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By T. E. Gray

This report describes the preparation characteristics of the three significant coal beds in Greene County, Pa. It is one of a series planned to determine which coals are suitable for the production of metallurgical coke, either as mined or after beneficiation. Over 12.5 million tons of coal was produced in Greene County in 1956, of which approximately 10 million tons was cleaned mechanically in 8 cleaning plants. The Bureau of Mines has estimated that 3.5 billion tons of recoverable coal remained in the county as of January 1, 1954.

Jan 1, 1958

By J. W. Town

The Bureau of Mines made continuous-circuit beneficiation studies to determine the optimum conditions for concentrating phosphate minerals from the intermediate-and marginal-grade ores of the Phosphoria Formation in southeast Idaho. Intermediate-grade ore was represented by a sample from Georgetown Canyon and marginal-grade ore from the Gay mine near Fort Hall. Two flow-sheets were developed: The first involved roasting, attrition scrubbing, sizing to remove a concentrate, grinding of the oversize, des liming, and flotation; in the other flowsheet roasting was eliminated. Controlled attrition scrubbing was used to remove clay and silt-size quartz particles imbedded in the phosphate pellets without breaking the pellets. The minus 35-plus 200-mesh fraction was removed by sizing as a finished acid-grade concentrate. The plus 35-mesh material was ground in a rodmill to minus 35 mesh and recycled to the attrition scrubber. The minus 200-mesh fraction was des limed at about 800 mesh to remove clay slimes and floated with 3 to 4 pounds of emulsion per ton of feed. The aqueous fatty-acid oil emulsion consisted by weight of 3 parts No.2 diesel oil, 3 parts crude tall oil, and 0.5 part water-soluble petroleum sulfonate.

Jan 1, 1967

By P Thompson, B W. Atkinson

Water treatment is not æcore businessÆ for mining companies.Just as mineral ores and coals are unique, each requiring detailed characterisation and pilot-testing to determine their optimum beneficiation route, so too are mine waters, each requiring careful assessment to determine the most appropriate treatment. There are many cases of æregret capitalÆ expenditure, whereby mines have installed off-the-shelf equipment only to find it inadequate for their purposes or grossly expensive and labour intensive to operate.Water may be required for potable purposes, ore processing, dust control and/or irrigation. A major driver will frequently be environmental constraints for off-site discharge. Mine water projects can become very complex, and detailed models need to be prepared and optimised to properly consider the raw water sources, the on-site storages, the on-site uses and the off-site discharges, as well as handling the residuals (by-products) of water treatment. By-products may be in the form of concentrated backwash streams or streams of elevated salt content. Careful management of the by-products is required to avoid recontamination of the source water.Regulators often drive mine owners toward reverse osmosis (RO) so that their discharges can be considered as æzero dischargeÆ in terms of potential pollutants. Such decisions need to be based on site-specific information rather than any form of æblanketÆ requirement. An analogy is that many humans like to consume mineral water rather than ænormalÆ tap water. Receiving environments also accommodate or even prefer their æmineralsÆ and so RO is neither warranted nor sustainable in many cases.This paper presents two case studies for operating mine sites, both of which have a significant excess of water requiring environmental discharge. The examples demonstrate a sensible balance between treatment type, environmental constraints, process implementation and residuals management. LIMN« æthe flow sheet processorÆ was used to model one of the case studies due to the complexity of the water system on that site.CITATION:Atkinson, B W and Thompson, P, 2013. Mine water - optimising for site and environment, in Proceedings Water in Mining 2013 , pp 9-14 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By Wallace W. Key

The California pesticide industry in 1962 consumed about 30,000 tons of clay, talc, limestone, diatomite, sulfur, and other minerals as fillers (carriers and diluents) in pesticide formulation. This was 10 percent of the U.S. filler requirement for pesticides. About two- thirds of the California total was supplied by a few local mineral producers; the remainder came mainly from Florida, Georgia, and Wyoming. The objectives of this report are to provide data on quantities, sources, specifications, and market conditions for minerals used as fillers by California pesticide formulators. The study disclosed that specifications for mineral fillers have become more rigid and formulators have become more numerous in recent years. During 1962 over 1,200 firms registered 16,000 pesticide products with the Bureau of Chemistry in California. Factors which will tend to diminish future need for mineral fillers include the trend toward greater use of organic sprays rather than dusts and further development of biological controls, such as the development of sterile insect strains.

