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By Hang Goo Kim

A computer simulation has been carried out to predict the distribution behavior of minor elements such as Pb. Zn, Bi, Sb and As in recently proposed copper smelting and converting processes with submerged oxygen injection in which tonnage oxygen is used with a shielding gas. In this study the technique of stepwise equilibrium modeling was employed and some of the thermodynamic data were updated or reassessed. The volatilization and slagging of undesirable elements were investigated in copper smelting (steady-state) system, copper matte converting (batch) system, and the combined (smelting + converting) system at extremly high oxygen-enrichment levels. The predicted minor-element behavior under high oxygen- enrichment was compared with that in the Noranda process (normally 42% oxygen-enrichment in smelting and 24% in converting) and the reverberatory process using air. The effects of various operating parameters such as temperature, the final matte grade in smelting, the initial matte grade in converting and the O/Fe ratio in slag on the behavior of minor elements are discussed.

Jan 1, 1991

By P. J. Remington

Field measurements utilizing a seat pad accelerometer were made on 61 surface coal mining machines in order to quantify the vibration levels experienced by the operators. Those data were combined with information on the statistics of the operating times of those machines in order to compare the operator's vibration exposure to the criteria in ISO 2631, ?A Guide for the Evaluation of Human Exposure to Whole Body Vibration.? The comparison showed that about ha]f of all surface coal mining machine operators can be expected to be exposed to vibration exceeding the fatigue decreased proficiency criterion, whereas only on the order of 15% would be expected to experience vibration exceeding the exposure limit. Detailed exposure statistics are presented and the implications of the results are discussed.

Jan 1, 1983

By D. R. Tesarik

The factor of safety, the traditional measure of stability for earth embankments, is graphically presented in factor of safety charts in this Bureau of Mines report. Factor of safety contours are drawn for homogeneous earth embankments for two contrasting situations: (1) no phreatic surface and (2) a phreatic surface that assumes 10-pct freeboard. The factor of safety can be read directly from the charts if the physical properties of the soil and the geometry of the embankment are known. The curves provide a quick first approximation of the "most stable" and "least stable" condition of the embankment. The Simplified Bishop Method was used for the safety factor calculations, and a sequence of least squares curve fitting steps was used to present the factor of safety in final chart form.

Jan 1, 1981

This consolidated index covers all publications of the Institute for the years 1926 through 1935. The following list indicates subjects of volumes and gives numbers or abbreviations used to designate them. TRANSACTIONS VOLUME *G26. Petroleum Development and Technology in 1925 (Published in 1926). *G26. Petroleum Development and Technology in 1926. *E27. Institute of Metals Proceedings. 73. Nonferrous Metallurgy, Milling and Concentration, Nonmetallic Minerals, Institute of Metals and Iron and Steel. [ ]

Jan 1, 1936

By Frank J. Cservenyak

Curtailment of bauxite importation by enemy activities during World War II focused attention on the necessity of developing domestic deposits of aluminous materials. Large quantities of aluminum ores such as kaolin, siliceous bauxites, high-iron bauxites, anorthosite, and diaspore clays are available but not readily amenable to Bayer processing because of excessive impurities. The Bayer process, which is the only commercial method in use in the United States for producing metallurgical-grade alumina, requires a high Al2O3 bauxite relatively low in SiO2 and Fe2O3. The Bureau of Mines was charged by Congress to investigate processes for the production of alumina from these low-grade ores. One part of the program was an investigation, in the laboratory and pilot plant, of the recovery of alumina by the lime-soda sinter process. Ores comprising kaolin, diasporic clays, anorthosite, and siliceous bauxites have been investigated and studied in the laboratory and pilot plant, and a series 'of reports covering these investigations has been prepared.

Jan 1, 1948

By R. L. Benner

The Bureau of Mines investigated the ZnO-Fe2O3-Fe3O4 system at 1,000°, 1,300°, and 1,400° C, with oxygen pressures between 1.0 and lx10-4 atmospheres. The results, divided into the thermodynamic properties as related to the spinel structure, and the thermodynamic properties as related to zinc concentrate roasting, were used to calculate the activities of ZnO, Fe2O4, and Fe3O4 within the spinel solid solution region of the ternary system, and the pseudo-binary activities of ZnFe2O4 and Fe304. The activities of both systems show large positive deviations from Raoult's Law, especially at high Fe3O4 concentrations. The free energies, the enthalpies, and the entropies of mixing for the binary system were calculated from the binary activities, and the entropies of mixing were compared with two statistical models, one representing an ideal solution, and one representing the mixing of a normal with an inverse spinel. The binary entropy of mixing seemed to be better represented by the latter statistical model, indicating that the tetrahedral and octahedral cations of the reactants tend to remain in the product, even at the high temperatures of the study. This comparison also indicated that the cations of the components are the major contributing factors to the thermodynamic properties.

