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By W. H. Strickland, R. H. King

Ultrasonic ranging sensors are inexpensive, have no moving parts, have no lenses to clean, are normally small and unobtrusive, and can measure distances through moderate amounts of dust, smoke, and humidity, so they are well suited to underground mines. In the work reported here, conducted by the U.S. Bureau of Mines, researchers tested ultrasonic ranging sensors for their abiity to define rib line features for computer-aided navigation of underground mine mobile equipment. The investigation began with laboratory tests of field of view, angle of incidence, intersensor variation, and ranging accuracy of the individual rangers in a ring array produced by Denning Robotics of Wilmington, MA. The results showed that the sensors have good accuracy and low variability. Additional experiments at AMAX's Henderson Mine showed the sensors could accurately and reliably measure the distance to mine features, including convex and concave corners and rib intersections. The results showed that when used properly, the ranger data are accurate enough for reliable mine vehicle navigation When used incorrectly, ultrasonic rangers do not provide the anticipated data. Therefore, this report explains the principles of ultrasonic range measurement, describes the ranger's strengths and weaknesses, and explains proper ranger use and data analysis.

Jan 1, 1993

By Daniel Gustavo Perucca

Los proyectos Veladero, Jagüelito, el proyecto binacional Pascua-Lama y otros ubicados en la zona Valle del Cura, provincia de San Juan, Argentina necesitan una vía acceso que permita el tránsito de camiones capaces de transportar los insumos necesarios en sus etapas de construcción y explotación. En este sentido, el objetivo del trabajo estriba en seleccionar la alternativa más conveniente y así cuantificar los costos y beneficios derivados de la construcción de un camino de vinculación entre los proyectos mencionados y las localidades de Rodeo o Las Flores. La metodología aplicada es la comparación entre costos y beneficios entre las situaciones “con proyecto” (obra ejecutada) y “sin proyecto” (situación actual), de forma que en un futuro, la construcción del camino estudiado posibilitará el abastecimiento de insumos a los yacimientos ubicados en el Valle del Cura, provincia de San Juan.

Sep 13, 2001

By V. B. Dale

This is one of a series of reports covering the mineral resources of the Nation. It describes briefly most of the known tungsten deposits in Yuma, Maricopa, Pinal, and Graham Counties, Ariz. Most of those described were examined by the author. An effort was made to determine the position of the various deposits by section, township, and range and to give accurate road direction to each property from a prominent landmark. All available maps have been used in making these determinations, but in unsurveyed areas it was necessary to make approximate projections of subdivisions. The township and range numbers refer to the Gila and Salt River base and meridian.

Jan 1, 1959

By J. Wennerstrand

Slender steel piles have found an increased use in Sweden in resent years. These piles are often driven throw soft normally consolidated clay to refusal in till or at the rock surface. In contrast to most other piles the bearing capacity with regard to failure of the shaft is in many cases smaller than the bearing capacity with regard to failure of the soil or rock at the lower end of the pile. Imperfections such as deviations from a straight line of the pile centerline and residual stresses in rolled and welded profiles are important for the capacity of the pile shaft. Even thow the second order moment caused by initial deviations in piles is only half of that in a column with the same slenderness, imperfections can and should be accounted for in much the same way as for columns.

Jan 1, 1989

By Matthew Kowalczyk, Steve Bloomer, Peter Kowalczyk

"Mineral deposits found near seafloor hydrothermal venting are of great economic interest. Valuable metals such as gold, copper, zinc, and other polymetallic sulfides are found in appreciable grades in seafloor massive sulfide (SMS) deposits associated with these vents. For mapping these deposits, electromagnetic prospecting is one geophysical method that is very useful because copper/gold rich deposits are highly conductive.Ocean Floor Geophysics (OFG) in 2008 developed the first EM system to successfully map the limits of conductive mineralization in a survey at the Solwara 1 deposit (Kowalczyk, 2008). Since then, towed coincident loop time domain systems have been developed by Waseda University (Nakayama and Saito, 2016) and have successfully detected known mineralization buried at 30m depth. Using a deep tow controlled source electromagnetic (CSEM) array, very clear anomalies have been measured (Murton, 2017) over known mineralization at the TAG field on the mid-Atlantic ridge.In 2014 and 2015, OFG partnered with Fukada Salvage and Marine Co. Ltd. and the Scripps Institution of Oceanography to map methane hydrate deposits off the coast of Japan using a towed controlled source electromagnetic (CSEM) system developed by Scripps. These hydrate deposits are resistive targets, and the Scripps system successfully mapped subsurface electrical resistivity distributions to depths of several 100 metres below the seafloor. OFG is attempting to extend the Scripps CSEM technology to map subsurface conductive SMS deposits to a similar range of depths below the seafloor."