Jan 1, 1965

By Roe-Hoan Yoon, Kaiwu Huang

Derjaguin and Dukhin (1961) were the first to develop a model for bubble-particle interaction in flotation from first principles by considering the surface forces in wetting (or flotation) films. The model predicted that the energy barriers to bubble-particle attachment arise from the ζ-potentials of fine particles, which corroborates well with an earlier work of Fuerstenau (1957) reported for the flotation of quartz using dodecyl ammonium acetate (DAA) as collector. In the present work, a series of surface force measurements have been conducted by accurately monitoring the changes in bubble curvature during bubble-silica surface interactions. The curvature changes are then used to determine the capillary force, which is the sum of the hydrodynamic and surface forces. By subtracting the former that can also be determined from the curvature changes, one obtains the surface forces (or disjoining pressure). The results obtained as functions of pH and collector concentrations show that control of the ζ-potentials of bubbles relative to those of the silica surfaces is critical for maximizing the negative disjoining pressure, which is conducive to promoting bubble-particle attachment in flotation.

By T M. Campos, J Silva, L M. Tavares, J Lichter, L P. Alves, B K. N Rocha, H D. G Turrer

The depletion of the richest ore deposits and the increase in number of mining projects involving deposits with complex mineralogy, higher competence and lower grade has led to an eminent need for improving understanding on multicomponent behaviour in mineral processing. One particularly relevant case is the ball milling of itabirite iron ores fed to the processing plant of Minas-Rio operation in Brazil. Dealing with the two main mineralogical components of the ore, namely hematite and quartz, the operation faces some challenges to improve understanding on how the two components behave in the process. Mathematical models have showed potential to give support in this task, but its applications to describe this type of industrial-scale grinding is still missing. The present work demonstrates the application of a multi-component ball mill model to simulate a closed ball mill circuit with hydrocyclones using the commercial software Integrated Extraction Simulator (IES). Model was calibrated on the basis of bench-scale tests and industrial surveys. Multi-component simulation results are then compared to those considering a single component in the feed, demonstrating the value and great insights that can be achieved by using the former in optimising plant operation.

Aug 24, 2022

By Sangseom Jeong, Kyoungyul Kim, Jaeyeon Cho

"Abstract The lateral earth pressure of vertical circular shaft is investigated by using experimental tests and a theoretical analysis. The emphasis was quantifying on the magnitude and distribution of a lateral earth pressure measured by three-dimensional arching effect. A framework for determining the earth pressure distribution on the basis of both centrifuge model and full-scale field test results is introduced. Through these studies, it is found that the lateral earth pressure decreases within active displacement (dh/H: 0.2×10-2, dh: horizontal displacement, H: Height of vertical shaft) of wall at deep excavation and the arching effect is more significant for deep excavation than for shallow excavation. It is also found that the lateral earth pressure acting on a vertical circular shaft considering arching effect is 70% smaller than that calculated by Rankine theory, and thus represents a significant improvement in the prediction of realistic earth pressure for vertical circular shaft subjected to arching pressure.INTRODUCTIONIn South Korea, an increasing need for underground excavation and the application of the vertical circular wall (i.e. vertical shaft) is becoming an important issue in engineering practice. Here the vertical circular wall is generally embedded in soft or hard rocks through weathered soil varying thicknesses ranging up to 15 m. Since 1980, a number of huge excavation projects such as underground space for constructing power stations, subways, high-speed railways, and many lifeline constructions have been performed in urban areas (Jeong and Seo, 2004). Although there have been considerable advancements in construction techniques involving vertical circular wall, it is still very important for tunnel engineers to control the lateral earth pressure. Additionally, Proper estimation of earth pressures is a key factor in design of vertical circular wall. Because of three dimensional arching effects, i.e. convex arching and/or inverted arching, the earth pressure acting on a circular type of wall is less than other types. Thus, the vertical circular wall is generally used."

Jan 1, 2014

By C. J. Badenhorst

Oxides of sulphur are corrosive and are produced when sulphur-containing fuels are burned. Sulphur dioxide (SO2) is a colourless gas with a characteristic, irritating, pungent odour. Exposure routes to the human body are mainly through inhalation and skin and/or eye contact. Symptoms of exposure to SO2 may include irritation of the eyes, nose, and throat; rhinorrhea (discharge of thin nasal mucous); choking; cough; and reflex bronchoconstriction. To protect employees against the ill health effects of SO2 exposure, they are often required to make use of respiratory protection whenever entering areas were the SO2 levels exceed the statutory limits. The use of respiratory protective equipment should always be a last resort and should be considered only after other control measures have failed to reduce occupational exposure levels to below the occupational exposure limit or whilst other control measures are being investigated or implemented. Whenever the use of respiratory protection equipment is considered, it should always be used as part of a comprehensive respiratory protection plan. It is also extremely important that all potentially exposed persons are adequately and comprehensively informed and trained.

