Search Documents

By A. J. Terrones

THE classical papers on contact metasomatic deposits by Lindgren on the Clifton-Morenci district,' by Barrell on Marysville, Mont.,' and by Gold-schmitt on the Oslo district, Norway,' laid the foundation for understanding of the importance of separating the metamorphic process from the subsequent metasomatic stage. Knopf' made a big step forward by recognizing that sulfide ore minerals are invariably younger than silicates and by further stressing the importance of structural control" in ore finding. Some years later Harrison Schmitt" fought the idea that contact metasomatic deposits are erratic, irregular, bunchy, economically marginal, and of small size, concluding that these descriptions have little factual basis. He emphasized the importance of detail mapping and careful geological study as fundamental requirements for a better understanding of these deposits. This article presents a comparative description of the structural features at the Magistral, Antamina, Morococha, Vilca, Ferrobamba, Katanga (Quibio), Tintaya, and Huarca contact deposits (Fig. 1). Further, it will describe how these structural features controlled the emplacement of the intrusives, their shape, distribution of metamorphic and metasomatic halos, and sulfide deposition in post-skarn structural channelways. Finally, the modifications introduced by a superimposed hydrothermal stage recognized at some localities will be discussed. Primary exploration and careful sampling of recognized structural targets were instrumental in outlining the copper ore potential at the Antamina and Tintaya districts, thus proving the benefits and reward of careful geological examinations in this type of deposit. The Magistral District: This district lies in the Province of Pallasca, Department of Ancash, in northern Peru, at 8o 16' S and 77" 47' W. High to medium grade copper orebodies in garnetite, bordering a quartz monzonite stock, are exposed at the bottom of a glaciated valley in the western slope of the Andes at 4250 m (14,000 ft)* elevation.

Jan 1, 1959

By Carlos Soria

El presente texto describe los Sistemas de Gerencia de la Información y su aplicación en la industria minera con el objetivo de optimizar la gestión total de la empresa. Dichos sistemas manejan información del proceso y sus valores de producción, cálculos, consumos de energia, emisiones de plantas, tiempos de funcionamiento de equipos, eventos, alarmas, mediciones de laboratorio y control estadístico, etc. De forma que dicha información pueda ser reunida y consolidada, convirtiéndose en materia de significado y relevancia disponible en base a análisis, reportes, listas, tendencias y gráficos para que el usuario final de una planta o en sus oficina pueda tomar mejores decisiones.

Jul 17, 2000

By E. B. Johnson

Cleveland-Cliffs lron Co., which operates Marquette lron Mining Co.'s Republic mine, conducted a test whereby 35,000 tons of self-fluxed pellets were produced in the grate-kiln system from specular hematite flotation concentrates. A brief description of the pelletizing plant is presented along with pertinent operating details. Date is included which compare operating conditions and the chemical and physical properties of the green and fired pellets for the self-fluxing pelletizing test with the normal acid pelletizing operation. The success of self-fluxed sinter in enhancing the operation of the blast furnace during the past few years has reasonably led to the assumption that the use of self-fluxed pellets might result in even greater furnace efficiencies. A great share of development work in agglomeration has been directed towards techniques related to the production of self-fluxed pellets, but only a limited tonnage of self-fluxed pellets had been produced on a commercial scale until this past year when The Cleveland-Cliffs Iron Co. produced 35,000 tons of such pellets by the grate kiln system at the Republic mine during the period May 21-June 5, 1962. REPUBLIC'S GRATE-KILN PLANT The grate-kiln pelletizing process consists of four stages, namely: feed or balling circuit, traveling grate, rotary kiln and annular cooler (Fig. 1). The balling section is conventional and utilizes four 9x30-ft balling drums in closed circuit with 5x14-ft vibrating screens having 3/8-in. rod decks. The traveling grate is 12 ft wide by 126 ft long and has 14 windboxes — six in the drying section and eight in the preheat section. The rotary kiln is 15 ft ID shell and 114 ft long. The annular cooler is 40 ft in diameter and has 12 windboxes. The cooler is divided into two zones by a moveable curtain wall. The high temperature air from the first zone is used as secondary combustion air in the kiln. Normally the only heat supplied is through the burning of No. 6 oil in the single kiln burner. Hot gases pass counter to the pellet flow through the system. The exit gases from the kiln pass down draft through the preheat section through cyclones and are drawn through the drying bed prior to exiting via the stack. The temperatures are normally held within the following ranges: Kiln 2400-2445 °F Preheat 1850-1950°F Drying 480-520°F Exit gas 200°F Pellets 120°F The design capacity of the Republic mine grate-kiln system was 2500 Itpd. Sustained production in excess of 35% over design capacity has been achieved. No screening of the cooler product is practiced. PELLETIZING TEST CONDITIONS When a decision was made to proceed with a test at the Republic mine pelletizing plant to produce 35,000 tons of self-fluxed pellets, several potential failure factors had to be carefully considered. Research work on a batch and pilot plant scale indicated that the grate-kiln system at Republic would require some major changes in order to obtain optimum conditions. In many cases compromises were agreed upon as major equipment changes and revisions were not feasible. The pelletizing conditions which laboratory development tests revealed were required in order to insure successful production of self-fluxed pellets were: 1) Good mixing of limestone and concentrate and proper moisture control; 2) Higher gas flow rates in the preheat section than are normally used; 3) Higher preheat temperatures than normal; 4) Maximum kiln temperature 2350°F. There was just cause for concern about balling problems that might occur. Approximately 10% of dry pulverized limestone was to be added to the specular hematite concentrate just ahead of the Pekay mixers on the belt feeding the balling drum. Large scale

