Search Documents

By Aldo Bendezú

En el Perú, el cobalto @>0.1% de concentración se da principalmente en sistemas hidrotermales, particularmente en yacimientos de tipo IOCG y en vetas altoandinas de Zn-Pb-(Ag)-Ni. El primer tipo se presenta en al menos dos segmentos del cinturón de yacimientos IOCG de la costa, entre Lima e Ica. El segundo ha sido documentado principalmente en la Cordillera Oriental, entre Huánuco y Puno. Se han identificado 29 sistemas de vetas y mantos significativos entre ambos tipos. En las vetas, estos ocupan porciones restringidas de 100-500 m de largo, 50-200 m de alto y 0.2-1.5 m de potencia, sugiriendo masas prospectivas del orden de 0.2-0.5 Mt por cada sistema.

May 10, 2023

By Javier Delgado Valladares

El presente artículo describe un caso donde se ejemplifica la irresponsabiliad de la empresa en accidentes de trabajo. Para ello, se revisa el artículo 53 de la Ley de Seguridad y Salud en el Trabajo (LSST), Ley Nº 29783, donde señala que probado el daño sufrido por el trabajador a causa de un accidente de trabajo, la empresa tiene la obligación de pagar una indemnización a la víctima, la cual será fijada por el juez conforme al artículo 1332° del Código Civil, salvo que las partes hubieran aportado pruebas documentales o periciales sobre el valor del mismo.

Mar 1, 2017

By Richard Palape

El presente trabajo cuenta la experiencia, metodología y tecnología desarrollada en varios sitios por más de media década y profundiza en una de las minas a tajo abierto más importantes del mundo en cuanto a su eficiencia y productividad situándose a la vez dentro de las 10 más grandes en producción de cobre a nivel global. En este nivel de operación se podría pensar que se encuentra todo bajo control; sin embargo, existen oportunidades de mejora para ir a un siguiente nivel al que llamamos Excelencia Operacional Digital.

Sep 30, 2022

By Lui Chocano

"El presente trabajo señala los beneficios de la aplicación de la tecnología de la virtualización en la empresa minera Yanacocha, la cual está enfocada en brindar soluciones tecnológicas que aporten beneficios directose indirectos en las operaciones del programa en conjunto y las áreas de Operación. Esta tecnología de la información provee recursos para el procesamiento de la información y soporte de los servicios ofrecidos a la operación. Así también la virtualización de servidores ofrece una ventaja diferencial para los negocios como la optimización de los recursos actuales en los centros de datos (servicios y servidores), de forma que permiteextender la capacidad para albergar y brindar nuevos servicios a nuestras áreas internas. "

Sep 24, 2008

By Lester Brown

La dependencia de los países ricos o desarrollados respecto de los países pobres es cada vez mayor -en tanto los primeros agotan sus abastecimientos requeridos por la industria y dependen de las reservas de minerales de los países pobres. La dependencia también implica que la economía de los Estados Unidos se está volviendo más vulnerable a las fuerzas externas como los pactos colectivos en los países suministradores, huelgas en las minas extranjeras o en la industria naviera. Por ello, los países pobres, dándose cuenta del progreso en el trato de su posición por algunos minerales, negocian en términos más favorables para sus materias primas. En ese sentido, el presente texto describe la dependencia económica de los países desarrollados hacia la materia prima de los países subdesarrollados.

Nov 1, 1973

By A. U. Seybolt, R. E. Honnemon

THE purpose of this communication is to present activity data of nickel in the Ni-A1 binary system that was obtained for oxidation studies in this system. This data has been calculated from previous aluminum activity data at 1000°C1,2 by two types of Gibbs-Duhem integrations. These results should be of particular current interest to oxidation studies of aluminide coated nickel-base superalloys3 as well as other problems. The aluminum activity of Steiner and Komarek1 is plotted in Fig. 1 as a function of composition in Ni-A1 alloys at 1000°C. The dashed parts of the aluminum curves represent our approximate extrapolations from the directly measured regions. In the terminal solution regions (a and L phases) standard parabolic solution functions of the following form are assumed: where i is the component subscript, Ki is a constant at a fixed temperature, and xi is the atom fraction. The resultant nickel activity curve at 1000° C from the Gibbs-Duhem integration4 of the aluminum data is shown in Fig. 1. The solubility ranges of the phases present in the Ni-A1 binary at 1000°C are also denoted at the bottom of Fig. 1. Corresponding values of the nickel activity, aNi and yNi, are listed in Table I at useful compositional intervals. including phase boundary values. The aNi and yNi data listed in Table I are subject to the uncertainties present in the experimental aluminum activity data1 and to deviations from parabolic solution behavior in the terminal solutions. The errors introduced into aNi and yNi due to the parabolic solution assumption are expected to be relatively small (<20 pct of the values given) in all the phases except the liquid phase. Some deviation from parabolic solution behavior in the liquid phase is indicated

