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By Charles Janin

ONE of the most interesting features of the world's platinum situation has been the steady increase of Russian production, which had dropped to 11,000 oz. in 1920, but increased to 92,000 oz. in 1926, and to probably over 100,000 oz. for 1927. It is ex-pected that Russian production of platinum will, be-fore long, closely equal its pre-war production, or approximately 200,000 oz. annually. The world production before the war was around 250,000 oz.; that for 1925 has been estimated at 160,000 oz., and for 1926 probably 170,000 oz. The consump-tion of platinum has, however, decreased. The esti-mate of the International Selling Agency was a de-mand of 130,000 oz. new platinum against a normal pre-war demand of over 200,000 oz. The high price of platinum during the war gave an added impetus to the search for substitutes for the metal, and sev-eral were developed that are now used extensively in place of platinum. The demand for platinum for high-class jewelry, however, was not greatly affected by the high prices, but "white" gold did replace platinum in the cheaper jewelry. Colombia is the most important producer of plati-num, next to Russia, and the production has increased from around 10,000 oz. pre-war production to 55,000 oz. or more in 1927. In 1924 important discoveries of platinum were made in South Africa. Prior to these discoveries practically all platinum was recovered from alluvial deposits, and the South African opera-tions are first to work an ore profitably for the pri-mary recovery of platinum. A number of companies were formed to develop these deposits, but only a few made any real progress. Total production for 1926 was about 5000 oz. The United States production is unimportant; that in Canada has increased to around 9000 oz., principally as a by-product in nickel-copper ores.

Jan 5, 1928

Economic Significance of High-grade Concentrates BY PAUL M TYLER AND CARLE R HAYWARD (Min & Met, Dec, 563 4000 words) Generally pyro¬mctallurgical methods yield a higher recovery but cost more per ton of ore treated Milling methods are inherently cheaper for the reason that they do not involve dissipa¬tion of heat energy in slag formation, ctc It is vaguely realized that the smelter man could do a better job if he were supplied with purer raw materials but hard¬headed mill men have been offered little inducement to do a really good job of cleaning concentrates To do this may involve some sacrifice in percentage yield and in mill capacity and unless there is a compensating saving in freight and smelter charges, it simply is not good business to go beyond a certain point in the way of making clean concentrate Opportunities exist for eliminating one or more steps in the expensive series of processes for recovering various metals, or at least reducing the volume of materials that has to be handled at the most costly steps The beneficiation of nonmetallic minerals likewise affords numerous examples of over-all economies obtainable through more refined methods of mechanical improvement All this leads to the conclusion that perfecting selective processes for isolating pure minerals (e g, galena) virtually free from other sulfides as well as gangue may be productive of industrial economies Conversely, cheapening smelting methods may invade the field of mechanical improvement of ores but, as Kiphng said, that is another story