Jan 1, 1963

By W. D. Monaghan

Flame cutting and welding is one of the major causes of fires and explosions in underground U.S. coal mines. On May 20, 2006, a flame cutting operation at the Darby Mine No. 1 led to an explosion that resulted in five fatalities. On January 22, 2003, another explosion caused by flame cutting at the McElroy Mine resulted in three fatalities and three serious injuries. On June 22, 1999, a flame cutting and welding operation at the Loveridge Mine caused a fire that resulted in sealing of the mine for an extended period. Finally, on March 19, 1992, an explosion at the Blacksville No. 1 Mine that was caused by welding resulted in four fatalities. The National Institute for Occupational Safety and Health (NIOSH) conducted a study on fires and explosions in underground U.S. coal mines that were caused by flame cutting and welding operations to determine the root causes of these types of fires and explosions. The methodology included interviewing mining personnel who perform flame cutting or welding operations in underground U.S. coal mines and visiting mines to observe these operations, and MSHA reports of investigations and accidents statistics were analyzed. The results were used to identify and compare differences between flame cutting and welding practices and techniques in small and large mines, Eastern and Western mines, low seam and high seam mines, room and pillar and longwall mines, and between experienced miners and new miners. As a result of this study, best practices and interventions were developed to reduce the number of fires and explosions caused by flame cutting and welding. This paper provides a summary of this work. Disclaimer: The finding and conclusion in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupation Safety and Health.

Jan 1, 2009

By Dave Ritchie

En el Perú existen 7 cable-carriles en funcionamiento, de los cuales la mayoría son bicables, cuyos baldes están suspendidos y son jalados por medio de un cable de tracción sobre un cable estacionario. En este aspecto, el objeto del estudio describe el empleo de los mismos en Cerro de Pasco Corporation, su historiografía, costos, procesos, instalaciones y el peso. Así, es menester conocer que dos de los más grandes bi-cablecarriles se encuentran en Mahr Tunnel de la Cerro de Paseo Corporation que conecta la mina de San Cristóbal con la Concentradora de Mahr Tunnel, mientras que el otro está en Quiruvilca, propiedad de la Northern Perú. También hay otros cablecarriles en Tamboraque, Atacocha, en las minas de San Luis y en la fundición de La Oroya. De otro lado, en 1864 se dispuso de parte de la Corporación, la instalación de un mono cablecarril para conectar la mina de Yauricocha con un lugar llamado Chaucha, el cual era el terminal de la línea del tren de Chaucha a Pachacayo. Siendo desde entonces, el único mono-cablecarril de la Cerro de Pasco Corporation, situado en Perú, mientras que los dos restantes pertenecen a la Reynolds Metal Co de Jamaica, y el otro a una mina canadiense, respectivamente. Asimismo esta cablecarril acarrea 48 toneladas de mineral por hora y permite ahorrar el costo de acarreo de madera por camión sobre los caminos de Chaucha a Yauricocha, aunque surgieron algunos defectos con el desprendimiento de los baldes transportadores. Finalmente el cablecarril de San Cristóbla a Mahr Tunnel

Jul 20, 1955

By A. W. Schlechten, R. P. Abendroth

Jan 1, 1960

Discussion of the paper of R. J. COLONY, presented at the New York Meeting, February, 1921, and issued With MINING AND METALLURGY No. 169, January, 1921. R. J. COLONY (author's reply to discussion).-The work of Sosman and Merwin on the system lime-ferric oxide, mentioned by Mr. Rankin, was not overlooked. When studying portland cements and portland-cement clinkers petrographically, however, the lime-iron compound was difficult to correlate with the very definite dicalcium ferrite described by those investigators, which possesses such well-defined optical properties. In portland cements, the calcium ferrite (or ferrate?) is an indefinite, fuzzy, and generally amorphous, or apparently amorphous substance that is distributed interstitially with respect to the other grains, from which it was very difficult to derive any satisfactory results. For this reason, the writer, tentatively, chose to regard it as related to the aluminate, and assigned to it the composition 3CaO.Fe203, which may be incorrect, however, as Mr. Rankin suggests.

