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By Alberto Terrones

"La demanda de metales y agotamiento de las reservas conocidas en el mundo, genera un incremento en las actividades de exploración minera orientadas a descubrir nuevas fuentes de producción mineral, ya sea en áreas vírgenes o en zonas o distritos mineros ya conocidos. En ese sentido, el descubrimiento de minas, ya sean grandes o medianas, se va restringiendo cada vez más al estudio cuidadoso de zonas mineralizadas,con expresiones superficiales poco impresionantes. Por ello, el presente artículo señala la aplicación de métodos de exploración minera en el Perú. El proceso comprende 6 fases: En la primera se debe encontrar las provincias metalogenéticas que suponen la existencia de yacimientos importantes a gran profundidad. La segunda fase determina la naturaleza, posición, orientación, longitud y costo de los trabajos de exploración primaria, tales como socavones, sondajes diamantinos, trincheras, etc., encaminados a probar la existencia de mineralización comercial en profundidad. La tercera fase concreta la posición, dimensiones y profundidad del objetivo, reduciendo a un mínimo el costo total de los trabajos de exploración primaria requeridos para probar la existencia o no existencia de un yacimiento comercial. La cuarta responde a la vigilancia y atención del geológo. La quinta fase comprende e inicio de una vida operativa."

Oct 1, 1955

By Edwan Anderson Ariza Echeverri

O processo de estampagem a quente também conhecido como press hardening, é um dos métodos mais utilizados atualmente pela indústria automobilística para produzir aços de alta e ultra alta resistência. Esse processo é principalmente usado em peças relacionadas à segurança passiva e à resistência ao impacto, tais como pára-choques e barras de proteção laterais. O uso desse processo aumenta a segurança dos passageiros e reduz o peço do veículo e, portanto, o consumo de combustível. No presente estudo, amostras de aço ao boro foram deformadas a quente, não isotermicamente, a 850ºC e 750ºC em 30% a uma taxa de 0,5s-1. As microestruturas obtidas após deformação a 850ºC foram quase totalmente martensíticas, diferente das amostras deformadas a 750ºC, onde houve uma diminuição da fração volumétrica de martensita e um aumento da fração volumétrica de ferrita. Portanto, a deformação aplicada a 750ºC resultou em uma diminuição dos valores de microdureza. Desta forma, tornou-se possível investigar a influência da deformação em alta temperatura na transformação martensítica, na fração volumétrica de ferrita e nos resultados de microdureza.

Aug 16, 2017

By John E. Udd

"For decades, writers have expressed concern about impending shortages of professionals for Canada's minerals industry. Even under the present difficult economic circumstances, it is anticipated that the supply which will be available will not be adequate to meet the requirements in certain key areas including mining and petroleum engineering. It is evident that, unless further initiatives are taken, shortages will exist for some time.In this paper, the writer reviews information which relates to both the demand for, and the supply of, persons with advanced-level education in minerals-related disciplines. In particular, a summary is made of the information regarding supply which has been collected by the CIM General Committee on Education for many years.In concluding, the writer expresses some personal opinions regarding imbalances between demand and supply and offers some recommendations for future actions.IntroductionLast year, in a paper which was presented at the Annual General Meeting of the CIM in Calgary, the writer presented a review of the situation regarding professionally educated manpower for the minerals industry, and concluded that indications were that the gap between demand and supply was widening and that the situation could be expected to continue. Since that time, the deterioration of the nation's economy has caused an appreciable reduction in demand. Simultaneously, a further annual survey by the CIM has shown that the numbers graduating in certain specializations, notably geology and some of the technologies, are rising very rapidly. One of the great concerns of educators at present is that adequate opportunities may not exist for all of those who are now graduating.The danger of the present situation, then, is that a momentary lack of opportunities may cause potential students to choose alternative careers . Because of the lead-time which is involved, it is very possible that this could result in greater shortages during a period of economic recovery or expansion. Action must be taken to ensure that adequate numbers will be attracted to the industry, and this applies particularly to those who have already made the career decision and who are enrolled in minerals-related programs."

