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By Arvid E. Anderson

The paper describes the unique operating features of the Lebanon Concentrator Plant wherein both magnetic concentration and froth flotation are used. Chalcopyrite is selectively floated by the use of dual collectors, Aerofloats and secondary butyl xanthate. Both potassium ethyl xanthate and sodium isopropyl xanthate (dual collectors) are dissolved and emulsified with pine oil for the flotation of the pyrite. Sketches describing the plant operations are presented and plant operating metallurgical results obtained are also given. The optimum production of minerals by the froth flotation process is normally achieved [ ] smooth operating conditions, The process, because of its many variables, becomes an art as well as a science. Therefore, any phase of the operation which will aid the operator in his control of the numerous variables will help produce a smoother operating plant, One of the most important variables which the operator deals with is the addition of reagents, These are usually costly items and should be used discretely with minimum amount of waste, The danger is that ,this emphasis may reduce the reagent amount to a point below that required, or, on the other hand an excessive amount is added, Both conditions usually yield poor results. The drea of the metallurgist is to provide the operator with the tools enabling him to produce a good mineralized froth at all times. Normally the operator has no control concerning the type of reagents which he must use. This has usually been worked out for him in the laboratory and by plant-scale tests. He does have limited authority to control the amounts of the reagents at his disposal. This, I believe, is as it should be. However, the operator should be provided with the best combination of reagents for his particular job. The providing of this combination of reagents for his particular job, The providing of this combination is often difficult, yet it is very important in order to yield good results, With this in mind, the dual collector idea was introduced for the selective flotation of chalcopyrite, and also later for the flotation of pyrite at the Concentrator Plant of the Bethlehem Cornwall Corporation in Lebanon, Pennsylvania, Supplying several types of collectors has given the operator an additional effective tool, even though great variations are encountered in ore tonnage treated and in ore composition, This paper deals with the use of the dual collectors and with the addition of the reagents in the form of a pine oil emulsion, or more accurately, a pine oil suspension. It is hoped that other operators may find the ideas helpful. There does not seem, to me, to be definite scientific fact which would substantiate the necessity for the use of dual collectors. However, in actual operations, the metallurgical results at Lebanon became more uniform with the use of dual collectors, I look upon it as an "insurance policy" which greatly aids the operator during those periods when he is having trouble, One theory has been advanced, i.e. one collector has a greater tendency to float the coarser minerals, whereas the other one may float the finer ones. Consequently, a combination of the two collectors will result in optimum recoveries, There has been some evidence that this is true, but it is not conclusive, on the other hand, the use of a xanthate-pine oil suspension (or emulsion) should speed up the surface reaction of the collector with the sulfide minerals, result¬ing in more uniform flotation, This has definitely happened in our particular case. A more interesting unexplainable observation has also occurred; i.e., the xanthate solution does not appear to lose its strength as rapidly when it is in the form of an emulsion (or suspension), This was first observed when a 50 gallon drum of a 20% ethyl xanthate solution was taken to Wilmington, Delaware, for a laboratory test, using a homogenizer to produce the xanthate-pine oil emulsion. Upon arrival, the drum of xanthate had developed a considerable internal pressure, The relief of this pressure was accompanied by a strong odor, When the emulsion was returned to Lebanon for the plant test orders were issued to release the pressure prior to emptying the emulsion. Nopressure had developed within the drum and there was no unusual odor present, Since this time it has been observed that xanthate pine oil suspensions have greatly decreased the possible decomposition of the xanthate solutions. In fact, suspensions have been exposed for more than a month without apparently effecting their reactions in the flotation plant. On the other hand, we found that the regularly mixed concentrated xanthate solutions, after standing for several days, did not give the same results as the freshly made ones. This effect was greatly reduced by the use of xanthate pine oil suspension (or emulsion)

Jan 1, 1958

By James L. Elder, J. P. Capp, James J. Dowd

The Bureau of Mines and the Alabama Power Co., jointly, conducted the first experiment undertaken in the United States in underground gasification of coal in place, at Gorgas, Ala. Milton H. Fies, manager of coal operations, Alabama Power Co., proposed the cooperative investigation to Arno C. Fieldner, chief, Fuels and Explosives Branch, Bureau of Mines; and assisted in supervising the experiment. The objectives of the experiment were to determine whether coal in place could be burned successfully and whether the burning could be controlled; the effect of the fire on the coal bed and the overlying strata; and the yield and quality of gas that could be obtained.

