Search Documents

By Edgar Peña

La efectividad de un equipo en la planta de la industria minera es importante en tanto se opere con eficiencia y efectividad. Empero, es necesario conocer el método de cálculo que se ha empleado para determinar la tasa de efectividad del equipo y sobre qué datos se han hecho los cálculos. En esta perspectiva, el presente trabajo describe las herramientas utilizadas en Southern Perú Cooper Corporation para el logro de la calidad de trabajo a través del incremento de la productividad y control de los costos. Para ello, se han utilizado herramientas como: la recolección de datos, visualización de datos, diagramas de Pareto y análisis de beneficios. Asimismo, para una óptima efectividad del equipo deben mantenerse registros precisos de la operación del equipo.

Sep 13, 2001

By Danilo Gonçalves de Oliveira

A linha de Decapagem e Laminação a Frio da ArcelorMIttal Vega vem recebendo constantes investimentos para aumento da sua capacidade produtiva sendo o mais recente a instalação do quarto tanque de decapagem química realizada em março de 2015. Para que esse investimento trouxesse o resultado esperado, eram esperadas melhorias de desempenho no processo de Laminação a Frio. O presente trabalho expõe a metodologia empregada para identificar os projetos necessários e os expressivos resultados obtidos com a sua condução ao longo do ano de 2014.

Aug 16, 2017

By G. S. Rice

The Experimental Mine of the United States Bureau of Mines is a unique coal mine that serves as a large-scale testing laboratory. It is used primarily for testing the explosibility of coal-dust and gases but is also the workshop for many other kinds of research work of which the chief object is to increase safety in mining. The mine is situated in Allegheny County, Pa., about 13 miles southwest of Pittsburgh among the high hills of the west bank of the Monongahela River, at the northeastern edge of the gas-coal district of the Pittsburgh coal bed which extends south through the Connellsville coking-coal district into West Virginia. The Pittsburgh bed, of the Upper Carboniferous age, is one of the most extensive continuous coal beds in the United States, if not in the world. Throughout large areas it shows remarkable uniformity of thickness, levelness, and character of coal, which is a coking coal of high-grade bituminous rank. Its thickness in the northern part is 5 to 5 ½ feet and in the central and southern part is 7 to 9 feet.

Jan 1, 1933

By Ö Aydan

Rock dynamics is one of the most important topics in the field of rock mechanics and rock engineering. The spectrum of rock dynamics is very wide and it includes the failure of rocks, rock masses and rock engineering structures such as rock bursting, spalling, popping, collapse, toppling, sliding, blasting, non-destructive testing, geophysical explorations, science and engineering of rocks, earthquakes, and impacts. Undoubtedly, the rock dynamics issues in Mars would remain to be the same. Although mankind has no direct access to Mars yet, the Mars exploration rovers (Opportunity, Sprit, Curiosity and Perseverance), Mars Reconnaissance Orbiter and InSight Lander provided very valuable data so that some rock dynamics issues can be recognised. The author reports his considerations on rock dynamics issues in Mars from very careful examination of images and data provided from MERs and MRO and discusses their implications.

Nov 29, 2022

By M Ash, P Bellairs

The world class iron ore mines at Mt Whaleback, Tom Price and Paraburdoo located in the Hamersley Province of Western Australia must mine the Mt McRae Shale to obtain high grade ore from the Dales Gorge Member of the Brockman Iron Formation. The Mt McRae Shale contains a Black Pyritic Shale lithology that reacts with Ammonium Nitrate based explosives. This paper provides an overview of the problems associated with mining this reactive rock type as well as the development of a comprehensive procedure to safely and efficiently blast, excavate and dispose of this material.

Jan 1, 1995

By Bruce Notthup

Using a Three Dimensional Laser Profiler, persomrel from Austin Powder were able to determine drilling patterns for use in underground mine Room and Pillar blasting operations, The faces had got out of alignment, causing concave faces across the 100 feet wide, 28 feet high tunnels. This was leading to poor drilling and poor blasting results. By profiling the faces, modifications could be made to the drilling pattern to help gradually straighten the faces. The Laser Profiler was also used to check the accuracy of collaring the holes and also perform post blast surveying of the positions of the bootlegs. This allowed recommendations to be made to improve drilling operations at the face. In addition, other volumetric calculations could be performed using the systems’ surveying software, all a lot more easily and quickly than by standard methods.

