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By E. D. Gardner

Oil shale, a long-considered potential source of motor fuel in the United States, is found over an extensive area in the Green River formation in Colorado, Utah, and Wyoming.4/ Oil has been retorted commercially from shale in Scotland for many years,5/ and work done by the Bureau of Mines and other investigators has shown that it is technically feasible to extract oil from American shales.6/ By refining, the shale oil may be converted into marketable products similar to those manufactured from crude petroleum. The present paper, which was finished in 1936, discusses methods that would be adaptable to mining certain American shales, and the treatment applies specifically to conditions iii the Green River formation on Naval

Jan 1, 1942

By C. Dirscherl

"Declining ore grade, leading to increased material transport and plant throughput requirements, is one of the major challenges in the current mining environment. This is accompanied by rising energy and labor costs, decreasing plant productivity and the requirement for highest plant availability. Siemens’ answer is the latest gearless drive technology for grinding and conveying. Gearless drive solutions are surpassing the mechanical limits of conventional drive systems serving to utilize the principle of economies of scale. By elimination of various components of the drive train, the maintenance activities and spare parts inventories are reduced. The advantages are culminating in the incomparable availability of the Siemens’ gearless drive technology of 99.46 to 99.71 percent — as confirmed by real operational data from the Antapaccay Mine in Peru. It was the first plant worldwide to use gearless drives for both applications.The gearless principleThe principal idea behind a gearless drive system is to reduce the number of components and diversity of parts, especially those components that are at the edge of current manufacturing or power limits are eliminated. The used equipment provides the possibility to scale up and increase the power transmitted to the driven machine. This finally results in a possible increase of throughput respectively transported or processed material.In order to apply this principle of simplification, the components of a conventional drive system are examined. They consist of:• Driven equipment (mill, conveyor, slurry pump).• Components altering the rated speed (gearboxes, girth gear/pinion).• The electric motor.• Starting devices for the motor (VSD, CCV, LRS, clutch), which are necessary because a direct across-the-line start of high power motors with load would result in a significant drop in the line supply voltage.• Alternatively a variable speed drive (VSD) or cycloconverter (CCV) to utilize the possibility of speed variation during operation.• The electrical supply system (cables, switchgear, transformers, protection equipment)."

Jan 1, 2015

By Patrick A. Turner, Timothy J. Olson, Abraham J. Schutte, Roman van Ommen

"The use of classifying devices in grinding circuits dates back to the early 1900’s when classifiers were installed to close ball mills. The search for ways to further improve grinding circuits led to the use of hydrocyclones in place of mechanical classifiers in South Africa in the early 1950’s. Today Hydrocyclones are considered as the best classifying devices to close grinding circuits. After 50 years of development the hydrocyclone has changed significantly when compared to the designs of the early days, but the focus to circuit optimization must be expanded to an understanding of the integral system consisting of mill, cyclone feed pump and cyclone.The key to good cyclone circuit design and operation in primary grinding circuits will be discussed including individual cyclone design features such as cone angle or materials of construction, as well as orientation and manifold configuration.Cyclone performance issues as well as maintenance considerations will be detailed in an effort to achieve consistent cyclone operation with minimal coarse solids in the overflow. “The importance of constant cyclone feed conditions is unquestioned today. The challenge of Cyclone sizing is a large number of not fully known variables prior to startup. The most significant unknown variable is slurry viscosity. Because of this, engineers often specify a conservative cyclone system that produces a finer than required separation. However, this approach often leads to higher circulating loads and a higher overflow density in order to produce the required separation. The higher cyclone overflow density results in a less efficient cyclone separation. The average concentrator can pick up 2-4% finer overall grind by having a more aggressive cyclone operation.”"

Jan 1, 2003

By Frank D. McGuirk

Underground coal mining is traditionally hazardous. Although many danger-prone human activities are now performed by mechanized equipment, this mechanization has itself brought new dangers to the underground mining industry, and the loss of life and limb has caused increased concern for mine safety. The 1969 Federal Coal Mine Health and Safety Act has precipitated a great deal of safety-related research on the part of the Government, industry, and private agencies. Much of this safety research has been focused on the new and varied man-machine interfaces caused by increased mechanization. Recent projects in this area have dealt with standardized controls, emergency shutdown capabilities (panic bars, strike plates, self-centering controls, "dead man" controls), and machine operator protective devices (fully enclosed cabs, canopies, side rails). There was a need for integration of the findings of current and past projects to move rapidly toward the smooth, orderly implementation of standardized operator work station designs for underground mining equipment.

