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By Ludwig Schmidt

Large quantities of gasoline are lost each year by evaporation from bulk-storage station tanks. The rate of evaporation from bulk-station tanks is influenced by two principal factors: First, the vapor pressure of the gasoline in the tank; and second, the amount of "breathing" of the tank. The vapor pressures of the gasoline govern the amount of the gasoline vapor in the air-vapor mixture above the gasoline in a tank at a given temperature. This is one of the principal factors in determining the total pressure of the air-vapor mixture within the tank. The "breathing" of the tank is caused by the inflow of air from the atmosphere during certain periods of the day and the expulsion of the air-vapor mixtures at other times, caused by atmospheric variations. The pressure built up within a tank and the amount of gasoline in the air-vapor mixture are both a direct function of the temperature existing within the tank. Therefore, two of the most common methods for reducing evaporation losses from bulk-station tanks are: (1) The use of vapor-tight tanks equipped with relief valves and operated at 1 or 2 ounces of pressure and about 1/2-ounce vacuum; (2) reducing the temperature of tanks and their contents by painting them a light color, by insulation, and in some instances by using water sprays. Water sprays, although effective, usually are too expensive to operate economically. In order to determine and compare the effects of various colors, insulation, and pressure in reducing the evaporation losses of gasoline held in storage in bulk-storage tanks, the Bureau of Mines made observations from May 29 to October 15. 1930, on five horizontal tanks of 12,000-gallon capacity each, which were erected at the plant of Black. Sivalls and Bryson Manufacturing Co., Kansas City, Mo. This report gives in detail the results of these evaporation tests.

Jan 1, 1931

By Robert H. Ridgway

Scrap iron and steel attracted attention during 1937 because of the unprecedented exports and the concomitant agitation in some quarters to prohibit the exportation of this essential raw material except on license by the President. This report does not attempt to analyze the statistics given in the light of the controversy over the limitation of scrap exports, but it is believed that students of this problem will find many essential basic data in the various tables presented herein. This paper presents the results of the third in the series of annual canvasses on the consumption of ferrous scrap and pig iron in the United States. The study was inaugurated in 1935 by the Bureau of Mines in response to requests from trade organizations and others for detailed

Jan 1, 1938

By Robert H. Ridgway

Scrap iron and steel attracted attention during 1937 because of the unprecedented exports and the concomitant agitation in some quarters to prohibit the exportation of this essential raw material except on license by the President. This report does not attempt to analyze the statistics given in the light of the controversy over the limitation of scrap exports, but it is believed that students of this problem will find many essential basic data in the various tables presented herein. This paper presents the results of the third in the series of annual canvasses on the consumption of ferrous scrap and pig iron in the United States. The study was inaugurated in 1935 by the Bureau of Mines in response to requests from trade organizations and others for detailed

Jan 1, 1938

By Anup Tiwari, Khanindra Pathak, BIBHUTI BHUSAN MANDAL

Failure of in-pit overburden dumps in open-pit coal mines causes debris to flow toward the active working face, threatening the safety of people and equipment. The evaluation of the potential mobility of failing mass will aid in hazard mitigation associated with unwarranted dump failure. The potential mobility is shown by mobility ratio (ratio of total drop between debris flow's initial and final deposition points to total travel distance) and runout characteristics. In light of above, a laboratoryscale debris flow flume was developed to investigate the effect of material gradation and slope angle on runout characteristics and mobility ratio. The total mass of experimental debris mix (Q) is fixed at 30 kg with 20% water content. Experiments at three different slope angles (30°, 35°, and 40°) demonstrate that increasing the proportion of fines in the experimental mix increases runout characteristics while decreasing the mobility ratio. The length and area of the runout decrease as the slope angle increases, while the mobility ratio increases. There is a positive correlation between d50 and runout characteristics at a fines content of 0.1Q, but a negative correlation at a fines content of 0.2Q and 0.3Q. Conversely, there is a negative correlation between d50 and mobility ratio for fines content of 0.1Q, but a positive correlation exists for fines content of 0.2Q and 0.3Q. A new index called the fine-to-coarse (F/C) ratio is used to identify the critical value of fines and coarse proportion that causes a transition from dry granular flow to fluidized debris flow.