Jan 1, 1982

By S G. Hagemann, M E. Barley

The Mt Tom Price deposit is a world-class high-grade hematite deposit in the Hamersley Province of Western Australia with an original resource of 900 Mt of almost pure hematite, averaging 63.9 wt per cent Fe. Petrological and geochemical studies at both the Southern Ridge and the North deposit at Mt Tom Price have identified three hypogene alteration zones between unmineralised BIF and high-grade iron ore: distal magnetite-siderite-stilpnomelane; intermediate hematite-magnetite-ankerite-talc-chlorite; and proximal martite-microplaty hematite-magnetite-apatite alteration zones.Fluid inclusions trapped in siderite within the distal magnetite-siderite- stilpnomelane alteration zone at the North deposit revealed primary high salinity (25.5 eq wt per cent NaCl-CaCl2) inclusions that homogenised between 107¦ and 142¦C into liquid. Fluid inclusions trapped in ankerite within ankerite-microplaty hematite veins in the intermediate hematite-ankerite-magnetite-talc-chlorite alteration zone at the North deposit revealed mostly H2O-CaCl2 pseudosecondary and secondary inclusions with salinities of 22.4 - 25.4 eq wt per cent and 22.9 - 25.9 eq wt per cent CaCl2, respectively. Pseudosecondary inclusions homogenised between 153¦ and 449¦C and secondary inclusions homogenised between 103¦ and 157¦C. Fluid inclusions trapped in apatite within talc-microplaty hematite veins in the intermediate hematite-magnetite-talc-chlorite-apatite alteration zone at Southern Ridge revealed that primary, medium salinity (7.0 - 9.0 eq wt per cent NaCl) inclusions homogenised between 181¦ and 257¦C and primary high salinity (22.8 - 25.9 eq wt per cent CaCl2) fluid inclusions homogenised between 118¦ and 257¦C into liquid. Microthermometric analysis of quartz from quartz-hematite veins from the Southern Batter Fault, Southern Ridge show a complex fluid inclusion history. Primary fluid inclusions consist of: low- and high-salinity H2O-NaCI inclusions trapped at temperatures of approximately 140¦ to 230¦C; vapour-rich inclusions of unknown compositions; and æcomplexÆ salt-rich (Ca, Mg, K and Na inclusions).Secondary inclusions consist of medium-salinity fluid inclusions trapped at temperatures of about 140¦ to 280¦C.A two-stage hydrothermal model is proposed for the formation of both the Southern Ridge and North deposits. Early 1a hypogene alteration involved the release of hydrothermal NaCl-CaCl2-rich (25.5 eq wt per cent) basinal brines (110¦ - 150¦C) from the underlying Wittenoom Formation and directed upward along normal faults and focused within the silica-rich rocks of the Dales Gorge Member, by the shales of the underlying Mt McRae Shale Member and overlying Whaleback Formation. Within the Dales Gorge Member hydrothermal basinal brines migrated laterally within large-scale folds with permeability controlled by shale bands and the NW trending dolerite dyke sets. Fluid rock reactions transformed unmineralised BIF to magnetite-siderite-iron silicate BIF, with subsequent desilification of the chert bands. Stage 1b hypogene involved an increase in temperature of the hydrothermal, CaCl2-rich saline (24 eq wt per cent) basinal brines (250¦ - 300¦C) resulting in formation of hematite-ankerite-magnetite-talc-chlorite alteration and the crystallisation of microplaty hematite. Late stage 1c hypogene alteration involved the interaction of low-temperature (~120¦C) basinal brines with the hematite-ankerite-magnetite mineral assemblage. At the Southern Ridge deposit this process was very intense (ie high fluid flux), therefore resulting in the almost total removal of ankerite and resulting in the increased porosity of the ore. Stage 2 supergene enrichment in the Tertiary resulted in the removal of residual ankerite and apatite and the weathering of the shale bands to clay.

Jan 1, 2005

By Richard B. Berg

Chlorite veins in the Silver Star district (40 km southeast of Butte) were of little interest to those who were mining gold and silver in the late 19th century. It wasn't until 1975 that unusually pure magnesian chlorite of the variety clinochlore was identified from a ?talc? claim in this district. In 1977 tests by Cyprus Industrial Minerals showed that this chlorite was suitable for use in ceramics. Mining begun in that year continues. These replacement veins of chlorite in Precambrian quartzofeldspathic gneiss differ from the metalliferous veins to the northwest in both attitude and mineralogy.

Jan 1, 1982

By B. G. H. Thomas, W. P. Yant, A. C. Fieldner, R. R. Sayers, W. J. McConnell

"One of the outstanding problems confronting automotive engineers in attempting to construct motors of greater economy is that of eliminating the ""knock"" from the operation of the engine. Recent investigations of this detonation or knock in internal-combustion engines, especially of the high-compression type, have demonstrated that it can be eliminated or reduced by decreasing the reaction velocity of combustion by adding small quantities of certain compounds to the gasoline, This makes it possible to use engines of a higher compression ratio, thereby greatly increasing the mileage per gallon of gasoline consumed. The savings in fuel reserves from increasing the proportion of crude oil marketable as motor fuel and in permitting the designing of more efficient engines are obvious.Ethyl gasoline, one of the widely used anti-knock fuels, is ordinary motor gasoline to which has been added 3 c.c. of tetraethyl lead and 2 c.c. of a halogen carrier, as ethylene dibromide or trichiorethylene, or approximately 0.06 per cent of the lead compound and 0.04 per cent of ethylene dibromide by volume. Ethyl gasoline should not be confused with ethyl fluid, which is a mixture of concentrated tetraethyl lead and ethylene dibromide in the prowler proportions for mixing with gasoline, but is not a motor fuel and is not sold to the public. Also tetraethyl lead is not a motor fuel, and likewise is act sold to the public."