Jan 1, 1975

By Staff

"The Weyburn Oil Field, located 80 miles southeast of Regina, Saskatchewan, was discovered by Central-Del Rio Oils Limited, in January, 1955. As of January 1st, 1959, the field had 357 wells capable of producing an estimated total of 45,100 barrels of oil per day.Highly portable, economical, drilling rigs are used to penetrate the pay at a depth of 4,400 to 5,100 feet. Presently, the complete drilling operation for an average field well, including drilling, coring, testing, and running casing, requires 12 days. Drilling procedures are conventional for a field of this depth and no serious problems exist. Central-Del Rio core the productive section of all their wells, which provides valuable information for well completions and reservoir studies. Production casing procedure is to set through the zone and perforate the productive inter-val. This was found advisable due to the lensing nature of the porosity and permeability throughout the reservoir, and to the high connate water saturation encountered in the tighter sections of the reservoir in the north and northeast areas of the field.Although a few wells in the field have produced naturally by flowing or pumping without acid treatment, it has generally been necessary to acidize the wells to make them commercial producers. To date, acid treatments appear to effect better stimulation of the limestone reservoir than fracturing treatments. Perforation sealing balls have been used as an aid in selectively treating all of the perforated interval.The majority of the field is on pump, producing at a low gas-oil ratio. The main part of the field has water-free production, with most of the water being produced in the north and northeastern area. Salt-water disposal is now available in the field through two disposal wells completed in the Basal Blairmore sand.The Midale Beds ""Marly"" and ""Vuggy"" zones form the principal reservoir, which is a stratigraphic trap, with the north and northeast edges terminated by a porosity and permeability pinch-out and the south-west and west edges bounded by water-laden porosity. There is no evidence to date of a gas cap. The reservoir apparently is producing on a fluid-expansion-type mechanism. The increasing water production in wells on the southwest and west edges of the field indicated water encroachment from these directions, and suggests some recovery energy may be available from this source.The total probable ultimate remaining recoverable reserves have been estimated at° 332,469,000 barrels of oil. Markets have not been able to keep up with the rate of development of the medium crude re-serves. However, it is felt strongly that substantial additional markets for Weyburn medium crude will be developed by the producers in the near future at realistic wellhead prices."

Jan 1, 1959

By J. S. Y. Wang, R. C. Trautz

A 9-meter-long drift was constructed in the unsaturated-fractured tuff at Yucca Mountain to evaluate the potential for water seeping into an underground opening. Forty seepage tests were performed by releasing a finite volume of water at a constant rate into short test intervals located in boreholes positioned above the drift. The seepage threshold flux, defined as the liquid-release flux at and below which water will not drip into the opening, was determined for 10 test intervals. The seepage data, observations, and model results indicate that a seepage threshold exists because a capillary barrier diverts water around the opening.

Jan 1, 2000

By Andrew Fletcher

AS good health is the most important asset in life, the development of healthful conditions should be the one common meeting ground of agreement between management and labor. Health should not be a subject to be pulled apart, shoved around, or bargained about. Differences of opinion may exist in the procedure and techniques employed in approaching the goal of maintaining the health of workmen, and in the method of increasing the ultimate profit of the employer by improved working and living conditions. Such matters are doubtless appropriate subjects for discussions between the interested parties, but techniques are only tools. If an employer fails to remedy a hazard or a menace which contributes to poor working condlions, this constitutes a legitimate grievance. It should not be necessary, however, nor is it desirable that fundamentals of health maintenance become matters of collective bargaining, any more than should the principles of management and engineering. I have been especially concerned during the last few months with the propaganda in collective bargaining negotiations throughout the country for including in union contracts a given number of days of sick leave with pay. We all