Jan 1, 1937

By Paul M. Tyler

YEAR after year, the kaolin industry of the United States has been setting new production records and making better products. High-grade paper, pottery, and rubber clays are produced in this country mostly in the South. Georgia alone contributes over 70 pct and South Carolina almost 20 pct of the total domestic output. Residual kaolin is mined in North Carolina, highly plastic but naturally sandy Tertiary (Eocene) potting clays are worked in north central Florida, and good white clays are produced in several other states, but the main sources of kaolin or china clay have been numerous deposits in the Tuscaloosa (Upper Cretaceous) formation. This formation of generally sandy sediments is called the Middendorf member in older geologic reports and corresponds in age with some of the New Jersey clays. As shown in fig. 1, it crops out almost continuously in a generally southwesterly direction across South Carolina and Georgia and into Alabama. Clay is mined from this formation in all three states but the principal producing centers lie within about 10 miles of a straight line drawn between Aiken, S. C., and a point about 10 miles south of Macon, Ga. The white kaolins of the South were recognized and used prior to the Civil War but suitable treatment processes were not introduced until World War I when imports, chiefly from England, were curtailed. Although imports of high-grade clays were resumed after 1918, the domestic industry managed to treble its prewar production record during the early 1920's and has continued to grow. Whereas the 1909 to 1913 average total production in the United States was only 132,104 short tons valued at $705,352 f.O.b. mines, the output in 1948 was 1,-568,848 tons worth $19,756,738. Paradoxically, it seems in retrospect that the early failure of the American industry to meet foreign competition was due to the superior quality of our sedimentary clays in their natural state. Kaolin, of course, is the principal decomposition product of feldspars which originate in acidic igneous rocks such as granite, aplite, alaskite, granodiorite, quartz porphyry, etc. English china clays occur in residual deposits and before they can be marketed they have to be treated to remove accompanying quartz, mica, and other impurities. Notwithstanding the relatively crude methods employed, the final product is a beneficiated clay which is subject to a certain amount of technical control as to quality and uniformity. Although the naturally concentrated deposits in Georgia and South Carolina contain some of the finest crude white kaolin in the world, even it can be made better by suitable treatment. In recent years well over half of the high-grade china clay produced in the United States has been used in making paper. Some qualities of paper clays are still produced by the dry process, or air flotation, but the paper industry's specifications have grown so exacting that wet processing was adopted and more refined methods had to be perfected. Notwithstanding notable advances in clay-preparation technology during the past decade, or possibly because these advances have implemented and encouraged technologic changes in consuming industries, demand has grown for products of higher uniform quality than can be obtained from even the best natural deposits without rigidly controlled fractionation. Largely as a result of the wide adoption of machine coating for paper, the clay industry has been obliged not merely to eliminate virtually all mineral impurities but also to segregate the clay substance itself into narrow particle-size ranges. By extraordinary coordination of sales effort and production technology, several Georgia companies manage to market a wide variety of specialized joint products but the commercial success of many producers depends upon their mining only the best parts of their deposits and then skimming the cream of this almost pure clay in order to obtain a maximum yield of kaolinite finer than about 2 microns in maximum particle size and possessing low viscosity as well as the more familiar attributes of suitable color and brightness, or reflectance. To the casual visitor from another mineral industry, the kaolin mines and plants may appear to be

Jan 1, 1951

By Paul M. Tyler

YEAR after year, the kaolin industry of the United States has been setting new production records and making better products. High-grade paper, pottery, and rubber clays are produced in this country mostly in the South. Georgia alone contributes over 70 pct and South Carolina almost 20 pct of the total domestic output. Residual kaolin is mined in North Carolina, highly plastic but naturally sandy Tertiary (Eocene) potting clays are worked in north central Florida, and good white clays are produced in several other states, but the main sources of kaolin or china clay have been numerous deposits in the Tuscaloosa (Upper Cretaceous) formation. This formation of generally sandy sediments is called the Middendorf member in older geologic reports and corresponds in age with some of the New Jersey clays. As shown in fig. 1, it crops out almost continuously in a generally southwesterly direction across South Carolina and Georgia and into Alabama. Clay is mined from this formation in all three states but the principal producing centers lie within about 10 miles of a straight line drawn between Aiken, S. C., and a point about 10 miles south of Macon, Ga. The white kaolins of the South were recognized and used prior to the Civil War but suitable treatment processes were not introduced until World War I when imports, chiefly from England, were curtailed. Although imports of high-grade clays were resumed after 1918, the domestic industry managed to treble its prewar production record during the early 1920's and has continued to grow. Whereas the 1909 to 1913 average total production in the United States was only 132,104 short tons valued at $705,352 f.O.b. mines, the output in 1948 was 1,-568,848 tons worth $19,756,738. Paradoxically, it seems in retrospect that the early failure of the American industry to meet foreign competition was due to the superior quality of our sedimentary clays in their natural state. Kaolin, of course, is the principal decomposition product of feldspars which originate in acidic igneous rocks such as granite, aplite, alaskite, granodiorite, quartz porphyry, etc. English china clays occur in residual deposits and before they can be marketed they have to be treated to remove accompanying quartz, mica, and other impurities. Notwithstanding the relatively crude methods employed, the final product is a beneficiated clay which is subject to a certain amount of technical control as to quality and uniformity. Although the naturally concentrated deposits in Georgia and South Carolina contain some of the finest crude white kaolin in the world, even it can be made better by suitable treatment. In recent years well over half of the high-grade china clay produced in the United States has been used in making paper. Some qualities of paper clays are still produced by the dry process, or air flotation, but the paper industry's specifications have grown so exacting that wet processing was adopted and more refined methods had to be perfected. Notwithstanding notable advances in clay-preparation technology during the past decade, or possibly because these advances have implemented and encouraged technologic changes in consuming industries, demand has grown for products of higher uniform quality than can be obtained from even the best natural deposits without rigidly controlled fractionation. Largely as a result of the wide adoption of machine coating for paper, the clay industry has been obliged not merely to eliminate virtually all mineral impurities but also to segregate the clay substance itself into narrow particle-size ranges. By extraordinary coordination of sales effort and production technology, several Georgia companies manage to market a wide variety of specialized joint products but the commercial success of many producers depends upon their mining only the best parts of their deposits and then skimming the cream of this almost pure clay in order to obtain a maximum yield of kaolinite finer than about 2 microns in maximum particle size and possessing low viscosity as well as the more familiar attributes of suitable color and brightness, or reflectance. To the casual visitor from another mineral industry, the kaolin mines and plants may appear to be

