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The value of processed materials of mineral origin was estimated to have exceeded $297 billion in 1991. U.S. raw non fuel minerals production in 1991 was estimated at $30.8 billion, a 5.8% decline from that in 1990. This estimate was based on data for the first quarter of 1991 (in some cases two quarters) for most of the 21 minerals that for many years have accounted for more than 95% of the industry's production value. The value of minerals production has increased in all but 4 of the last 30 years. The metals component of production value has fluctuated much more than the industrial minerals component, reflecting the greater volatility of metal prices. Employment in metal mining rose slightly in 1991, but this gain was more than offset by a decline in employment in industrial mineral mining, resulting in an overall decline of 3.0% to 164,600 workers in 1991. Prices of several major metals declined during 1991, reflecting weakness in the economy, causing some metal mines to shut down or reduce operations.

Jan 1, 1992

By Robert C. Merritt

Laboratory amenability studies as well as a pilot heap-leaching investigation of low-grade sandstone uranium ores from Wyoming, New Mexico, and Colorado are described. Sulfuric acid heap leaching with oxidation, for 120 days, extracted up to 98 percent, 90 percent, and 79 percent U308 from Wyoming, New Mexico, and Colorado ores, respectively.

Jan 1, 1976

By Jesús Guerra, Edgard Atencia, Edwin Cereceda

En la actualidad la minería se sitúa en un escenario donde se tiene recursos con menor contenido de ley, sumado a la actual coyuntura del país con la desaceleración económica y la inflación. Frente a ello es de vital importancia buscar oportunidades de mejora que permitan que sea rentable el minado mediante la optimización del proceso con el objetivo de reducir el costo operativo. En particular la mediana minería aporta con una producción de Cu del 12.5% del total nacional, lo que se traduce en 304,828 Ton finas /año de Cu.

Sep 29, 2023

By Carlos España Ch

El presente texto plantea la mecanización en la mediana minería como método de trabajo para el tratamiento de minerales y trabajos auxiliares. La ejecución de esta mecanización es de acuerdo al tipo de yacimientos de cada caso particular. En este sentido, la compañía minera Alianza S.A. es un ejemplo de este enfoque empresarial, así como las minas Hércules y Coturcán, las cuales implementaron la minería sin rieles, donde el desarrollo y preparación de las vetas se realiza por medio de rampas que puedan tener pilares de 200 mt.s de largo, posibilitando el uso del método de explotación mecanizado-fronton pilar e incrementando la productividad en comparación con las etapas de mecanización incipiente.

Oct 14, 1980

By Noel Díaz Bernal

El presente texto señala las concentaciones de metales preciosos, oro y plata dentro de las menas comunes de metales básicos de plomo y zinc en vetas dentro de volcánicos terciarios.

Sep 1, 1974

By F. Habashi

The peninsula that lies between the Black and Mediterranean seas, called Asia Minor by the Romans and Anatolia by the Greeks, was one of the crossroads of ancient civilizations. The fall of Constantinople in 1453 was a turning point in the history of mankind. Visits to Istanbul, Ankara, Eskisehir, Cappadocia, and Trabzon will be given together with the history of the country. Mineral resources of the country will also be briefly outlined.

Feb 23, 2014

By C. K. Eilerts

Knowledge of the phase relations of the fluids that exist in the porous spaces of rocks constituting natural petroleum reservoirs and of the behavior of these fluids under various field conditions of operation is essential to the conservation of petroleum and natural gas and to their efficient recovery. The problem of determining whether these fluids are in the liquid or gaseous state and of recognizing the transitions that may take place as the material in the reservoir is subjected to different conditions of pressure and temperature confronts many producers today, especially in certain fields. The subject has grown rapidly in importance since the discovery of and production from deeper reservoirs that have correspondingly higher pressures and temperatures as compared with shallower