Aug 1, 1947

By Enir da Silva Fonseca

Este trabalho tem como objetivo principal analisar os dados obtidos através dos ensaios a flexão em 40 corpos de provas cerâmicos preparados de acordo com a NBR 13818:1997 e aplicar uma probabilidade estatística para cálculo da resistência à fratura. O modulo de resistência à flexão para a ruptura de cada corpo de prova foi calculado de acordo com a fórmula apresentada no anexo C da norma citada, e aplicada posteriormente no lote à estatística para distribuição de Weibull. Os resultados obtidos não apresentaram uma variação significativa na resistência mecânica à flexão para os corpos de provas sem umidade em relação aos submetidos à imersão em água.

Aug 16, 2017

By Bruno Valladão Fraga

Esse trabalho tem como objetivo apresentar a estratégia adotada para a migração dos sistemas de otimização de processo dos três Altos Fornos da ArcelorMittal Tubarão. O desenvolvimento dos novos sistemas é baseado no Plano Diretor de Tecnologia de Automação (PDTA) que definiu a arquitetura, tecnologias e elaborou o Framework como base das aplicações. Para a migração dos sistemas foi elaborada uma especificação detalhada de todos os módulos e funcionalidades existentes, permitindo dessa forma a criação de uma camada com as principais regras de negócios relativas ao processo para serem reutilizados em todos os Altos Fornos. Essa camada deu origem ao Framework dos Altos Fornos. Os resultados obtidos já podem ser vistos nos três sistemas migrados para a nova plataforma, com um alto desempenho e estabilidade, garantido dessa forma a segurança operacional objetivada.

Aug 17, 2017

By R. V. Norris

The anthracite coal trade, with a shipment averaging about 70,000,000 tons per year, differs essentially from other coal business, iii the fact that the larger sizes, comprising about 65 per cent. of the total, are used almost exclusively for domestic purposes, principally during the winter months; and that for proper combustion close-sizing is imperative, so that eight sizes are made; broken, egg, stove, and nut, known as prepared sizes, and pea, buckwheat, rice, and barley, known as steam sizes. These sizes are made in the regular course of preparation, and but little variation in the natural percentage of each is practicable. Thus it is necessary either to work the collieries intermittently, or to dispose of all the varying sizes in their fixed proportions. Unfortunately, the market does not at all times absorb the coal in proper proportions, and rather than interfere with the regular operation of the mines it has been found economical to provide storage for the excess. While the cellars of' the consumers are the great storage-plants of the country, this capacity is not under the control of the trade, except so far as reduced prices during the spring and summer months may tempt the use of this reserve. The same remark applies but with less force to the retail yards, which, though usually small, store in the aggregate a large amount of anthracite. While every effort is made to utilize to the utmost the individual storage-capacity of the country, there still remains the necessity for taking care of the irregularities of the market by the construction of storage-plants under the direct control of the producers. Such plants are usually the property of the railroads, and are situated at points most convenient from a traffic stand-point.

Jan 1, 1912

By Alini Luisa Diehl Camacho

Este artigo apresenta a caracterização física, química e mineralógica do resíduo casca cerâmica (RCC) gerado em indústria de fundição de precisão. Este setor tem predominância nas regiões sul e sudeste do país com cerca de 35 empresas das quais cada uma gera mensalmente de 50 a 100 toneladas do resíduo. Desta forma, apresenta-se uma metodologia baseada na caracterização do resíduo como forma de reciclagem interna cujo foco é a sua valorização. A metodologia aplicada para o desenvolvimento do estudo envolveu uma caracterização físico-química do RCC obtido através de etapas de moagem. Os parâmetros analisados foram distribuição granulométrica, massa específica, área superficial, composição química quantitativa e mineralógica estrutural semi-quantitativa. A partir da segregação do material foi possível realizar a separação de materiais nobres presentes no resíduo. Em especial, as frações 40 (4.25 mm) e 80 (1.80 mm) concentrou 72.12% do total da massa do material. Apesar de apresentar um alo de amorfismo entre os ângulos 0 a 15º, o RCC tem comportamento predominantemente cristalino. Considerando a caracterização realizada e bibliografia referenciada, este material tem grande potencial como matéria-prima refratária, seja no processo de origem como em outras aplicações.