Jan 1, 1951

By A. Simkovich, C. W. McCoy

THE relationship among chromium, carbon, and temperature during the oxidation period of stainless steel melting was developed by Hilty et a1 1-3 whose studies were confined to plain chromium stainless steels. The simplified version of their relation is given by the equation:

Jan 1, 1962

By Ira B. Joralemon

INDIVIDUALS and small companies have discovered and brought into production the mining districts of the United States. Hardly an exception comes to mind, save for the disseminated copper properties and the great iron mines. In spite of this fine record that has made possible the industrial greatness of the country, mining by small companies and by individuals has become a vanishing phenomenon. In Nevada, the lair of rugged individualism, there are fewer operating mines and fewer miners than at any time since the 1860's. The situation in other states is nearly as desperate.

Jan 8, 1950

By S. C. Carapella, E. A. Peretti

DURING a literature survey of the indium-zinc phase diagram, controversial reports on the composition of the eutectic point were encountered. The value reported in the investigation of Wilson and Perettil and in a later investigation by Valen-tiner' was 4.0 wt pct zinc. The most recent work recorded on this system consisted of an exhaustive survey of alloys by Rhines and Grobe8 in which they indicate a value of 2.8 wt pct zinc for the eutectic composition. To clarify this aspect of the diagram, a series of alloys were prepared by melting the respective constituents in a glass test tube under a covering of mineral oil and slowly cooling the melt in a furnace. The zinc used was Baker's C.P. and had the following analysis: insoluble in H2SO4—0.0l pct; pb—0.001 pct; Fe-—0.001 pct. The indium, which was supplied by the Indium Corporation of America, had a purity of 99.9'7 pet with the following impurities: Cu—0.002 pct; Pb—0.006 pct; Sn—0.01 pct; Zn—0.01 pct. The alloys were prepared for metal-lographic examination using a technique already reported' and a new value of 2.0 ± 0.1 wt pct zinc was observed. An alloy containing 2.00 wt pct zinc was also made by melting the constituents under a vacuum. In both of these methods of alloy preparation the losses can be kept extremely small. Again, the characteristic eutectic structure was obtained, assuring confidence in this value. The accompanying micrographs are presented in support of this point. Fig. la represents an alloy containing 4.00 wt pet zinc, and reveals excess zinc particles, which precludes the value of both Wilson and Peretti, and Valentiner. Fig. lb, gives the structure of an alloy containing 2.2 wt pct zinc, also showing the presence of excess zinc. Fig. lc is a micrograph of a typical structure of the eutectic observed in several sections of the 2.0 wt pct alloy. In the 1.8 pet zinc alloy, fig. id, the definite presence of the primary indium can be noted. From these re-