Jan 1, 2017

By J. Douglas Causey

A U.S. Bureau of Mines study indicates over 200 million yd3 (153 million m3) of cinder resources occur in the Mount Washington Wilderness. No future demand for the deposits is anticipated. Based upon the geologic environment, the area is considered favorable for discovery of geothermal resources. INTRODUCTION The Mount Washington Wilderness, located about 32 mi (51 km) west of Bend, Oregon, contains 46,655 acres (18,881 ha) (fig. 1). A 6,300-acre (2,550-ha) addition on the northeast and east boundaries has been proposed by the Forest Service under RARE II. The U.S. Geological Survey made regional geological, geophysical, and geochemical surveys, and the U.S. Bureau of Mines examined, analyzed, and evaluated the economic potential of prospects and commercially important mineral resources.

Jan 1, 1982

By E. W. Dewing

The solubility of A14C3 in cryolite melts has been determined by holding the melt with aluminum in a graphite crucible for 4 hr at temperature, quenching the crucible in water, and analyzing the frozen salt by CH4 evolution. The solubility is given by log(wt % Al4C3) = 1.298 -1.l74 (wt ratio NaF/AlF3) independent of temperature in the range 985" to 1080°C. Additions ofA1203, .NaCl, CaF2, or LiF up to 10 wt pct do not affect the solubility, provided that LiF and CaF2 are replaced by equivalent NaFin calculating the ratio. The variation with ratio can be accounted for quantitatively on the hypothesis that the Mechanism of solution is Al4C3 + 2AIF3 = 3Al2CF2 since the solubility varies as (aAIF3) 2/3; Mechanisms involving C", C2- , AlC- , A12C2+, and Al2CF+are re-jected. At ratios above 1.5 truces of c;- are also present. It was noticed some years ago in this laboratory that carbon specimens made cathodic in a cryolite bath decrease in diameter over a period of time.' It was also found that cryolite which had been melted with aluminum in a graphite crucible was sometimes yellow, and that A14C3 could be seen intimately embedded in the cryolite crystals. CH, could be recovered by acid attack. There was thus reason to believe that A14C3 had a genuine solubility in molten cryolite, and the object of this work was to measure it. EXPERIMENTAL AND RESULTS A graphite crucible, 2 in. ID and 2.5 in. deep with a close-fitting lid, contained about 150 g of cryolite (plus additives) and about 20 g of 99.99 pct pure Al. It was placed in a vertical Inconel furnace tube, covered with refractory brick to provide thermal insulation, and the top of the tube was roughly sealed with disks of asbestos paper. An alumina tube led argon down to the level of the top of the crucible to expel air, and an alumina sheath with a Pt-10 pct Rh ther-mocouple inside was positioned between the crucible and the wall of the Inconel tube. The tube was heated in an electrical resistance furnace for the desired length of time; the refractory bricks were then removed, and the crucible was lifted out with tongs and quenched in water. After such a crucible was broken open it could be seen that its inner surface was yellow owing to the presence of A1,C3, and sometimes needle-like crystals could be observed (at X75 magnification) growing out into the nielt. It was concluded that Al,C, had been present as a separate phase when the crucible was at tenlperature and that the melt had been saturated: in

Jan 1, 1970

By B K. Da, S A. Balaji, G P. Roy, T K. Dutta

The raw material handling complex at the Durgapur steel plant provides iron ore, crushed coke and flux to two sinter plants. Either some facilities were not envisaged or not properly designed before the project stage which caused problems during operation of the plant. The absence of an in situ roll turning facility, used to increase maintenance activities for disassembly, transportation of rolls to central machine shop and assembly of rolls, led to decreased crusher availability and increased activities for the maintenance crew. The provision of a smaller vibro feeder/screen in place of a suitable sized screen caused jamming of the screen deck, adversely affecting screening efficiency and the crushing index of crushed coke. Some design modifications and developmental work was undertaken, such as the development and installation of an in situ roll turning facility in the existing limited space, achieving low feed (0.1 - 0.2 mm/rev), lower cutting speed of 30 - 40 m/minute for 350 BHN hard roll, which was also a difficult engineering challenge to bring within the tolerable limit of vibration. This was successfully achieved. Modifications to the screen deck, introduction of differential speed crushing and modification to the vibro screen and vibro feeder for uniform distribution of feed have been incorporated. These innovative design modifications to the in situ roll turning have led to a drastic decrease in maintenance activities and an improvement in the crushing index. Modifications to the screen have resulted in the elimination of jamming and improved screening. Modifications to the vibro screen before the primary crushers and to the vibro feeder before the secondary crushers have prevented excessive wear in the central portion of rolls, ultimately leading to increased roll life. Incorporation of differential speed crushing has resulted in an increased crushing index and decreased generation of micro fines. All the above modifications have led to distinct improvements in equipment availability, increased roll life and a decrease in maintenance activities and improvement in crushed coke granulametry, ultimately resulting in improved productivity and quality of iron ore agglomeration at the sinter plant. The innovative design modifications mentioned above are discussed in detail in this paper.

