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By B. Egeberg

BRITANNIA metal is a white alloy consisting primarily of tin and antimony, the tin greatly predominating. The alloy usually contains a small amount of copper and occasionally very small amounts of one or two, other metals, such as bismuth, zinc, and lead. It is capable of being cold-rolled, it takes a high polish, and it is fairly noncorrosive; properties which make it a popular metal for many household and traveling utensils. Britannia metal is similar in many respects to pewter and has largely replaced pewter in the arts, but it should not be confused with that alloy, because pewter is essentially a tin-lead alloy, while Britannia is a tin-antimony alloy. In view of the fact that so little has been published concerning Britannia metal, the authors feel justified in presenting the results of their investigation, particularly since the behavior of this alloy under cold rolling and heat treatment differs so greatly from that of other metals and alloys. The old craftsman, engaged in the making of ornaments or tableware, heated the cold-rolled sheet metal or his finished product to a straw color corresponding to about 375° F., claiming to produce thereby a harder and more rigid article. The fact that possibly led him to this heating was that a reheated article or sheet made from Britannia metal has a distinct metallic ring when struck a sharp blow, whereas an unheated article or sheet has a leady, dead note. No doubt he has associated the metallic ring with a greater rigidity and strength, and justly so, as will be seen later.

Jan 1, 1928

By Alan E. Gallie

SHERRITT Gordon Co. was formed in 1927 to exploit a copper zinc orebody located in the bush 90 miles north of The Pas, Manitoba. The mine went into production in 1931, operated for a year and a half, and closed because of the low price of copper. Reopened in 1937, it operated continuously until mined out in 1951, producing 8.5 million tons of ore. From 1937 on Sherritt Gordon conducted an energetic prospecting program throughout northern Manitoba, giving particular attention to the belt of favorable greenstone rocks north of the Churchill River. From 1937 to 1941 a number of gold showings were located but nothing of economic value was found.

Jan 3, 1957

By H. S. Rankin

THIS paper is condensed from several reports by members of the staff of the Minerals Testing Laboratory of the Tennessee Valley Author-ity, on a series of experimental tests in the beneficiation of barite of the Valley area. These experiments were conducted upon a large number of samples taken from several mines in three different districts. The area contains numerous producing deposits, nearly all of which are hampered by the high iron and silica content of the ores. Because of the small difference in specific gravity between the iron oxide and the barite, a gravity separation is generally poor. The removal of the iron thus offers a special problem. Some of the operators have turned to magnetic separation to meet the shipping requirements for less than one per cent iron. The present experiments were conducted to determine the application of decrepitation or flotation in simplifying the concentra-tion of the barite by removing the iron oxide and silica in one operation. Practically all the barite marketed in the area has been as "off-color" crude. The bleaching studies were made to determine the bleach-ability of the ores to alleviate this inferior grading, placing them on the market as bleached barite.

Jan 1, 1938

By Akira Ishizu, Nobuo Matsui, Tatsuya Nagahama

In the concentrator of Kamioka Mine, lead-zinc bulk differential flotation is practiced. It results in three kinds of thickener over- flow, namely; tailing, lead concentrate and zinc concentrate, which are discharged as wastewater. Since these three kinds of overflow differ from each other in water quality, they are separately recycled to appropriate processes based on their water quality. The tailing and the lead concentrate thickener overflow are directly recycled to their respective suitable processes. However, as the zinc thickener overflow contains Cu(CN)3--, ZnS, CdS, CN-, xanthate and frother, the total zinc thickener overflow cannot be recycled at one time to any one process without creating harmful effects. Consequently, all the ingredients in the zinc thickener overflow other than CN- are floated by Ion-Precipitate-Ultrafine-particle flotation, using Nagahm flotation machine. After this treatment, the zinc thickener overflow, containing only CN-, is effectively recycled to the lead-zinc differential flotation circuit. Thus the integrated recycling of waste-water greatly reduces environmental problems, and in addition it generates a sizeable profit by improving overall mill recovery, and permitting the reduction of reagent consumption.

