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By José Luis Vitteri

Dado que se generan largas colas de los camiones mineros en los puntos de carga, es necesario revisar las causas principales que la originan. Entre estas tenemos: el desconocimiento de la variabilidad y sus efectos nocivos y la aceptación de que el mínimo costo de operación se obtiene con la mayor utilización de la excavadora. En este sentido, el presente texto describe el manejo de la variabilidad en los procesos de carguío y transporte con equipos pesados a través del estudio de sus causas, de forma que la única manera correcta de reducir el perjuicio de la variabilidad en el transporte, es manipulando la frecuencia inicial de los camiones.

Oct 1, 2013

By Oliver Bowles

A conviction is growing that depressions and other adverse conditions are not entirely unavoidable if a knowledge of past achievements and shortcomings is intelligently, applied in shaping the course of industry. Mineral producers have available a source of such knowledge concerning; their industry in the statistical records of the United States Bureau of Mines, and by scanning, this increasingly exact history can obtain information on which to found a more stable future. This paper contains a brief history, covering more than 50 years, of the activities of the nonmetallic mineral industries as a group, followed by short histories of each of the more important commodities in which are noted the circumstances that lave influenced their development.

Jan 1, 1933

By M. E. Tyrrell

Research objectives were to determine the reasons for erratic behavior of semisilica horizontal zinc retorts in service; to investigate potential corrective measures including the possible utilization of more refractory materials in the retort body; and to delineate laboratory tests suitable for process control in the manufacture of retorts. Correlation of laboratory test results and data supplied by the cooperating smelters indicated that structural failures due to thermal shock and laminations in the retort body are largely responsible for the erratic behavior of horizontal zinc retorts in service. The most promising modifications made in the retort body and evaluated on a laboratory scale included finer grinding of the plastic clay fraction, substitution of mullite grog for calcined fire clay and grain alumina for silica, plus the use of an organic binder. Lamination-free extrusions having excellent thermal shock resistance were prepared from a mixture composed of 50 percent low-silica Missouri plastic clay through 100 mesh, 25 percent mullite grog through 6 mesh, and 25 percent alumina through 100 mesh. The mix was pugged under 28-inch vacuum with 1 percent ligno sulfonate binder in 12 percent tempering water. Laboratory tests suitable for process control in the manufacture of retorts are described.

Jan 1, 1969

By Madgwick J. C

Leaching column techniques and microbiological methods have been described in detail in Madgwick and Ralph (1980) and Madgwick, Ralph and Sadler (1981).Sixty-nine kilograms of copper porphyry ore (0.4 per cent Cu, 2.7 per cent Fe) (particle size 2.4-11.2 mm; 60 The effect of sodium chloride (O.6M) irrigation on bacterial leaching of Bougainville copper porphyry ore was studied.Viability of suspended Thiobacillus ferrooxidants was reduced to less than 10 cells/ml in NaCI (O.6M) compared with 10' eells/ml in dilute II,SO, (0.01 M, pll 2). Salt irrigation had no significant effect on heterotrophic and sulphur oxidizing bacteria. Increascd short term recovery of copper (145 g/tonne/ 15 days) was followed by a marked decrease in tenors to less than 20 mg/litre/day compared with an acid leach, steady release, of 110 mg/litre/day. Resumption of acid leaching restored average solution copper to 46 mg/litre/day and the viability of suspended T Ierrooxidates to 10 cells/ml.Quantitative removal of sodium ehloride from ore particles was difficult and t races of NaCI remained for more than 200 days.

Jan 1, 1982

By Rogers Wade

THE Pilares mine of the Moctezuma Copper Co. is situated at Los Pilares de Nacozari, Sonora, Mexico, about 75 mi. (120.7 km.) South of the international boundary and about 7 mi. (11.26 kin.) east of the town of Nacozari de Garcia. It is situated at an elevation of 5000 ft. (1524 m.) in one of the northward trending ridges that form part of the mountain mass that culminates in the Sierra Madre de Mexico. To the east, south, and west, the topography is rugged and diversified; to the north less diversity exists, ranges of mountains rise sharply out of almost level ground and give the basin range structure characteristic of the southwest. The climate is dry, the average rainfall of 15 in. (38 cm.) being confined almost entirely to the months of June, July, and August. The

Jan 8, 1919

By C. A. Heiland

THIS year's review of geophysical activities has a somewhat different complexion than usual. With the ending of the war, the time seems opportune to supplement the customary report on operations and discoveries in oil and mine exploration by a review out-lining the contributions of geophysicists to the. war effort. To give as much space as possible to the latter, presented as Part 2, some of the usual review features have been omitted from the statistical section, given as Part 1 immediately following.

