Search Documents

By Harold M. Wrigth

El siguiente estudio refiere al diseño y costo de construcción de las plantas concentradoras, así como el de plantas de beneficio realizadas en la provincia de British, Columbia. Para ello, el autor, quien diseñó aproximadamente 16 plantas para el tratamiento de minerales en el mencionado lugar, propone la dfusión y aplicación de este tipo de máquinas en nuestro país, considerando los tonelajes, las ubicaciones, resistencia del terreno, el flow sheet, para sentar las bases del diseño de los equipos.

Jun 20, 1954

By V. Cabrera

El objetivo del presente es descubrir el sitio adecuado donde exista mayor producción económica para la instalación de una planta minera. En este sentido, se describe los factores técnico-económicos que afectan la ubicación de instalaciones mineras y se ofrecen ejemplos peruanos de ubicación planificada de plantas de procesos minerales. También se plantea la importancia del análisis económico del sistema para seleccionar la ubicación más económica de la planta. Finalmente, se evalúa las condiciones que disminuyan los costos de construcción, eliminen los riesgos naturaless y tengan suministro económico de mano de obra y recursos utilizados durante el proceso metalúrgico.

Nov 20, 1972

By Juan Francisco Retamozo

Hoy es indispensable que los profesionales de ingeniería de minas se capaciten en gestión y habilidades blandas, para responder adecuadamente a los nuevos retos que plantea el mercado laboral. Como producto de su extensa práctica como ingeniero de minas y coach personal en el sector, el autor desarrolla en este artículo diversos aspectos de interés para aquellos profesionales interesados en acceder a posiciones de liderazgo.

Aug 30, 2020

By Pitter Chumpitaz, Pedro Gonzáles, César Espejo

En nuestra Planta de procesos de La Arena, uno de los principales insumos químicos en nuestro proceso es el cianuro de sodio. La lixiviación del oro con una solución de cianuro sigue siendo el proceso hidrometalúrgico más ampliamente utilizado para la extracción de oro en los minerales. El cianuro de sodio por ser parte esencial del proceso también es el que tiene un alto impacto en los costos operativos del área. En base a resultados de pruebas metalúrgicas se concluyó que, a partir de la segunda mitad del ciclo de lixiviación del mineral, el requerimiento de cianuro para continuar con la lixiviación del oro es menor. Es por ello que se analizó la viabilidad de implementar un sistema de bombeo para realizar un riego diferenciado en el Pad y así optimizar el consumo de este reactivo.

Sep 30, 2022

Northern Iron Ltd (NIL) is an Australian listed company that recently brought the historic Sydvaranger open pit Magnetite Mine (the Project) in Northern Norway successfully back into production. NIL made the decision to operate the Project on an owner mining basis, due to limited large scale mining expertise amongst Norwegian mining contractors, a long mine life, a limited range in planned mining rate and to minimise costs. As a new mine operator in a country where labour practices are strictly regulated, there was the desire to reduce the risk associated employing and managing skilled personnel. This was achieved by coupling the purchase of the required mining equipment from the original equipment manufacturer's (OEM) regional dealers with OEM supported Maintenance and Repair Contracts (MARC). This paper examines the process that was followed to implement an owner mining operation in a short time frame; approximately 12 months from the initial requests for quotation to actual delivery of mining equipment to site, and some of the challenges faced. By following a formal and well-tested process, not only was the implementation achieved in the set time frame, but significant value was added through the cost savings achieved in the equipment purchase price and MARC rates that were negotiated through this process.