Dec 1, 1924

By W. P. Campbell

Foreword At the outset, it should be stated that this paper does not pretend to present a panacea for the ills that 'frozen' wells are heir to, but rather is an attempt to bring to the attention of those whose special concern it is, a little theory and some facts, which have been brought to light recently, in connection with the problem of 'freezing' as it applies to naphtha-producing wells in the Turner Valley field, and to draw some conclusions that follow from the facts discovered. It should also be stated that the investigation is not to be regarded as in any sense complete, but in progress. Doubtless new facts will be brought to light from time to time which may modify present ideas on the subject, but whether favourable or contrary, these will be welcomed, as the purpose of the Department is to secure as complete information as possible of the factors contributing to 'freezing', since this must be the first step to an intelligent attempt to remedy or prevent its occurrence, if such can be done. It is possible, too, that the cause or causes of freezing may not be the same in all cases, but whether this be so or not will have to be determined later as new information comes to hand. Introduction One of the worries which must constantly confront the operators of gas-naphtha producing wells in Turner Valley-although all, fortunately, have not met with it-is the possibility of the occurrence of what is commonly called 'freezing' (going off production).

Jan 1, 1930

By J. W. Motter

Currently, virtually all new electric power generation systems under construction are designed with natural gas as the primary fuel. Factors driving these construction decisions involve sustained low prices for natural gas, environ-mental (and consequent regulatory) risks associated with the use of coal for power generation, and relatively high costs of construction for conventional coal-fired power plants. Despite the unarguable abundance of coal in the US. and worldwide, a fundamental question arises: What will be the role of coal in electric power generation in the 21st century? Congress, recognizing the vital and strategic importance of preserving the coal option for electric power generation, authorized the Clean Coal Technology Program. This pro-gram, with original funding in excess of $2,500 million, is intended to promote the demonstration and commercialization of a new generation of clean, efficient coal-based energy technologies through collaboration and partnering with private industry. The two technologies being demonstrated under this program which are the key to the continued use of this nation's huge coal reserves are coal gasification and the pressurized fluid bed. Either or both of these technologies, coupled with a combined cycle will pro-vide the continuing future coal option, while responding to increasingly more restrictive environmental standards. Recent Congressional budget-cutting efforts, however, could threaten the effectiveness of that model program, and ultimately other subsequent government-industry collaboration.

Jan 1, 1996

This paper provides an update to a paper by the author on an overseas explorer's perception of New Zealand, presented at the 1997 New Zealand Minerals & 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 F. C. Canney

Geochemical prospecting seeks hidden mineral deposits by sampling for variations in the chemical composition of naturally occurring materials. Usually the samples are of soils and other products of weathering and erosion-surface materials extremely susceptible to contamination by human activities. Except when a survey is conducted well away from populated areas, contamination is an ever-present hazard. The program's success is particularly endangered when the contaminants are the elements sought; if these occur erratically throughout an area, spurious anomalies completely unrelated to mineralized areas can be formed. Evenly distributed contamination can be dangerous too, if it raises the background to such a level that true anomalies can no longer be easily detected. Suppose, for ex- ample, that in an area where the lead background is 20 parts per million the soil over a lead vein contains 1000 ppm of lead. Here the contrast would be 50 to 1, which is very satisfactory for geochemical surveying. Now if 1000 ppm of lead from some source were added evenly to the soil in this area, the contrast would be reduced to about 2 to 1, and the anomaly would no longer be readily detectable because a threshold of significance twice the value of the background is the minimum generally used for interpreting geochemical data.