Jan 1, 1946

By R. D. Brown

"AbstractIn order to raise the enormous amounts of capital which will be essential for the development of Canada's mineral and petroleum resources, this country's resource industry must be permitted to earn an acceptable rate of return. The existing tax regime, with its high rates, complexities and misdirected incentives, presents a serious obstacle to our resource industries in their development of Canada's immense , but increasingly lean, resources. Government tax and other policies are not the only cause of the crisis now facing the resource sector in Canada, but a reformed tax system, with stable and reasonable tax burdens, is required if Canada's resources of minerals, oil and natural gas are to continue to contribute in the future, as in the past, to our national well-being.An independent task force, organized under the auspices of the Canada West Foundation, has recently completed a wide -ranging report: on the future development of Canada's mineral, oil and gas resources. This five-volume report, completed after almost two years of research and study, concludes that Canada •is facing a major crisis •in the development of our resources, It states that unless corrective action is taken now, mineral production and exports could decline drastically after 1985, at the same time that Canada would face massive bills for imported oil because of inadequate and declining production.The task force, chaired by the author of this article, has put forward recommendations for a fundamental shift in both federal and provincial policies in order that Canada's mineral reserves can be developed in the national interest. This article consists of excerpts from the summary of the task force's report."

Jan 1, 1977

By K. C. Dean

Discarded automobiles represent the greatest single resource of reusable metals, plastics, and rubber in the United States. This report presents results of Bureau of Mines research, conducted from 1965 to 1983, on separating and recovering useful materials from the scrapped hulks, using old and new metallurgical techniques combined with standard scrapyard methods. The Bureau determined the materials composition of three composite cars designated as circa 1960, mid-1970's, and early 1980's, and used these cars to study smokeless incineration and hand-sorting techniques. In studies on treating rejects from automobile shredders, the Bureau designed a process that included air classification, water elutriation, magnetic separation, handpicking, and heavy-medium separation, and also investigated cryogenics and liquation. Complete recovery of cop-per and other metals was economically made by hand and tool dismantling, leaching, or selective melting of starters and generators. Techniques are also discussed for plastic recovery and waste tire treatment.

Jan 1, 1985

By Carlos Guillen Morales

Como parte del proyecto de estudio de impacto ambiental presentado por la Compañía Minera Antamina (Ancash), el presente trabajo describe la reutilización de las aguas residuales de los procesos mineros realizado en Huarmey. El estudio plantea el transporte el concentrado de mineral desde la mina hasta el puerto de embarque en Huarmey a través de camiones utilizando una carretera que facilitaría el desplazamiento de los mismos. Una vez llegado el concentrado al puerto de embarque, se separaría el agua del concentrado y el agua sería tratada para luego descargarla en el mar. Sin embargo, por análisis posteriores, se optó por otra propuesta más ecológica, donde se traslade los concentrados de cobre y zinc en suspensión acuosa a través de un minero ducto, y el agua tratada remanente del transporte de mineral, sería disipada mediante una plantación forestal, evitando la descarga al mar, generando empleo y una extensa área verde en el desierto de Huarmey. De forma que se innova en la minería a través de la reutilización de las aguas y se desafia las condiciones extremas del desierto costero para desarrollar una superficie vegetal que consumiera esta agua.

Sep 12, 2005

By ALBERT E. HALL, Arno C. Fieldner, Alexander L. Field

As a safeguard against excessive clinker troubles, specifications for the purchase of coal can be drawn to include the "softening" or "fusing" temperature of the ash. The value of such information has been recognized by the Bureau of Mines and has induced the bureau to investigab~ laboratory methods of determining the fUSIbility of coal ash, and the bearing of the results on clinker formation in fuel beds. The bureau realized that the fusibility of a mixture of oxides and silicates snch as is comprised in coal ash ,'aries according to the conditions under which tests are made, and that in the absence of any generally accepted method, no agreement is to be expected among tests made in differ«:-nt laboratories. Indeed, Marks a has recently called attention to differences as great as 3900 C. that were obtained with the same sample of ash by two different laboratories. Therefore if a fusion-temperature clause is to have any place in specifications for coal, a standard m('thod of t('sting should be adopted in order to insure comparable results by different laboratories and to obtain the softening or fusing temperature of the ash unde:'r conditions similar to those of a fuel bed. After a consistent method has been devised for obtaining comparable:' results at different laboratories, there will remain the correlation of these results with those from the burning of coal in furnaces before the value of fusibility tests in coal specifications can hE' finally determined.