May 29, 2023

By P. D. Merica

MY remarks are addressed to the question whether a program of international mineral control can effectively serve as a means of maintaining world peace in the kind of world envisaged by the Atlantic Charter. They do not touch the quite different questions whether such control could be appropriately used for postwar punishment of Germany and Japan, or for other purposes. I assume also that the question relates, not to the transition period immediately following the war, but to the more normal years which we hope will succeed this. Finally, they deal primarily with metals and metallic minerals rather than with. oil or coal or other minerals, although they may be applicable also to these other nonmetallic materials.

Jan 1, 1944

By G. R. Fitterer, M. B. Royer

The application of manganese in iron and steel metallurgy is very inter¬ esting historically. In general, ancient- irons and steels contained virtu¬ ally no manganese, probably because the available iron ores contained■only small amounts of the manganese oxides. Occasionally, samples of ancient irons were found to have appreciable amounts of manganese, but their presence is considered accidental and dependent upon the ore available to craftsmen of that time. Two specimens of iron (139;— made in 500 A.D. contained .negligible quantities of manganese. A sample of steel which constituted the base of .the Khan Baba pillar in India was probably processed in 12p B. C. by the1 cementa¬ tion of wrought iron. This material; contained 0.02 percent manganese and 0.70 percent carbon (20) . One Damascus-steel sword forged some time between 11'60 ' and l400 A. D. was found to contain 0.1^-i percent manganese and 0.j6l percent carbon. The manganese content of this bla.de was much higher than that of any other material of this type which has been analysed. In every other instance the manganese content was below 0.02 percent. A cast steel manufactured by the East India. Co. in India in the early nineteenth century, under the name of Wootz steel, contained rather appreciable amounts of manganese. This material was made by melting and refining fairly high-manganese pig iron prepared from high-manganese ore. Heath (106), who was working at the Co. plant between 1S20 and 1S40, was convinced that the manganese content of the steel was the determining fa,ctor in its high quality. He learned of certain difficulties English steel manufacturers were having in making even fair-grade steel, and analyses of the material indicated low manganese contents. This convinced him that.if the use of manganese could be introduced in England its steel would be greatly benefited. In consequence, he moved to England and soon was producing certain grades of ferromanganese for use with the crucible process. He recommended addition of this metallic material to the ingot mold just before pouring. It was soon found that inferior brands of steel containing only traces of manganese could be greatly improved by such additions. All metallurgists of that time became convinced

May 1, 1934

By W. W. Fowkes

The Federal Bureau of Mines examined a low-temperature tar obtained from a small-scale commercial unit for carbonizing North Dakota lignite for products that might be important to the economic processing of the tar. Tie tar may be divided into three distinct parts: (1) Tar acids, 45 volume-percent; (2) tar bases, 1 volume percent; and (3) neutral compounds, 54 volume-percent. It has a boiling range of approximately 150° to 380° C. (the decomposition temperature) and yields 18 weight-percent as hard pitch. The tar distillate up to 365° C. may be separated as: (1) Tar acids, 48 volume-percent; (2) tar bases, 1 volume-percent; and (3) hydrocarbons, 51 volume-percent. The tar-acid distillate, boiling to approximately 265° C., was characterized in some detail; the neutral fractions and the tar bases were less thoroughly examined. In general, as might be expected of a primary low-temperature tar, the lower boiling fractions are less in quantity compared with the usual high-temperature tar. The homologous series of each major class appears to be rather complete, although some components are present in very small amounts. The tar is quite unstable thermally, and might be more conveniently processed by extraction methods rather than by distillation procedures. The neutral fraction of the tar is highly aromatic, and might be considered as base stock for the production of liquid fuels.

Jan 1, 1961

Process variables in flotation circuits are outlined with a view to producing mathematical models of circuits. The nature of the kinetics of flotation are discussed and the effect of process variables on the kinetics considered. An approach for a possible model is briefly outlined.