Jan 1, 1966

By Bernard G, Limpach R, Ulveling L

A major aspect in competitive ironmaking is to replace metallurgical coke by injecting alternative cheap fuels. Whereas in the past, heavy oil injection as well as on a lower scale natural gas injection have proved to be reliable, the progressing high price level of these fuels has prompted international interest in looking for alternative cheaper fuels, especially pulverized coal. Theoretical analysis and practical operations showed that for constant adiabatic flame temperature, potentially more coke may be replaced by injected coal than by heavy oil, because of less endothermic cracking of hydrogen components. Since about 1974, the ARBED-Group has been looking for alternative fuels and in 1976 came to conclusion to select for first trials pulverized lignite for the following reasons:

Jan 1, 1981

By A. Himsley, E. Byleveld

"With reference to the chemical constraints underlying the ion exchange process for uranium recovery, a generalized view is presented on the actual and the achievable efficiency of the process. The area considered is restricted to acid leach circuits in combination with nitrate, chloride or sulphuric acid elution.A comparison between actual plant results and the chemical requirements shows that:(a) Unless new and better ion exchange resins are developed, no dramatic change in equipment size and resin inventory is""anticipated. (b) Elution efficiency, especially for sulphuric acid, may be improved considerably. More concentrated eluates may beproduced at lower chemical consumption. A possibility of achieving additional purification solely by ion exchange is discussed.IntroductionThis paper presents a generalized view of the actual and the achievable efficiency of the ion exchange processes for urannium recovery. The study is restricted to acid leach circuits in combination with nitrate, chloride or sulphuric acid elution. The ultimate efficiency attainable with ion exchange is dietacted by the chemical reactions underlying the process. The most sophisticated technology cannot change the diffusion rates in the ion exchange resin nor make the uranium loading exceed its equilibrium valueThe design of an ion exchange plant for uranium recovery involves a considerable number of parameters as a result of the wide variety of pregnant solutions produced from different orebodies. Therefore, a generalized approach of the ion exchange process inevitably neglects some parameters which maylead to significant variations in apparently identical situations.The uranium concentration in the pregnant solution, together with its pH, are the principal variables which determine resin loading and residence rime in the ion exchange system. On the elution side, the type of eluant and its concentration will determine the contact time required and the amount of eluant needed to strip the resin. The temperature, the properties of the ion exchange resin, the total dissolved solids in the feed solution and the competing ions are other variables that affect the chemical performance; these, however, may be considered as a correction of the principal parameters if one is interested only in general trends."

Jan 1, 1980

By S. Murdock, R. L. Fleischer, H. W. Alter, J. E. Gingrich

The use of solid state track deters allows totally passive, integrating measurements of 222Rn (radon) or of 220Rn (thoron) plus radon. A track-detecting solid is placed in a holder that is closed by a selective membrane and exposed to the atmosphere of interest to produce an accurately time-averaged record over times of interest that range typically from a week to a year. By selection of the proper membranes, dosimetry can be done for radon or for the sum of radon and thoron. A different membrane is appropriate for measuring radon under humid conditions such as are found in the ground. Large numbers of measurements have been made with these systems both in the ground, where radon levels are high, and in indoor environments, where levels are orders of magnitude less. Calibrations have been carried out at both high and low concentrations of radon. New results in the air at the site of the Shirley Basin mine and mill give reproducible results with month-long integrating periods. The off-site background levels are in the range 0.7 to 1.0 pCi/l (26-37 Bq/m3). The average yearlong on-site level is 1.5 pCi/l (56 Bq/m3); at the mill it is 2.6 pCi/l (96 Bq/m3); and the level measured at the backhoe in the open pit mine is 3.9 pCi/l (144 Bq/m3). The region of significantly elevated radon levels is confined to a radius of 1.6 km of the mine and mill. All of the on-site radon concentrations are less than but comparable to the typical values found in the living areas of modern energy-efficient homes.

