaughlin's office overlooking Sun Francisco Bay, and he's going to be good enough to talk about early days in California, maybe about his college years in Berkeley, maybe about his first jobs in mining. Now, Don, would you be good enough to start it off by saying something about George Hearst. I know he died before you were born, but you know a lot about the family, and you no doubt know a lot about him. Certainly, nobody in those days matched his record in getting hold of good mines. McLaughlin: George Hearst died, actually, in the very year that I was born, but as I more or less grew up in the home of Mrs. Phoebe Hearst, who was his widow, I heard a great deal about the mines and the people that made the great fortune she inherited and used so wisely. But I don't think I really had an appreciation of George Hearst until 1 became active in the mining world and realized how many major mines he had picked in the early days and how much he had to do with their development into successful properties. He started in the California gold fields, but it was on the Comstock that he made his first big stake out of his substantial share in the Ophir mine. I believe at that time he was on his own. Then, later, he became associated with Ben Ali Haggin and Lloyd Tevis in San Francisco, and scoured the West for them. They made a little money in Eureka, Nevada, and other places, but the first important property that he obtained for them was the famous Ontario Mine in Park City, which became one of the great silver lead producers of the Continent. Then later he acquired the Homestake.

Jan 6, 1965

By A. C. Fieldner

In November, 1926, the American Engineering Standards Committee (now the American Standards Association) called a meeting of representatives of various professional societies and industrial, educational and governmental organizations to consider what action, if any, should be taken on the classification of North American coals. This meeting was called because a system for the use classification of coal, proposed by George H. Ashley, had been referred to the committee by the Coal Mining Institute of America. This meeting, at Pittsburgh, was well attended and was definitely in favor of taking up the whole question of scientific and use classification of coals, including all the various ranks from lignite to anthracite. The American Society for Testing Materials was recommended as the sponsor organization to take charge of the work and organize the sectional committee according to the rules of the American Standards Association. The American Society for Testing Materials proceeded with the organization of the sectional committee, holding a meeting in Philadelphia, June 10, 1927. Officers were elected, regulations adopted, and general plans for carrying out the work were outlined. The total membership of 28 comprising the sectional committee consists of 8 producers, 2 distributors, 9 consumers and 9 members representing general and scientific interest. From this committee three technical committees of 10 to 12 members each were organized: Scientific Classification, H. J. Rose, chairman; Use Classification, W. H. Fulweiler, chairman; Marketing Practice, F. R. Wadleigh, chairman. The Technical Committee on Scientific Classification was requested to formulate a system of coal classification based on chemical and physical properties of coal and with reference to origin and constitution. The Technical Committee on Use Classification was charged with developing a system of classification, if possible, based primarily on the uses of coal and commercial practice; this system to be correlated with the scientific system as far as possible and desirable. The Technical Commitlee on Marketing Practice was formed to collect and collate information on commercial practice for the benefit of the other two committees. The first meetings of the technical committees were held on Nov. 17, 1927, and the first informal progress reports were submitted to the

Jan 1, 1930

By T. D. Thomas

CONTENTS PAGE T. D. Thomas-Misfires in Anthracite Coal Mines 3 W. H. Forbes-Misfires in Bituminous Coal Mines 12 A. W. Worthington-Misfires in Non-metallic Mining (Limestone) 18 Misfires in Anthracite Coal Mines BY T. D. THOMAS,* LANSFORD, PA. (New York Meeting, February, 1929) IN THIS paper, major attention is given to misfires in mines where electric multiple shot-firing is the system used. Misfires are sometimes caused by one action or condition and at other times by a combination of two or more. They may be divided into two classes: (1) those caused by workers in the mines, (2) mechanical or manufacturer's causes. The second cause will be discussed first. MISFIRES CAUSED BY FAULTY DETONATORS The important part of an electric blasting cap, to the user where multiple shot-firing is done, ass in the steep-pitch, thick-vein, anthracite mines, is the bridge wire. In single shot-firing this factor is not apparent, but in mines where multiple firing is done any variation in the resistance of the bridge wire, where full or even rated battery capacity is required, will most likely cause a misfire The reason for this is obvious. If the resistance in the bridge wires is not the same, some of the detonators will fire because of their greater comparative resistance. Variance in resistance of bridge wires is caused by a slight difference in the diameter of the bridge wire, also to a difference in the composition of the bridge wires. Again, where the bridge wires have become rusted, there will be a variance in resistance. About the year 1922, one of the large coal companies was greatly alarmed by the number of serious and fatal accidents caused by misfires. The general manager issued an order that these accidents must be greatly reduced, and if possible, entirely prevented.