Aug 17, 2017

By Jogeshwar P. Singh, Mohamed Ashour

The Soil-Foundation-Structure-Interaction (SFSI) problem involves Kinematic Soil- Foundation Interaction occurring during large (cyclic and permanent) ground deformations as well as Inertial Foundation-Structure Interaction occurring during shaking all of which take place while the soil and possibly structural properties degrade with time. The design of the deep foundations for liquefaction induced lateral spread loads include estimation of passive pressure applied by the liquefied material as well as the amount of anticipated displacement. Coupled analyses for SFSI problems that account for liquefaction induced lateral spread and their interaction with the deep foundation system can be performed using sophisticated numerical modeling techniques based on finite element and/or finite difference methods using computer programs such as FLAC or OPENSEES. Such complete SFSI analyses are very tedious and expensive and not feasible for most projects. In 2011, California Department of Transportation (Caltrans) released guidelines for foundation loading and deformation due to liquefaction induced lateral spreading. This simpler prescriptive approach combines empirical and analytical methods through decoupled analyses using computer programs such as LPILE and SLOPE-W together with liquefaction induced lateral spread estimates based on published empirical equations. Pile group effects and pile caps are accounted for using a concept of super-pile. In this paper, we discuss the solution of the same lateral spreading related SFSI problem using computer program CGI-DFSAP (CGI-Deep Foundation System Analysis Program) based on the strain wedge theory that can account for liquefaction, lateral spreading, pile groups, pile caps and nonlinear behavior of piles in a more coupled manner to analyze the foundation system under the lateral spread loadings. CGI-DFSAP can be used to analyze piles in sloping ground conditions as well as piles beneath the abutments near a free-face slope. We have included Strain Wedge Model (SWM) solutions using CGI-DFSAP of several field and laboratory case studies of lateral spreading related to pile foundations. Finally, we have also included the SWM solution of one of the Caltrans (2011) example problems.

Jan 1, 2015

By K. L. Paciorek

The aim of this program was to develop a reliable and meaning-ful basts for assessing certain safety aspects, namely fire and, in particular, toxicity hazards of articles employed in underground coal mining operations. This investigation was centered on the thermal oxidative degradation of "pure" ingredients used specifically in the formulation of conveyor beltings. To achieve this goal all products formed on thermal oxidative degradation of the materials studied were analyzed, identified I and the amount of each individual species present was determined quantitatively on a weight of product per weight of material basis. The weight/weight data thus obtained can then be factorized to reflect the relative toxicity of each individual species present, using for example the Threshold Limit Values adopted by the American Conference of Governmental and Industrial Hygienists, whereby an overall "toxicity index" can be arrived at which makes it possible to compare the different potential formulation components in a quantitative manner insofar as their "toxicity" is concerned. Furthermore, knowing the off-gassing characteristics of the commonly used additives I their contribution to the product mix obtained from actual belting can be postulated. Conversely, from the species obtained on thermal oxidative degradation of conveyor belts the type and to a degree the content of additives can be deduced. Based on the se data meaningful regulations governing the material selection for underground use can be developed. For these studies a quiescent system at 370°C was employed. Thermogravimetric and differential thermal analyses were performed to supplement and extend the sealed system investigations and to provide information regarding thermal oxidative behavior under dynamic conditions.

Jan 1, 1975

By J. P. Powell

Records show that systematic water flooding was begun as early as 1935 in Greenwood County and in 1937 in Butler County. Water flooding on some earlier projects in Greenwood County were described in a Bureau of Mines Report of Investigation.2/ This report presents a discussion of 4 projects -2 in Butler County, 1 in Greenwood County, and 1 in Butler and Greenwood Counties. The location of these projects is shown in figure 1. The projects have been in operation 6 to 12 years and have recovered about 6.6 million barrels of additional oil from the injection of 84.7 million barrels of water. Three of the projects take advantage of the elevation of the nearby hilly terrain, and water from the treating ponds flows by gravity through the filters into the clear-water tanks. By utilizing gravity flow, fewer pumps and less electrical energy is required, resulting in more economical operation.

Jan 1, 1956

By C. G. Storm

Permissible explosives are those that have passed the tests pre- scribed by the Bureau of Mines for explosives intended for use in coal mines, and are therefore recommended by the bureau as suitable for this class of work when used under the prescribed conditions. The tests for permissible explosives and the conditions prescribed for their use are described in Miners' Circular 6 of the Bureau of Mines. Up to June 1, 1915, 168 explosives had been classed as per- missible explosives; 133 of them were then on the bureau's "per- missible list" and 35 had been withdrawn by the manufacturers. In addition to the required physical tests, each explosive is sub- jected to a complete chemical examination in order that its exact composition may be known and also that the composition of future samples of the same explosive collected in the field may be compared with that of the sample which originally passed the bureau's tests, for by such comparison it may be possible to ascertain whether or not the explosive as supplied to the miner is still "permissible." This bulletin is published primarily for the purpose of informing manufacturers of such explosives as to the methods used by the Bureau of Mines in the analysis of samples received for tests to determine their permissibility. Such information may be of value in cases of possible controversy over the results obtained in the analysis of a field sample as compared with those obtained in ana- lyzing the sample originally tested by the bureau. Also, a descrip- tion of the methods used by the Bureau of Mines in the analysis of explosives should be of assistance to the many chemists engaged in similar analytical work.