Jan 1, 1918

Raw materials account for over 60 per cent of the cost of hot metal production in classical blast furnaces and the principal cost component is cost of coke. Dependence on coke is a traditional weakness of blast furnace ironmaking and while efforts have been made to evolve alternative ironmaking technologies which do not use coke, such as direct reduction, smelting reduction, and the more recent method of making iron carbide, blast furnaces continue to be the most efficient means of producing bulk hot metal even today. Coal injection, to the extent of 150 - 200 kg/t of hot metal, has been one of the major innovations made in blast furnaces to decrease cost and to reduce the dependence on coke. This has, however, given rise to more stringent coke property requirements (which often means more expensive coke) - a `tail spin' of Sorts!

Jan 1, 1999

By Eleanor Abshire

This bibliography is the result of a cooperative project undertaken by the Bureau of Ships and the Bureau of Mines to accumulate literature published to date on zirconium and hafnium and to establish an information center on these metals for the use of any interested research organization or library. This bibliography, which will be supplemented as additional information is accumulated, consists of references, with abstracts, to pertinent literature on the subject published from 1907 to date.

Jan 1, 1957

By E. H. Burroughs

HISTORICAL REFERENCES OCCURRENCE-GEOLOGY AND ORIGIN. 4. ARNOLD, RALPH. Conservation of the oil and gas resources of the Americas, Econ. Geol., vol. 11, Apr.-May, 1916, pp. 203-222; June, 1916, pp. 299-326; Proc. 2nd Pan American Sci. Cong., 1915-1916, vol. 3, Conservation of natural resources, pp. 207-237. Shows occurrence of oll, and status and possibilities of oil Industry in each country. Discusses briefly ways in which oll reserves may be conserved. 5. RUTIS, A. A. Petroleum known since remote times. Oil and Gas Jour., vol. 15, Nov. 2, 1916, pp. 33, 37. Gives historical reférences to the use of petroleum from Bible times to its discovery In America. See also Nos. 3, 257, 202, 337, 1843.

Jan 1, 1919

By W. L. Josey

The Stibnite Project is an open pit/cyanide heap leach gold property located in the Yellow Pine mining district of central Idaho. The gold ore is in an oxidized zone of an epithermal deposit which is associated with a fault system related to Tertiary igneous activity of the region. The faults transect a roof pendant of metamorphosed sediments within crystalline rocks of the Idaho Batholith. Seasonal mining is at a rate of 3900 mt/d (4300 st/d) of ore with a 2:l waste to ore ratio. Gold and silver are recovered through a process of cyanidation, carbon adsorption and desorption, and electrowinning. Disposal of the leached ore requires chlorination of the residual cyanide.

Jan 1, 1984

By J. Ritchey

This report describes the engineering feasibility and economic advantages of using a mobile bridge-type cross-pit belt conveyor system in conjunction with a large dragline to excavate and transport spoils in a typical Western surface coal mine. The studies show that such a system could be built to survive operational and climatic mining conditions, and that its implementation would offer a reduction in both acquisition and operating costs versus conventional mining units of comparable capacity. Reclamation costs can also be significantly reduced, and the total reclamation process accelerated, making the cross-pit conveyor system attractive to mine owners and environmentalists alike.

Jan 1, 1976

By Theodore Hatch

Si bien la existencia de la silicosis fue conocida desde hace 100 años atrás, los primeros estudios se realizaron en 1900 en Inglaterra, delimitando sus causas a la exposición de partículas de polvo en general, sin considerar la sílice libre como agente causal de la anomalía. En este sentido, el texto revisa y describe la historiografía de la silicosis como enfermedad causada por la exposición al polvo en las minas de Sud África. Después del término de la Segunda Guerra mundial, en Sudáfrica se produjo el agotamiento de los depósitos superficiales de oro, generando nuevas formas de búsqueda del mineral a través de labores de perforación neumática de hasta 2000 metros de profundidad. Dicho cambio de método, conllevó consecuencias fatales en la salud de los trabajadores. Así, en 1902 se evidenciaron resultados donde un trabajador solo podía desempeñar labores de subsuelo por 5 años, declarando su incapacidad por el tiempo restante. Ante esta situación, en 1912 se buscó solucionar el problema de la silicosis a través de un chequeo radiográfico de los trabajadores, adjuntando evaluaciones de las concentraciones de polvo y las primeras medidas de control. La muestra de los últimos 50 años en Sud África, determinó que las primeras medidas por disminuir la enfermedad fueron la ventilación y los métodos húmedos de perforación. Posteriormente y a partir en 1916, se instituye un programa de Higiene industrial que incluye una cuenta rutinaria de polvo y supervisión médica anual, cuya vigencia se prolonga hasta la actualidad. En consecuencia, durante los cinco primeros años del periodo 1910 y 1950 no se produjeron variaciones de casos de silicosis por año, dado que los efectos de mejoras ambientales no fueron evidentes. Sin embargo, en la actualidad se ha comprobado que con una supervisión médica y control ambiental, hay una disminución de concentración de polvo, como de silicosis. Lo curioso en el caso de Sud África, es que pese a la aplicación de todas las medidas preventivas, no se prosperó en eliminar la silicosis puesto que fue modificada una ley de compensación por enfermedad ocupacional, estableciendo que no solamente se compensaría por esta enfermedad, sino por Neumoconiosis en general. Por ello, se buscó estudios que determinaran los límites entre ambas anomalías sin generar confusión. A esta medida, se sumó la labor de la salud ocupacional ya que con el uso de métodos reguladores como lOS de control de polvo, perforación en seco, entre otros, otorga una información complementaria que reduce la confusión entre puntos de vista médicos y legales respecto a la neumoconiosis y silicosis.