Jan 1, 1981

By Alfred H. Bell

Drilling activity increased in Illinois in 1935. There were 34 com-pletions as compared with 26 in 1934 and 18 wells were drilling at the end of 1935. Some large blocks of acreage were leased in Marion and Clay counties near the central part of the Illinois structural basin. Production of oil in the state totaled 4,305,000 bbl., a decrease of 4 per cent from that of 1934 There was some curtailment of production in the early part of 1935 but none after April 30 as shown in the following table. Percentage Pro-duced of Potential ProductioN (USING September 1934 Period as BaSis) Jan. .l-Feb. 20............................................ 79 Feb. 21-Feb. 25............................................ 85 Feb. 26-Feb. 38............................................ 79 Mar. 1-Mar. 11............................................ 85 Mar. 12-Mar. 31............................................ 100 Apr. 1-Apr. 9.......................................... 80 Apr. 10-Apr. 30............................................ 86 May 1-Dec. 31........................................... 100 This is equivalent to an average curtailment throughout the year of 5 per cent. The price of Illinois crude oil at the wells remained constant during 1935 at $1.13 per barrel. A small amount of oil was sold at a 1ower price, notably from the Dupo field, but to arrive at a value for the state's production there would be little error in assuming an average price of 81.13, giving a total value of $4,864,465. The following table shows production in Illinois by moths in 1935, according to the U.S. Bureau of Mines. Jan............. 332,000 May.......... 382,000 Sept ,............. 370,000 Feb............. 295,000 June. ........... 858,000 Oct.............. 391,000 Mar............ 370,000 July............ 377,000 Nov............. 369,000 April............ 338,000 Aug............. 379,000 Dec............ 344,000

Jan 1, 1936

By Alfred H. Bell

Drilling activity increased in Illinois in 1935. There were 34 com-pletions as compared with 26 in 1934 and 18 wells were drilling at the end of 1935. Some large blocks of acreage were leased in Marion and Clay counties near the central part of the Illinois structural basin. Production of oil in the state totaled 4,305,000 bbl., a decrease of 4 per cent from that of 1934 There was some curtailment of production in the early part of 1935 but none after April 30 as shown in the following table. Percentage Pro-duced of Potential ProductioN (USING September 1934 Period as BaSis) Jan. .l-Feb. 20............................................ 79 Feb. 21-Feb. 25............................................ 85 Feb. 26-Feb. 38............................................ 79 Mar. 1-Mar. 11............................................ 85 Mar. 12-Mar. 31............................................ 100 Apr. 1-Apr. 9.......................................... 80 Apr. 10-Apr. 30............................................ 86 May 1-Dec. 31........................................... 100 This is equivalent to an average curtailment throughout the year of 5 per cent. The price of Illinois crude oil at the wells remained constant during 1935 at $1.13 per barrel. A small amount of oil was sold at a 1ower price, notably from the Dupo field, but to arrive at a value for the state's production there would be little error in assuming an average price of 81.13, giving a total value of $4,864,465. The following table shows production in Illinois by moths in 1935, according to the U.S. Bureau of Mines. Jan............. 332,000 May.......... 382,000 Sept ,............. 370,000 Feb............. 295,000 June. ........... 858,000 Oct.............. 391,000 Mar............ 370,000 July............ 377,000 Nov............. 369,000 April............ 338,000 Aug............. 379,000 Dec............ 344,000

Jan 1, 1936

By H. C. George

IN 1901, the United States produced 69 million barrels of crude oil, which was 41.4 per cent of the world production. By 1931, these figures were 850 million barrels and 62.1 per cent respectively, showing over this period of thirty years an increase in the world production of 718 per cent. Over this same period, the increase in the demand for technically trained men in the industry was much greater than the increase in crude-oil production. This was because much of the increase in production was secured by the application of geology and physics to the finding of new oil fields and by .the development of engineering methods and equipment incident to drilling and producing from much greater .depths.

Jan 1, 1934

By N. W. Johnson

The behavior of non-sulphide gangue in chaloopyrite flotation circuits has been investigated. Plant and laboratory tests were carried out on five different ores, and linear relationships were found to exist between the rates of recovery of water and free nonsulphide gangue in the concentrates although there was evidence from pilot plant tests that these were linear approximations to parabolic curves over the limited regions which were observed. There was evidence that the free non-sulphide gangue enters the concentrate by hydraulic classification and a classification function has been proposed to define this behavior. This function is suitable for inclusion in a mathematical model of the process.

