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By W. W. Adams

In mining coal, the Nation's principal mineral fuel, loss of life has been much lower recently than in earlier years when coal mining contributed so heavily to the industrial-accident death toll in the United States. Particularly notable has been the relatively small number of deaths during the past few years compared with the number that occurred 20 or 30 years ago. Reports received by the United States Bureau of Mines, covering all commercially operated mines that were active during all or any part of the calendar year 1935, showed that accidents during that year had resulted in the loss of 1,242 lives. This death toll, although regrettable, represents a material improvement over the industry's experience during most years prior to 1935, and especially over the industry's worst year, 1907, when 3,242 men were killed. Fewer lives were lost in 1933, when 1,064 men were killed at work, than during any year for which complete figures are available.

Jan 1, 1938

By Robin J. Hickson

El Abra is one of the world’s premier copper de-posits. The project is located in northern Chile, 140 km (87 miles) inland from the Pacific coast. It has the same geologic age and structural setting as the world-class Chuquicamata copper mine located 42 km (26 miles) to the south. The current development plan for El Abra extracts798 Mt (879 million st) of high-quality oxide ore. This will require building a solvent extraction/electrowinning(SX/EW) facility that can produce 225 kt/a (248,000stpy) of cathode copper. This will make El Abra the largest SX/EW copper operation in the world, and the world’s seventh-largest copper producer.

Jan 1, 1996

By S. D. Hill, G. E. McClelland

To maximize productivity and improve minerals processing technology, the U. S. Department of the Interior, Bureau of Mines, is investigating a particle agglomeration technique as a means of increasing the percolation rate of leaching solutions through heaps of clayey or finely crushed, low- grade, gold-silver ores. Bench-scale and pilot-scale experiments conducted on different ores indicated that the percolation rate of cyanide leaching solution was enhanced markedly by mixing the ore with a binder, such as lime or portland cement, moistening the mixture, then mechanically agglomerating and aging the feed prior to heap building and leaching. In addition, the rate of silver and gold extraction markedly increased without sacrificing total recovery of values. The use of concentrated cyanide solution instead of water during the agglomeration procedure substantially decreased the leaching time required to obtain maximum recovery. Results from bench-scale and pilot-scale experiments using the particle agglomeration technique are discussed.

Jan 1, 1981

By George M. Robles

Dado que la máquina de flotación ha sido aceptada por la industria minera, el uso de la celda de flotación de volumen ofrece mayores ventajas y beneficios en tanto que el tonelaje a tratar va aumentando. En este sentido, el objeto del texto señala los beneficios de las celdas con mayor volumen individual en máquinas de flotación puesto que suministra suficiente cantidad de burbujas finamente dispersas que se adecúan a las partículas deseadas. Asimismo mantiene un espacio que lo separa de la especie flotable del resto de la pulpa y evita la atracción material inerte una vez que se forme la capa de espuma.

Nov 8, 1982

By Víctor Guimaraes

El presente texto señala las estrategias de planteamiento de minado en la minera Tintaya con el objetivo de maximizar el valor neto de la operación minera y a un nivel aceptable de riesgo. Este ciclo de planeamiento, evalúan diferentes alternativas dentro de los siguientes procesos como: optimización del pit (Uso de ley corte durante el proceso, diseño de taludes, Pit descontado, inclusión de nuevos procesos metalúrgicos y de recursos inferidos), generación de fases de minado (Parametrización de fases), programación de la producción (uso de optimizadores basados en programación lineal), planeamiento de desarrollo mina (incluye planes de drenaje subterráneo y superficial), Planeamiento corto plazo y actualización del plan de cierre.

Sep 9, 2007

By AIME AIME

BESIDES commanding increasing importance as an alloying element in combination with ferrous and other nonferrous metals, the variety of uses for pure nickel continues to widen. For coinage it is growing in popularity. These coins have been minted for 27 countries in 72 issues representing 69 denominations. Approximately 3,000,000,000 pieces have been struck, the aggregate weight, of which amounts to nearly 14,000 tons. . Danzig, Iraq and Japan are the most recent governments to adopt, pure nickel coinage. France is adding the denomination of five francs to its other nickel currency; they replace silver pieces. Germany is now minting a new issue of one Reichsmark coins of pure nickel. The Japanese program for 1933 called for the issue of 35,000,000 10-sen pieces and 30,000,000 5-sen pieces. In radio tube manufacture the consumption of pure nickel was approximately twice that of 1932. During 1.933 the nickel plating process by which bright deposits may be plated