Jan 1, 1970

By J. E. Hipp

Three electrostatic field sensing proximity warning devices were tested using full-scale cranes and power line systems, a scaled model facility, environmental testing facilities, and theoretical/numerical analysis. The design objective of each device is to assist in safe crane operation near overhead power lines. Several design deficiencies (varying from device to device) were observed, including inadequate overlap in sensitivity ranges, utilization of vacuum tubes and electro-mechanical parts, temperature sensitivity and inaudible alarms. In addition, the testing showed major device limitations including sensitivity to boom orientations and length, polarization dependent responses, and unreliable operation in the presence of multiple power line circuits. The multiple power line circuit problem is intrinsic to electrostatic sensing devices. The remaining deficiencies and limitations are correctable within a state-of-the-art design. This investigation is not intended to evaluate the safety aspects or policy of utilizing proximity warning devices. Rather, the purpose is to determine the performance characteristics of such devices in relation to the criteria specified in proposed MSHA regulation 77.805-4 (i. e., the devices must alarm at a distance of 10 feet from the power line).

Jan 1, 1980

By V. B. Achanti, A. W. Khair

Laboratory studies were carried out at West Virginia University to investigate the rock fragmentation mechanism by continuous miners using an automated rotary cutting simulator. The primary factors influencing the fragmentation process were found to be: bit spacing, bit geometry, depth of cut and cutting drum rotational speed. This paper presents the influence of these parameters in achieving optimum energy consumption and minimizing dust generation during rock fragmentation process. Tree bits were used simultaneously on Indiana limestone while the bit tip angle was varied from 60° to 900. Bit spacing was varied from 2.54 cm (1 in.) to 5.08 cm (2 in.) while the cutting process was assessed for varying cutting depths. Restorable dust generated during the course of the experiments was analyzed utilizing cascade impactors. Assessment of these parameters has led to a better understanding of the cutting mechanism by continuous miners in terms of energy consumption and dust generation.

Feb 24, 1997

By Jan Zwarcendyk

This study is primarily directed toward providing an understanding of the economic complexities associated with subsidence damage on the surface resulting from underground mining. Some of the pertinent theories on the physical stresses involved are reviewed, and both remedial measures and relevant laws in various countries are discussed. Part I (Chapters 1-3) is an historical overview of various aspects of subsidence problems (theoretical, remedial, and legal) during pre-World War I, between World Wars, and post-World War II, respectively. Part II (Chapters 4-9) presents a comprehensive analysis of the economic aspects of subsidence in relation to the following mining alternatives: (a) carrying out the lowest cost mining method without regard for any surface subsidence, (b) special mining techniques, (c) partial mining, (d) full recovery with stowing, and (e) sterilization or leaving the mineral unmined beneath selected areas. These alternatives are evaluated in terms of their measurable expenses.

Jan 1, 1971

By R. Farrar

The survey work on protective canopy design was conducted in a 2-month period commencing November 15, 1973. The reported re¬sults under this contract are intended to provide guidance to coal mine operators in complying with federal regulations pertaining to incorporation of protective canopies on underground coal mine electric face equipment. All coal mine electric face equipment manufacturers and 11 coal mines were visited in the course of conducting this survey. Canopy designs currently being manufactured and those now being used underground were examined and discussed with manufacturers, mine operators, machine operators, and safety committeemen. The general objective was to find out what kind of canopies are now being made and used underground, what the operational problems are, and what can be done to secure improvements. Specifically, the survey scope was as follows: a. Survey all electric face equipment manufacturers. b. Survey 10 coal mines (seam height 60 inches and greater). c. Identify current production canopy configurations and minimum mine entry dimensions for each model and type of electric face equipment. d. Assess in-mine operation of canopies developed by manufacturers and/or coal companies. e. Specify optimal canopy configuration and minimum mine entry dimensions for each type and model of electric face equipment.