Jan 1, 2007

By Wallace W. Key

The California pesticide industry in 1962 consumed about 30,000 tons of clay, talc, limestone, diatomite, sulfur, and other minerals as fillers (carriers and diluents) in pesticide formulation. This was 10 percent of the U.S. filler requirement for pesticides. About two-thirds of the California total was supplied by a few local mineral producers; the remainder came mainly from Florida, Georgia, and Wyoming. The objectives of this report are to provide data on quantities, sources, specifications, and market conditions for minerals used as fillers by California pesticide formulators. The study disclosed that specifications for mineral fillers have become more rigid and formulators have become more numerous in recent years. During 1962 over 1,200 firms registered 16,000 pesticide products with the Bureau of Chemistry in California. Factors which will tend to diminish future need for mineral fillers include the trend toward greater use of organic sprays rather than dusts and further development of biological controls, such as the development of sterile insect strains.

Jan 1, 1965

By F. X. Tartaron

Behavior of hard-burned quicklime was compared with that of soft-burned quicklime in an oxygen converter utilizing oxygen blowing in a rotating cylindrical vessel, set at a 30° to 60° angle to the horizontal and operated at a predetermined speed of rotation. Four pairs of tests were made) each comparing hard lime with soft lime. Three of the pairs differed from one another in the quantity of lime employed) and the fourth differed in blowing time, All four pairs showed an increase in yield when soft lime was used. Three of the pairs revealed that the ratio of the oxygen consumed with soft lime to the oxygen consumed with hard lime was the same as the ratio of metal yield with soft lime to the metal yield with hard lime. The fourth pair contained an error and could not be included. Finally, a close inverse relation was found between the combined iron in the slag and the combined lime in the slag, which can be expressed by the equation pct Fe = 52.67 -0,906 (pct CaO).

Jan 1, 1967

By John W. Shield

Oxide gold reserves are being rapidly depleted, especially in regions with long histories of gold mining, such as the Black Hills of South Dakota. However, these districts often have substantial additional deposits, where gold is refractory. It is not amenable to traditional cyanide extraction due to the presence of sulfide minerals that encapsulate or otherwise preclude the economic extraction of the gold. Several technologies have been developed to render refractory sulfide deposits amenable to traditional cyanide processing. These include roasting and pressure autoclaving. Unfortunately, these oxidation processes require substantial capital investment and incur significant operating costs. Microorganisms that obtain energy for their life processes by the oxidation of iron sulfides can be used to treat gold-bearing refractory sulfide minerals. As the bacteria convert the sulfide to sulfate, they expose any gold associated with the sulfide matrix. This makes the gold amenable to cyanide extraction.

Jan 1, 1996

By Gregory J. Chekan

The U.S. Bureau of Mines is investigating longwall panel and gate road layouts to increase coal recovery and reduce multiple-seam interactive problems. This report presents design practices for longwall mining multiple seams to provide mine planners and operators with practical guidelines for designing productive longwall mines. Key aspects of mine design that control longwall interactions are examined, including sequencing of seams, design of gate road pillars, and orientation of gate roads and longwall panels. Theories that describe stress transfer between multiple scams and the mechanics of interaction are addressed in relation to geology. Common longwall designs were further investigated using a boundary element model, MULSIM/NL. The model provided insight into relative stress transfer and distribution that occurs between longwall operations in multiple seams. Findings from the model show that (1) a longwall panel should be mined from the gob to the solid coal of an overlying mine, because the stress concentrations are lower; the approach angle should be kept under 30°; and (2) when mining in descending order, superpositioning gate roads usually produces the worst stress condition. To prevent this, the overlying isolated gate roads should be positioned from the centerline toward the headgate side of the underlying panel.