Jan 1, 1938

By A. L. Podia

The purpose of this research was to develop a system capable of detecting changes in the structure of rocks, leading to failure of mine roofs, and/or excavations. A prototype system was developed, field tested and delivered to the United States Bureau of Mines for further evaluation and research. This system is based on the analysis of acoustic signals generated on the surface of the roof by an impact device and which are reflected or backscattered by flaws and discontinuities in the rock. The specially designed impact source is capable of generating high frequency acoustic signals with excellent repeatability. The system can also be used in conjunction with conventional acoustic pulse transducers. The received signal is digitized and the data transferred to a minicomputer for processing and display. This capability allows the immediate determination of wave velocity and/or distance to a reflecting interface. Various data processing techniques such as averaging, differentiating, and comparing of different signals can be selected by entering the appropriate commands on the keyboard. Being a programmable system it is possible to implement more advanced signal processing techniques. All results as well as the signal are displayed on a CRT. Furthermore, a permanent record of the data can be generated on paper tape, which can be reentered and processed at a later date. A communications interface allows transmission of the sampled signal to a large scale re-mote computer. The system was tested extensively in the laboratory, and field tested at the York Canyon Coal Mine. These tests proved the feasibility of operation in the mining environment. Results indicate that further investigation and development will have to be undertaken to fully develop the potential of this system in satisfying the goals of this research.

Jan 1, 1973

By D. A. Barr

High-grade gold-silver mineralization associated with electrum and argentite was discovered in a quartz vein at the Chappelle property, 273 km north of Smithers, B.C., in 1969 following a regional geochemical reconnaissance program in the Cassiar-Omineca Mountains. Subsequent exploration resulted in the discovery of numerous quartz veins with associated precious-metal values in a belt 17 by 3 km in area centrally located within Toodoggone Group volcanic and sedimentary rocks of Lower to Middle Jurassic age and a window of Takla Group volcanic rocks of Upper Triassic age. More detailed investigations, consisting principally of 5677 m of surface drilling in 57 holes and crosscutting, drifting and raising on Chapelle Vein A, has outlined a high-grade gold-silver-bearing shoot with a strike length of 200 m, an average width of about 3 m and extending to an average depth of about 40 m below surface.

Jan 1, 1978

By J. E. Johnson

IT is the purpose of the present paper, while not excluding chemical considerations, to deal more extensively with some of the physical and mechanical aspects of the blast-furnace process, and to point out its dependence in these respects on well-known laws. The quantity and cost of ore and flux required to make a ton of iron being determined by circumstances over which the furnace-man, under given conditions as to quality and quantity of product, has commonly little control; the principal item of cost, apart from the saving of labor, which he can aspire to reduce, is that of fuel. To determine the limits of possibility in this direction is clearly the first step in d practical inquiry; and this step is represented herewith in Fig. 1, a diagram showing the total useful effect obtained from a pound of fuel under various conditions, and thus permitting direct comparison, under any given conditions, between actual results and the maximum possible results. The following statements will explain the basis upon which this diagram has been constructed. One pound of fuel, containing 90 per cent. of fixed carbon (which represents average conditions), is taken as the unit. The degree of oxidation of the carbon is measured by the ratio of the two oxides of carbon contained in the top-gases. It is necessary to remember that a considerable quantity of carbon is brought in as carbon dioxide by the flux, and to take account of it and of its condition. It is here considered that the carbon dioxide liberated by the limestone does not affect the analysis of the toll-gases, and that the ratio of CO to CO., will remain unchanged by the addition of limestone; enough CO, being reduced by the solution

Sep 1, 1905

By Nahiri Hirsh

El programa de fortalecimiento de capacidades Capas y Capaces impulsa el trabajo articulado de las instituciones educativas Nuestra Señora de La Merced, Rafael Loayza Guevara y Dos de Mayo, organizaciones de base, Yanacocha y la Dirección Regional de Educación, para el desarrollo sostenible de las comunidades. Se trabaja en el desarrollo y mejora de capacidades técnicas en estudiantes de 3°, 4° y 5° año de secundaria, así como de padres y madres de Cajamarca, con el objetivo de prepararlos para la vida y desterrar la dependencia económica. La capacitación se realiza con métodos innovadores (haciendo uso de laboratorios, equipos y maquinaria moderna) que han logrado convertir al programa en referente del Ministerio de Educación para la educación técnica en instituciones públicas a nivel nacional.