Jan 1, 1994

By Carlos Gonzalo Alvarez Rosario

A reciclagem de resíduos eletroeletrônicos (REEs) é importante tanto no aspecto ambiental quanto econômico, uma vez que através do reaproveitamento do REE há diminuição da quantidade de resíduos a ser destinados, além disso, contribui para a sustentabilidade do setor minero metalúrgico, pois é possível a recuperação dos metais provenientes de REEs. Presentes na maioria dos equipamentos eletroeletrônicos, as Placas de Circuito Impresso (PCIs) são compostas por materiais cerâmicos, metálicos e poliméricos. Além disso, a heterogeneidade do material influi diretamente no tipo de processamento/tratamento a ser utilizado, desta forma a caracterização prévia do resíduo é uma etapa fundamental para determinação da rota de processamento a ser utilizada. Assim, no presente estudo é apresentado o processo de caracterização de PCIs proveniente de computadores obsoletos objetivando a determinação e quantificação dos metais presentes, de forma a estudar a influência dos mesmos em processos de biolixiviação futuros. A rota de processamento físico incluiu inicialmente processo manual utilizando guilhotina e, posteriormente, moinho de martelos com grelhas de aberturas de 6 mm e 2 mm. A caracterização foi realizada através de ensaios de perda ao fogo, lixiviação ácida e MEV/EDS e a concentração dos metais foi determinada por ICP-OES. Os resultados mostraram que 50% do material particulado tem granulometria maior que 0,25 mm; as PCIs estudadas possuem 35,6% de metais, 27,2% de polímeros e 37,2% de cerâmicos. Dos metais presentes nas placas o mais representativo foi o cobre com 21,4% em massa enquanto que metais como Fe e Al apresentaram 1,1% e 1,9% em massa.

Aug 8, 2018

By Emad Farouz

The resistance of very dense glacial outwash formations consisting of sand, gravel and cobble formations can be quite high, and techniques for measuring the strength and deformation properties often cause engineers to underestimate the strength of these layers in drilled shaft design. More realistic measurements of this dense formation can be achieved with slotted steel casing pressuremeter tests. To minimize disturbance and achieve accurate measurements, drilling a pilot hole prior to probe insertion is necessary. Characterizing geologic formations that contain significant amounts of gravel and cobbles is challenging because of scale factor. Inserting a standard pressuremeter probe into this formation without damaging the membrane is difficult. This paper presents a case study for the IR-75 project in Dayton, Ohio, USA, where these dense materials were characterized using a slotted casing pressuremeter, optimizing design by providing more realistic properties of these materials.

Jan 1, 2006

To simplify programming, image analyzers commonly measure either linear intercepts or the areas of particles and grains to determine liberation based on polished section mounts. However, the concentration of minerals by flotation is based on reagents that interact with the exposed surfaces of the minerals. Thus, it is often perceived that image analyzers should measure the perimeter of the mineral of interest in the ore particles. A comparative liberation study of thirteen samples collected from a flotation plant processing a complex base metal sulfide ore showed that the liberation of the ore minerals determined by area measurements is very similar to the liberation determined by the exposed perimeters. The liberation determined by exposed perimeters is more appropriate only for those cases where the mineral texture is so complex that it is retained in the small particles generated in conventional grinding operations.

Jan 1, 2002

By S. Möllerherm, E. Drüppel

"The development of indicators to assess the sustainability of mineral raw materials operations is amajor task with respect to its actuality and difficulty. This holds true even more when dealing withenvironmental indicators.The use of existing environmental indicators in the mineral raw materials industry leads to false orat least distorted results. Therefore the Institute of Mining Engineering I from the RWTH AachenUniversity developed indicators and an assessment system for the mineral raw materials industryon operation, company and sector level on behalf of the Federal Ministry of Economics and Labour(Bundesministerium für Wirtschaft und Arbeit, BMWA) and the Federal Institute for Geosciencesand Natural Resources (Bundesanstalt für Geowissenschaften und Rohstoffe, BGR).In total 30 indicators were defined and designed to assess the performance of the mineral rawmaterials industry in terms of sustainable development, 10 indicators for each pillar (economical,ecological and social pillar).The following paper describes some of the results focussing on the development of environmentalindicators. These had to be adapted or completely new designed in order to match the specificcharacteristics of the mineral raw materials industry."