Jan 2, 1959

By C. A. Geffen-Fowler

This report, sponsored by the Bureau of Mines, presents the results of an examination of the safety of the Blind Shaft Borer (BSB) shaft sinking system and an alternative modified BSB design concept in comparison to conventional shaft sinking technology. Detailed study of the two systems was also performed to identify and recommend design changes for optimum safety conditions. A comparison of the BSB systems with conventional shaft sinking was made on the basis of relative risk levels. Risk incorporates both the frequency and the potential consequence of accidents. A safety evaluation of the component operations of the two BSB systems was performed using a Failure Modes and Effects Analysis (FMEA) methodology. The results of this analysis show generally that both BSS systems are safer than conventional shaft sinking. The potential risk of conventional shaft sinking operations could be reduced by over 30%, on the average, with the use of the original BSB system, and by an average of about 10% with the modified BSB. Design change recommendations to further improve the safety of these systems include a better fire suppression system, improved man haulage systems and more compact hydraulics. An operational safety manual was also developed for the modified BSB system.

Jan 1, 1981

By Viviane de Melo Borges

O presente trabalho avaliou as influências da adição de boro nas características mecânicas e micro estruturais do fio máquina e arame trefilado. O estudo foi realizado por meio de análises no aço 10B45 com variações na adição de boro. Foi verificado que a adição de boro reduz a resistência do material. O boro reduz os efeitos do envelhecimento pois associa-se ao nitrogênio formando o nitreto de boro alocado no contorno de grão. Quanto maior a adição de boro menor resistência à trefilação, o que pôde ser comprovado pelo ensaio de torção. Através das micrografias de fio máquina foi possível evidenciar que o boro também atua como refinador de grão e inibe o crescimento do mesmo. Por fim, foi possível avaliar o modo de fratura relacionado com a quantidade de boro adicionada. Neste ponto não foi possível atribuir maior ductilidade à amostra com maior teor de boro.

Oct 30, 2017

By J. Hendry, K. Brady, J. Yorzyk

Drawing from the experience of nickel, copper, aluminum and mineral borates, this paper illustrates the business value that the mining, minerals and metals industry as a whole can gain from applying life cycle assessment (LCA) to products and operations. Through the use of case studies, the paper explores how companies and industry associations have used LCA to their advantage: from evaluating capital investments, meeting customer information needs, supporting new product applications, and developing credible marketing information on the environmental performance of their products. It also explores the dynamics of LCA adoption and integration within companies, and provides recommendations to further strengthen institutionalization of LCA.

Jan 1, 2010

By G. Bartolacci, G. Couture, Levasseur. B., A. Lockhart, D. Nathan

"Pulp and froth zone characterization in a flotation circuit to improve transport of valuable minerals remains a challenge. Even though some significant breakthroughs have been made in the development of collectors in terms of selectivity, the control of gangue drainage is still the main bottleneck to achieve the production of a clean concentrate.Over the last decade, COREM’s team has been working on technologies to improve the selectivity of flotation circuits by tuning their hydrodynamic conditions using online instruments such as the bubble viewer, Jg sensor and gas hold-up. As part of its research program, COREM also developed the half-life column that establishes the relationship between the collection zone (bubble-particle attachment) and the cleaning zone (foam) of a flotation machine. In recent years, COREM has continued the development of the prototypes to make them more robust and improve the accuracy of their measurements.Recently, these hydrodynamic instruments were installed in an industrial process at Raglan Mine in order to diagnose and control the impact of hydrodynamic parameters versus the recovery and the quality of the Ni concentrate produced. Sampling campaigns of hydrodynamic parameters demonstrated that froth height could be optimized in order to increase recovery and quality of the concentrate at the same time. The specific effect of the froth height impacts both the pulp and the froth zones. Along with the impact on the drainage of the concentrate, it was observed that froth height also contributes to enhance the collection of particles in the pulp leading to an increase in metallic units.IntroductionOnce the particles of the minerals of interest are attached to the air bubbles injected in the pulp, the flotation process is driven by air dispersion parameters and froth properties. The pulp is usually responsible for the collision between air bubbles and hydrophobic particles of interest while the froth zone aims to upgrade the selectivity of the particles floated through drainage of the unwanted hydrophilic particles. Over the last four decades, flotation hydrodynamics has been extensively studied. Superficial gas velocity (Jg), gas hold-up (eg), Sauter mean bubble diameter measurements (d32) and bubble surface area flux (Sb) are among the most assessed parameters in flotation plants worldwide either to quantify the gas dispersion parameters or to optimize them (Fournier et al., 2015). McGill University has developed several sensors able to measure these parameters at industrial scale (Tavera et al., 1996; Finch et al., 1999; Chen et al. 2001)."