Jan 1, 1976

Diffusion in Solid Metals. BY ROBERT F MEHL (Institute of Metals Division Lecture Tech Pub 726 in Metals Tech, Aug , also Trans, vol 122 22,500 words ) Diffusion in solid metals constitutes one of the important fundamental phenomena in metallurgical behavior Apart from its obvious importance in processes such as chromizing, carburizing, nitriding and calorizing, it plays an important part in the processes of homogenization, age-hardening, and transformations in steel, its scientific importance is no less great Diffusion may occur within a grain, along a grain boundary, or upon a surface, though the exact and even the relative values of these separate processes are known for only a very few cases The requirement of solid solution formation presents the possibility of identifying solid solution phases by a study of diffusion layers Some distortion accompanies diffusion, leading to little¬ understood grain-size changes Distortion assists diffusion though usually it dis¬appears before diffusion has become extensive In a binary system the rate of diffusion is the more rapid in the lower melting metal Many of the published data are too qualitative to permit sound scientific conclusions Age-hardening data may be treated as diffusion data and rates of reaction in steel could profitably be studied from this point of view Studies on diffusion are of great importance to the develop-

Jan 1, 1937

R. S. Shoemaker: Our first question is, is there a need for a grizzly before a primary crusher? What is its effect on crusher capacity and crusher maintenance? Is it worth the extra capital cost in a crusher installation? Vincent: ASARCO has a grizzly at Mission. Utah Copper uses grizzlies ahead of their gyratories. There is some quite abrasive ore at Mission, an argillite type of rock, which has a work index of 16.5 to 20, which is getting up toward the taconite classification. We get a life of 12- 16 million tons per set of concaves or per mantle with the grizzly ahead of the crusher. At Duval Corp., some 6 miles to the south of Mission, their crusher installation on a good, hard rock does not have a grizzly, and the last information I had is they get a life of about 2 ½ -3 million tons on their mantle and concave. At Silver Bell, our other copper unit in Arizona, they do not have a grizzly ahead of the gyratory and there they get a life of about 5-6 million tons. At Utah Copper, which we all know is a fairly soft ore, relatively speaking, they get a life of 24-27 million tons with grizzlies ahead of the crushers. I think a grizzly has a very definite effect on the life of the mantle and the concaves. As far as a jaw crusher is concerned, I think that usually it is desirable to have a grizzly if it is properly designed, which means it is self- cleaning. Otherwise I would not like to see one in the circuit.

Jan 9, 1967

By H. W. Norman

DURING the first few years of the new atomic age the Colorado Plateau was the focal point of uranium exploration. There was little incentive to expend time and effort in an area so far removed from the known deposits as the Pacific Northwest, and there were too few local prospectors to cover the vast territory involved. In 1949 the AEC established an exploration office in Spokane to evaluate the uranium potential of the northwestern states. Interesting occurrences were found in the Coeur d'Alene district in Idaho and in the Boulder Batholith of central Montana, but the AEC discontinued the Spokane office in 1952, and for the next two years prospecting in the area was negligible. In April 1954 John and James LeBret, prospecting on the Spokane Indian Reservation with an ultra violet lamp, located an occurrence of the fluorescent uranium mineral autunite. This discovery was not announced until the following September, after a lease had been granted by the Spokane tribe. Exploratory drilling carried on by the AEC throughout the winter verified the existence of a commercial orebody. This property, the Midnite mine, has since developed the largest known ore reserve in the district.

Jan 6, 1957

By Charles W. Schwartz, Subash Kolluru

INTRODUCTION Creep of rock in situ, like most rock mass behavior, will be largely governed by the behavior of the natural discontinuities -- bedding planes, faults, and joints, in particular, Several past studies have investigated various aspects of the time-dependent deformation of rock discontinuities; examples include Amadei and Curran (1980), Engelder and Scholz (1976), Johnson (1975), Kaiser and Morgenstern (1979), Solberg et al. (1978), and Wawersik (1974). These studies have provided much insight into the general phenomenon, but they have also produced some inconsistent conclusions and left many unanswered questions. This paper will attempt to shed some light on one of these questions: What is the influence of stress level on the creep of unfilled rock joints? The discussion will follow a two-part approach to the problem: (1) laboratory creep experiments on small scale jointed specimens, (2) a simple theoretical mechanism to explain, at least in qualitative terms, some of the results from the experimental program. EXPERIMENTAL PROGRAM Uniaxial creep tests were conducted on intact and jointed samples of a specially formulated gypsum plaster "synthetic rock." Synthetic rock materials have several advantages over natural rock for long-term creep testing: (a) higher creep rates, (b) lower strength and therefore lower loading requirements, (c) simpler specimen preparation, and (d) more controlled and consistent properties. Gypsum based plasters have been used previously in studies of short-term strength and deformability of jointed samples (Patton, 1966; Einstein and Hirschfeld, 1973). Furthermore, Williams and Elizzi (1977) demonstrated that natural gypsum, at least, creeps in a manner similar to that of most other creep-susceptible natural rocks.