Jan 1, 1934

By Érika Aline dos Santos

Este trabalho tem como objetivo a síntese de materiais híbridos nanoestruturados à partir da funcionalização do argilomineral haloisita com (3-aminopropil)trietoxissilano (APTES) para aplicação em processos de adsorção. A rota de modificação baseou-se na acidificação e posterior reação química entre as hidroxilas superficiais da haloisita e os grupos hidrolisáveis de APTES na presença de tolueno sob refluxo. Haloisita em sua forma natural e modificada foi caracterizada por análise termogravimétrica (TG), área superficial específica (BET), espectroscopia de infravermelho (FTIR) e difração de raios X (DRX). A quantidade de APTES enxertado, calculado através da análise termogravimétrica foi de 7,32% para a amostra funcionalizada previamente acidificada e 6,50% para a amostra funcionalizada sem pré tratamento ácido. A área superficial das amostras diminuiu com a funcionalização. As amostras funcionalizadas exibiram novas bandas características de grupos de APTES no espectro obtido por FTIR confirmando a ocorrência da funcionalização do organosilano na haloisita. A análise de DRX indicou que a estrutura original não foi alterada após a funcionalização.

Aug 16, 2017

By Mike Amick

As virgin coal reserves dwindle, more and more mines are being opened in areas with previous mining. As addressed in this conference before, there are solutions available for designing mines extracting coal from reserves with known underground workings above or below the target seam. Often times, however, mining begins with limited knowledge of the underground workings. Even with careful planning, the proposed design has limited success because the ?facts? as presented during planning turn out not to be as accurate as one would like. At National Coal?s Mine #14, mining the Walnut Mountain seam, after driving the main entries in some 34 crosscuts, it was found during routine mine examinations that the pillars had separated from the roof in a few areas of the mains. Immediate roof conditions proved to be sound but questions arose concerning the stability of the main roof and floor. Core tests were done to better determine the rock strengths and characteristics. The paper presents the ideology used to tackle the effects of mining over old works in an operating coal mine. This paper discusses the analysis of the symptoms observed and the steps taken to ensure that this pillar separation was caused by the underlying old workings and that the separation was expected and controllable.

Jan 1, 2009

By V. V. Nazimko

Abandoned coal mines cause subsidence and structural damages. Shallow abandoned mines induce the most severe and harmful damages. In addition, they produce time-dependent subsidence which is difficult to predict. Backfilling of underground cavities with waste materials have been used to prevent the time-dependent subsidence or to mitigate its effect. However, this procedure is expensive. A new drill and blast technique has recently been proposed to prevent surface damage from time¬dependent subsidence over abandoned mines. It utilizes the principle that blasting in the caved rock and roof in the vicinity of a cavity will dilate the ground and create a self-supporting effect owing to increase in the volume. Physical modeling has demonstrated that artificial dilation of caved rock using the drill & blast technique creates positive effects due to the following sequence of events: the dilated rock creates a supporting effect for the suspended rock strata and reduces its span which decelerates 3.4 times the process of caving. The roof span is reduced by the next caved layer, which causes the hole boundaries to incline to each other. This effect converts the process of caving from a developing mode to a reduction mode. Finally, the sinkhole zone assumes a triangular shape with a negative angle of draw 64-700 in contrast to a rectangular shape of the chimney zone for natural caving. Vertical dimension of the triangular zone is 3.87 times of the room height. Final surface subsidence decreases at least 2.09 times; displacement 1.31 times, slope 2 27 times; curvature 3.42 times, horizontal strain 1 21 times in comparison to natural caving of the ground over an abandoned mine.

Jan 1, 1999

By Luis A. Maradiegue

El presente estudio refiere el diagnóstico correcto de la silicosis a través de una revisión de la historia ocupacional, historia clínica y el ambiente del trabajo del trabajador. El control del trabajador y del ambiente de trabajo, lo deben realizar los médicos e ingenieros, para evitar o retardar la progresión de la silicosis o enfermedades respiratorias y facilitar el cambio de lugar de ocupación del trabajador, controlando el medio ambiente, respectivamente. Asimismo, en la evaluación del riesgo silicógeno en una industria extractiva, el ingeniero utiliza el instrumento Midget Iapinger, el muestreo, y los métodos de "campo brillante" para la cuenta de particulas, y la dispensación de la muestra en aceite de inmersión para la medición de partículas. El análisis de sílice libre comprende los métodos petrográficos, difracción de rayos X y el de fusión. Finalmente se hace una interpretación de resultados y se presenta un informe detallado de la condición de salubridad del trabajador.

Aug 20, 1963

By Thomas M. Barczak

A critical safety component for all underground mining is intrinsic and standing support systems. Specifically, tabular hardrock mining exploits a wide variety of deposits that require various methodologies to safely mine the ore material. Several new support systems have been developed in recent years for hard rock applications which have been modified or applied in a variety of ground control applications. These include prestressing devices, improved cribs, and free standing supports. Various standing support and prop-type systems have been designed for hard rock applications with seismic loading conditions to accept prestressing. The prestressing, using water-filled cells, creates an active load upon installation and is considered essential to maintain support during and after the blasting of the mine faces. Heavy seismic activity is also present in these mines and the prestressing units can provide some energy absorption capability to help preserve the integrity of the support. This paper presents an overview of these innovations in support technology.