Jan 1, 1916

By H. L. Retcofsky

Carbon-13 nuclear magnetic resonance (18CNMR) spectra of nine 2-substituted pyridines, seven 3 -substituted pyridines, and nine 4-substituted pyridines have been obtained and analyzed. Substituents included both electron-releasing groups and electron-with hawing groups. Substituent effects on the magnetic shieldings of the ring carbons, except for those in the 2-positions of 2-substituted pyridines, were found to be quite similar to the effects reported for the monosubstituted benzenes, Thus, at least to a first approximation, the two classes of compounds have similar shielding mechanisms. Shieldings of the carbon atoms in the 5-positions of 2-substituted pyridines and those in the 6-positions of 3-substituted pyridines were found to reflect electron release or withdrawal by substituent groups, The pyridinium cation and the compounds 2,2'-dipyridyl and benzonitrile were also investigated.

Jan 1, 1969

By Charles Prasky

This report describes and appraises recent progress in the development of a differential sulfatizing process for recovering a ferrograde manganese oxide from low-grade manganiferous ferruginous materials in the Cuyuna range. Individual process steps were carried out successfully using a 20-inch-diameter shaft for continuous countercurrent sulfatization of the manganese, a multiple-compartment rotary drum for leaching the water-soluble manganese sulfate, a submerged-combustion evaporator for the recovery of monohydrate crystals of manganese sulfate, and a shaft furnace for the thermal decomposition of sulfate crystals for production of a ferrograde manganese oxide and a sulfur dioxide gas suitable for sulfatization of fresh are. Of the two general kinds of Cuyuna manganiferous materials--the carbonate slates and the oxidized ores--only the slates were studied at pilot scale.

Jan 1, 1963

By A. M. Evans

Because of an urgent national need for manganese, the deposits in the Little Florida Mountains of Lune County N. Mex., were visited by O.H. Metzger, an engineer of the Bureau of Mines, on June 12 and 13, 1940, accompanied on the second day by S. G. Lasky, a geologist of the Federal Geological Survey. After this preliminary examination, it was recommended that exploratory work be done by the Bureau of Mines on several properties in the district. An exploratory project of trenching, sampling, and core drilling was started by the Bureau of Mines in September 1940 and completed in May 1941.2/ Work was done on three properties - the Luna mine, the American group of claims, and the Manganese Valley mine. The Little Florida manganese district is situated on the eastern slope of the Little Florida Mountains about 2 miles south of U. S. Highway 80-90, 12 to 14 miles southeast of Deming, Luna County, N. Mex. The principal claims comprise the Luna Manganese, American, and Manganese Valley groups.

Jan 1, 1949

By Jadson Barbosa

Corpos de prova de ferro com diferentes níveis de pureza – um de pureza ultraelevada, dois de pureza elevada e um puro comercial – foram testados mecanicamente com diferentes taxas de deformação no âmbito de um antigo projeto. O objetivo era obter a resistência à tração de cada material e verificar a influência das impurezas e da taxa de deformação nas propriedades mecânicas do ferro de pureza ultraelevada. Para melhor compreender os resultados desses ensaios de tração, uma caracterização microscópica detalhada dessas amostras é realizada através deste trabalho. Para tal, foram analisadas as superfícies lateral e de fratura dos corpos de prova de tração no estereomicroscópio e no Microscópio Eletrônico de Varredura (MEV). O dano foi analisado em seções longitudinais ao longo do eixo de tração utilizando o microscópio óptico; a estrutura dos grãos deformados foi investigada por meio da técnica de microscopia EBSD (Difração de elétrons retroespalhados). Microestrutura, padrão de deformação, orientação dos grãos e as características das superfícies lateral e de fratura são então comparadas quanto ao processo de fabricação, nível de pureza e taxa de deformação.