Jan 1, 1982

By W. L. Watts

The existence of petroleum in California has been known for many years. From time immemorial the California Indians used this mineral, in the form of asphaltum, for various purposes. In the early history of the State the Catholic fathers utilized it for roofing their missions and other buildings. It is said that in 1855 or 1856 Andreas Pico distilled petroleum on a small scale for the San Fernando Mission. He obtained his crude oil from Pico canon, near Newhall, in Los Angeles county; and he was probably the first refiner of petroleum in this State. In 1856 a company commenced work at the La Brea ranch, in Los Angeles county, and tried to refine the crude oil. In 1857 an attempt was made to produce illuminating-oil from crude petroleum at Carpenteria, in Santa Barbara county; and there are records of similar attempts in other localities previous to 1860; but none of them were successful. The first scientific report on petroleum in California was made by Prof. B. Silliman, who published his researches in 1865. He spoke favorably of the possibility of obtaining petroleum in remunerative quantities in this State, and gave the results of his experiments in the fractional distillation of California petroleum. The next decade was marked by a considerable oil-excitement in California; and a great many companies mere formed for the purpose of petroleum-mining and for distilling crude oil. In most instances these companies did not meet with success; but it must be remembered that the pioneer oil-miners did not

Jan 1, 1900

By T. Tanaka, H. Kiuchi

The combination of the following two exothermic reactions was studied with the purpose of recovering H2 from H2S formed in acid leaching of sulfide ores, direct reduction of metal sulfides with H2 or desulfurization of crude oils: In the kinetic study of the recovery of H2, the reaction rate was measured by the two methods of single-stage and circulation blowing of H2S through molten Pb in the temperature range of 550 to 750°C. The experimental results showed that the rate determining step is in the chemical reaction itself and also that this reaction is accelerated markedly by the addition of a trace of Ni, which may be responsible for the catalytic action of Ni dissolved in molten Pb. In the experiments where Pb metal was produced, PbS was oxidized in a stream of atmospheric N2 containing 0.5 to 20 vol-% 02 or in the same 02 partial pressures as in N2 though under reduced pressures in the temperature range of 400 to 800°C. It was found from these experiments that the formation of PbSO4, basic sulfates and PbO are suppressable to yield Pb metal alone above 750°C and for 02 concentrations of less than 1 vol-%. Vapor of PbS was thought to take an important part in the Pb formation mechanism, and the probability thereof was demonstrated thermodynamically.

Jan 1, 1978

By H. B. Charmbury, D. R. Mitchell

Recovery of fine coal from solids reporting to wash water has become increasingly important. These solids range from about 28 mesh to 0 and constitute 3 to 7 pct by weight of the feed tonnage to a coal preparation plant. In the past they were usually wasted to streams, but present clean stream legislation makes it necessary to remove them from the wash water and, if economically possible, recover the associated coal as a saleable product. Where these solids are not wasted to streams or to slime ponds they are recovered by thickeners and filters. Since filter cake is often high in ash or sulfur, or both, it is not readily marketed or used. Common practice is to mix it with other plant products, generally slack or cleaned run-of-mine. Uniform blending is difficult, not only because the impurity is usually high, but also because during certain operating periods it is possible to get a concentration of this filter cake in a railroad or barge. At some plants filter cake has been derived from the froth flotation clean-up of Dorr thickener underflow. The operating circuits required for a froth flotation plant make this a comparatively high-cost treatment, and in the last few years experiments have been carried out with bulk oil methods. These also are quite expensive and lend themselves only to special situations. Table I gives some characteristics of thickener underflows for plants in the Pittsburgh area treating Pittsburgh seam coal. It will be noted that there is a concentration of impurities in the -200 mesh sizes.

Jan 1, 1960

By Philip R. Whitney

Deposition of manganese oxides is of common occurrence in streams of the north-eastern United States. Manganese entering the stream in solution in ground water is oxidized and deposited in the stream, primarily as oxide coatings on detrital materials. Prevalence and thickness of the coatings increases with increasing particle size in the coarse sand and gravel range. A number of metals of economic and environmental interest are enriched in these coatings. Samples of 8 to 16 mm pebbles were obtained from two streams in the Shawangunk region of southeastern New York State, an area of know71 Pb/Zn/Cu mineralization. The pebbles were leached to remove the oxide coatings and the resulting solutions analyzed for Mn, Fe, Pb, Zn, Cd, Cu, Co, and Ni. Trace-metal/Mn ratios in these streams are generally one to two orders of magnitude higher than regional background values. Profiles of trace- metal/Mn ratios along the streams show considerable detail; contributions of metals from tributaries are sharply reflected in the metal content of the oxides. The potential advantages and disadvantages of using coated stream gravel for geochemical prospecting and environmental studies are discussed in the light of these and other data.