Jan 1, 1929

By D. W. Levinson, L. E. Tanner

DURING the course of an investigation of the zirconium-iron-tin system the zirconium-iron system was reexamined up to 55 pct* Fe. The alloys pre- visible melting3 and X-ray diffraction studies were made of samples of the alloys. The ferromagnetic properties of ZrFe2were determined by Professor P. W. Selwood* using a modified Faraday balance.4 The zirconium-rich portion of the phase diagram is presented in Fig. 1 and compared with the work of Hayes et al.1 The maximum solubility of iron in ß is somewhat decreased while the eutectic temperature is raised. There seemed to be no change in the eutectic composition of 16 pct Fe. Since the base material was so low in iron content, it was possible to establish the maximum solubility in a between 0.017 and 0.025 pct Fe at the eutectoid temperature. The observation of fine ZrFe, particles in the micro structure of a specimen of 0.012 pct Fe alloy quenched from 700°C indicated that the solubility drops below this composition at 700° C and lower. Further study was made of the intermediate phase ZrFe2. wallbaum5 identified the compound initially as ZrFe2 with a C 15 (MgCu2) structure, placing it at 55 pct Fe stoichiometrically. Hayes et al.1 believed they found the phase at about 47.2 pct Fe and called it Zr2Fe3 but reverted to ZrFe, in the discussion of their paper.6 Jordan and Duwez7 confirmed Wallbaum's work as well as finding the same single-phase structure to about 62.3 pct Fe or Zr0-61 Fe2-18. In order to establish the ternary phase relations in the zirconium-iron-tin systema the exact position of this phase had to be known. This was accomplished by X-ray diffraction, visible melting, and metallographic techniques. Elliott8 obtained a single-phase ZrFe2 X-ray diffraction pattern from an alloy of about 55 pct Fe. This was confirmed in the present study with an alloy of 54.81 pct Fe. However, extra lines (attributable to a or ß zirconium) were found in diffraction patterns of the 47.42 and 49.83 pct Fe alloys. The melting characteristics of these same alloys were studied by suspending 47.42, 49.83, and 54.81 pct

Jan 1, 1960

By Robert C. Weed

Leaching in place at Cananea began in the 1920's on a limited scale. The first plants were small wooden boxes located underground in the Capote and Oversight mines, and output was low. Scrap iron was used as precipitant. Later several other small plants were started up. Leaching was limited entirely to underground areas, and production remained low. The Veta precipitating plant, the first on a larger scale, was put into operation in the late 1920's. After a period of intermittent service it was rebuilt in 1946 and has since been running continuously.

Jul 1, 1956

E. M. BROHL. It seems as though the physicists in this crowd in the case of the cartridge cases have been a little in advance of the chemists in the crowd. What I am curious about here, and the way this appears to me, without too much study, is that in season cracking we get an atomic distortion so that both by sound means and by magnetic means we are finding a reluctance of the atomic planetary system to line up in accordance with the so-called good metal. The point that is brought up, or rather that has not been brought up-and I think perhaps we could think of that from the chemical point of view-is that this season cracking as I am used to the stress-corrosion cracking, appears to act much as though it were copper oxide. You remember when YOU take copper oxide films in which we again use this distortion of the atomic system to allow currents to pass selectively in one direction only, we get results almost identical with what we saw on the oscillograph report. In other words, on the one section of this season cracking we had a trace of one phase and if you notice on the sections three and four of the numbered oscillograph trace we had what appears 180 deg. out of phase.

Jan 1, 1945

By P. Somasundaran

Adsorption of a nonionic polyacrylamide (PAM), an anionic polyacrylamide with sulfonate functional groups (PAMS), and a cationic polyacrylamide with amine functional groups (PAMD), on hematite was investigated as a function of different solution conditions. Adsorption results indicate that the major mechanisms of adsorption of polyacrylamides on hematite is through hydrogen bonding, with electrostatic forces playing a secondary role. All the polymers exhibited irreversibility of adsorption upon dilution. Also, entropic effects were determined to be important in adsorption. Surface chemical properties of hematite and solution chemistry of the polyacrylamides are considered to explain the polymer adsorption behavior on hematite.

Jan 1, 1985

By G. A. Vissac

MOISTURE in coal must be considered as an impurity, just the same as ash, from the standpoint of utilization of the coal. Being incombustible, it reduces directly the heating value of the coal, and in addition absorbs heat for its evaporation. Its presence means useless expenditures in handling and transportation. In coke plants, extra moisture reduces capacity and may cause damage to brick work and equipment. Accordingly, the removal of extra moisture can be considered just as important as the removal of other impurities, such as ashes, in the modern coal preparation plant. Moisture, which can be removed by heating the coal up to a temperature of 100°C, may be retained in various forms: 1. As a film, on the surface of each coal particle, and in the interstices between particles, retained by capillary forces. 2. Or "occluded" inside the coal particles. This occluded moisture may be either free moisture (as in a sponge), or hygroscopic moisture which varies with atmospheric conditions, (also called "regain").

Jan 1, 1949

On October 20, 1964, in his Waldorf Towers suite, death came to Herbert Clark Hoover, 31st President of the United States. At his bedside were his two sons, Allan A. and Herbert Hoover, Jr. Many years of humanitarian and public service earned him the gratitude of millions here and abroad. The Nation mourned his death. For the mining fraternity and AIME in particular, the life of Herbert Hoover held particular meaning. During the years from 1895 to 1914 when he was actively engaged in mining, he conducted himself with extraordinary competence, energy and integrity. In the years following, when his qualities of administration and leadership literally forced him into the limelight, he continued his interest and lent his talents for the benefit of the engineering profession.

Jan 11, 1964

By R. W. Raymond

HAVING had recently the opportunity of examining a transit and a plummet-lamp, manufactured by Messrs. Heller & Brightly, of Philadelphia, and intended for the use of mining engineers in under-

Jan 1, 1873