Jan 1, 1951

By F. R. Brotzen, A. R. Troiano, E. L. Harmon

Precipitation processes leading to drastic property changes are a frequent occurrence in titanium alloys containing large amounts of the retained high temperature P phase. In order to establish the kinetics and nature of these precipitation processes, a series of Ti-V alloys was studied. Time-temperature-transformation diqgrams were obtained for 12.5 and 15 pct V-Ti alloys. These diagrams consisted of two intersecting C-shaped curves: one in the high temperature region for the euilibrium transformation P +u+P, and another at lower temperatures depicting the formation of the meta-stable transition phase, o. Presence of the transition phase retarded the precipitation of the equilibrium a phase. Deformation of retained P resulted in the formation of the o phase. Reversion and retrogression phenomena of the transition phase were observed. A negative temperature coefficient of resistance was found in quenched alloys containing from 15 to 20 pct V. CERTAIN titanium-base alloys can be heat treated to produce appreciable changes in properties. For example, remarkably high hardness values may be obtained by aging or isothermal quenching treatments. Most of the information available to date on the hardening of titanium-base alloys has been systematized recently in an article by L. D. Jaffe.' It was pointed out by that author that the hardening was the result of the decomposition of the retained j3 phase to the equilibrium constituents, a and p, and that this decomposition had many of the characteristics of an age-hardening reaction. Recent work by Frost et al.' 3 has contributed much to the fundamental understanding of the hardening mechanism in titanium-base systems. These authors established the presence of a transition phase in the transformation from j3 to a + j3, which they designated o. The transition phase, in their opinion, was at least partially responsible for the hardening and embrittling effects which accompanied low temperature aging. The present investigation of the mechanism and kinetics of the hardening reaction was carried out for the Ti-V system. Ti-V alloys were ideally suited for a study of the decomposition of j3, since age hardening was known to occur readily in this system." Moreover, no intermetallic compounds occur in this system, Fig. 1, thus simplifying the interpretation of the results. Material and Procedure Alloys containing 12.5 and 15 pct V were prepared by Battelle Memorial Institute from iodide titanium furnished by Watertown Arsenal and vanadium of 99.8 pct purity. Ingots of 8 Ib each were prepared by arc melting in an inert atmosphere with a tungsten electrode and water-cooled copper crucible. Each of the ingots was melted once, forged at 1600°, and rolled at 1400°F. Following this, the ingots were remelted, forged, and then rolled to % in. sq bars, which were subsequently grit blasted, pickled, and wire brushed. Another set of alloys containing nominally 17.5 and 20 pct V was produced by the Research Div., New York University. These alloys were arc melted in an inert atmosphere in lots of 20 g each. Heat-Treating Procedure: Whenever feasible, specimens were heat treated in high vacuum resistance furnaces at pressures below 5x10." mm of Hg. Aging and isothermal quenching treatments were generally carried out in salt baths. Specimens were not attacked by the salt, provided the tempera-

Jan 1, 1956

By Donald L. Katz, Leslie J. Noaker

Experimental data are presented for hydrate formation conditions for mixtures of hydrogen sulfide and methane. Vapor-solid equilibrium constants for hydrogen sulfide are also presented. Equilibrium constants, defined here as the ratio of the mole fraction of hydrogen sulfide in the vapor phase (dry basis) to the mole fraction of hydrogen sulfide in the solid phase (dry basis), were calculated using the vapor-solid equilibrium constants for methane presented in an earlier paper. The conditions at which a natural gas will form gas hydrates with water may be computed from its composition, when hydrogen sulfide is present in addition to carbon dioxide and the paraffin hydrocarbons. INTRODUCTION Many gases are known to form solid hydrates in the presence of liquid water at temperatures above 32°F. This hydrate formation is of importance to the natural gas industry inasmuch as most of the constituents found in natural gases will form hydrates. The attention of the industry was called to hydrates by Hammer-schmidtl0 in 1934. A number of papers have been written giving the temperatures and pressures at which these hydrates will form3,4,5,6,7,8,9,10,13,14,15,18,19 and a bibliography on the subject has been compiled13. Deaton and Frost4,5,6,7,8 report work for various pure gases and for some natural gases. Katz and co-workers3,4,13,14,18,19 have reported data for various gases at high pressure. They developed a method of predicting conditions for hydrate formation from equilibrium constants3,19 and from gab gravity." The effects of anti-freeze agents on the formation of hydrogen sulfide hydrate were reported by Bond and Nelson.' The hydrogen sulfide-water system, including hydrate, has been the subject of recent investigation by Sage and co-workers." Mixtures of hydrates behave as solid solutions and an equilibrium exists between the vapor phase and the solid phase that appears to be comparable to the equilibrium between vapor and liquid phases.3,10 By means of the vapor-solid equilibrium constants which have been published for methane, ethane, propane, iso-butane, and carbon dioxidel6 it is possible to determine the temperature and pressure at which hydrates will form for a specific gas mixture when water is present. Hydrogen sulfide which is frequently found in natural gases has a very strong tendency to form hydrate and must enter the solid solution when present in a natural gas forming a hydrate. To determine the effect of hydrogen sulfide when computing the conditions for gas hydrate formation, it is necessary to have the equilibrium constant giving the ratio of the concentration of hydrogen sulfide in the gas phase to the concentration in the solid phase. This paper presents data on hydrate formation for mixtures of hydrogen sulfide and methane and presents the equilibrium constants which were calculated from these data. EXPERIMENTAL PROCEDURE The apparatus used to determine the conditions of hydrate formation for the methane-hydrogen sulfide system was similar to that employed by previous investigators.3,18,19 A charge gas cylinder was used to supply the hydrogen sulfide-methane mixtures, called the charge gas, and to supply the pressure up to 1.000 psia. This