Jan 1, 1974

This paper provides an update to a paper by the author on an overseas explorer&apos;s perception of New Zealand, presented at the 1997 New Zealand Minerals &amp; Mining Conference. New Zealand has one of the most open and internationally competitive economies in the world. The petroleum exploration industry in New Zealand is booming with a record number of wells planned for 2000. New Zealand is keen to encourage investment in mineral exploration to develop its natural resources. A study of the geological potential of New Zealand estimated the value of known and potential resources of metals at $86 billion. Gold has the greatest potential, with a total resource estimated at $33.5 billion. The price of gold has averaged NZ$554 since the beginning of 1998, and NZ$593 in the last year, which is very competitive with other countries. An assessment of country risk compared New Zealand with twenty other countries in ten risk categories: sovereign risk, land access, environmental issues, land claims, mining legislation, social risk, infrastructure, civil unrest, natural disasters and workforce. New Zealand ranked fifth, showing it has low country risk. This provides a high degree of certainty for investment, which is important for the perception of New Zealand as an exploration destination. Corruption was considered separately, and New Zealand ranked third out of ninety countries, showing it is one of the least corrupt countries in the world. New Zealand has a favourable business environment, good geological potential, low country risk and no corruption. Despite this, New Zealand has not registered on the radar screens of overseas mineral explorers, and the positive factors appear to have been overlooked. New Zealand has considerable undeveloped mineral potential, and with the current rise in commodity prices, it is hoped New Zealand can participate in a resurgence in mineral exploration.

Jan 1, 2000

By Juan Carlos Ramírez

El presente trabajo señala la importancia e influencia del Sistema Privado de Pensiones (SPP) y las AFP para el desarrollo e inversión del sector minero. Para tal fin, se analiza la interfase necesaria entre cada agente del sistema y así lograr tres objetivos: la garantía real de los fondos, fondos disponibles para el sector productivo minero y una alternativa más de colocación de fondos para las AFP. Asimismo, se minimiza la creación de mecanismos de control adicionales para conectar el sector minero hacia otros sectores económicos-financieros, no solo a través del sistema bancario tradicional, sino con otros campos financieros, bolsas y SPP.

Nov 24, 1993

By Jasper L. Stuckey

PYROPHYLLITE, first identified as soapstone,&apos; later as agalmatolite,2 and finally as pyrophyl-lite, has been known to occur in North Carolina for more than 130 years and has been produced intermittently in commercial amounts for the past 100 years. Pyrophyllite mining, however, has become a major industry in North Carolina only during the past 25 years. North Carolina and California are the chief producing states. Current annual production averages 125,000 tons, of which slightly more than 90 pct comes from North Carolina. Distribution and Geologic Setting: All known pyrophyllite deposits in North Carolina are associated with rocks of the Carolina Slate Belt,&apos; which is composed of a vast series of metamorphosed volcanic and sedimentary materials, occurring as two zones extending in a northeast-southwest direction across the state. The larger of these zones, lying in the central Piedmont region, varies from 8 to 50 miles wide. The smaller zone lies along the eastern edge of the Piedmont region and is partly covered by coastal plain sediments. The rocks in both zones consist of a great volcanic-sedimentary series, composed of air-laid and water-laid tuffs and breccias, lava flows, and slates. On the basis of composition, they may be classed into three groups: 1) tuffs, breccias, and lava flows of acid or rhyolitic composition; 2) tuffs, breccias, and lava flows of a basic or andesitic composition; and 3) water-laid slates composed of fine grained materials derived chiefly from the acid tuffs and breccias and

Jan 1, 1959

By H. Warren Newcomen

Assessments of the stability performance of open pit highwalls have traditionally been based on consideration of surface movement rates. Although generally accepted in industry, this approach presents challenges for establishing appropriate threshold values to allow for safe mining operations and does not address the issue of total strain. Surface movement monitoring data from a limited number of open pit mining operations in North and South America has been evaluated in terms of highwall strain, rock mass quality and inferred mechanism of instability. Threshold strain levels for key stages of highwall stability proposed from previous work have been reviewed and are generally endorsed based on evaluation of additional data. An empirical highwall strain criteria for the assessment of highwall stability performance is postulated based on the observed trends in highwall strain data from the case histories presented.