Jan 1, 1976

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members) The following is a partial list of members and guests who called at Institute headquarters during the period Mar. 10, 1917, to Apr. 10, 1917. George S. Blair, Pittsburgh, Pa. E. P. Mathewson, Toronto, Canada. H. M. Boylston, Cambridge, Mass. T. Poole Maynard, Atlanta, Ga. F. J. Brule, Toronto, Canada. . W. J. Mead, Madison, Wis. M. B. Cohen, Miami, Ariz.. D. G. Miller, Denver, Colo. W. M. Corse, Buffalo, N. Y. P. N. Moore, St. Louis, Mo. F. G. Cottrell, Washington, D. C. R. H. Morris, Ansted, W. Va. E. C. Cross, Cleveland, 0. W. J. Morrison, Toronto, Canada. Nelson Dickerman, San Francisco, Cal. M. F. Ortin, Petrograd, Russia. F. N. Flynn, Chuquicamata, Chile. G. W. Paymal, New York, N. Y. F. L. Garrison, Philadelphia, Pa. Edward H. Perry, Boston, Mass. J. S. Grasty, Charlottesville, Va. 0. G. Petersen, Somerset, Ky. H. D. Hibbard, Plainfield, N. J. H. C. Price, Bartlesville, Okla. H. L. Hollis, Chicago, 111. C. A. Richardson, Toronto, Canada. F. H. Jackson, Marysvale, Utah. Hallet R. Robbins, Vancouver, B. C., Can. W. Strickler Jones, Silver City, N. M. A. H. Rogers, Boston, Mass. E. B. Kirby, St. Louis, Mo. H. G. Smith, Princepulca, Nic. J. M. Lovejoy, Electra, Tex. Edwin G. Steele, Van Horn, Tex. A. F. Lucas, Washington, D. C. 'S. A. Taylor, Pittsburgh, Pa. Edwin Ludlow, Lansford, Pa. A. P. Thompson, Salt Lake City, Utah, E. Francis McCrossin, Birmingham, Ala. Milton A. Allen is now engaged in the New York office of Messrs. Arthur L. Pearse & Co. Percy E. Barbour, managing editor of the Engineering & Mining Journal, has been appointed, by Governor Whitman, Deputy Superintendent of Police of the State of New York.

Jan 6, 1917

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 J. Landau, A. Dim, R. Houlihan

Recent developments in the application of solvent extraction in hydrometallurgical processing make it desirable to reassess the present state of availability of suitable equipment for these applications. The range of solvent extraction applications now includes very large scale applications with a modest demand on separation performance (the treatment of some base metals) and applications in which the decisive factor is a very high requirement on separation performance. The extraction column to be described in the present paper is of the type in which mechanical energy is provided for the two- liquid system inside the column. The active elements for this are reciprocating sieve plates designed and mounted so as to uniformly load the driving mechanism, to eliminate vibration of the plant, to have sufficient control over the degree of dispersion of the dispersed phase, and to reduce axial mixing effects, which are highly detrimental to the separation performance of production-scale plant. The operating features of the reciprocating-plate column will be illustrated mainly by experimental results obtained on a 4" diameter column in the extraction of uranyl nitrate with TBP. Some mechanical features of the operation of reciprocating-plate columns will also be discussed.

Jan 1, 1973

By Ajoy K. Ghose

INTRODUCTION Longwall mining made its debut in Indian coal mining scene around 1900. Despite this headstart, the application of the method has been slow and halting. Currently, there are some 16 operating longwall faces only in different Indian coalfields contributing to perhaps less than 3 percent of the total underground coal production. Ambitious plans for expansion of longwall mining notwithstanding, apprehensions on the cavability of Indian coalmeasure roof rocks and some unsavoury experiences with face collapses in caved longwalla have impeded wider adoption of the technique. Between 1960 and 1983, some 41 caved longwall faces were worked in Jharia, Raniganj, Karanpura and Korba Coalfields in India, of which 6 faces reportedly had collapsed(1). The first powered support longwall face was started in August 1978 at Monidih colliery which marked a major step forward in the introduction of advanced technological system in Indian coal industry. This paper attempts to analyse critically the experiences with longwall ground control in caved longwall faces in India. Experiences from powered support faces at Monidih, Dhemomain and Pathakhera are synthesized to provide an appraisal of the present status of caved longwall faces under the Indian coalmeasure roofs, which thus far have been characterised as “massive”. The geotechnical site factors at the powered support faces are evaluated and conclusions drawn on the pre-assessment of caving characteristics and support resistance required at the faces.