Jul 20, 1959

By H. Foster Bain

THERE has never been a great civilized nation which did not have a mining industry; civilization cannot flourish without metal mining. Without tools we can have none of the 'industries that are the foundation of civilization and without metal mining we cannot produce the material of which tools are made. Therefore, if we have no metal mining we have no metals, no tools, no civilization. An example to illustrate this may be drawn from a recent article in the Saturday Evening Post which described the run-down condition of modern Athens. Athens is nothing but a busted mining camp! In its palmy days the Greeks so applied the leasing system to the silver mines of Laurium that the royalties, paid the expenses of government and instead of a tax bill the inhabitants received a pay check. The Persians came over to capture these mines but the Greek navy was built to defend them. When the silver mines played out, Greek civilization declined.. Our mining must continue if our civilization is to continue.

Jan 1, 1921

This volume constitutes the Survival Subsystem portion of the final report for the Coal Mine Rescue and Survival System (CMR&SS) program, which was conducted by the Westinghouse Electric Corporation under contract to the United States Bureau of Mines (Contract Number H0101262 dated June 17, 1970). The program was directed by the Special Systems Department of the Westinghouse Baltimore, Maryland, facility. The basic objectives of the CMR&SS program were to develop and test hardware to determine the efficacy of a variety of coal mine rescue and survival concepts and techniques. These concepts were drawn from two major sources: the Request for Proposal from the Bureau of Mines1 and the final report on the Mine Rescue and Survival Study conducted by the National Academy of Engineering2 (NAE).

Jan 1, 1971

By Frank G. Wickert

One key to maintaining successful mining operations in today?s global economy is in having the ability to access real-time machine operating data ([1] G. Brown, B. Ebacher, W. Koellner,2000)([2] Brochure of Siemens E&A, Order Number 141000-1). With recent and ongoing advances in mining equipment systems it is imperative that mine managers have full knowledge of the status of their equipment at any given point in time. This knowledge is critical to ensuring that the productivity of each and every machine is maximized. Knowledge of machine status is only the first step, however, in controlling and optimizing a piece of mining equipment. Computer based diagnostic systems, traditionally offered on mining equipment, have provided a link for collecting data and trouble-shooting problems as they occur. One problem existed, though, that those systems stopped short of providing full drive systems access. A maintenance technician could see the data but to make critical adjustments or make repairs the technician needed to be on the machine. In extreme cases the machine would be down until OEM assistance could reach the mine site. The key then to reducing down-time and maximizing machine productivity was creating a system that could not only monitor drive systems but also provide remote access to those systems. Essentially a link needed to be created through which a technician could gain drive access remotely then make adjustments or repairs without being on the piece of equipment. This paper will introduce AccessDirectTM, a new remote diagnostic system for Bucyrus mining shovels and draglines. AccessDirectTM combines all three important elements of remote diagnostics: ? Vital Signs and Production Monitoring (SiRAS-M) ? Automatic analysis (SiRAS-A) of faults, and tracking of trends for preventive and reliability centered maintenance , and ? Fast, direct Intervention (SiRAS ? I) for troubleshooting support, repairs, and system optimization.

May 1, 2002

By John S. Hutchins

Two potential modified in situ methods are described for recovering the 68% "unrecoverable" hydrocarbons in oil reservoirs. For the 300 billion barrels of conventional light crude a Drip Drainage system is suggested by mining underneath a reservoir and producing from below by controlled gravity flow. For the 200 billion barrels of heavy or viscous oil and tar sands deposits a Flip Flop process is described using surface flooding with hot water saturated with surfactant and weighting additives. Mining engineering description of shafts and tunnels required are included as is discussion of the tunnel proximity to a reservoir. Petroleum engineering flow equations to describe production rates and candidate reserve areas of the U.S. are described. DCF economics are provided to indicate that current oil prices may be sufficient to commercially develop these recovery methods.

Jan 1, 1978