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By J. S. Kirkaldy, W. J. Slater, G. R. Mason

Activation analysis for copper and manganese in 10 mg samples machined from aluminum-base diffusion couples has been used in the study of ternary diffusion in the Al-Cu-Mn system. The accuracy, economy and convenience of the method are considered to be very competitive with other methods for analysis of such small samples. Neutron-activated aluminum-zinc alloys in the range from 10 per cent to 100 per cent zinc have been equilibrated with a known volume and the vapors subsequently condensed and collected. The vapor pressures relative to pure zinc (the thermodynamic activities) have been determined at 550°C' by recording the relative count of /'-rays from zn65 in the collected samples. The method is a sensitive one, although subject to serious obstacles to experimental accuracy.

Jan 1, 1961

By Geology Staff, C. H. Stockwell

"The Flin Flon base metal mine, owned and operated by the Hudson Bay Mining and Smelting Company, is on the Manitoba-Saskatchewan interprovincial boundary at a point 400 miles north of the International boundary. The deposit was discovered in 1914 by Thomas Creighton and the Mosher and Dion brothers. Since production commenced in 1930, 25,000,000 tons of ore have been mined. On January 1st, 1946, reserves were estimated to be 26,000,000 tons, averaging 2.99 per cent copper, 4.i4 per cent zinc, and 0.089 oz. gold and 1.25 oz. silver per ton. In addition to the four metals named, others recovered from the ore include- cadmium, selenium, and tellurium. The mine workings extend to the 3,750-foot level, but little development work has yet been carried on below 3,250 feet.The known ore occurs in six lenticular to irregular bodies within a zone 500 feet wide. These bodies average 900 feet long, 70 feet wide, 1,500 feet in vertical depth, and 2,500 feet in length along the plunge. They were formed by replacement of the country rock and include ore of two types, solid sulphides and disseminated sulphides. Seventy per cent of the total known ore is of the solid sulphide type. This consists essentially of metallic sulphides- chiefly pyrite- with included remnants of the host rock, and additional quartz and carbonate. In places, the ore exhibits banding, inherited from pre-existing structures. The disseminated ore occurs usually on the footwall side, and along the bottom of the plunge, of the solid sulphide bodies."

Jan 1, 1954

By Edwan Anderson Ariza Echeverri

O aumento das exigências para reduzir o consumo de combustível e aumentar a segurança dos passageiros tem estimulado o desenvolvimento da nova geração de aços de alta resistência. Esses objetivos tornam-se atingíveis com a redução do peso dos componentes de aço do veiculo, pelo uso de chapas mais finas e resistentes, mas não menos dúcteis. Com esse propósito, no presente trabalho pretendeu-se analisar os efeitos de diferentes rotas de processamento: estampagem a quente, têmpera e partição e o inovador processo que combina a deformação a quente com a têmpera e partição. Os ciclos térmicos foram projetados para obter a maior fração de austenita retida, além de ferrita e martensita. Para cada amostra tratada, amostras de tração de tamanho reduzido foram extraídas de amostras previamente tratadas em simulador termomecânico avançado Gleeble 3S50. A microestrutura foi analisada por microscopia óptica e eletrônica de varredura. Com o novo processo combinado acredita-se que seja possível atingir uma boa associação de propriedades para a nova geração de aços de alta resistência pela transformação da austenita retida metaestável em martensita induzida por deformação, contribuindo para a absorção de energia durante impacto.

Aug 16, 2017

By Fernando Llosa

El presente trabajo describe el origen y la geología del proyecto Trapiche, como propiedad de la Cía. El Molle Verde SAC subsidiaria. Dicho proyecto está ubicado 100 km al sur de la ciudad de Abancay, región de Apurímac, parte central del sur Perú y fue descubierto por Cedimin, producto de un intenso programa de grassroot realizado a partir del año 1995 hasta el 2001 en que fue perforado. Luego fue explorado por Cía. de Minas Buenaventura a partir del 2,005 hasta la actualidad. El yacimiento es del tipo pórfido de cobre y molibdeno, su localización metalogenética es en el borde oeste del batolito Andahuaylas – Yauri, de composición calco-alcalina con presencia de pórfidos activos, que están intruyendo sedimentos clásticos – carbonatados del Jurásico – Cretáceo. En dicho "belt" se emplazan importantes yacimientos tipo pórfido y skarn de cobre y molibdeno y oro como los Chancas, Cotabambas, Las Bambas, etc.