Jan 1, 2017

By Ian Hooper, Alan Winter, Stefan Sadokierski, Craig Covil

The existing Tappan Zee Bridge was built in the late 1950s and has been working over its design traffic load for some time now. A new project, which is being jointly sponsored by the New York State Thruway Authority and Metro-North Rail Road, is looking at new alternatives to provide new road and rail crossings of the Hudson River. These include 2 to 5 mile and potentially longer tunnel crossing options that include hardrock TBM and EPBM opportunities. The paper describes the project needs and tunnel concept design work done on some of the alternatives. It also relates to the current EIS process for the project and talks about a possible double-stacked tunnel option. It also talks about the geology and environmental constraints relating to tunneling and provides and introduction to the tunnel ventilation work necessary for tunnel crossing of this magnitude. It does not report on the bridge engineering options being evaluated.

Jan 1, 2005

By L Neindorf

The development and application of paste fill, cement slurry aggregate fill and shotcrete bulkheads at Mount Isa Mines is described. The progressive changes in filling style in the Mount Isa copper mines from a dry fill based cemented rock fill to tailings based paste fill and slurry fills is explained. The development of shotcrete arched bulkheads and engineered drainage system is described. Details on how Mount Isa Mines has achieved approximately 30 per cent cost reduction in backfill operations through innovations are given. The development of a rocky paste fill is explained.

Jan 1, 2005

By P D. Katsabanis

According to Persson(1) steady state detonation along a cylindrical charge can be regarded as a self propagating process in which the axial compressive effect of the shock front discontinuity changes the state of the explosive so that exothermic reaction sets in with the requisite velocity.

Jan 1, 1990

By Pedro Máximo Ángeles

El presente texto señala el proceso «Strategic-Udy Modificado Angeles» utilizado para la producción de fierro o semiacero en Chimbote, Ancash. En ese sentido, durante la producción de aceros, es opcional el uso de fierros secundarios en la fundición (Scrap). La gran flexibilidad que ofrece el proceso permite producir tan bajo tonelaje sin sacrificar el costo de producción por tonelada de metal. Asimismo, las reparaciones pueden hacerse con gran facilidad, quitando la alimentación, drenando el horno eléctrico y cortando la corriente. Se puede operar el tonelaje deseado en una planta ya instalada con un pequeño descenso en la eficiencia. Por ello, es el método más adecuado en los lugares donde no se dispone de coke, tal es el caso de Chimbote - Perú y en donde se dispone de energía eléctrica barata, y de carbones que requieren procesos caros para su coquificación.

Nov 1, 1963

By Frank E. Cash

As a part of its safety program the United States Bureau of Mines has fostered the development, use, and improvement of portable electric mine lamps. Although there is still need for better illumination in mines and the replacement of open lights has been slow, improvement in electric cap lamps and increase in their use indicate one phase of recent progress toward safer and more efficient mining This report is the result of a recent survey of electric-lamp installations in the Alabama mining; district; it shows the misuse, increase in use, and relation to certain classes of accidents of these installations.

Jan 1, 1935

"El presente estudio describe el proceso de combate contra incendios efectuado por la mina de Cerro de Pasco. Dicho procedimiento incluye una revisión anterior al año 1936 en dos etapas, las técnicas actuales y los planes futuros preventivos sobre incendios. Anteriormente al año 1936, los siniestros ocurrían en los tajos del último tipo y la forma de contrarrestarlos era a través de tapones, aislando la zona de incendio y creando un enfriamiento por medio de chimeneas de ventilación. Sin embargo, esta forma de combate contra los incendios no resultó efectiva, dado que no evitaba completamente el ingreso del aire por medio de los tapones y a su vez, la proliferación de minerales con el tiempo volvía inaccesible la zona. Por tal motivo, la minera solicitó los servicios de un consultor, quien propuso tres sistemas: inundación de la zona del incendio, sofocación del incendiopor medio de anhdriddo carbónico y el sistema Plenum. De los tres sistemas, se consideró a este último pues mantenía la zona de incendio bajo presión de aire y no alteraba el resto de la zona de trabajo. Posteriormente se sugirió el uso del sistema ""Slimming"" o relleno de lodos, los cuales cubrían hidraúlicamente los espacios vacíos alrededor del incendio con un material inerte, adquierendo la forma de un fluído. La efectividad del método era suficiente que fue adoptada a partir de 1938 hasta el presente. Entre los procedimientos actuales se propuso el reemplazo del pino de oregón por la madera de eucalipto por su costo y composición menos inflamable. Asimismo el entablado del piso se sustituyó por una capa de concreto de tres pulgadas de espesor, limpieza del tajeo y equipamiento adecuado de las chimeneas, la ventilación adecuada, el entrenamiento permanente de las seis cuadrillas de combate, construcción de galerías y cruceros auxiliares de transporte, el relleno por lodo y el uso del sistema de alarma denominado ""Stench Mercaptan"", que se inyecta en las tuberías de aire comprimido y sistema telefónico. "

Jul 20, 1957