May 1, 2007

Ante la baja recuperación del oro encontrado en la mina Calpa, perteneciente al Consorcio Minero del Perú S.A, el objeto del presente texto señala los experimentos, conclusiones y recomendaciones que resuelven dicha situación. La minería Calpa se sitúa en la provincia de Caravelí, departamento de Arequipa, donde la mineralización se presenta en vetas de cuarzo, con pirita y chalcopirita, de tal forma que el oro y la plata se encuentran impregnando dichos minerales. El tratamiento minerológico se realiza en la planta mixta de flotación-cianuración, cuya capacidad media es de 200 toneladas diarias y la ley de cabeza es de: Au: 14.6 Gms/Tn.; Ag: 0.6 Onz/Tn.; Cu: 0.8%. El relave experimentado se realizó en los laboratorios que el consorcio tiene en sus minas de San Juan de Lucanas, encontrándose que agregados el lavado y remolienda al actual funcionarmiento de la planta, puede bajarse el relave a 1.46 Gms/Tn., recuperando el oro por cianuración a un 90%, mientras que el 10% restante es rebelde a la cianuración encontrada en los compuestos del oro. Por último, la concentración de pirita y su tostación posterior ofrecen la mejor solución al beneficio de los minerales de Calpa, ya que elevarían la extracción al 99 ,7%, dejando el relave con 0. 33 Gms/Tn. de contenido de oro, sin mencionar posibles dificultades como el cambio de acidez en la pulpa, flotación de las piritas, tostación de vetas y posterior cianuración.

Jul 20, 1957

By Marlos Henrique Alves Gomes

Aços resistentes ao desgaste são amplamente aplicados em partes estruturais que exigem propriedades como resistência mecânica, tenacidade e resistência ao desgaste abrasivo. O presente trabalho foi realizado devido à necessidade de desenvolvimento de materiais necessários para minimizar os efeitos causados pelo desgaste abrasivo. Os objetivos são: obter microestrutura multiconstituída (ferrita, bainita, martensita e austenita retida) por meio de tratamentos térmicos; e compará-la a microestrutura martensítica revenida. O aço estudado possui a seguinte composição química 0,26%C-1,13%Mn-0,92%Si-0,72%Cr- 0,29%Mo-0,18%Ni-0,17%Cu. Conduziu-se os tratamentos térmicos na sequência apresentada: recozimento subcrítico a 700°C, têmpera em óleo (temperatura de austenitização 940°C) e tratamento isotérmico de transformação bainítica (temperatura de austenitização de 820, 860, 900 e 940°C) ou recozimento subcrítico a 700°C seguido de têmpera/revenimento (940°C e resfriamento em água/250°C por 2 horas). Microscopia Eletrônica de Varredura (MEV) foi empregada para se avaliar a microestrutura do aço. Dureza Rockwell C foi utilizada com intuito de comparar a dureza das diversas microestruturas obtidas. Constatou-se que com a diminuição da temperatura de austenitização houve decréscimo do valor de dureza; e as amostras temperadas e revenidas demonstraram dureza média maior que as amostras que passaram por tratamento isotérmico de bainitização. A microestrutura multiconstituída foi obtida.

Aug 17, 2017

By Steve Stuart

Deep-sea mineral SMS deposits present some of the world’s most challenging conditions for drilling equipment. As robotic seabed drilling services mature so too the ways that clients engage with service providers to maximise their data requirements. This presentation reviews key considerations for planning and executing a successful seabeddrilling program in variable mineralised deposits. Some of the means of collaboration between robotic seabed drilling contractors and those hiring their services are explored; where improved efficiencies and recoveries over the period of a drilling programme could be achieved. Potentially new technology or methodology can be looked at to further improve these approaches.

Sep 1, 2014

By Moyle F. J

This paper describes an apparatus which was developed to study solid-vapour equilibria and presents results which were obtained during a study of the FeCI3-AlCI3-CI2 system. Analysis of the results showsthat fractional desublimation might offer a means of achieving a useful separation of the iron and aluminium chlorides produced by the chlorination of bauxite. The results, presented in the form of isothermal vapour pressure curves covering the range of temperature 160-200°C, support the earlier findings of Semenenko et al (Dokl Akad Nauk SSSR, 154: 42-43 (1964)) that the solid phase contains two terminal solid solutions.The equilibrium constant for the formation of the mixed dimer, FeAICI6, was approximately 4. The latent heat of sublimation of aluminium chloride varied from 18 to 26 kcal/mole AI2CI6 for solid compositionsfrom 0.9 to 0·5 mole fraction FeCls3.