Jan 1, 1946

By Charles Barrett

SINCE 1925, when the preferred orientations in compressed aluminum were first determined1, 2 the orientations have been described as a fiber texture in which a face diagonal, [110], of the face-centered cubic lattice is parallel to the compression axis. Subsequent experiments have seemed to confirm this texture,3-5 and a number of theories (recently summarized in references 6 and 7) have been proposed to explain it and to relate it to the behavior of single crystals during compression. 3,8-11 The experiments reported in this paper prove that the orientations are not adequately described as quoted above-i.e., as a [110] fiber texture-although this is a first approximation to the actual texture. They also show that the texture cannot be thought of as a stable orienta-tion that is reached and maintained after a sufficient amount of deforma-tion. The actual texture, when studied in detail at successive stages of compression, indicates that a hitherto unsuspected range of orientations is present, both in the polycrystalline metal as a whole and in various individual grains in its interior, and that a state of dynamic equilibrium exists within this range. The reasons for the failure of previous theories to predict the actual texture become obvious when the heterogeneous nature of the flow is considered. In addition to the deformation texture, the manner of its develop-ment, and its theory, this paper presents data on the following related subjects: the identity of strain markings in aluminum; the orientation changes in aluminum single crystals during compression and a com-parison of these with the conditions in individual grains of a polycrystal-line specimen; the origin of asterism in deformed single crystals, which heretofore has been regarded as a distortion localized at the surfaces of slip planes; and the relation of plastic strain in individual grains in an aggregate to the strain of the whole.

Jan 1, 1939

By Robert H. Peters

This report presents a literature review conducted by the U.S. Bureau of Mines. The review summarizes what has been learned from recent empirical studies of the relationship between mine safety and characteristics of miners, mine management, and mining companies. The review is based on literature published in the United States during the period from 1976 to 1988. In addition to summarizing the empirical findings, this report discusses the implications and limitations of these studies, and gives recommendations for improving mine safety. An annotated bibliography section appears in the appendix.

Jan 1, 2009

By R. W. O. Kersten

The shrinkage method of stoping with pillar support has been used at Agnes Gold Mine since mining commenced. Until recently, rock instability did not have any detrimental effect on safety or production. Presently sill pillars are failing not only on the current production levels, but also in shallower old worked-out areas. The incidence of failure raises the question as to whether the pillar dimensions are adequate at the current working depths and what their size should be at greater depths. The effect of pillar dimensions on the economics of the mining operation is of paramount importance because of the amount of ore that can be left unmined.

Jan 1, 1982

By Uwe Wyink, Guenther Thiele, Isabel Gollnick, Klaus Thyrock

"The application of a thin spray on liner was implemented in longwall T-junction sections in 2009 for the first time. The development of the material and the application is based on a technical cooperation between RAG Deutsche Steinkohle AG and BASF Corporation. The report gives an overview of the first trials. The underground test occurred in a seam with a height of 1.5 m (5 ft) in a depth of 1,100 m (3,609 ft). The roadway is dual-use entry and the roof strata is composed of shale and sandy clay. In some sections geological faults impact the surrounding strata. The poor conditions induce separating and loosening of roof rock. Several remedial actions have to be implemented for decreasing deformations at the face entrance.The application of thin spray on liner (TSL) provides simplification and cost reduction of supporting work at longwall T-junction. The installation of TSL to avoid roof and coal fall operations for lagging are omitted.INTRODUCTIONFor safe operation of face retreat in dual-use roadways, the processes of securing and stabilizing the face end area are very important in order to minimize deformation and stress. Avoiding roof and coal fall are the main concerns for safe operation. For that reason different methods of reinforcement are tested in underground operation. In this paper the application of TSL is presented.The specifications of TSL are described, followed by the case study results. The underground study is located in one mine of RAG Deutsche Steinkohle. The extraction of the hard coal in this mine is characterized by great depth and high stress. There are poor geological and geotechnical conditions. The roadway used for the underground application was headed with the support system combination type A, which will be described later in the paper. After the first face retreat, deformation of steel arch support and bagging destroyed the roadway, so for the second face retreat remedial actions had to be undertaken. For this a new system of reinforcement, simplifying the supporting work at the longwall T-junction was tested. The reinforcement consisted of different parts that are described in the following report. Furthermore two different versions were applied. One method is the operation with TSL and the other one is the use of concrete for sealing. Both methods are compared in the text."

Jan 1, 2010

The modern theory of sampling of particulate minerals essentially consists of a recent generalization of the procedures for applying and calibrating the formula usually known as ?Gy?s Formula? for sampling variance control, in which the central concept is a parameter called the liberation factor l. A model which can be experimentally adjusted was proposed by one of the authors several years ago, based on geostatistical considerations. This new model, which relates the liberation factor to the sizes of the fragments and mineral grains, solves the usual difficulties faced in the past, and permits predictions that are well verified in practice. Unfortunately, an older, arbitrary and less general formula is still widely used. The vast majority of today?s misapplications of Sampling Theory of Particulate Materials can be traced back to the use of this antiquated and generally incorrect model. Following a brief history of the models used for the liberation factor and a description of its main variable, the liberation size, and to illustrate the importance of proper modelling of l, this paper presents demonstrative calculations of the absurdity of the incorrect model using the particular case of gold mineralization as an example, followed by some more positive examples of application.