May 1, 2010

By L. C. IlsLey

"The maintenance of permissible equipment which is tested and inspected at the Pittsburgh Experiment Station of the United States Bureau of Mines is dependent to a surprisng degree upon the voltage at which the equipment is operated. The difficulty of maintaining 500-volt equipment is frequently brought to the bureau's attention, and it is quite possible that if the bureau had appreciated at the beginning the full hazard involved, it would never have undertaken the approval of equipment operating at voltages greater than 250 volts.In this connection, the following statement from State mine inspection departments and other sources are of interest as showing the general feeling in safety organizations with respect to voltages higher than 250. These statements, although obtained as a result of a questionnaire sent cut several years ago, still apply very well to present conditions.A. I have not had time to consider seriously the proposed change from every angle, but looking at it from a standpoint of hazard, feel that the danger would be greatly increased. I have always occupied the position that underground voltage on portable equipment should never exceed 250 volts.High voltage of course would mean smaller transmission lines, which would be more economical and no doubt would require in several instances smaller equipment; notwithstanding, if this statement is true, the writer is still favorable to low voltage on underground portable equipment.B. I believe 500 volts should be the limit on the best equipment ender the best conditions and that the U. S. Bureau of Mines should do all in its power to limit the voltage to 500 volts on permissible equipment, as any increase in voltage means increased hazard.C. I will refer you to a section of our mining law, entitled ""An Act to Regulate the Tine of Electricity in the Mines of the State of ----"" which reads in part, as follows: Trolley wires, or other exposed electrical wires, shall not carry a voltage above 275 volts.You may readily see by this that we are not permitted to operate mining machines under ground in -----, with more than 275 volts at the terminals, except that we are permitted to install transforming stations throughout the mines, after complying with certain regulations at the mine.However, as we have had to date, within the calendar year of 1925, six men electrocuted in the mines of the State, using a voltage of 275 volts, I am of the opinion that if this voltage was increased, the hazard would also be increased in proportion.D. I do not care to make a statement for publication: however, I am referring you to our mining laws. On page 27 and 28 you will find what the laws of -----¬require relative to the installation of electricity in the mines.""Hereafter where electricity is installed no higher than two hundred seventy-five (275) volts shall be used underground, except for transmission, or for application to transformers or other apparata, where the high-voltage circuit is stationary. High-voltage motors, and transformers, shall be installed in suitable chambers, built of fire-proof construction, and well ventilated, and shall not be placed on intake, or between intake and return air courses. All high-voltage lines lines and apparata must be clearly marked, to indicate their danger. Main and distribution switchboards for high voltage shall be made of insulating and incombustible material, such as marble or slate, and to be free of all metallic veins, or of material equivalent thereto. Same shall be installed in a dry place. All switches or other instruments used in connection with high voltage shall be installed on suitable switchboards, with at least a three-foot passageway in front and rear properly floored, and kept looked by a door at each end that can be opened from the inside without a key. With higher than medium voltage, there shall not be any live metal work on the front of switchboard, and the entry circuit must be protected by an oil breaker s"

Apr 1, 1932

By Paul S. Fisk, Arne Fareth, Julie Frietas, Francis Lo, Fidel L. Mallonga

INTRODUCTION This report describes the inspection of parts of the New Croton Aqueduct (NCA)undertaken for the New York City Department of Environmental Protection (NYCDEP)by Parsons Brinckerhoff Quade & Douglas, Inc., (PB) in association with Montgomery Watson Engineers of New York, P.C. (MWH). Support for the inspection was provided by AFC Enterprises, Inc., under Construction Contract CRO-333, “WM-11 New Croton Aqueduct Rehabilitation and Inspection Program.” The scope of the inspection work under CRO-333 included assessing the condition of the 10.3 km (6.4 mile) long, pressurized section of NCA and inspection of shafts, head houses and blow-off structures in both the pressurized and gravity sections. The CRO-333 inspection continued investigation work begun under ContractCRO-196, which ran from 1993 to 1997. The CRO-333 inspections were conducted from November 2004 to September 2005. Background The New Croton Aqueduct was put into service in 1891 to deliver water from the Croton River Watershed in Westchester County to consumers in New York City. Figure 1 shows the location plan of Croton Water Supply System. The design flow into Jerome Park Reservoir was 12.7 m3/s (290 mgd) and into the135th Street Gate House, further south, was 10.9 m3/s (250 mgd). The NCA has been operated as a gravity conduit from Croton Lake to Gate House No. 1, just north of Jerome Park Reservoir, since its original construction. The length from Gate House No. 1to 135th Street, which includes a major siphon under the Harlem River, has been operated under pressure. Croton Lake gate house, the north end of the alignment lies at Station 4+75; Shaft 33, the south end of the alignment lies at Station 1628+05. The diameter of the tunnel is 3.2 m (10.5 ft) in the siphon and 3.7 m (12.3 ft) in the Bronx and Manhattan sections. The pressurized sections, constructed in rock, consist of a brick lining surrounded by a mortared and grouted rubble backing. Figure 2depicts a typical tunnel cross section. The objective of the shaft and tunnel inspections was to locate and document defects, such as leaks, deterioration of lining material, cracks, spalls, delaminations,