Sep 20, 2019

By Hernán Alvarado

"En los últimos años, la minería ha utilizado los relaves de concentradora, previamente deslamados como material de relleno en las labores subterraneas. Sin embargo, el tonelaje disponible por este sistema no satisface lasnecesidades de relleno de la mina. En ese sentido, el presente texto señala la aplicabilidad del sistema complementario en la mina Francois. Por ello, se han considerado dos sistemas principales para la recuperación y tratamiento de los relaves antiguos: Dragado e Hidráulica. Estos sistemas contienen un equipo de extracción y dilución del relave antiguo, equipo de bombeo, estación de tratamiento para los relaves antiguos, el equipo de almacenamiento y dosaje y equipo de bombeo. Las variantes de los dos sistemas son: equipos, densidades del relave y volumen de agua. De forma que la cantidad de agua recuperada de los relaves de flotación es suficiente para operar el circuito con cualesquiera de los sistemas propuestos. "

Sep 1, 1964

By R. Luchese de Moraes, J. A. Matthews, C. Feliciano Bruzual

The role of biomass char in blast furnaces has been re-examined by scientists worldwide, as a feasible option to reduce the carbon intensity of ironmaking. This contribution makes a technical and economic analysis of the ferro gusa industry in Brazil, with the last 172 charcoal-Blast Furnaces operating in the world. A key strategic question is presented: what is the current status and future prospects of biomass use in Blast Furnaces? Findings provide significant implications to metallurgists: while ferro gusa from charcoal is regarded as carbon neutral iron with low impurities, there are limiting factors that hinder the further proliferation of charcoal-BFs: biomass generation requires vast extensions of arable land and aggregates have low production capacity. Additionally, most of the charcoal is presently generated in beehive kilns with low yields. These elements combined make charcoal-hot metal expensive in price. With respect to the future prospects of biomass, the injection of small biochar particles through the PCI rigs in BFs (here coined Bio-PCI) and iron ore sintering may offer a practical alternative to significantly reduce the CO2 emissions in the ironmaking process.

Jan 1, 2015

By David del Pino Ávila

El incremento de los costos de tareas, materiales, repuestos y la contínua baja del precio de los metales, conllevó que los ingenieros a cargo de las operaciones en la mina Carahuacra, mejoren sus métodos de minado y reduzcan sus costos, aumentando la productividad, así como las leyes de mineral de zinc mediante una mejor selectividad de los block a minar. En este sentido, el presente texto busca mostrar las actuales operaciones unitarias de perforación, voladura, sostenimiento robotizado, limpieza, acarreo del mineral y relleno de las áreas vacías, en tajeos explotados por el método súper bresting, con anchos de labor de 10 metros, alturas de 6 metros y longitudes de 200 metros. De forma que la automatización en el sostenimiento de las grandes áreas abiertas permite aumentar la eficiencia y productividad bajando costos, así como la selectividad con el objetivo que la mina sea rentable y segura.

Sep 14, 2009

By Charles Hardy, George D. Cremer

POWDER metallurgy has been established for some time as a novel method for manufacturing a great variety of articles generally specialties that could not be made conveniently by any other method. In this category are such parts as porous hearings cutting tools of sintered carbides, and electrical contacts in which the metallic constituents do not tend to alloy in the proportions employed. The industry, however, is now at a stage where it has begun to manufacture articles that can and have been made by other methods. Thus, powder metallurgy is now preferred technique for the production of numerous machine parts characterized by high strength, accuracy of configuration, and substantial lack of porosity. Manufacture of such machine parts from metal powders has no doubt been stimulated by the war, although the trend in this direction has been apparent for several years. In any case, quantity production of high-density precision pieces by ponder metallurgy is now in full suing in the United States, and such production can and should continue to expand during and after the war.

Jan 1, 1942

U.S. Gold Commission Established. - The President, with the authorization of Congress, has named a gold commission made up of 17 individuals, most of them Government officials, to study U.S. policies related to the role of gold in domestic and international monetary systems and report its findings and recommendations to Congress. U.S. Lead Exposure Ruling. - On June 29, the Supreme Court upheld the Government's right to set lead exposure levels for employees at the workplace. The Court ruled in favor of the Occupational Safety and Health Administration (OSHA) in a challenge by a group that alleged that OSHA had failed to conduct a cost-benefit analysis prior to issuance of the lead standards. It was the Court's contention that Congress did not require such an analysis when it empowered OSHA to establish workplace standards. The petition to the Court was made by the Lead Industries Association Inc., Battery Council International Inc" American Iron and Steel Institute, St. Joe Minerals Corp., and other lead mining and consuming firms.