Jan 1, 1971

By Smith C. B

Major diamond pipes discovered in Western Australia in the late-1970s exhibited a number of unique features that not only resulted in Australia becoming the largest diamond producer in the world in volume terms by 1986 but also changed geological thinking on the primary occurrence of diamond. They were: - lamproite is an alternative primary diamond host to kimberlite. - the extremely high mean grade of the Argyle lamproite pipe at 5 ct per tonne. - the tectonic setting of the lamproite pipes in mobile zones mar- ginal to the Kimberley Craton in contrast to the traditional African setting within stable cratons. Diamond was one of the earliest economic minerals discovered in Australia but 128 years elapsed between its first recognition and the first Australian economic pipe discovery (Argyle). During that period some 200,000 ct of alluvial diamonds were mined in Australia (mostly in New South Wales), but such alluvial output is insignificant on the world scene where annual production today runs at 95 million ct of natural stones some 76010 of which comes from primary pipe sources such as Argyle which alone produces 30 million ct per annum. Of particular significance therefore is the geological nature of the primary diamond source rocks in Australia. The Argyle and Ellendale Pipes are lamproites, differing from kimberlite in their mineralogy and geochemistry, and characterised by the presence of typical lamproite minerals such as leucite, priderite, potassic richterite, and the abnormally high content of chemical elements incompatible with ultramafic rocks. But not yet widely appreciated is that many other Australian olivine-rich lampro- phyres also contain diamond. Such picritic alkaline rocks can

Jan 1, 1988

By F. S. Wartman

Recent changes in metallurgical practice, particularly those in flotation, have altered greatly the functions of the different units of a copper smelter. Gangue minerals are removed from the feed so much more thoroughly that the reverberatory furnace, once virtually a concentrator in which a low-grade ore was concentrated into a rich matte by virtue of the removal of gangue elements as slag, has become very largely a melting furnace in which the rich flotation concentrates are rendered molten so that they may be converted. Moreover, since the proportion of matte to slag in the reverberatory furnace output is greater than it was formerly, the amount of converter slag returned to the reverberatory for cleaning is, in comparison to the amount of slag actually formed in that furnace, also much larger. In some cases, approximately half of the reverberatory dump slag may have originated in the converter. The increase in the proportion of convertor slag to total slag produced has brought about certain consequences not entirely desirable. Converter slags contain a high percentage of iron and therefore are high in specific gravity and are very basic. A considerable guantity of magnetite, both dissolved and suspended as solid crystals, is always a component, The basic nature of the ordinary converter slag and the presence of the suspended magnetite crystals make impossible the reduction of the copper content of the slag below approximately 1 per cent by even the most prelonged settling, and a re-treating process is necessary. At present, general practice in western copper smelters is to return the converter slag molten to the reverberatory furnace. Here dilution by mixing, with slag formed in the reverberatory furnace and reaction with raw sulphides and siliceous materials in the reverberatory feed reduce the magnetite and increase the silicates to the point necessary for a satisfactory dump slag.

Jan 1, 1930

By C. Q. Cupps

n view of increased interest in secondary recovery of oil in the Cut Bank field, Montana, a review has been made of unpublished data obtained during a 1943-44 study of reservoir oil characteristics in this field. Considerable uncertainty was attached to interpretations of subsurface oil sample analyses from six Cut Bank zone wells, one Lander sand well, and one Moulton sand well, because of adverse sampling conditions and wide range in the data. Much of this uncertainty has been removed by this review which has shown two of the Cut Bank zone samples and the Moulton sand sample to be representative of the reservoir oils. Estimates of original reservoir oil characteristics derived from differential-liberation analyses of these samples show that the oil in the Cut Bank zone was initially saturated at the gas-oil contact pres-sure, 750 psia, and the oil in the Moulton sand was undersaturated with a saturation pressure of only 380 psia. The rest of the samples were indicated to be nonrepresentative of the reservoir oils because of a disproportional vaporization of heavier components of the solution gas. The vaporization of these components is believed to be a cumulative effect of contact of the oil with bypassing, light-gravity gas which had been liberated at higher pressures from solution in oil farther back in the formation, or which had come from the gas cap, rather than from the singular effect of gas evolution caused by excessively low bottom-hole pressures. Change of oil composition caused by the latter was found to conform closely to that occurring during a differential liberation of gas in the laboratory.