Jan 1, 1955

Much has been written in the past about the non- cataracting ball mill as typified by the installations of the Tennessee Copper Co. at Copperhill and the three units of the Cleveland-Cliffs Iron Co. in its Humboldt and Republic mills. Because no direct comparisons are available from the Cleveland-Cliffs plants and because the published data of Tennessee Copper Co.'s London mill covered a period of development over several years, it has been difficult for engineers to grasp the full significance of the non-cataracting economics.

Jan 11, 1957

By William B. Plank

For the first time in four years the number of mineral engineering students in the 228 engineering colleges of the U. S. and Canada exceeds 10,000. According to figures just released by the American Society for Engineering Education, the current enrollment of all engineering students is 222,178. The total of 10,274 mineral engineering students, undergraduate and graduate, is a 4% pct increase over a year ago. Total engineering is 11 pct larger than last year, about the same as in 1949-50, and 24 pct above 1950-51.

Jan 4, 1955

By R. McDonald, B. C. Maine

CERRO'S power system consists of three main hydroelectric plants and one steam-electric plant. These are located on the eastern slope of the main Andes range at altitudes between 12,000 and 13,000 ft. The hydroelectric group utilizes the watershed which extends for about 150 kilometers south from Cerro de Pasco, divided into two catchment areas which lie adjacent. The northern area serve,, the medium-head plant of Mal¬paso. while the southern area provides for the high-head plants at Pachachaca and Oroya. The rainfall, as registered at the rain gauging stations of the three hydroelectric plants, averages 33 in. per year; all these stations are subject to the same hydrological conditions, and the bulk of precipitation occurs between October and March. Rainfall during the dry season, April till September, has no appreciable effect on the total annual runoff. Table 1 shows the storage capacities of the main reservoirs of the hydroelectric group. The four plants are tied together electrically by a 50-kv. transmission network, the system being 3-phase 3-wire at 60 cycles with a solidly grounded

Jan 1, 1945

FRED. MACCOY, Raton, N. M. (written discussion *).-In the review of the Chilean nitrate industry presented by Messrs. Rogers and Van Wagenen, the most critical point relating to the future of the industry has been summed up in the last paragraph: when nitric acid can be produced synthetically cheaper than from the Chilean deposits, the Chilean industry will cease. A study of the prevailing mining methods and extraction process leads one to suspect that much can be done to reduce the present cost of the finished product; and a reasonable reduction of the cost would make available immense reserves of low-grade caliche, the locations of which are fairly well delimited. In a study of costs, one finds that actual data are very hard to procure. The average operator does not know, with any degree of reliability, his "head assay," what percentage of the caliche is lost in mining, nor what tonnage of caliche he is putting into the maquina. One manager remarked to me, "We are not concerned in what it costs to treat a ton of caliche, we are interested only in what it costs to, produce a quintal of' finished nitrate." Apart from the crude methods of mining, and the inefficient work in extraction, attention is at once drawn to the fact that the 40d., stated as the cost of the nitrate at the plant, has become 80d. by the time it is on board ship. Of this 100 per cent. increase in value, 70 per cent. is