Jan 1, 1979

By Jack S. Watson, Rasika Nimkar, Robert M. Counce, Matthew Gordy, Patrick Zhang

Waste phosphatic clay presents a difficult disposal problem and a significant loss of P2O5. Recent developments make this study on the use of phosphatic clay as a feed material for H3PO4 production worthwhile. (a) New data from Florida Industrial and Phosphate Research Institute (FIPR) suggest that the Bclay^ waste can be effectively treated by improved solid separation coupled with flotation to produce feed material for recovering additional phosphate. (b) The use of BOLI Flowsheet^ provides capability to predict performance of aqueous-based processes for a range of possible operating conditions. Using the new FIPR data and BOLI Flowsheet^ enabled the design of a new process that can potentially extend the usefulness of current P2O5 ore deposits. Predictions using OLI Flowsheet were able to identify process conditions that effectively overcome the difficulty of high Mg content of phosphatic clay. Estimated manufacturing cost in the current study lead to valuation of the P2O5 content of the phosphatic clay recovered/utilized at 60 to 70% of that of the phosphate rock feed material currently used. Phosphatic clay should be considered as a valuable material that is currently given zero value. The new FIPR data and BOLI Flowsheet^ enables the design of a new process that can potentially extend the usefulness of current phosphate ore deposits by extending the fraction P2O5 of recovered

By William P. Stroud

Chemical alteration of the compressive strength of sandstone has been investigated by the U.S. Bureau of Mines (USBM). Successful development of this technology would offer an attractive alternative to the methods now used for stress control in mines. Sandstone cores were stressed to failure under uniaxial compression at two different strain rates. Specimens saturated with either distilled or tap water showed an average 14% reduction in stress at failure compared with those dried in vacuum. Samples saturated with dilute solutions of aluminum chloride, hydrochloric acid, and polyethylene oxide showed no statistically significant difference in failure stress compared with those saturated with water. By contrast, compressive strength of the cores was increased some 7% by saturation with the nonpolar solvent carbon tetrachloride. No correlation was found between zeta potential and compressive strength.

Jan 1, 2010

THE solid nonmetallic inclusions present to some extent in all commercial steels have been variously designated. In early references they were usually called slag inclusions, and this terminology is still retained to some extent. On the premise that all nonmetallic matter produced in a metallurgical process is slag, this can be justified. We have come to think of slag, how- ever, in a more restricted sense, and calling these particles slag inclusions is further objectionable because it fosters the erroneous concept that they are actually incorporated portions of furnace slag. Rarely is this true. The term sonims (coined from solid nonmetallic impurities) was proposed many years ago but never came into common use. In general, the term non- metallic inclusions seems to be satisfactory and adequate. NATURE AND CONSTITUTION OF NONMETALLIC INCLUSIONS From the standpoint of origin, inclusions fall naturally into two classes: (1) those occurring as a result of reactions taking place in the body of molten or solidifying metal and (2) those resulting from mechanical incorporation of refractories or other materials with which molten steel comes in contact. The former are by far the more numerous and have been called indigenous, natural, or native inclusions. The latter are by their very nature sporadic in occurrence and have been called exogenous, accidental, adventitious, or foreign inclusions. They are often referred to as the "slag-stringer" type, though here also the material is not likely to be furnace slag. Substances Found in Inclusions. Nonmetallic inclusions are composed principally of oxides and sulfides but carbides and nitrides sometimes play an important role. In the case of indigenous inclusions the reactions by which these particles are precipitated from molten or solidifying steel may be caused by: (1) oxidation such as may occur during refining or during tapping and teeming, (2) deoxidation by added alloys, (3) change

Jan 1, 1951

By J. H. Rowland

The Mine Improvement and New Emergency Response Act of 2006 (MINER Act) amended the Federal Mine Safety and Health Act of 1977 to improve the safety of mines. The MINER Act established a Technical Study Panel (the Panel) to provide independent scientific and engineering review and recommendations with respect to the utilization of belt air and the composition and fire retardant materials in underground coal mining (1). Because frictional heating is a common cause of belt fires, the Panel recommended that the Mine Safety and Health Administration (MSHA) evaluate the drum friction test to determine if such a test would contribute to conveyor belt safety beyond that provided by the Belt Evaluation Laboratory Test (BELT). This paper compares the results of the drum friction test to results from the BELT and large-scale tests for six different conveyor belts. The results are used to evaluate the drum friction test as a method to determine the fire resistance of conveyor belts.

Jan 1, 2011

By Glenn Lyle

CEMI Introduction ? Introduction of the CAF VOD Project ? Who are our partners ? What were the Outcomes What is next

May 1, 2011