Jan 1, 2002

By Guilherme Liziero Ruggio da Silva

Uma marcha estável do Alto Forno está bastante ligada à consistência das propriedades químicas, físicas e metalúrgicas das suas matérias-primas, especialmente, do coque. O desafio da produção de coque está em projetar misturas de carvões que produzam coque a custo baixo e com elevada qualidade. Neste contexto, este trabalho visa avaliar a utilização de moinha de carvão vegetal na mistura de carvões reduzindo a necessidade da importação de carvões minerais, mantendo a qualidade requerida pelo Alto Forno, além de desenvolver uma rota para minimizar a emissão de CO2 proveniente do processo de obtenção de ferro gusa em Altos Fornos a coque, reduzindo seu impacto ambiental. Foram realizados testes em escala piloto com até 20% de moinha de carvão vegetal. Os resultados das análises realizadas no coque mostraram a viabilidade técnica e comercial para utilização em até 2% na carga.

Aug 17, 2017

By Fernando de Oliveira Boechat

Dentre as etapas de pelotização de minério de ferro, a fase de mistura tem grande importância devido ser responsável por dar homogeneidade a aos insumos e minério que serão processados nas etapas seguintes. Desta forma ela ajuda a garantir a boa formação das pelotas verdes e seu posterior endurecimento na etapa de queima. No desenvolvimento de misturadores, o auxílio de ferramentas de simulação são uteis para o correto dimensionamento destes equipamentos. Nos últimos anos a utilização do método dos elementos discretos (DEM) tem sido implementada para este fim e por isto vários cuidados têm sido tomados para ter-se resultados compatíveis com o comportamento real das partículas. Entre os fatores que podem inviabilizar o uso do método dos elementos discretos, o tempo e capacidade de processamento computacional tem sido um dos mais impactantes. Assim, este trabalho foi desenvolvido de forma a avaliar a influência do tamanho das partículas no resultado de capacidade de mistura de um misturador horizontal. Para isto, foi feito o escalonamento do modelo de um misturador e testado dois tamanhos de partícula avaliando o comportamento da mistura ao longo do tempo e o seu índice de mistura Lacey. Como resultado, pode-se verificar que o tamanho da partícula tem influência direta no resultado da simulação e que cuidados devem ser tomados no escalonamento destas para que haja compatibilidade entre as simulações e o comportamento real do sistema.

Aug 17, 2017

By Cezar Henrique Gonzalez

Processos de conformação plástica têm sido aplicados nas ligas com memória de forma (LMF) para melhorar suas propriedades mecânicas. No entanto, estes processos provocam alterações das suas propriedades termoelásticas (temperaturas e entalpias de transformação, cargas críticas de indução da martensita, deformação termoelástica reversível e outras). Para aplicações tecnológicas destas ligas, por exemplo como atuadores termomecânicos, elas devem manter suas características constantes ao longo de sua utilização (propriedades termoelásticas). Neste trabalho são analisadas estas propriedades das ligas de Ni-Ti com memória de forma que foram conformadas termomecanicamente pelos processos de laminação convencional e de extrusão angular (Equal Channel Angular Extrusion - ECAE). As analises foram realizadas por calorimetria diferencial de varredura, microscopia eletrônica de varredura e teste de tração sob carga constante (simulação do efeito memória de forma para determinar a propriedades termoelásticas). Os resultados mostraram que os processos de conformação alteram drasticamente as propriedades, principalmente para aquelas amostras submetidas ao ECAE que chegam a bloquear a transformação martensítica. Tratamentos térmicos foram aplicados com o objetivo de melhorar ou restabelecer as propriedades do efeito memória de forma. Resultados das difrações de raios-X e das micrografias indicam que cada tipo de processo de conformação plástica e a formação de precipitados influenciam de forma preponderante nos comportamentos das propriedades termoelásticas. Estas análises são relevantes para aplicações tecnológicas destas ligas, pois requerem boa resistência mecânica combinada com as propriedades funcionais dos fenômenos de memória de forma.