Jan 4, 1918

By Eugene Guccione

FOREWORD-In an interview published in the May 1975 issue of MINING ENGINEERING, one of the world's most respected scientists, nuclear physicist Hans Bethe discussed the reliability of nuclear power plants and their unmatched safety record. The Nobel laureate also refuted the anti-nuclear lobby's claims that nuclear plants emit harmful radioactive effluents. When asked whether the US has sufficient uranium resources, Dr. Bethe replied that "it depends on the time of introduction of the commercial and advanced breeder reactors which, in effect, can generate more nuclear fuel than they consume." The United States has enough U3O8 to last until the breeders can take over in 1995, said Dr. Bethe. But lie warned that extensive environmental damage would be caused if "environmentalists" succeed in delaying the development of the breeder. Any such delays, he noted, would vastly increase the demand for U3O8 in conventional reactors; this, in turn, would impose an immense burden on the US uranium mining industry, which would then have no alternative but to mine the low-grade Chattanooga deposits.

Jan 4, 1977

By AIME AIME

THE year 1940 was an important one in the life of Carl Swartz. At the annual Institute meeting in February of that year, he was inducted into the office of Vice-Chairman of the Institute of Metals Division, and a few months later he assumed another and possibly even more important responsibility-he became the son-in-law of Robert H. Leach, genial vice-president of Handy and Harman, who had just ended his term as Chairman of the Division. The young man who took on this dual obligation in 1940, and who is now commander-in-chief of I.M.D., was born near Danville, Ill., and graduated with honors from the University of Illinois in 1923. (Ed. note: It's a small world. About the time Carl was a freshman in high school at Danville, or slightly before, the University of Illinois students held beer parties in Danville's hotel. We know; we were there.) Continuing his education at another of our fine Middle-Western colleges, Carl received his Master's degree from the University of Wisconsin and his Ph.D. from the same school in 1926. For the next nine years he worked in that splendid training school for non-ferrous metallurgists-the research laboratory of the American Smelting and Refining Co., at Barber, N. J., leaving there in 1935 to take the position of metallurgist of the Cleveland Graphite Bronze Co. in Cleveland, where he is still working (in a modern, air-conditioned office and laboratory) today.

Jan 1, 1942

By Robert W. Hunt

THE first pump of this character, made by H. R. Worthington, and, so far as the writer is informed, the first and only one of this kind ever constructed, is now in daily use in the above-named works. The water-pressure necessary for the working of the hydraulic machinery of this plant had been supplied, up to the time of the building of this pump, by two Worthington Duplex High Pressure Pumps, having steam-cylinders of 20 inches diameter and 12-inch stroke, with water-plungers of 72 inches diameter; eight inlet and eight outlet valves of 22 inches diameter, and pumping into a 6-inch pipe. These pumps required a large amount of steam, and, in consequence of the various additions to their duty, their capacity became far short of the work required. In preference to putting in another engine of the same class, it was decided to accept Mr. Worthington's proposition to build the compound one under description, he guaranteeing that it should be equal to the demands of the works, and at the same time cause a saving of from 5 to 6 tons of coal per day from the amount required to run the two old pumps. The new engine has been in operation about one month, and so far has exceeded the most sanguine expectations. It consists of two high-pressure cylinders of 21 inches and two low-pressure ones of 36g inches diameter, by 36-inch stroke, with water-plungers of 91 inches diameter. There are two air-pumps of 20 inches diameter by 18-inch stroke; the condenser being 24 inches diameter by 60 inches high. Both cylinders are jacketed with wood and felt, and the low-pressure cylinder also with live steam. The high and low pressure steam-cylinders are in line and immediately adjoining each other, while the inconveniences attending an internal stuffing-box are avoided by having two piston-rods for each of the low-pressure cylinders, running through stuffing-boxes on the outside of the smaller high-pressure ones. The steam-valves are very ingeniously designed balanced