Sep 21, 2013

By Lucien Eaton

The mining methods described in this paper are those used in a large mine producing hard specular ore on the Marquette Range in the Upper Peninsula of Michigan. Although the conditions of mining are unique in this district, they are similar to those in many other districts, and information in regard to the methods used and the results obtained should be of interest. The methods now used are an outgrowth of those of former years which have been adapted to conform with improvements in mechanical appliances, changes in the wage scale and labor supply, and the' selling price of the product. The mine is situated' at Ishpeming, in the Upper Peninsula of Michigan, 16 miles west of Marquette, its shipping port on Lake Superior.

Jan 1, 1929

By Gustavo De la Torre

El presente texto describe una serie de herramientas que optimizan los procesos unitarios en la concentradora de Cerro Lindo de compañía minera Milpo S.A.A., cuya base fundamental es el ciclo de mejora continua y productividad en general. Como primer recurso está la Geometalurgia -en tanto identifica los niveles de producción (que dependen de la dureza y moliendabilidad), la recuperación (función de la liberación de las especies mineralógicas) y la calidad del concentrado. Mientras que el segundo recurso estriba en la construcción de un diseño secundario, con el objetivo de liberar eficientemente todos los elementos de valor económico como son el cobre, plomo y zinc, Asimismo, la identificación óptima del tamaño de los valores metálicos flotables y su pronta extracción permiten optimizar la performance metalúrgica, la cual repercute en lograr mejores calidades de los productos por efectos de menor presencia de contaminantes sobremolidos y pérdidas de valore metálicos como lamas.

Oct 21, 2015

By Richard Palape, Nicolás Rojas, Álvaro Díaz

El presente trabajo cuenta la experiencia, metodología y tecnología desarrollada en varios sitios por más de media década, donde en minas con tal nivel de producción y tecnología, 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. Como se relató, las tecnologías pueden parecer muy completas o robustas, pero normalmente no son adoptadas por los trabajadores. Esta falta de involucramiento tiene diversas causas tales como falta de empatía de parte de los proveedores de tecnología, poco entendimiento e involucramiento de los trabajadores o bajo entusiasmo que causa la tecnología en el día a día.

Sep 29, 2023

By P J. Minehan

The investigation of the potential of the Webb/Baynes block of the Buller coalfield for anode carbon manufacture has generated much information on the physical beneficiation characteristics of the Buller coals in general. A further 36 drill holes of the block in question and several other samples have been analysed by sink/float analysis, either at a single density or over a range of densities. In addition, many samples have been beneficiated on a laboratory shaking table or by flotation. The ash content can be reduced by a variable factor. The reduction factor of between two and four by sink/float analysts is understandably less for tabling where separation is not perfect. All Buller coals behave similarly, there being greater ash reduction factors for higher ash coals.

Jan 1, 1983

By K. Heasley, A. Yassien, A. Khair, S. Peng

There are three major components of a fully grouted roof bolt which primarily determine its ability to develop and sustain load: the steel rebar, the resin annulus, and the rock/grout interface. The untensioned, fully grouted roof bolt is subjected to loading only when the surrounding rock deforms. Vertical rock deformation is generally a result of strata sagging and bedding plane separation, whereas horizontal deformation is typically a result of bedding plane sliding. These two types of deformation create different types of internal loads with-in the roof bolt, tensile stress for vertical rock deformations and shear stress for horizontal rock deformations. Also, as a result of the mutual load transfer between the rock and bolt, shear stress will be developed along the grout/rock interface. According to the exact bolt loading conditions, different failure modes may occur: bolt axial failure, bolt shear failure, and shear failure along the grout/rock interface. Understanding these possible failure modes and their root causes is the key to eliminating roof failures in underground mines employing fully grouted resin bolts. Using ABAQUS 5.8, a finite element model was developed to simulate the components of the fully grouted bolt and its interaction with the surrounding roof strata. Several models were conducted to investigate how load transfer occurs between the rock and the bolt under different geological and mining conditions. The effects of bed-ding plane location and properties, and strata sequence on bolt stability were studied. Also, the effects of hole roughness on bolt stability were discussed. Bolt axial failure was not observed within the range of the studied parameters; however, a combination of high overburden depth, a bedding plane located at 2 to 3 ft from the roofline or a low coefficient of friction along the bedding plane caused strata sliding and shears failure in the bolt. Also, in the case of a weak immediate roof, the shear stress at the grout/rock interface could exceed its ultimate capacity lead to slippage.