Jan 8, 1921

By Carlos Magno Palacios Arbizu

La calidad total es la estrategia que busca la mejorar la productividad y eficiencia de los productos que ofrece -en tanto sean reconocidos por este valor-, de forma que genera competitividad en las organizaciones peruanas y se presenta como respuesta a nuevos enfoques de gestión surgidos ante el proceso de globalización. En este sentido, el presente trabajo analiza la forma del avance en el nuevo enfoque de gestión de las empresas mineras, para así proponer alternativas de tratamiento e implementación de un modelo basado en la Calidad Total, de manera que esté alineado dentro de un sector que tenga características propias y diferenciadas de organizaciones de otros sectores productivos.

Sep 12, 2005

By Dupuy. Leon W., R. T. C. Rasmussen, W. A. Calhoun

"INTRODUCTION For many years it has been known that low-grade manganese deposits occur in the bluffs along the Missouri River Valley. Frequent attempts have been made to develop the ore and to produce a marketalble commodity but they have had little success. Under pressure of the war emergency and the shortage of manganese, the attention of the Federal Bureau of Mines was directedtoward the deposits.Manganese-bearing shale occurs from a point near Pierre, S. Dak., down the river to the Rosebud bridge near the Nebraska line (1).5/ The Bureau of,confined its work to the more accessible central portion of the deposits near Chamberlain, S. Dak. The ore occurs principally as concretionary nodules in the form of iron and manganese carbonates (manganosiarite and perhaps some manganocalcite; rhodochrosite has not been identified). At the surface the carbonate is often broken down so that the oxide of manganese gives the nodules a black The matrix or host rock is generally known as Pierre shale, composed of ""interbedded layers of bentonite, an altered volcanic ash, and dissemi¬nated bentonite particles,"" (2) and montmorillonite-beidellite clay minerals (3). The shale weathers to the very sticky gumbo characteristic of South Dakota and well-known to hunters and travelers in the area.The area selected for the experimental mining and pilot-plant work discussed in this report lies about 8 miles westerly from Chamberlain and is a few hundred feet north of U. S. Highway,16, on land owned or controlled,by M. Q. Sharpe of Kennebec, S. Dak., and the General Manganese Corp."

Feb 1, 1946

By Klaus-Peter Kinzel

Staves Coolers de cobre proporcionaram uma excelente proteção da carcaça do alto-forno em áreas de alta temperatura. Isso resultou para que os operadores de alto-forno alcançassem alto desempenho em termos de produtividade e taxa de combustível, além de campanhas de mais de 15 anos. No entanto, nos últimos anos, alguns altos-fornos experimentaram um desgaste prematuro nos staves de cobre. Algumas dessas empresas se alinharam com Paul Wurth para investigar a causa fundamental desse fenômeno com base em todos os fatores de influência e, em seguida, propor ações corretivas. Estes resultados são discutidos e apresentados a seguir no trabalho técnico.

Oct 30, 2017

By Unknown

Blast Site Security Involves: * Clearing the area * Controlling Access * Warning Signals

Jan 1, 2003

By A. Mahmoudkhani

Primary cementing is the process of placing cement in the annulus between the casing and the formations exposed to the wellbore. Portland cement was first used in 1903 in the Lopoc Field in California for well cementing. Since then, the major objective of primary cementing has always been to provide zonal isolation in oil, gas and water wells, i.e. to exclude fluid(s) in one zone from another zone in the well. To achieve this objective a hydraulic seal must be created between the casing and cement and between the cement and the formations, while at the same time preventing fluid channels in the cement sheath. This requirement makes primary cementing the most important operation performed on a well. Without complete isolation in the wellbore, the well may never reach its full producing potential. The industry knowledge on cements relies heavily on empirical data, but the chemistry, physics and structure of cement are not fully understood yet. The strength of concrete can be increased essentially by reducing its porosity through optimizing the size distribution of its components and filling the residual porosity of the hydrated cement phase with inorganic fillers. This approach has successfully utilized in different ways and several technologies for placing high performance oil and gas well cements have been developed over the last few decades. There are reasons to believe that the next source of improvement will lie in the fine-tuning of the hydrates themselves and of the different parameters that drive short (ionic?covalent bonding) and long (ionic correlation) interactions.

Jan 1, 2012

By Gerald E. H. Verbeek

As the number of driven concrete piles with Embedded Data Collectors increases, it has become possible to compare the widely used Beta Method to assess pile damage (using the change of pile impedance) with the so-called Measured Pile Integrity (MPI) method (a combination of two approaches using both the change of pile impedance and the change in pile pre-stress levels). After a brief introduction of both methods, this paper presents the outcome of that comparison based on data from more than 400 concrete piles driven in Florida, which brings into question the reliability of any damage assessment method based solely on the change of pile impedance (such as the Beta Method), especially to detect damage near the pile toe. Moreover the paper demonstrates the need to re-assess the damage classification used for the Beta Method as well as the use of Pile Driving Analysis (PDA) to detect pile toe damage.