Jan 1, 1876

NEARLY one hundred members of the Mining and Metallurgical Society of America and friends of Professor Peele met at dinner at the Aldine Club, New York, on the evening of April 26, to take part in the ceremonies attending the presentation of the Society's annual gold medal. This had been awarded to Professor Peele by the Society in recognition of his laborious and painstaking work as Editor-in-chief of the monu-mental "Mining Engi-neers' Handbook. Carl A. Meissner acted as toastmaster. W. Y. Westervelt, a student and lifelong asso-ciate of Professor Peele, then recounted some of his friend's early exploits, be-ginning with his mining adventures in the paternal cellar, whereby the neces-sity for adequate ventilation was indelibly impressed on his mind. Graduating from the Columbia School of Mines in 1883, Robert Peele for several years followed the typical mining career, as assayer and superinten-dentatan outlying Colorado mine; mill foreman and assistant superintendent of the Silver King, in Ari-zona; in charge of a mine at Fairplay, Colo.; and superintendent for the Ore-gon Gold Mines Co., at Cornucopia. At intervals during this experience, he spent parts of four years on two mineral investigations m in Peru, Bolivia, Colombia, and Dutch Guiana. He i was called to Columbia as Adjunct Professor of Mining in 1892, and became Professor in 1904. During his sabattical leave in 1903 he travelled around the world, r stopping at some of the most important mining cen-ters, and in 1910 he renewed his acquaintance with South Africa and South America.

Jan 6, 1923

By John Dasher, M. C. Chang

The Crucible mine in Pennsylvania, operating on Pittsburgh seam coal, is rated at 5000 tpd. The washing plant, built in 1943, is rated at about 400 tph, using hydroseparator boxes to wash the coarse coal (4 x 5/16 in.) and hydrotator units for the fine coal (5/16 x 0). It is generally acknowledged that gravity concentration equipment cannot be used efficiently to beneficiate coal finer than about 65 mesh. Before the present flotation circuit was installed, Crucible recovered its fine coal slurry, predominantly -24 mesh material, by passing it through a battery of five 14-in. and one hundred and ten 3-in. Hey1 & Patterson cyclones in parallel with a 75-ft Dorr thickener. About two thirds went to the cyclones and one third to the thickener. Underflows from cyclones and thickener were filtered, respectively, in one 12-disk Eimco and two 4-disk Oliver filters fitted with stainless steel cloth. The resulting cakes were added to the coarse metallurgical coal. The filtrates, overflow from the 3-in. cyclones, and thickener overflow were recycled to the coarse coal plant.

Jan 3, 1959

By P. C. Keith

IT is difficult to talk about atomic energy and the engineer without repeating a number of phrases that have been worn smooth with use Mr John M. Hancock has spoken to you of the two-sidedness of atomic energy, one useful, and the other destructive. If a control plan of the type that he has outlined is adopted it will be perfectly possible to go ahead with the peacetime development of atomic energy Failing the adoption of such a plan, emphasis will of necessity be placed upon the perfection of atomic energy as a weapon of destruction I want to speak, however, in the hope that atomic energy will be developed for peace-time use, and speak about the role of the engineer Before I can do that I must, outline the framework within which the engineer must work, and then I would like to go back and tell of some of the things that he has done, in the hope that that may throw some light on what he may be expected to do in the future Last year the McMahon Committee the Senate Committee charged with drafting domestic atomic-energy legislation-held extensive hearings in an effort to strike a balance between the negative attitude of what to do about atomic energy and the positive attitude of what to do with it Out of these hearings grew the United States Atomic Energy Act, calling for a civilian commission to exercise control over all atomic-energy activities in this country As you

Jan 1, 1947

Crushed limestone is now being "de-dusted" at the Warner Co. plant in Bellefonte, Pa., by a new high-efficiency classifier utilizing aerodynamic principles not previously employed in classifiers. Crushed limestone for certain glass industry requirements must not have more than 10 pct fines in the overall aggregate, and it is the function of the new-type classifier to separate these fines from the coarse material. During the development of this classifier by the Buell Engineering Co. of New York, it was found to have possible applications for separating pulverized coal, sintered metals, ores, mineral flours, and fillers, among other items. Limestone from Warner's deep mine is initially crushed and particles larger than 3/8-in. mesh are burned in kilns to provide calcium oxide for the chemical industry. The 3/8-in. screenings are dried and crushed to -16 mesh for use by the glass industry. For those applications requiring a minimum of fines, no more than 10 pct -100 mesh material is allowable in the end product. Hence the need for high-efficiency separation.

Jan 11, 1960