Jan 1, 2007

By Joseph L. Jordan

Coal is essential to America?s future energy needs. To meet these needs mining methods must be safe, economical, and environmentally acceptable. Belt conveyor systems for coal haulage from surface mines offer great potential in this situation. The advantages over conventional truck haulage are particularly promising for area strip mines in western coal fields such as the Powder River Basin where relatively thick, flat-lying coal seams occur. The current demand for low-sulfur coal specifically emphasizes the need for better mining methods in these areas. Underspoil haulage is the term applied to transportation of coal from the pit to the surfate in area strip coal mines by belt conveyors in tunnels under the spoil. The advantages over trucks include lower manpower requirements, greater pit safety and efficiency, and improved reclamation procedure. This evaluation includes a comparison of total mining costs for truck haulage versus six variations of the underspoil haulage concept. The more efficient of these underspoil haulage systems have economic advantages over truck haulage which become more pronounced with deeper overburden, thicker coal, and higher annual production.

Jan 1, 1977

The lead concentration of flotation feed ore slurries is determined using two ?-ray absorption gauges mounted directly on a 6 in. diameter flotation feed pipeline. One gauge is a conventional "density" gauge using CS137. The other is a "lead-sensitive" gauge, which depends on the preferential absorption. by lead of 225 key y-rays resulting from Compton backscatter of CS137 y-rays.Gauge outputs are combined using an analogue computer the output signal of which is directly proportional to the lead concentration of the pulp. The accuracy of measurement of the pulp lead concentration is ± 3·6 per cent for ore slurries with lead concentrations in the range 0'07-0·16 g/c.c. and pulp densities 1.43-1.60 g/c.c.This paper sets out the development of the technique and details are given of the two experiments (1964, 1966) conducted in the plant at North Broken Hill Limited. The installation of the two-gauge system inthe plant during May 1968 is described. Details are given of the calibration technique used and the results obtained.

Jan 1, 1969

By A. V. Roschin, N. V. Malkov, V. N. Karnoukhov, V. E. Roschin

Reduction interactions in solid phases are widespread and occur in most complex metallurgical processes. Among these processes, reactions between oxides and carbon have a special importance. The authors conducted experiments for comparison of reduction by different reducing agents of impregnated chromite ores, in which grains of the reducible chromite spinel are isolated from direct contact with the reducing agent by layers of non-ore material. The results of the experiments have revealed that the beginning of reduction is preceded by thermal and impurity order-disorder transformation of the oxide lattice whilst the transformation of the oxide lattice into the metal lattice takes place as a result of removal of oxygen anions from the zone of metal germ nucleation. Since anions are charge carriers, increase of their mobility can be monitored by changes in electrical conductivity of oxides. Respective measurements of electrical resistance of ores of different metals and a number of pure refractory oxides under heating have indicated that the beginning of reduction coincides with the time of drastic (tens of thousands times) increase of conductivity of the oxides. Besides, the temperature of the beginning of carbon-thermal reduction is in line with the Tammann temperature, i.e. the temperature of transition from the predominantly surface diffusion to volume diffusion. Segregation of metals from the oxide lattice occurs as a result of merging of anion vacancies with defect electrons on defects of the oxide lattice. The transformation of the oxide lattice into the metal lattice requires a certain concentration of anion vacancies and inflow of electrons from the reducing agent to the site of metal segregation. Such inflow has no difficulties due to the mixed anion-electron nature of high-temperature conductivity of oxides. Thus, the reduction is not determined by oxygen diffusion, it is determined by oxygen vacancies diffusion whose speed exceeds the speed of oxygen diffusion by orders of magnitude. This determines that the kinetics of reduction considerably exceeds the kinetics of oxidation at similar temperatures since oxidation proceeds by means of mass transfer of oxygen through the layer of the generated oxide.