Jan 1, 2005

The AusIMM is concerned about the longer tem sustainability of the minerals sector in Australasia. Our contention is that the sustainability of the sector is at risk if we do not:   ò encourage more exploration in Australasia by removing impediments and         increasing incentives; ò fund our university and research centres appropriately to increase both our   prospectivity, and our processing efficiencies; and ò manage our human resources better.   This paper will focus on how we can better manage our human resources to assist in ensuring sustainability of the sector in Australasia .   From a production point of view:   Economic output = f (Land, Labour, Capital, Environment) where Land refers to all of the natural resources used in production. As well as land itself it includes water, forest, fisheries, oil, gas and mineral deposits. Labour refers to the skills and capabilities used by humans in the production process. Capital describes all of the manufactured aids used in the process of production1. The challenge for management is to ensure maximum efficiency and effectiveness of labour in the production process whilst maintaining sustainable development.   The 1992 Rio Summit defined sustainable development as maintaining and enhancing:   ò natural capital û defined as all natural resources, both environmental and   those of traditional economic value; ò manufactured capital û made by human kind, including produced goods,     infrastructure and built environment; ò human capital û defined as the health, well being, intellectual capabilities and   spiritual welfare of individuals; and ò social capital û defined as social relations and consultations within and   between societies, their norms and functionality2.   The minerals sector in Australasia has successfully focused on the technical aspects of each of these components of sustainable development with primary attention applied to natural capital and efficient utilisation of manufactured capital. The technical aspects of human capital and social have also been addressed through an emphasis on occupational health and safety and interaction with local communities however I suggest that, to date, insufficient emphasis has been placed on labour (human capital) to maximise economic output1.   It has become increasingly common practice to identify land as natural capital, labour as human capital and capital as physical capital. That is labour has been treated as a commodity rather than an opportunity to create a comparative advantage and this will be the greatest challenge for mine management to show leadership over the next decade of the 21st Century.   This paper will outline characteristics of the sector which are relevant to the management and utilisation of labour, outline the outcomes of recent AusIMM surveys, review the reasons for the current and future anticipated skills shortages, some innovative responses to the challenges and finally, suggestions on how mine management can show leadership.

Jan 1, 2006

By Pierre Beaudoin

"This paper deals with the repairs made on two damaged mills. It investigates briefly the causes of the damage, explain its nature and the design of the repair. It explains the detrimental effect on operation and the solutions implemented to reduce them. Finally, to review the follow-up required for such repairs. LOCATIONThe Holt McDermott Mine is located 75 kilometers Northeast of Kirkland Lake and 30 kilometres west of the Quebec border in Northeastern Ontario. The town of Kirkland Lake is located approximately 500 kilometres north of Toronto. HISTORYThe discovery of gold in Holloway Township dates back to early 1920. In 1984 Barrick Resources, which amalgamated with Camflo Mines, acquired more claims on the property and initiated an extensive drilling program. By 1985, the drills indicated reserve increased to 2,500,000 tonnes grading 6.8 g/mt. In 1986 a production decision was made and in 1988 the mine was officially opened.As of December 31, 1998, 4,691,507 tonnes grading 5,66 g/tonnes have been milled from 4 ore-bodies. The mill started up in June 1988."

Jan 1, 2001

By B. J. Dalton

The Bureau of Mines Helium Activity has developed a computer program for use in the reduction of pressure-volume-temperature (PVT) data obtained with a Burnett compressibility apparatus. This program includes important modifications and extensions of some of the methods currently used for treating these types of data and yields statistical information that cannot be obtained from any other published work. The methods of calculation make use of a general nonlinear least-squares technique developed at the Helium Research Center. Because of a need to investigate different functional forms for representing the compressibility factor isotherm, 2, the computer program has been written in such a way that the only additional coding required is the so-called compressibility function subroutine. This subroutine defines the analytical form of Z and certain of its partial derivatives. The program described herein is believed to be the most advantageous for use in treating isothermal Burnett compressibility data.