Jan 1, 1981

By Enrique Cervantes

Durante mucho tiempo, las vetas angostas generaron inquietud para los operadores mineros - en tanto su morfología provoca una baja productividad, así como el aspecto técnico obliga a depurar sus sistemas. En ese sentido, el presente texto refiere el método de corte y relleno como el más adecuado para la explotación de vetas puesto que puede adaptarse a las características de este tipo de yacimientos, además del alto grado de flexibilidad para adoptar algún cambio de sistema.

Sep 1, 1982

By Keith L. Harris

Economic activity in the United States picked up in the third quarter, according to the latest estimate released by the Department of Commerce. Real gross national product (GNP)--the Nation's output of goods and services--grew at a seasonally adjusted annual rate of 4.3%, or $17.6 billion, compared with a rate of 1.9% for the second quarter of 1985 and 1.6% for the third quarter of 1984 (table 1). The 4.3% rate is one percentage point above the preliminary estimate reported in the August/September issue of Minerals and Materials. Most of the upward revision was due to the change in business inventories and Government purchases, while the figure for net exports was revised downward substantially. The 4.3% growth bettered by 1.5% the average rate of growth in GNP from 1974 through 1984 and was 1.1 % above that of the period from 1975 through 1984 and 0.7% above that of 1980 through 1984. Of importance to the minerals industry was the $14.4-billion growth in personal consumption expenditures, $10.2 billion of which was for durable goods (especially domestically produced automobiles) and the growing residential investment. The net export deficit continued to grow, however, and investment in nonresidential structures, producers' durable equipment, and business inventories declined. Prices, as measured by the GNP fixed-weighted price index, increased at an annual rate of 3.1% in the third quarter, compared with 3.9% in the second quarter. The slower rate of inflation resulted mainly from a decline in energy prices, following second-quarter increases. Fourth-Quarter Prognosis Many of the economic data available for October and November indicate that the economy is growing modestly and will continue to grow over the next 3 to 6 months. The composite index of leading indicators, designed to predict economic activity within 3 to 6 months, rose 0.3% in October, the sixth consecutive monthly advance, according to the Department of Commerce. Six of the 11 available leading indicators were positive: Stock market prices rose, as did sensitive material prices, credit outstanding, and manufacturers' new orders for consumer goods and materials; initial claims for unemployment insurance decreased, and firms were getting slower delivery of goods. Four of the indicators were negative: Business formations, homebuilding permits, contracts and orders for plant and equipment, and money supply all declined. The average hours worked per week, already at a high level, remained unchanged.

Jan 1, 1985

By Enrique Herrera, Manuel Munguía

La Fundición de cobre de Ilo de Southern Perú, arranco sus operaciones en 1960 con el proyecto Toquepala, en 1976 se expandió con el proyecto Cuajone, y en 1995 inició su proceso de modernización con la implementación de un convertidor Teniente y Plantas de Ácido Sulfúrico y de Oxígeno para reducir las emisiones gaseosas de dióxido de azufre al ambiente. En el 2007 se comisionó el proyecto de modernización de la Fundición de Ilo, con la implementación de un horno de fusión “Isasmelt” en reemplazo de los hornos reverbero y convertidor Teniente, y plantas adicionales de ácido sulfúrico y de oxígeno de mayor capacidad a fines de capturar el azufre de los concentrados por encima del 92%, y que se constituyó en el proyecto ambiental con la mayor inversión desarrollada en la historia del país.

Sep 30, 2022

By Ricardo Cortés Arana

El presente texto describe el ausentismo y las relaciones humanas como factores de productividad y equilibrio dentro de la compañía minera Atacocha. La asistencia continua al trabajo asegura la estabilidad del empleo y no altera el ritmo de producción de la planta minera. Por consiguiente, la ausencia inmotivada de un trabajador en la mina, afecta el rendimiento de los demás miembros y a la misma empresa. En cuanto las relaciones humanas, estas deben ser constructivas y basadas en el espíritu de cooperación entre obreros y patrones, así como destacar el conocimiento técnico, interés genuino y personal por las personas que trabajan en ella.

Jul 20, 1960