Aug 17, 2017

By Charles D. Litton

This Bureau of Mines report presents a discussion of the essential components of pneumatic monitoring systems and their associated functions. Design criteria are presented which can be used for the design and fabrication of pneumatic monitoring systems having total system response times on the order of 15 to 30 min. To illustrate the utility of these design criteria, two detailed design examples are presented,

Jan 1, 1983

By WenJun Dong

This paper presents the stability assessment of the steel pipe piles that are used to support a deadman beam to anchor an adjacent bulkhead wall. Finite element analyses are performed to assess the stability of the bulkhead wall and determine the required tie-back force to the pile. The piles are relatively close to the bulkhead wall such that their soil resistance wedge zones are not fully developed but truncated by the bulkhead wall. The reduced lateral resistance capacity of the anchor piles is determined by applying the Coulomb wedge method on the truncated soil passive zones between the pile and wall. Both the conventional soldier pile stability (in terms of force and moment equilibrium) and Winkler soil spring (for soil-pile-interaction) analyses are used to assess the stability of the anchor piles.

Sep 8, 2021

By Nilabjendu Ghosh, Satyendra Kumar Singh, Gautam Banerjee, Harshit Agrawal

High-production methods like longwall mining with hydraulic powered supports are necessary to increase underground coal production in India. Longwall mining had a mixed success record for Indian geo-mining conditions. In this paper, an analysis is presented to optimally design an array of chain pillars in multi-seam longwall mining panels in the deepest coal mine in India. The study found that a chain pillar of 80-m width and 195-m length is necessary for long-term stability without any reinforcement. It was also observed that an optimum chain pillar can be designed by providing suitable side reinforcement (side bolting) which will reduce the chain pillar dimensions to 55-m width and 160-m length. Optimum design of chain pillars will reduce the coal locked up in these chain pillars by ~ 77%. This will also reduce the gestation period of longwall mining panel development. This paper also evaluates the maximum tensile subsidence strain induced at the surface and finds that the values are within the safe working limit of 3 mm/m. Thus, this paper finds direct application in the design of future multi-seam retreating longwall mining panels in Indian geo-mining conditions.

By J. Clark

The objective of this study has been to determine the state of the art in underground, thin-seam-mining systems, to identify new technology and procedures that would reduce the hazards of thin-seam mining and to recommend areas for further research. The study was carried out in two phases, the first of these being devoted to a survey of authoritative literature. Subsequently, the practices adopted in the various mining countries were analysed and comparisons made to identify machines and methods with the potential for application in the USA. Published figures on US bituminous coal reserves show the high proportion contained in thin seams and US accident statistics demonstrate that the risk is greater in thin-seam operations. A comparison has been made with the experiences of foreign operations. The Phase 11 study proceeded along two separate avenues to examine the distinctive problems associated with seam thicknesses above and below 30 in. Current systems of mining appropriate to seams greater than 30 in were elaborated and compared by means of a simulation exercise in terms of safety, production and cost. For seams below 30 in, less conventional systems, some presently disused, were studied and their potential evaluated; the research and development work necessary to make them viable has been indicated.

Jan 1, 1980

By E. Chin

Although Japan is a major producer of crude steel, it is poor in industrial raw materials. This Bureau of fines report describes Japan's raw material needs for chromium, cobalt, manganese, nickel, and tungsten to produce ferroalloys and alloy steels. Japanese imports of these ores or metals by quantity and source are given for 1972-81, inclusive, to indicate (1) the changes in the consumption and supply pattern, and (2) the degree of Japan's dependence on foreign sources. This report also describes measures implemented by Japan to reduce the risk- of supply interruption, and discusses the possible implications of supply shortages.

Jan 1, 1983

By J. W. Meier

Introduction The great importance of air warfare during World War II and the introduction of large-scale air transportation and airborne operations created an immediate demand for large quantities of high quality light alloy products. Before this war, the use of magnesium, the lightest structural metal, was barely in the development stage, and considerable research work was needed to overcome difficulties in improving its properties and to attain uniform quality in mass production of magnesium alloy products. The Canadian Bureau of Mines was frequently called upon, by various agencies of the Armed Forces and of the newly established war industries, to examine magnesium alloys that had failed in fabrication or in actual service, and to advise on proper alloys and fabrication methods to be used. Failures in magnesium alloy castings were connected mainly with lack of knowledge of proper founding and surface-protecting techniques. Most of the defects were due to microporosity and faulty heat treatment. To aid the foundry industry, small-scale investigations were started on the effect of various factors in the casting technique in order to improve the quality of the products. These investigations were made in co-operation with representatives of the Armed Forces and the Canadian magnesium industry. This work was later co-ordinated into a broad research programme on magnesium alloys, comprising problems on melting, refining, various casting methods, heat treatment, and testing of properties of standard and special alloys. This research programme? is still in force, and the present paper contains some results of the first series of investigations on magnesium casting alloys carried out at the Experimental Foundry of the Bureau of Mines.

Jan 1, 1948