Jan 1, 2004

By Alfred Bodenlos

El presente texto señala los depósitos de zinc y plomos encontrados en los cateos del flanco noroeste del cerro Huancapetí, perteneciente a la Cordillera Negra. En el flanco noroccidental del cerro Huancapetí, hay varias vetas que han sido exploradas por pequeños cateos, cuyas altitudes van desde 4480 hasta 4670 metros. Para llegar a esas vetas solo hay caminos malos que cruzan la cumbre de la cordillera al sur del área de la mina Huancapetí. De otro lado, en 1947 la única mina en actividad era la de Wilson, alcanzando 10 toneladas de concentrados al mes escogidos a mano, así como la mina San Idelfonso, la Improvisada, Mariscal y los cateos Señor de la Soledad y Fernandiita.

Nov 1, 1957

By Andrés Gómez

El estudio considera la fusión de simulación y gestión de flota como una estrategia de innovación para seguir incrementando el rendimiento de los equipos en el proceso de la mejora continua que se aplica en la minería superficial. Como resultados se tiene el incremento de la producción en las minas que se aplicó en prueba, aunque en un principio no fue fácilmente recibido por lo complicado al inicio de la aplicación. En conclusión, esta innovación de fusión de simulación con los sistemas de gestión de flota en la empresa minera permite mejorar la producción y esto representa un incremento significativo de la producción

Sep 29, 2023

By Jerry Rosas Esquivel

En los últimos años, algunas empresas del sector minero reemplazaron progresivamente el manejo tradicional del Programa de Seguridad e Higiene Minera, por una verdadera y eficaz gestión de riesgos, a través de la implementación de Sistemas Integrales de Seguridad, Salud y Medio Ambiente (SSMA) puesto que esto es lo que necesita el equipo gerencial de cualquier organización para ser exitosa, competitiva de categoría mundial. En este sentido, el presente trabajo describe la implementación de este sistema para identificar, evaluar, medir y controlar los problemas de seguridad, salud, procesos, incendios y ambiente relacionados con la producción y operaciones conexas.