Jan 1, 1972

By J. S. Hansen

To advance technology that can conserve critical materials, the Bureau of Mines investigated a cast-on hard-surfacing that wear resistance and confines alloy additions to wear-prone surfaces. Wear-resistant material in form is on a polystyrene , the is embedded in a mold of unbonded s and the wear-resistant material is transferred to a cas surface at the time of For low-stress abrasion, derived from high-carbon ferro-chrome had higher wear resistance than did commercially available weld-hard. The microstructure of the was typi-white iron carbides. Free carbon added to the ferrochrome powder produced more M7C3 carbides than did material contained in surfacings made from ferrochrome alone, and improved the wear resistance. Several white iron powders with greatly reduced chromium contents also white iron contain-M7C3 carbides. One derived from white iron powder had wear resistance to that of weld-deposited hard facings. Among the parameters investigated, surfacing thickness was found to have a or influence on diffusion of elements out of the , microstructure, and wear resistance. The results of field tests on bucket-wheel excavator teeth and plowshares with cast-on hard surfacing are given.

Jan 1, 1985

By N. V. Hansell

The preparation of low-grade iron-ores by concentration, whether or not followed by an agglomeration of the concentrate, has in the United States only recently been recognized as a metallurgical process of vast economical importance for its iron indust.ry. This importance of the process lies not only in the fact that it makes possible the use of ores heretofore discarded on account of their low iron-content or their too high percentage of elements deleterious in the iron industry, but also in its produetion of a raw material for the blast-furnace that is more uniform in its physical character and chemically purer, with a higher iron-content, than the general run of natural ores. When mixed in the burden of the furnace, it lowers the amount of coke and fluxing-stone required per ton of pig-iron produced. The furnace-operations become more regular and more easily controlled. The pig-iron is of higher quality and more uniform in character. In brief, it is becoming recognized that the beneficiating of the natural iron-ore, even if it makes the furnace-ore higher in cost per unit of iron entering into the burden, may mean a lowering of the production-cost of the pig-iron and an improved product. At the present time, the Lake Superior district furnishes about 80 per cent. of all the iron-ore yearly produced in the United States. If the Southern States arc exempted the percentage runs as high as 93 per cent. These ores are showing a steady decrease in grade from year to year. For the past 10 or 15 years this falling off in the average grade has been about 0.5 per cent. a year. The lowered grade of ore means an in-

Jan 1, 1913

By K. Buxmann

Climate change is a subject of growing concern. Based on the International Energy Agency, about 19% of man made greenhouse gas emissions globally are generated by the transport sector. This paper will focus on the environmental aspects of the light-weighting in transport and the resulting savings of fuel and electricity. Aluminium is an option for lightweight applications in transport, with very high benefits not only in the use stage, but also in the stage of vehicle recycling. Life cycle assessment is used to quantify the relative benefits of light-weighting specific components of cars, commercial road vehicles, buses, ships and trains. A vehicle consists of many components, which are produced by different processes and undergo different types of end-of-life operations. This document does not intend to compare a generic aluminium vehicle with a generic "heavy materials" vehicle. It rather tries to use a pragmatic approach based on specific examples of components where aluminium is used and can be used in the design of new vehicles, also taking into account future developments. The case studies in this paper are based on real cases where aluminium was used. For each component, sensitivity analyses are applied to see the impact of specific parameters such as the end-of-life recycling rate and the use stage driving distance. Significant greenhouse gas savings by the use of aluminium are demonstrated for cars and even higher ones for trucks, buses, trains and ships. In addition, the total potential benefits of light-weighting with aluminium are shown on the global level.

Jan 1, 2007

By P. Clinton Milne

Uranium mines in Washington State include the producing Midnite and Sherwood mines and several mined-out deposits, the most productive of which was the Daybreak mine. The Midnite mine is generally classified as a hydrothermal deposit consisting of tabular orebodies in Precambrian pelitic and calcareous metasedimentary host rocks. The host rocks occur as roof pendants in a Cretaceous porphyritic quartz monzonite intrusive; the quartz monzonite averages 12 ppm U308 The uranium deposit appears to have undergone a complex genesis, involving a series of depositional and enrichment stages. The Sherwood uranium deposit, approximately 4 miles south of the Midnite mine, occurs near the bottom of a basal Late Cretaceous to Paleocene arkosic conglomerate. The conglomerate lies nonconformably on the porphyritic quartz monzonite that is associated with the Midnite deposit. The Sherwood and Midnite uranium deposits may have had a similar genetic history linked by a common uraniferous pluton source, ground-water action, and/or leaching of uranium-rich ash flows from now-eroded, overlying, Eocene volcanics. The Daybreak deposit, in northeastern Spokane County, consists entirely of secondary uranium mineralization (metaautunite) in a quartz monzonite pluton. Mineralization is confined to a low-angle fault zone and is most highly concentrated at the intersection of primary and secondary shears. Both hydrothermal and ground-water origins are feasible. Besides the Midnite-Sherwood area, 14 other areas in the western Okanogan Highlands physiographic province and Cascades region have favourable characteristics for uranium potential. Criteria include the existence of uranium occurrences, Tertiary basin sediments with intercalated volcanic and volcaniclastic rocks, favourable geochemical data, alkaline plutons associated with uranium occurrences or borders of Tertiary basins, and structural controls.