May 1, 2004

By Alberto Ramirez Sauri

El concepto de rentabilidad se relaciona con un sistema de medida de rendimiento expresado en términos de utilidad de una inversión, una actividad económica o negocio. Mientras que la productividad se relaciona con la cantidad de producto extraído con determinados factores de producción y factores. Por ello, el presente texto analiza las tendencias de los diferentes grados de utilidad con el capital invertido, los márgenes con respecto al ingreso y su relación directa con la productividad del sector minero. Así también es necesario que el sector minero uniformice sus criterios contables para poder llegar a obtener indicadores de rentabilidad, productividad y de otro carácter económico, que permita a cada unidad ubicarse con relación al promedio del sector, facilitándole al empresario el conocimiento necesario para optimizar su gestión en beneficio del sector y la economía del país.

Nov 1, 1972

The London Metal Exchange began its first official session of aluminum trading on Monday, October 2, LME prices based on 3-month forward contracts opened Monday at 52.4 cents per pound, fell midway through the week to 52.3 cents and ended Friday at a high of 52.7 cents. For the week, LME metal averaged 52.5 cents. Although Reynolds Metals Co. and Aluminum Co. of American continued in September to value unalloyed 99.5 percent aluminum ingot at 53 cents per pound, other producers were at higher positions of 55-57 cents. Alcan Aluminum Corp. of Alcan Aluminum, Ltd., a Canadian producer, increased prices for its U.S.-marketed ingot by 2 cents to 55 cents per pound, effective September 21. New York merchants increased ingot quotes by approximately 0.5 cents to 52.8-53.5 cents per pound.

Jan 1, 1978

By Gordon I. McPhail

"El presente texto señala un método de conservación del agua y diseños de drenajes para el control de ARD (Drenaje Ácido de Rocas). El método fue aplicado en el desarrollo de un proyecto aurífero en Argentina, donde dada la cercanía de la mina con el pueblo, se eliminó el uso del cianuro y se empleó el procesamiento off-site que contó con una gran cantidad de escenarios de desarrollo viables. Este planeamiento considera un proceso integral de molienda, concentración y relaves que reemplaza las instalaciones para el almacenamiento de relaves (TSF) como entidades independientes. Así también cuantifica las compensaciones hechas entre los beneficios y efectos sociales, económicos y ambientales. "

Jul 1, 2016

By Walter E. Vanderpool

Three drilled foundations for an elevated water-tank were instrumented, tested and monitored during construction and the first two years in service. One shaft was load tested by the Osterberg method. A void was detected in one shaft by cross-hole sonic logging, pulse-echo logging and concrete coring. The void was instrumented, hydrostatically tested and pressure grouted. The shaft was ?abandoned? and replaced by two smaller shafts with a straddle beam cap. One of the replacement shafts and the cap were instrumented. The strain that appeared in the abandoned shaft, the replacement shaft and the cap were monitored during the remainder of the construction, through the commissioning test and the first two years of service. The results demonstrate the precision and sensitivity of the vibrating wire strain gage.

Jan 1, 2004

By S. L. Huang

The location and shape of potential failure surfaces in soil slopes were directly determined based on the stresses induced in the soil mass and the strength of the soil itself. Stress calculations were carried out by the finite element method with the Drucker-Prager nonlinear material model. The Mohr-Coulomb failure criterion and Mohr&apos;s circle stress analysis were then applied to the calculated stresses to determine the characteristics of the failure surface.

Jan 1, 1989

By Enrique Monge

El presente texto señala las plantas de tratamiento mecánico de acero, así como las plantas de rodamiento para barras y planchas semiterminadas, las de rodamiento para la producción de barras comerciales, la producción de formas estructurales en la industría del acero en los Estados Unidos de Norteamérica.

Jan 1, 1958