Jan 1, 1970

By Hubert Gamarra

El presente trabajo señala el proyecto de evaluación y recuperación del molibdeno en la mina Chabuca Sur, perteneciente a BHP Tintaya. El proyecto sigue la metodología de Excelencia operacional (EO) o metodología de mejora continua utilizada en BHP Tintaya S.A y se realiza a corto plazo, con la finalidad de incorporarla bajo un costo mínimo en el stock. Asimismo, se determina una asociación del S2Mo como un pulso tardío de mineralización sin cobre en la zona de alteración argílica de los diques monzoníticos y en el endoskarn.

Sep 13, 2001

By S. H. Ash, E. M. Brooks

"Many of the hoisting slopes at the mines in the State of Washington are driven on extra steep dips. To facilitate hoisting they are driven wide enough to provide two tracks. The cars are handled by high-speed, first-motion electric hoists and the trips run in balance.The State mining laws a provide that special man-cars be provided on slopes of 20° or more and that no one be allowed to ride while any loaded car is being hoisted in any slope in a mine. Obviously, in addition to the fact that it is more or less hazardous to ride while an empty trip is being hoisted, considerable hoisting time is lost during the day if some one has to ride the trips in the slope.Owing to the locations of pumps and various types of equipment, more or less travel is required up and down the slope. Not only to provide a proper safety factor but also to comply with the law, some other means of transportation in an¬other passageway is desirable. This is sometimes recognized in large mines by pro viding separate hoisting shafts, or slopes, and necessary equipment, which are use for transporting men and material. The handling of material in itself would justify the system in most large mines.The following description of an automatic electric man-hoist was prepared from data furnished through the courtesy of Mr. Thomas Murphy, superintendent of the Northwestern Improvement Company's mines in the Roslyn-Cle Elum coal field.The special features of this hoist are that no hoistman is required and its operation is always under the control of the person or persons riding the trip.The hoist was installed at mine No. 5, Roslyn, Washington, to provide a means of entering and leaving the mine on idle days or at night when no hoistman was on duty and to make it unnecessary to use the main hoist for a man trip during working hours. It has been in operation for about two years and has given very satisfactory service.The hoist, with all accessories, is housed in a concrete building 200 feet back from and in direct line with one of the main airways. One car with a capacity of six men operates over a distance of 1,200 feet on a 38° pitch.The wiring details of the electric circuits which control the operation of the hoist are shown in Figure 1-a.The hoist is driven through a worm gear by a 500-volt shunt-wound direct-current motor at a car speed of 120 feet per' minute. A gravity friction brake with magnetic release is mounted on the- motor shaft and is wired in multiple with the motor field coils. The hoist drum is also equipped with emergency friction brakes, which operate by gravity and are released, in case of overspeed, by the governor geared direct to the drum shaft. When these brakes set the control circuit is opened at contact 2E-2C and the motor stops.If the descending car meets some obstruction and is stopped, the hoist continues to run and unwind the rope. To guard against this occurrence, a weighted sheave wheel rides the rope 4 feet from the drum, and if the rope becomes slack the rider drops downward and opens the contact 2C-2E which stops the hoist.Limit switches, S1 and S2, are located on the hoist indicator, which is connected to the drum shaft through sprockets and chain. The pointer P indicates the position of the hoist at all times."

Jul 1, 1930

By Theo Lehner

Turning matte into anodes continues to be an area to watch: for visitors to see pyrometallurgy in action; for metallurgists to keep up with modern smelting furnaces and ever increasing production rates; for management to remain profitable using more tools than taught in school; and for environmentalists to detect the last small clouds from the ever cleaner smelter. Current converting practices have been screened and analyzed, and today, converting and casting is a modern industry. An impressive, though typical learning curve of converter productivity may be detected. Local conditions such as availability and type of raw materials, products extracted, cost factors, etc., have stimulated the development of add-ons or even alternatives to the still dominant method of converting by Peirce-Smith technology. Turning blister copper into anodes follows a similar path, namely increased productivity and improved quality. We dare to predict that development will continue.