Jan 1, 1967

By W. O. Philbrook, K. Natesan

The oxidation kinetics of spherical pellets of zinc sulfide made from Santander concentrates were studied using a thermogravimetric technique. The experiments covered a temperature range-. of 740" to 102O°C, 0-N mixtures varying from 20 to LOO pct O2, and pellet diameters between 0.4 and 1.6 cm. Mathematical models were formulated to Predict the reaction rate on the assumption that a single transport or interface reaction step was rate -controlling. Analysis of the data indicated that the process of oxidation was predominantly controlled by transport through the zinc oxide reaction-Product layer. ROASTING processes, which are reactions between solids and gases, are very important because they are employed in the production of a number of basic metals. These processes are highly complicated, and one needs to consider the transport phenomena of heat and mass between the solids and gases in addition to the kinetics of various chemical reactions involved. Because of such complications there is a lack of knowledge concerning the rate-limiting factors, which may strongly depend on temperature, particle size, gas composition, and solid structure. The oxidation of zinc sulfide, which is of commercial importance in zinc production, falls into this class of reactions. The major goal of this work was to elucidate the roles played by different process variables, such as reaction temperature, gas composition, pellet size, and pellet porosity, on the kinetics of oxidation of single pellets of zinc sulfide. Roasting of zinc sulfide single particles has been a subject of both experimental and theoretical investigations.&apos;-&apos; The reaction is exothermic and may be considered to be irreversible. Such a reaction has been found to proceed in a topochemical manner. In other words, as the reaction proceeds, a progressively thicker outer shell of zinc oxide is formed, while the inner core of unreacted sulfide decreases. It has been found experimentally, both in the present work and in the previous investigations,1-9 that the particle retains its original dimensions and the process requires transport of gaseous oxygen across the porous product layer for continued reaction. The reaction may be represented by ZnS(s) + 3/2 O2(g) = ZnO(s) + SO2(g) [1] The solid product considered here is only zinc oxide, since the diffraction patterns of zinc sulfide pellets oxidized partially at &apos;798" and 960°C showed K. NATESAN, Junior Member AIME, formerly St. Joseph Lead Fellow, Department of Metallurgy and Materials Science, Carnegie-Mellon University, Pittsburgh, Pa., is now at Argonne National Laboratory, Argonne, Ill. W. 0. PHILBROOK, Member AIME, is Professor of Metallurgy and Materials Science, Carnegie-Mellon University. This paper is based on a them submitted by K. NATESAN in partial fulfillment of the requirements for the Ph.D. degree in Metallurgy and Materials Science at Carnegie-Mellon University. Manuscript submitted December 2, 1968. EMD lines corresponding to original zinc sulfide and the newly formed zinc oxide. OXIDATION MODEL The generalized model for gaseous oxidation of zinc sulfide is illustrated in Fig. 1. This depicts a partially oxidized sphere of zinc sulfide in a gas stream surrounded by a laminar film of gas. The spherical sample of zinc sulfide of unchanging external radius r0 is suspended in a flowing gas stream of total pressure PT and composition specified by the partial pressures of the individual components. Partial pressures of the gaseous species in the bulk gas phase, at the exterior surface of the pellet, at the ZnS/ZnO interface, and at equilibrium for Reaction [I] are identified by the superscripts b, o, i, and eq, respectively. The overall reaction involves the following ~te~s:&apos;~&apos;~&apos; Step 1. Transfer of reactant gas (oxygen) from the bulk gas stream across the gas boundary layer to the exterior surface of the pellet and the reverse transfer of the product gas (sulfur dioxide). Step 2. Diffusion and bulk flow of oxygen from the pellet surface through the product shell (ZnO) onto the ZnS/ZnO interface and the reverse transfer of sulfur dioxide. Step 3. Chemical reaction at the interface, which results in consumption of oxygen gas and generation of sulfur dioxide gas and heat; at the same time the _________ PARTICLE SURFACE / x^^^^n^X / MOVING INTERFACE core-----/ sJSNxy " /T^T^02 \ V\V$\ ^NWX/ "*/— GAS BOUNDARY x. \\ZnO SHELLV/ / \^ . / &apos; ^ BULK GAS --------N_______ _____,------p£ w \ P« / (f> \ / a \ <i) / <----------------- _(o) ^^--------------(b) °- pso, pso2 ro ri 0 ri ro RADIAL POSITION Fig. 1—Generalized model for oxidation of a sphere of zinc sulfide.