Jan 1, 2004

By Stephen Iverson

The National Institute for Occupational Safety and Health (NIOSH) is currently performing research to help mine operators minimize the amount of loose or damaged rock surrounding a blasted opening. Improperly designed blast rounds can result in excessive wall rock damage that may reduce the rock mass competency and increase ground support requirements. Unnecessary blast damage can cause many safety and operational concerns including an increased potential for injury from rock falls and other hazards resulting from sub-optimal blast designs. This paper focuses on the ground control and safety implications of blast damage in underground mines. A reduction in rock quality due to blasting can increase the amount of ground support required. Case study data collected by NIOSH in underground metal mines during standard drill and blast production rounds included blast vibration monitoring, detailed three-dimensional laser scanning of the as-built excavation, and geotechnical mapping of development headings.

Jan 1, 2007

By Han-Tao Hu

Keywords: RH refining process, flow of molten steel, two-phase flow, gas holdup, circulation rate, mathematical modeling A three-dimensional mathematical model for the flow of the molten steel in the whole degasser during the RH refining process has been proposed and developed with considering the physical characteristics of the process, particularly the behaviors of gas-liquid two-phase flow in the up-snorkel and the momentum exchange between the two phases. The fluid flow fields and the gas holdups of liquid phases and others respectively in a 90 t RH degasser and its water model unit with a 1/5 linear scale have been computed using this model. The results showed that the flow pattern of molten steel in the whole RH degasser could be well modeled by the model. The liquid can be fully mixed during the refining process except the area close to the free surface of liquid and zone between the two snorkels in the ladle, but there is a boundary layer between the descending liquid stream from the down-snorkel and its surrounding liquid, which is a typical liquid-liquid two phase flow, and the molten steel in the ladle is not in a perfect mixing state. The lifting gas blown is rising mostly near the up-snorkel wall, which is more obvious under the conditions of a practical RH degasser, and the flow pattern of the bubbles and liquid in the up-snorkel is closer to an annular flow. The calculated circulation rates for the model unit at different lifting gas rates are in good agreement with the determined values.

Jan 1, 2005

By Simon St J Tose

The objective of this paper and presentation is to review the different criteria and methodology used by AEL and other organisations to create a pre-split design which delivers a stable highwall for the life of that part of the mining operation. It will look at the need to adapt and change the way, size and direction of the production blasts as the mining phase approaches the highwall position for which a pre-split has been created. Key Words: Pre-split: Design; Highwall; Perimeter

Jan 1, 2006

By J. R. Sims

Gold assays from production blastholes in the Mercur Hill Pit were used to delineate known ore zones and to determine how well previous exploration drilling defined these zones. The most important factors causing inadequate ore zone definition were: 1) inappropriate location of drill holes relative to the ore zones, 2) presence of stopes from previous mining, 3) sampling and assaying errors, and 4) smoothing of the ore zone boundaries during ore reserve estimation. Infill drilling strategies were evaluated to determine the efficiency with which a given drill pattern defined the known ore zones. A drilling strategy was developed which improved ore zone delineation when compared to techniques which maintained uniform drill spacing.

Jan 1, 1992

By Mateus Augusto Martins de Paiva

Este estudo tem como objetivo avaliar a possibilidade de remediação de águas e áreas contaminadas com Arsênio(V) e Crômio(VI) em pH levemente ácido pela biomassa Polygonum punctatum Elliot, planta presente na imediação da lagoa da Pampulha em Belo Horizonte e em várias regiões do estado de Minas Gerais. Todos os ensaios de adsorção foram realizados em pH 5 por 24h a 25°C. A biomassa foi caracterizada por espectroscopia de infravermelho e o ponto de carga zero (PCZ) foi determinado por titulação potenciométrica. A concentração inicial e remanescente após adsorção para As(V) e Cr(VI) foram obtidas por espectrometria de absorção atômica (AAS). A capacidade de remoção para As(V) foi de 1,14 mg por grama de biomassa enquanto para Cr(VI) foi de 7,4 mg por grama de biomassa. A biomassa apresentou excelente resultado de adsorção para a espécie Cr(VI), portanto um bom potencial para aplicação para descontaminação de efluentes contendo este contaminante.

Aug 16, 2017

By Jon C. Volkwein

The Bureau of Mines conducted a series of tests to evaluate the effectiveness of mixing a compressed-air-generated foam with dried whole-grain silica sand to suppress dust in minerals processing plants. Dust at downstream transfer points was monitored with personal gravimetric samplers and with Real-Time Aerosol Monitors (RAM's) that were connected to strip' chart recorders. Results showed dust reductions of 80 to 90 pct on three separate occasions at two different plants. The mechanism by which foam suppresses dust is discussed, as are the constraints on the use of foam, which may include incompatibility of the foam with the mineral product, difficulty in controlling the foam generator, and cost.