Jan 1, 1979

By C. Leticia Hernández, P. Martín Reyes, D. Iván Alejandrox Reyes, L. Miguel Pérez, T. Julio Cesar Juárez, G. Mizraim Uriel Flores, T. Raúl Moreno, R. Aislinn Michelle Teja

This study shows the characterization of tailings from the mining district of Coscotitlán, State of Hidalgo, Mexico. Chemical analysis by Spectroscopy of atomic absorption (AAS) allowed to quantify the concentration of Fe, Mn, Zn, and Pb as the most abundant elements in the mineral sample; in addition to the presence of Sn, Te, Bi, Ni, Co, and Cd. The presence of precious metals as the Ag (64 g ton−1) and Au (0.65 g ton−1) were identified. The greater distribution of Ag was detected in particles with diameter of 74 lm. Species as pyrite (FeS2), galena (PbS) and hematite (Fe2O3) were observed in a matrix of quartz (SiO2) by Polarized Optical Microscopy (POM), these species were also identified by X-ray Diffraction (XRD). Both the elemental and mineralogical composition of tailings was corroborated by the technique Scanning Electron Microscopy - Energy Dispersive Microanalysis (SEM-EDS).

Mar 1, 2018

By M. K. McCarter

In 1963, a major expansion program at Kennecott's Bingham Canyon mine converted rail operation in the upper portion of the pit to truck haulage. Since that time truck-haulage capacity has increased to about 272 000 Mg (300,000 tons) per day. The majority of this production is waste material which is deposited in monolithic dumps located on the eastern slopes of the Oquirrh Mountains. The largest of these dumps, referred to as Copper Notch and Keystone, measures approximately 1830 m (6000 ft) in length, from 180 to 300 m (600 to 1000 ft) in height, and contains some 430 Tg (470 mil lion tons) of waste. The height, structure, rapid rate of growth, and anticipated leaching suggested the possibility of dump failure. In order to evaluate this possibility, an outside consulting firm was retained in 1966 to investigate the stability of the growing dumps. Their investigation indicated that, other than superficial movement, the waste dumps would be stable under static loading, and that soil distribution was not continuous enough to sustain massive foundation failure. Since this investigation, however, several failure processes have been observed. Crest settlement occurs frequently in response to compaction and over-steepening in the upper portion of the dump surface. Over-steepening results from accumulation of fines near the crest caused by natural segregation. Normally, coarse material, near the base of the dump, exhibits an angle of repose near 0.65 rad (37"). The fine material, however, stands as steep as 0.75 rad (40"). Periodic equilibrium adjustments cause stepwise settlement (Figure 1) of the dump surface and occasional sloughing of the protective berm. Routine surface preparation by dozers and graders and frequent inspections by supervisory personnel have proven adequate in preventing problems associated with this form of crest instability.

Jan 1, 1976

By J. A. Venter

Mineralogical studies indicate the Pt-Pd-Bi-Te class to react poorly on the flotation stimuli and indications are that these minerals are slow floaters. However, recent studies performed on a number of minerals from this class indicated strong interactions with potassium ethyl xanthate resulting in the formation of dixanthogen (only one of several xanthate species). The poor flotation response is not a result of poor interaction of xanthate with the surface. It is proposed that the oxidation products of sulfides in the process water interact with the PGM surface. To test this, the effect of thiosulfate (an important oxidation product of sulfides) was investigated by employing electrochemical measurements and FTIR spectroscopy. The electrochemical investigations indicate no strong effect of thiosulfate on the interaction of xanthate with the minerals surface as well as the reduction of oxygenthiosulfate is likely not responsible for the poor flotation response of these minerals in industrial plants.

Jan 1, 2014