Jan 1, 1993

By Luiz Flávio Pereira Costa

O espessamento de lamas no processo de beneficiamento de minério de ferro é de fundamental importância para a recuperação de água de processo, pois 75% da água é recuperada nesta etapa. Além disso, a qualidade da mesma interfere diretamente no bom desempenho das demais etapas do processo, principalmente na etapa de flotação. Vários são os parâmetros que interferem para obtenção da clarificação ideal do overflow, como: pH, dosagem de coagulantes e floculantes, percentagem de sólidos na alimentação, etc. O pH pode ser considerado o mais importante, pois a partir dele é que se determina as dosagens de coagulante e floculante referentes ao ponto ótimo de coagulação reduzindo assim os efeitos negativos na etapa de flotação. O teste de sedimentação em proveta é uma forma simples e rápida de realizar uma análise da velocidade de sedimentação e clarificação da água frente a diferentes combinações dos parâmetros citados. A Samarco resgatou e implementou na rotina dos operadores da área de espessamento a realização de testes de sedimentação em proveta com o objetivo de reduzir o tempo decorrente de coleta de material, envio ao laboratório e espera pelos resultados. Após a implementação dos testes na rotina operacional, observou-se motivação da equipe em redução de custos, embasamento teórico e assertividade na tomada de ações, diminuição de incidência de eventos de má clarificação da água overflow e diminuição do consumo de floculante em cerca de 30%.

Aug 16, 2017

By Martin Berman

Tables of 28 positions for all the transitions for nine common analyzing crystals for first, second, and third order reflections were compiled by the Bureau of Mines to facilitate elemental X-ray fluorescence analysis on multi-element systems. The tables are based on a compatible set of wavelengths for 2,346 observed X-ray transitions of the elements lithium to americium. The results are tabulated in order of increasing wavelength as well as by increasing wavelength for each element.

Jan 1, 1969

By J. K. Whyatt

The U.S. Bureau of Mines conducted an overcore stress measurement on the 5300 level of the Lucky Friday Mine, Mullan, ID, to investigate the stress regime around an experimental stope in a rock-burst-prone mine. The result indicated a stress field with unexpected magnitude and orientation [s 1 ?135 MPa (19,600 psi) oriented S 80° W). An unusual amount of rock-burst activity was encountered during subsequent excavation. A careful review of the overcore data suggested the overcore strain measurements were valid. Moreover, concentrated rock-burst activity suggested that the measured stress field did exist, but was localized and therefore did not represent the far-field in situ stress field.

Jan 1, 2010

By Valentín Pamo

El presente trabajo describe los procesos y equipos que permiten la extracción de metales preciosos de la refinería de Ilo en condiciones agresivas, obligando a investigar materiales resistentes a la corrosión. Asimismo, se presentan alternativas que aseguren la continuidad de las operaciones en el proceso productivo de dicha refinería.

Sep 9, 2007

Watershed Jll in Jefferson County, Ohio we instrumented in 1977 as one of three watersheds established for the purpose of investigating surface mining and reclamation effects upon local hydrology, sediment discharge, and sediment and water quality. Each watershed was less than 50-acres in size, and was in a different geologic setting within southeastern Ohio. Surface runoff and ground¬water levels were monitored. Samples were taken for sediment determination and chemical analysis prior to mining. Monitoring and sampling continued through the period of watershed disturbance caused by mining and reclamation activities, which began in May 1980 at Watershed Jll. A psuedo-postreclamation period followed the initial cessation of man-machine activity on the watershed. A second reclamation effort occurred in the fall of 1981 and was to be followed by a third in 1982 after observations ceased. A true final postreclamation period was not monitored at this site, because the erosion control practice (terrace diversions) failed after each reclamation. Watershed Jll was a small pasture and wooded watershed with sandstone and shale above the mined coal seam prior to mining. A clay layer under the coal supported a perched saturated zone, termed the top aquifer for convenience. A lower underclay supported a second saturated zone called the middle aquifer. A lower perched aquifer had been dewatered by previous deep mining. After about three years of premine data and about two and one-half years of mining reclamation and psuedo-postreclamation data, the following general observations may be made: 1. The mining-reclamation phase was very short, and the postmining period was characterized by erosion failures and remedial disturbances that kept the watershed condition and size in a state of change. It was impossible to collect sufficient data to confidently characterize the hydrologic-sediment-chemical aspects of the mining period or of a postreclamation period and, most importantly, of the future watershed after its various properties and characteristics have ceased adjusting to its severe disturbance and reconstitution. 2. A seeding of wheat followed by grasses and legumes was not a particularly successful reclamation practice in terms of stabilizing the new soil. Numerous rills and small gullies developed in spite of installed diversions. 3. Storm runoff rates and yields at the watershed outlet increased from the premine, (phase 1) to the mining-reclamation (Phase 2) periods, and remained at or near the Phase 2 level through the postreclamation (Phase 3a) period. 4. The top aquifer changed in physical and chemical character as a result of mining and was becoming reestablished as the project drew to a close; but it is impossible to predict its final configuration or character. 5. Dewatering of the top aquifer resulted in a complete cessation of baseflow because the middle aquifer water table lay below the elevation of the watershed outlet. 6. The top and middle aquifers were merged in one area of the watershed where the upper coal underclay was disturbed. 7. Failure of the diversion terraces and their outlet obscured the effects of the reclamation practice upon sediment concentration and yields. There was little difference in sediment concentrations between Phases 2 and 3a. 8. Drinking water standards were met by surface waters throughout the period of observation except for two samples that exceeded the nitrate-N allowable level of 10 mg/l. 9. In all Phase 3 surface-water samples, iron concentrations were within the limits established by OSM, and manganese concentrations exceeded the regulation level only once. pH fell below the lower regulation level of 6.0 between 10% and 20% of the time. 10. The chemical quality of sediments was generally about the same after reclamation as before mining, with the exception of organic carbon, which decreased.