Jan 1, 1984

By J. H. Johnson, H. J. Schock

The cases of no auxiliary ventilation and ventilation with tubing were mathematically modeled, using a turbulent dispersion model. The Scooptram® used to load is modeled as a variable-speed, variable-strength source of pollutants moving in and out of the dead-ended drift. Model predictions are compared to experimental measurements. A parametric analysis was performed to determine If a relationship existed between C02 and NO levels. It was concluded from this analysis that when modeling a load-haul-dump cycle, it is necessary to use a model that can predict changes in source strength as well as source location. Carbon dioxide was used as a tracer to calibrate the model since, knowing the fuel flow rate, it is possible to calculate C02 production. The model was then verified after this calibration process using additional experimental results. With the calibrated model, it is possible to predict pollutant concentrations at any location in the heading using an engine map and the previously calculated flow field.

Jan 1, 1984

By Mahesh C. Jha

Arsenical gold ores occur in many parts of the world, including numerous mines in Canada and the western United States. Free gold is often finely disseminated in the grains of sulfide minerals, arsenopyrite, pyrite, orpiment and realgar. Generally a sulfide concentrate is produced by flotation. Arsenical ores or concentrates are not amenable to direct cyanidation and therefore are considered refractory. A wide variety of roasting equipment and conditions have been used by the mills to remove arsenic and sulfur from these concentrates. The resulting calcine is easy to cyanide and gold is recovered from the cyanide solution by zinc dust cementation. Room-temperature potential-pH diagrams and high-temperature phasestability diagrams are presented to discuss the chemistry of the gold cyanidation, cementation, and roasting steps in the presence of arsenic. The environmental aspects of arsenic discharge are also included.

Jan 1, 1984

By Frederick T. Fischer

The New Jersey Zinc Company began a program of exploration in Middle Tennessee in 1964. The target horizon of the exploration project has been the Knox Dolomite which is a low-yield aquifer over nearly the entire Central Basin of Tennessee (1). With the exception of a few hundred acres in the Wells Creek and Flynn Creek disturbances (astroblemes?), the Knox Dolomite in Middle Tennessee is known only in subsurface. In January of 1969, New Jersey Zinc announced the discovery of a major zinc deposit near Elmwood, southeast of Carthage. This is on the northeastern flank of the Nashville Dome where the nearly flat-lying beds have an average eastward slope of about 50 feet per mile. The anticipated development of a mining situation has emphasized the significance of hydrologic relationships in the region as a whole and especially in the Elmwood area. These relationships affect several areas of concern which ma be generally grouped into two broad classes; i. e. , (1) Problems of a Public Nature - involving the prevention of the contamination of potable aquifers, the prevention of the contamination of surface waters, the prevention of the capture of presently utilized water, etc.; and (2) Problems of Mining Economics - involving pumping capacity and costs, the possible need for equipment of special composition, underground environmental conditions, etc. Exploration drilling in Middle Tennessee has contributed additional information about the Knox aquifer and

Jan 1, 1970

By F. V. Tideswell

THE suggestion, which appears to find increasing favor, that the elementary composition of coals should be used as the basis of their classification, makes it important that our methods of expressing this elementary composition should be refined. It is doubtful whether many published ultimate analyses of coals are accurate within 1 per cent. carbon. Many are probably as much as 3 or 2 per cent. in error in carbon. It is, perhaps, not always realized that the extreme variation in carbon content over the range of bituminous coals is but 16 per cent. An error of 1 per cent. in carbon on analysis corresponds therefore with one-sixteenth of the whole range, an amount which is unjustifiable even for the application to commercial needs of a system of classification based on ultimate analysis. For the purposes of scientific research such limited accuracy is of little value. The object of this paper is to examine one important source of error in ultimate analysis, that due to the occurrence in coal of inorganic material, and to emphasize the need for the quantitative measurements (of carbon more particularly) on coals to be rendered independent of their contents of such material.

Jan 1, 1928