Sep 13, 2001

By Yeonuk Choi, Gus Van Weert

"In regular CIL circuits, activated carbon is used for two purposes: avoiding solid/liquid separation after cyanide leaching, and minimizing gold losses in the tails. The carbon distribution and gold profiles in the successive CIL stages are operating variables, not objectives. When the CIL feed contains a preg robbing constituent however, such as native carbon, there will be competition for gold cyanide and this conflicts with minimizing of losses of gold to CIL tails. This paper examines some of the limitations of activated carbon in CIL circuits handling preg robbing Carlin Trend ores.INTRODUCTION Carbon-In-Leach (CIL) has been a great success treating regular gold ores, but the technology is still challenged by preg robbing feedstocks. Little information is available in the gold milling literature on CIL gold extraction from “free” milling gold ores which are preg robbing, or on autoclave discharge (POX’ed) slurries of double refractory ores. Neither feedstock is readily available for experimentation. No literature reference could be found describing deliberate modifications to CIL operations or CIL circuits due to the presence of two types of carbon: “native” and activated. There is some literature on the gold cyanide adsorption activity of native carbons (Schmitz, Duyvesteyn, Johnson, Enloe & McMullen, 2001). Various tests have been devised to measure this activity, commensurate with CIP and CIL practices (Tretbar, Arehart & Graves). In this paper, the term “native” carbon indicates (severely) preg robbing carbonaceous materials found in gold ores. There is considerable literature on the gold cyanide adsorption activity of man-made “activated carbons”. Various tests have been devised to measure this activity, commensurate with CIP and CIL practices. These tests are comparative, i.e. results relate to a standard carbon and depend on the test methodology and carbon history. The test results are equilibrium oriented, hence of limited value to CIL circuit designers or plant operators handling preg robbing solids; in CIL circuits most carbons are not loaded to capacity. Information on gold cyanide adsorption and desorption kinetics might be more relevant and that is one subject explored in this paper."

Jan 1, 2012

By Nelson Reátegui

El presente trabajo describe los sistemas computarizados utilizados en el centro de operaciones, explotación y beneficio de Hierro Perú, compañía minera localizada en el departamento de Ica. Inicialmente, la función de un sistema computarizado se limitaba a la reducción de costos en la mano de obra y a realizar operaciones básicas en los negocios. Posteriormente, esta situación cambió ya que estos sistemas se utilizan en los niveles de la gestión empresarial.l. Asimismo se explica las aplicaciones de este sistema al comercio, al tipo técnico-científico, así como el cálculo de reservas y el desarrollo del sistema computarizado de performance de equipo.

Nov 20, 1978

By D Nobes, D Trumm, D Manhire, A OÆSullivan, M W. Milke

Coal seam gas (CSG) exploration and development requires the abstraction of significant amounts of water. This is so because gas desorbtion in coal seams takes place only after aquifer pressure has been reduced by prolonged pumping of aquifer water. CSG waters have a specific geochemical signature which is a product of their formation process. These waters have high bicarbonate, high sodium, low calcium, low magnesium, and very low sulphate concentrations. Additionally, chloride concentrations may be high depending on the coal depositional environment. This particular signature is not only useful for exploration purposes, but it also highlights potential environmental issues that can arise as a consequence of CSG water disposal. Since 2002 L&M Coal Seam Gas Ltd and CRL Energy Ltd, have been involved in exploration and development of CSG in New Zealand. Anticipating disposal of CSG waters as a key issue in CSG development, they have been assessing CSG water quality along with exploration work. Coal seam gas water samples from an exploration well in Maramarua closely follow the geochemical signature associated with CSG waters. This has helped to identify CSG potential, while at the same time assessing the chemical characteristics and water generation processes in the aquifer. Neutral pH and high alkalinity suggest that these waters could be easily managed once the sodium and chloride concentrations are reduced to acceptable levels.

Jan 1, 2005

By Donald P. Tuchman, Justin R. Patts, Emanuele G. Cauda, Andrew B. Cecala, Elaine N. Rubinstein

Video techniques for monitoring exposure, such as NIOSH’s “Helmet-CAM,” employ both real-time dust monitors and mobile video cameras to assess workers’ respirable dust exposures. Many real-time personally worn dust monitors utilize light scattering sensing elements, which are subject to measurement biases as a function of dust type (size, composition, shape factor) and environmental conditions such as relative humidity. These biased and inaccurate dust measurements impair the monitor’s ability to properly represent actual respirable dust concentrations. In the testing described, instrument mass concentration data was collected using three different types of commonly used commercial off-the-shelf personal dust monitors and compared to a reference standard. This testing was performed in a calm air (Marple) dust chamber in which three units of each make and model (for a total of nine monitors) were used for each test. Equivalency factors (EF, a multiplier to match the Thermo TEOM 1400a reference instrument) ranged between 0.746 and 1.879 across all dusts and environmental conditions tested, and between 0.821 and 1.519 on the ISO test dust.