Jan 1, 1983

By Walter Loel

THE application of aerial photographs to all phases of geologic mapping is set forth, indicating the advantages to be gained in different types of country and under varying climatic conditions. Methods of field and office procedure are given from a geological point of view, as well as suggestions regarding the best methods of aerial mapping for different uses and under varying field conditions, including the study of submarine geology. Aerial photographs with accompanying geologic maps are shown to illustrate the appearance from the air of different geologic features under varying climatic and topographic conditions.

Jan 1, 1938

By Chulgi Suk, Hoon Park, Hyonsoo Kim, Hakman Kim, Sangho Cho

Dust emission from blast demolition and other construction activities can be a nuisance; it is widely recognized that fine particles less than 10 µm in equivalent diameter (called PM10) may cause health problems. Mist spray systems, such as rain guns, sprinklers, water/surfactant sprays (or foams) etc., are some of the most effective dust suppression methods. A large amount of research has showed that when water droplets are produced in an equal amount to that of dust particles, the airborne dust is suppressed by the agglomeration of dust and mist particles. A method for generating micro-sized mist from water, achieved by the detonation of explosives in the water tube, was suggested and is called the ‘detonationdriven water bag burst system’. There are many experimentally observed limitations of the explosioninduced water break-up process. The water bag explosion tests were simulated using the AUTODYN software, in order to investigate the aerosolization mechanisms of the detonation-driven water and water break-up process into micron-sized droplets. As a result of the numerical analyses, the diffusion direction of water when detonating in the central interior part of water tube was radioactive and significantly stronger than when detonating in the bottom exterior part; this is due to the compressive flow of the volume change inside of the water tube, which resulted from the blasting wave inside of the tube, as well as the reflected pressure on the ground. Blast tests of full-scaled reinforced concrete columns were conducted to verify the effectiveness of the suggested detonation-driven water bag burst system. The water breakdown and dispersion that occurred while blasting the reinforced concrete columns were observed using a high-speed camera, and dust generation was monitored using four density detectors. The suggested detonation-driven water bag burst system showed that the average dust density decreased by up to 7 mg/m3.

Jan 1, 2016

By J. G. Craig

This paper initially was to be on the design, construction and operation of the Lucky Friday mill. However, this subject has been pretty well covered in some of the mining publications in the past few years - specifically Mining Congress Journal for April, 1961 and Mining World for March, 1962- : In order to avoid too much repetition, we decided to present in this paper a comparison of the Lucky Friday mill constructed in 1959, and the Mayflower mill built by us in 1962. During the past three years Hecla Mining Company has constructed two relatively small mills: The Lucky Friday mill at Mullan, Idaho 750 T/day; and the Mayflower mill at Heber, Utah - 450 T/day. These mills were engineered, designed and constructed by Hecla, using principally our own personnel, with very little outside (contractor) labor employed. This paper presents a comparison of some of the interesting features of these mills, and where differences occur, it discusses the reasons for the various differences. It compares such points as the testing program, physical layout of the plant, construction costs, the grinding section, the flotation section, tailings disposal, metallurgy, recovery, grades, operating costs, etc. To help illustrate, and to compare these features, we will project pairs of slides showing each of the two mills. First a little background and history on the properties ---

Jan 1, 1964