Jan 1, 2005

By Nic Slatalla

Resin anchored rock bolts are an effective tool to control the deformation of an underground opening because they combine high support capacity with fast installation. However, there are still numerous shortcomings concerning the understanding and interaction of the system bolt-resin-rock. Field and laboratory test series have been conducted for evaluating the load capacity and bond strength of resin grouted rock bolts in different host rocks under axial load. This paper describes that the behavior and shear strength of the system bolt-resin-rock depends on the rock type and discusses a simple correlation between peak shear strength and shear stiffness in the ratio 1:1000 which may moreover be helpful for estimating rock bolt capacity after installation.

Jan 1, 2006

By D. B. Taliaferro

[Recovery of core specimens from subsurface formations and their subsequent analysis are important aids in efficient development and operation of oil and gas fields. Core specimen first were obtained mainly for the geologic information they revealed; now they are on analyzed to determine many of the physical characteristics and conditions of the subsurface formations as well. Cores recovered from the producing formations may be analyzed for porosity, permeability, oil content, "connate" water content, and other physical and chemical properties of the formation, all to the end of furnishing enough data for making reliable estimates of the quantity and availability of oil and gas within reservoir and in devising efficient means for their withdrawal.]

Jan 1, 1939

By J. R. Donald

Electric arc furnace (EAF) dust, which can be considered as a by-product of the steel recycling process, contains significant quantities of recoverable zinc and iron, as well as hazardous elements such as cadmium, lead and chromium, which can be leached by ground water. The zinc in the EAF dust is found almost entirely in the form of either zinc oxide or zinc ferrite, the latter accounting for 20 to 50 percent of the total zinc. It is important that an efficient process be developed which renders the dust inert, while reclaiming the valuable metals to off-set processing costs. During the conventional carbothermic reduction processes, iron is formed, and this iron can participate in the reduction of the zinc oxide in zinc ferrite. In the present work, the reduction of the zinc oxide in zinc ferrite by iron according to the following reaction: ZnO-Fe2O3(s,s) + 2 Fe(s) = Zn(g) + 4 FeO(s) was studied in an argon atmosphere using a thennogravimetric technique. First, a thermodynamic analysis was performed using the F*A*C*T computational system. Then, the effects of briquette aspect ratio (lid), temperature, zinc ferrite particle size, amount of iron added, as well as additions such as lime, sodium chloride, and calcium fluoride were investigated. It was found that, initially, the reaction was chemically controlled with an activation energy of 178.1 kJ/mol. Then, after a product layer had formed on the outer surface of the briquette, the reaction was restricted by the diffusion of zinc gas away from the reaction interface. The parabolic rate law was fitted to the experimental data, and the parabolic rate constant was found to be: = -6.2275 + 0.0054 T (K)

Jan 1, 1995

By A. Uiga

The U.S. Bureau of Mines funded a project which addressed objectives concerning irrigation of native plants and inoculation of native plants with vesicular-arbuscular mycorrhizal (VAM) fungi. The specific irrigation objectives were 1) to demonstrate the performance capabilities of solid-set irrigation for reclaimed mineland conditions, and 2) to demonstrate and evaluate three irrigation concepts under two separate water supply conditions. The VAM inoculations were to assess irrigation benefits in establishing VAM relationships for transplanted native species. Following the seasonal demonstration (May to September 1983) at 3 separate mine sites, conclusions were made that apply to the 6 state Western mining industry. The demonstration sites were located in Montana, Wyoming, and New Mexico. Positive conclusions were reached for 1) the use of soil moisture sampling with or without irrigation, and 2) the selection of solid-set sprinklers as the irrigation method. The conclusions about the irrigation concepts and strategy were mixed, due to the short-term (1 season) nature of the project. No conclusions could be reached for the VAM inoculations because the study time was too short.

Jan 1, 1984