Jan 1, 1983

By S. A. G. Poppen, J. Konopka

"Petro-Canada's project investigative and experimental underground work in the Galt coal seam at Kipp, Alberta included the construction of an emergency egress and ventilation raise from surface.The Galt coal seam is 206 m below the surface and covered by 8 m of shale, sandstone and clay beds of the Oldman Formation, 128 m of shale, bentonite beds and sandstone of the Bearpaw Formation, and 70 m of glacial till and basal gravel. Free water was encountered from sand lenses in the glacial till and the basal gravel.Excavation for the ventilation raise was a nominal 2 m diameter and it was lined with a welded, continuous, steel liner of 1.2 m 1.D.Excavation in the glacial till was carried out with a surface bucket drill rig combined with hand mining. Ground support in the glacial till consisted of liner plates and backfill grout. The Bearpaw and Oldman formations were excavated by employing standard raise boring techniques. The individual liner sections of the continuous steel liner were assembled on surface and the entire liner column was lowered into the raise by employing hydraulic lift climbers. The liner column was back-filled with concrete.IntroductionThe Lethbridge Coal Field comprises an area of approximately 1 165 square km in the vicinity of Lethbridge in southern Alberta. Pacific Petroleums Ltd. proposed in a Preliminary Disclosure in January 1979 ""to open an experimental mine prior to development of a producing underground mine with an initial rate of 540,000 tonnes per year"". A 2 900-hectare group of leases in the Kipp-Coalhurst area was selected as the primary target for the Kipp experimental mine. The scope of work for the experimental mine included the construction of an access shaft with production capabilities, the construction of a ventilation and emergency exit raise, drive-ages in coal to yield a bulk sample, gathering of geotechnical information and the testing of experimental mining methods."

Jan 1, 1983

By G. Konak

In-pit crusher location selection has had an important role recently, since increasing diesel prices. One way of reducing the haulage costs is to shorten the truck haulage distance by bringing the truck dump point into the pit. This study covers the work done on the optimum crusher location definition for a company that produces aggregate near Izmir, a city of Turkey located in the west. This paper will discuss the effects of pit geometry and mine access requirements on optimum crusher location selection that are mainly based on the establishment of minimum haulage distance. The method will be introduced first and then the computer algorithm developed for this study will be discussed later in the paper. Keywords: in-pit crushing, optimum location selection, optimizing haulage, computer aided design.

Jan 1, 2007

By Gregory Krohn

This report investigates the effects of adding a layer of extra padding to the palm area of leather gloves typically worn by low seam coal miners. The first study showed that added glove padding provides more potential protection but does not affect manual dexterity. The second study, in a simulated low seam coal mine, showed no significant differences using padded and non-padded gloves in crawling, shoveling, timbering, and cart pushing task completion times. In general, subjects preferred the padded gloves although they expressed some complaints about awkardness and loss of sensitivity. Recommendations are given for the design of padded gloves that will provide comfort, protection, and maximum hand sensitivity for miners.

Jan 1, 1980

By Luis de la Cruz Rengifo

El presente trabajo señala el tratamiento del concentrado gravimétrico con alta ley de oro en la planta concentradora Compañía de minas Orcopampa S.A. La aplicación del tratamiento se realiza a través del proceso de cianuración convencional y la implementación de la electrodisposición de las soluciones ricas. Como resultado del proceso, se obtienen barras de oro y plata metálicas puras y el concentrado cianurado sin presencia de oro grueso, eliminando el problema de ensayo y muestreo respectivos.

Apr 1, 1991

Every two years, industry leaders and practitioners of tunneling and underground construction gather at the Rapid Excavation and Tunneling Conference (RETC) to learn from their peers about the most recent advances and breakthroughs in this unique fleld. Industry experts from around the world highlight their most recent projects and share real-world experiences. They also share with their colleagues new technologies and methodologies that attendees can take home to their respective projects. The 2013 RETC was held June 23-26 in Washing-ton, D.C., itself home to several major tunneling and underground construction projects. The conference is sponsored by SME. Attendance was 1,384 professionals. The accompanying exhibit hosted 159 companies in 188 booths. A few of the topics covered in the technical sessions dealt with caverns and large spans, contracting practices, tunnel linings, design and planning, geotechnical considerations and instrumentation. The conference was preceded by four short courses, all well attended. They were ?Grouting in Underground Construction,? ?Tunnel Lining Design,? ?Microtunneling Application? and ?Risk, Uncertainty and Hard Decisions.? In addition, a sold-out field trip to D.C. Water?s Blue Plains Tunnel took place following the conference. The Blue Plains Tunnel is part of the agency?s Clean Rivers Project. Also during the meeting, three students each received $5,000 scholarships from the UCA of SME, while another three students each received $2,500 scholarships from RETC (See page 53).

Sep 1, 2013