Jan 1, 1970

By Hugh Haddow

This paper describing the methods of recovery and treatment of a sand and gravel deposit and the preparation of these materials for a number of special markets is one of a series being prepared by the U. S. Bureau of Mines. It is of particular interest to those sand and gravel operators who have a surplus of fine sand which must be sent to waste, both from the point of view of, equipment and the variety. of markets supplied, and in that it describes one of the few sand and gravel plants which have resorted to hydraulic classification for sizing fine sand. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance of J. R. Thoenen, mining engineer of the Bureau of Mines, in the preparation of this paper.

Jan 1, 1931

By Eugene Frey

"INTRODUCTION The Blue Bell fluorite deposits were examined in August and November 1944 by an engineer 3/ of the Bureau of Mines, and an underground project was set up. The Bureau of Mines began development of fluorite here February 10, 1945, and completed its survey on June 21, 1946.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepared the final report. The Metallurgical Branch, C. C. Ralston, chief, analyzes samples and perform beneficiaticn tests. The exploratory project was under the direction of Paul T. Allsman, chief, Salt Lake City Division, Mining Branch. Acknow¬ledgment is due R. Thurston of the Federal Geological Survey for mapping the topography of the area, and to F. H. Gunnell and W. A. Young of the divisional office for detailed mapping of the surface and underground development and interpretation of the results.The chemical analyses included in this report was performed under the direction of H. E. Peterson, analytical chemist; the petrographic studies on the ore were written by LaMar Evans, petrographer; and the beneficiaticn section was written by C. H. Schack, metallurgist, under the direction of S. R. Zimmerley, chief, Salt Lake City Division, Metallurgical Branch."

Jul 1, 1947

By Robert L. Tremblay

Dans le but de voir si une région comme la Gaspésie, qui a subi la derniere glaciation , se prête avantageusement à la méthode de prospection alluvionnaire, environ 800 concentrés de minéraux lourds furent prélevés dans les districts électoraux de Matane et de Gaspé-Nord. Les différentes phases minérales présentes dans les concentrés ont été examinées à la loupe binoculaire. Afin de mieux valoriser ce type d&apos;inforrnat ion, nous avons été arnenés à expérimenter et à mettre en oeuvre des techniques multivariables adaptées au traltement d&apos;une information semi-quantitative en utilisant le principe d&apos;un codage logique préalable. La structuration des résultats de la Gaspésie a conduit à l&apos;élaboration de cartes de synthèse qui constituent un support nécessaire à l&apos;interprétatlon des répartitions plus ponctuelles des minéraux "utiles" sur le plan de la recherche minière.

Jan 1, 1978

By A. Matzick

In its work under the Synthetic Liquid Fuels Program the Bureau of Mines has developed on a 6-ton-a-day-pilot-plant scale a continuous, gravity-feed retort far distilling oil from oil shale. The development work covered by this report was done from January 27, 1950, to January 26, 1952, at the ail-Shale Experiment Station near Rifle, Colo. Over 300 pilot-plant tests were made during the investigation. The basic retort developed has been named the Gas-Combustion retort. In this process, part of the heat for retorting of the shale is generated by burning recycled product gas in a combustion zone within the descending shale bad in the retort. Additional heat is supplied by combustion of the carbonaceous residue remaining in the spent shale after the oil has been distilled. Air for combustion is admitted through an air distributor in the center of the bed at about the mid-point of the retort. Hot gas rising from the combustion zone heats countercurrently the descending raw shale and liberated shale oil by pyrolysis of the shale. After passing through and exchanging heat with the incoming raw shale, the oil is condensed as a fog or mist in the gas, which is withdrawn at the tip of the retort. The cool gas is then piped to an oil-recovery system where the oil is separated from the gas in centrifugal separators or other types of mechanical or electrostatic separators. The hot, spent shale below the combustion zone is cooled by heat exchange with recycle gas, which is a portion of the effluent gas from the oil-recovery system.