Jan 1, 2011

Plant-Based Trials of Monitoring of Coal Flotation Systems Using Electrical Impedance Spectrum Technique

Sep 13, 2010

Longwall mining has existed in Utah for more than half a century. Much of this mining occurred at depths of cover that significantly exceed those encountered by most other U.S. longwall operations. Deep cover causes high ground stress, which can combine with geology to create a coal burst hazard. Nearly every longwall mine operating within the Utah’s Book Cliffs coalfield has been affected by coal bursts.

Jan 7, 2020

By Blanchard R

In stopes of the 2000- and 2150-ft. levels in the North mine section of North Broken Hill Limited, whence a substantial proportion of the company's production is being drawn, and especially in stopes which involve the portion known as the Northern orebody, occurs it light-coloured friable porous material which represents average grade ore from which the lead and zinc minerals, and certain gangue constituents, have been largely or wholly removed by leaching. The 2000- and 2150-ft. levels lie, respectively, 1550 and 1700 ft. below extreme base of the pre-mine oxidized zone. Composition of the cellular product shows it to be supergene. The oxidation and leaching, therefore, must be assumed to have taken place since drainage of the affected areas was accomplished by mining operations.The matter is of more than passing interest, because the post-mine...

Jan 1, 1942

A review is made of the limited published experience of the effects of cemented fill in flotation.A general approach is adopted in listing and discussing possible sources of, and reasons for, ore contamination by cemented fill, together with basic, fundamental approaches to minimizing this contamination. These approaches involve basic mining design, effect of fill placement density, optimization of curing time and of cement content, variation of fill particle grading, use of flocculants and of pozzolans, fill placement and dewatering, and or blasting and handling practice.

Jan 1, 1974

By J W. Hedenquist

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Epithermal deposits (Au or Ag dominant, ± base metals) form within ~1 km of the surface in volcanic belts, both arcs and rifts, with the different tectonic settings reflected in distinctly different characteristics. Within arcs, deposits are typically intrusion centred and commonly associated with hypogene advanced argillic alteration, both in lithocaps and as halos to shallow or proximal portions of some veins; such alteration is coupled with processes that form porphyry Cu-Au deposits at depths of ~1–3 km. Introduction of metals is related to the subsequent phyllic-stage overprint; if this fluid rises to the level of the lithocap or into epithermal veins, Au mineralisation with Cu or Ag may occur, associated with sulfate minerals or muscovite. By contrast, Au-rich (both low Ag:Au ratio and bonanza grade) colloform quartz veins form at shallow depths in volcanic rifts, typically within a few hundred metres of the surface, with clay halos and topped by silica sinter if the palaeosurface is preserved. The geologic variability in volcanic belts, including host rocks, structures and hydraulic gradients, means that many epithermal deposits vary from the end-member features of the principal styles. Effective exploration requires familiarity with end-member styles as well as potential variations, plus the mineralogical indicators of palaeotemperature (eg evidence for erosion depth, fluid flow channels). This knowledge helps the geologist in the field to imagine what might be buried and where, and how to best test the target with drilling.CITATION:Hedenquist, J W, 2015. Recent developments in understanding of and exploration for epithermal deposits in volcanic arcs , in Proceedings PACRIM 2015 Congress, pp 11–16 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Properties of coal which are significant in relation to preparation for carbonization and conversion are reviewed, and existing coal preparation technology which has been used for production of cleaned coal of suitable ash content and petrographic composition for carbonisation, pyrolysis, hydrogenation and similar processes is described. Possibilities for application of this technology to some Australian coal seams is examined briefly. It is concluded that further survey work is required related to the optimization of selective crushing and concentrating operations, with the aim of maximizing production of quality products for carbonisation, etc mainly from Australian seams with only moderate coking characteristics.

Jan 1, 1980

By Peter Swanson

A seismic monitoring network has been installed in western Colorado (USA) in the vicinity of three underground coal mines to (i) distinguish and characterize seismic activity as either mining related or naturally occurring, (ii) implement a real-time event monitoring and notification tool, and (iii) collect data for use in research studies aimed at quantifying impacts from mining-related and natural seismicity. These potential impacts include dynamic rock mass failures such as coal bumps as well as strong shaking in the vicinity of critical structures such as impoundment dams, reservoirs, mine seals, mine openings, and steep slopes. Examples of two damaging seismic events are presented and the mining and geologic factors attending these dynamic failures are described.

Jan 1, 2008