By Donald P. Tuchman, Justin R. Patts, Emanuele G. Cauda, Andrew B. Cecala, Elaine N. Rubinstein

Video techniques for monitoring exposure, such as NIOSH’s “Helmet-CAM,” employ both real-time dust monitors and mobile video cameras to assess workers’ respirable dust exposures. Many real-time personally worn dust monitors utilize light scattering sensing elements, which are subject to measurement biases as a function of dust type (size, composition, shape factor) and environmental conditions such as relative humidity. These biased and inaccurate dust measurements impair the monitor’s ability to properly represent actual respirable dust concentrations. In the testing described, instrument mass concentration data was collected using three different types of commonly used commercial off-the-shelf personal dust monitors and compared to a reference standard. This testing was performed in a calm air (Marple) dust chamber in which three units of each make and model (for a total of nine monitors) were used for each test. Equivalency factors (EF, a multiplier to match the Thermo TEOM 1400a reference instrument) ranged between 0.746 and 1.879 across all dusts and environmental conditions tested, and between 0.821 and 1.519 on the ISO test dust.

DEFENSE Materials Procurement Agency has been moving rapidly to encourage copper industry expansion programs. Although copper production is at a high level, a shortage exists on a world-wide basis as well as on the domestic scene. Projected expansion programs will not ease this current demand for most of them are 2 to 5 years off. Refining facilities are adequate but there is a shortage of ore and scrap, and it is for this reason that the expansion programs are directed at developing more sources of supply. The domestic expansion programmed thus far and understood to have been arranged with price escalation should the domestic price go to 271/20, were summarized by American Metal Markets as follows (dates of announcement are given in parenthesis: .1-Copper Cities Mining Co.'s, $15,000,000 expansion near Miami, Ariz., to be operating about 1954. DMPA will buy 22,500 tons of copper a year up to a given amount on an agreed price of 23¢ per pound, with some exceptions and depending upon salability at a higher price to other purchasers in the U. S. (September 25th). 2-An RFC loan of $60,000 to North Butte Mining Co. to be paid off on the basis of deliveries at a purchase price of 241/20 per pound (September 25th). 3-A $25,000,000 expansion program by Phelps Dodge to provide 38,000 tons per year by late 1954. DMPA would purchase it at a price of 22¢ per pound up to 112,500 tons providing other purchasers in the U. S. will not pay a higher price (September 26th). 4-Anaconda Copper Mining Co. $40,000,000 expansion in Nevada to provide more than 30,000 (might be increased to 45,000) tons per year. DMPA would purchase the copper at 250 per pound for a limited period of time if it is not salable to industrial users at above this price. Production would start around 1953 (November 14th).

Jan 1, 1952

By Y. Bai, J. J. Liu, D. Q. Li, S. Z. Liu, X. T. Wang

"This paper presents the results of an industrial test using 8 t/d of Baotou concentrate (50% REO) of a clean metallurgical process, which includes: 1. Roasting with H2SO4 at low temperature (220~260 0C) in a batch roasting furnace followed by water leaching to obtain a leach liquor as feed with a yield of >95% RE and Th, recovering F as fluoride, producing a leach residue amounting to 1/3 of an equivalent high temperature residue and containing <0.03% Th and radioactivity < 3×104 Bq/kg compared to the normal high temperature residue containing 0.2-0.3% Th and 1×105 Bq/kg. 2. Separating Th with N1923 and extracting RE by P507 has been completed in mixer-settlers. Test results indicate that the ThO2 product has a purity of > 95% with a yield of 99%, and the RE has a yield of >95%, in which ThO2/REO <5×10-6, and that P507 loaded RE connect straight with separating RE using P507-HCl system. 3. Treatment and multipurpose use of "three wastes" (water, gas and solids) are discussed in some detail."

Jan 1, 2014