Jan 1, 1955

By Alan Reed

"Afton Mines Ltd. (N.P.L.) operates an 8500-tpd open-pit copper-gold mine near Kamloops, R.C. The pit is currently 480 feet deep and will reach an ultimate depth of 800 feet. The east, south and west walls of the pit are composed of Triassic andesites (Nicola Volcanic Formation) and contemporaneous sub-volcanic intrusions of micro-syenite, microdiorite, diorite and picrite-basalt (Iron Mask Pluton). The north wall of the pit consists of Tertiary sandstones, shales and mudstones (Tranquille formation) and dacitic dykes, sills, flows and tuff s (Kamloops Volcanic Formation).The Afton copper-gold orebody (30 million tons of open-pit ore with a grade of 1.0 per cent copper, 0.016 oz/ton gold and 0.12 oz/ton silver) occurs within the Triassic Iron Mask Pluton adjacent to its faulted contact with Tertiary rocks. The Triassic-Tertiary contact is a complex fault system dipping 65 degrees southward and causing the Triassic rocks to overlie the Tertiary rocks. The detailed trace of this contact is very intricate due to the mutual interference of three principal fault systems.The dominant geological structures in both Triassic and Tertiary rocks are faults striking WNW and dipping 65 degrees southward, i.e. sub-parallel to the orebody (strike faults). Cross faults and oblique faults are abundant and highly significant in some sectors of the pit. The Tertiary sedimentary rocks show an early series of northwesterly plunging folds deformed by a later series of northeasterly striking folds. Major lithological and structural boundaries divide the pit into 8 structural domain s within which the pitwall slope stability is controlled by the local geological structures and lithology.Assay data from production blasthole samples and exploration diamond drillhole samples show a log-normal frequency distribution, with a fairly low relative variance. Variograms computed from production blasthole samples show good continuity with elliptical horizontal zones of influence which are truncated by the major faults that bound the ore zone."

Jan 1, 1983

By John Dasher

The impetus given to mineral dressing arid chemical engineering by the war has placed many persons without previous experience in positions where they are concerned with the size of solid materials they are testing. Many good textbooks cover this field in considerable detail but are more concerned with the "why" than with the "how" For beginners and those to whom size is not of primary concern, this brief circular has been prepared. Refer-

Jan 1, 1942

By Amado Yataco Medina

Año a año el incremento de muertes por ignición del gas metano o carbón en concentraciones mayores a las soportable, se hace cada vez mayor. Por tal motivo, el presente texto refiere la importancia de las normas de control y seguridad, como las factores sobre la explosividad del polvo del carbon. Entre estos tenemos: la distribución de partículas, composición de polvo, el gas inflamable en el aire, cantidad de polvo, distribución de polvo en la mina, fuentes de ignición, rugosidades de la labor y cambio de sección. Existen dos formas de prevenir dichas explosiones: la primera, es a través de la prevención de acumulación de gas por medio de la ventilación y la segunda, es por medio de la eliminación de las posibles causas de la ignición. Asimismo, se sugiere una serie de recomendaciones de prevención de explosión, como se describe los reglamentos del Código de Minería.

Aug 20, 1965

By Paavo Eerola

In May of 1984, it was decided that Outokumpu Oy would design and build a new nickel flotation mill to process ore from the newly discovered Enonkoski mine in eastern Finland. Since there hart peen a number of successful process charges in the existing mills, the design effort included the study and incorporation of several new developments, including all-autogenous grinding, "flash flotation", lane cell roughing, large cell cleaning and a computer-based, profit optimizing, process control system. The paper discusses the background and results of those studies, and a description of the resulting mill which will begin production in 1986.

Jan 1, 1985