Aug 16, 2017

Management of Mining Wastes in European Union and Developments in Turkey

Sep 13, 2010

By David J. Barr

Public Law 91-190 - January I, 1970 states that, "The purposes of this Act are: To declare a national policy which will encourage productive and enjoyable harmony between man and his environment; to promote efforts which will prevent or eliminate damage to the environment and biosphere and stimulate the health and welfare of man; to enrich the understanding of the ecological systems and natural resources important to the Nation; and to establish a Council on Environmental Duality." The administrative aspects of this National Environmental Policy Act of 1969 have in essence established the requirement that all agencies of the Federal government assess the consequence of their actions with an Environmental Impact Statement. Furthermore, five states have already enacted environmental legislation, and others will surely follow. The Environmental Services Project Director for Dames and Moore has stated in the June issue of that company's publication, "Elements," that, "The nuclear power industry has perhaps been most affected to date by the Act [NEPAL but recent court decisions, legislative trends and general public concern will accelerate the spread of the Act's impact on other industries. Mining and petroleum are already involved in environmental affairs." There can be little doubt that within a very short time all environmental aspects of the minerals industry will be strictly regulated and monitored by some agency of Federal and/or state government. Indeed, it is probable that any future effort to extract natural resources will be contingent upon a favorable review of an Environmental Impact Statement. It is also quite possible that continuation of present operations will have to be justified on the basis of proof of an acceptable environmental impact. It is the objective of this paper to present some ways in which remote sensing technology can be applied toward an efficient collection of environmental data necessary for the preparation of an Environmental Impact Statement.

Jan 1, 1972

By Edward Thomas

In 1947 the Bureau of Mines, as an accident-prevention measure, decided to advocate the adoption of roof bolting (suspension roof supports) in coal mines where it appeared to be applicable. Subsequent experience has disclosed that the applicability of this support is more general than was first suspected; moreover, comparison of the accident records of mines before and after adoption of the roof-bolting method shows results that more than justify the effort and funds expended. The industry has responded enthusiastically, because roof bolting proved to be not only an accident-prevention measure but also one to increase productive efficiency. In some instances this increase in the productivity of men and machines has been almost incredible and has led many mining men to conclude that through some hocus-pocus they can now cast aside many or all of the time-proven rule of good mining practice. If this tendency is not counteracted, it could easily result in an increase of roof-fall accidents, which may outweigh the benefits of roof bolting and discredit an innovation in roof control that shows great promise of materially reducing our mining accidents. From an economic standpoint it may represent the margin between profit and loss in many mining operations. The purpose of this manuscript is not to propose an inflexible code or set of rules but to summarize the experience to date as a guide for those who have the responsibility for the installation and inspection of roof bolts. This experience consists of approximately 250 investigations of roof failure in which roof bolting was involved either directly or indirectly. It should be pointed out that many of these failures were controlled, occurring during experimental periods, and comparatively few of the accidental failures actually resulted in personal injury, yet a significant number represented potential hazards.

Jan 1, 1951

By Janine Feitosa de Deus

Compósitos ambientalmente corretos, fabricados a partir de fibras naturais lignocelulósicas (FNL), estão entre os mais investigados e aplicados atualmente. Dentre as FNL, destacam-se as fibras de Rami (Boehmeria nivea), que surgem como alternativa em sistemas de blindagens multicamadas, para uso em coletes de proteção balística, por serem leves, de baixo custo, resistentes e ambientalmente corretos. No presente trabalho, investigou-se o comportamento mecânico de compósitos de matriz epóxi reforçados com tecido de rami, através de testes de flexão. Compósitos contendo separadamente 0, 10, 20 e 30% em volume de tecido de rami e resina epóxi, foram fabricados em um molde metálico, sob condições de vácuo. Os corpos de prova fraturados foram analisados em MEV e os resultados foram avaliados visando algumas propriedades de flexão com a incorporação do tecido de rami, visando sua posterior aplicação em blindagem balística.

Oct 30, 2017

WASHINGTON, D. C. HERBERT C. HOOVER, Chairman H: FOSTER BAIN, Vice-chairman DAVID WHITE, Vice-chairman HARVEY S. MUDD, Secretary-Treasurer, Room 2114, Dept. of Interior Bldg. J. F. CALLBREATH HENNEN JENNINGS E. W. PARKER T. T. READ An inspiring meeting of the Washington, D. C., Section was held at the Cafeteria of the Interior Building on Friday evening, Dec. 6, 1918. One-hundred and thirty-five members and guests attended, and Vice-chairman H. Foster Bain presided. The Committee on Nominations reported: for Chairman, Herbert Hoover; for Vice-chairmen, Frederick G. Cottrell, and F. L. Ransome;

Jan 1, 1919