Jan 1, 2005

By J. P. Bennett

The Bureau of Mines is investigating the acid resistance of ceramic materials to identify construction materials for emerging technology in chemical and metallurgical processes. Eight commercial ceramic materials, including two red shale, two fireclay, a silica, a silicon carbide, a carbon, and a high-alumina brick, were evaluated. Samples were exposed to 40 wt pct HN03 at 70° and 90° C and 60 wt pct HN03 at 50°, 70°, and 90° C for time periods of 110 days. Statistically significant changes in cold crushing strength were generally small or not detected, except for a strength drop in the high-alumina brick, which decreased in strength when exposed to the chosen acid concentrations at 90° C. Vol-ume and weight changes were also measured. The leach rates of Al, Ca, Fe, K, Mg, Na, Si, and Ti were monitored. Increasing temperature or a decrease in the acid concentration resulted in an increased ion leach rate. Of the conditions tested, the most severe corrosion occurred at 90° C for a 40-wt-pct-HN03 solution. The silica brick had the best overall acid-resistant properties, followed by a red shale and a fire-clay brick. The carbon and silicon carbide bricks are not recommended for service.

Jan 1, 1984

By J. C. O'Rourke

"This paper presents an overview of Alberta Oil Sands Technology Research Authority's in situ oil sands recovery project at its underground test facility near Fort McMurray. It covers the rationale for horizontal wells drilled from tunnels below the oil sands, the tunnel layout, the drilling program, and the recovery process and facilities. INTRODUCTIONThe Alberta Oil Sands Technology and Research Authority (AOSTRA) has constructed an Underground Test Facility (UTF) in the Athabasca oil sands deposit in northern Alberta, approximately 50 km northwest of Fort McMurray (Fig. 1). The facility initially is to serve as an underground laboratory from which to field test new approaches to in situ recovery of the bitumen (oil) in the Athabasca deposit.The UTF employs mine access to get at the effective exploitation of an oil reservoir. It does so, however, under conditions considerably more difficult than those faced by most other applications of the technology. Because of the unconsolidated nature of the McMurray formation, the development of drilling chambers directly in the reservoir would be prohibitively expensive. Further, mobilization of the extremely viscous bitumen requires intensive steam stimulation with the attendant concerns of large, complex well completions and potentially hazardous operations Over-all, the oil sands presents mining, drilling and operations challenges which push the technology to a new state-of-the-art. The UTF as it now exists consists of:• a 20 000 ha lease with all-weather road access;• 925 m of 5 m by 4 m tunnels in the limestone 15 m below the oil sands at roof depth of 178 m below the surface (Fig. 2);• two 3 m diameter steel lined shafts to a depth of 213 m;• administration and sur face mine support facilities from which to operate the UTF (Figs. 3 and 4);• underground piping systems to transport drill fluids, steam, produced fluids and services to and from the future well heads underground (Fig. 5);• surface steam generation and production handling facilities (Figs . 3 and 4).• a drilling rig and auxiliary systems specifically designed to drill long horizontal wells into the oil sands from tunnels in the underlying limestone (Fig. 6);• an experienced staff to engineer and operate the facility (Fig. 7)"

Jan 1, 1989

By S. R. McCutcheon, D. R. Lentz

"Abstract - The 12.1 Mt Brunswick No. 6 Zn-Pb-Cu-Ag massive sulfide deposit (New Brunswick, Canada) lies between two subaqueous felsic volcanic formations near the base of the Middle Ordovician Tetagouche Group. The footwall comprises rhyodacitic pyroclastic rocks (Nepisiguit Falls Formation), whereas the hanging wall comprises a sequence of rhyolitic flows, breccias, and hyaloclastites (Flat Landing Brook Formation), with an age difference of less than 3 m.y. The Brunswick No. 6 deposit is a proximal autochthonous deposit with a well-zoned massive sulfide body and a basal Cu zone that, at depth, develops into a stockwork stringer sulfide (feeder) system. The massive sulfides are capped sharply by a layered magnetite-chert unit that extends regionally beyond the deposit. The deposit has a keel shape (sheath) formed by the F1F2 interference pattern. The heterogeneous ductile deformation and upper greenschist-grade regional metamorphism has transposed many of the epigenetic stockwork structures and alteration within the host sequence. Hydrothermal alteration is much more extensive, both vertically and laterally, in the footwall (a few 100 m) than in the hanging wall (<100 m). Anomalies farther up in the hanging wall sequence seem to be associated with independent alteration systems related to the rhyolite domes. The least-altered footwall units exhibit keratophyric alteration (albite or adularia) and weak Mg enrichment (chlorite). More intense micaceous (sericite and Mg-rich chlorite) alteration occurs around the footwall sequence. The transposed stockwork stringer sulfides are typically composed of Fe-rich chlorite (± sericite, ± silica) with pyrite, pyrrhotite, chalcopyrite, arsenopyrite, and sphalerite. The (Fe2O3T+MgO)/(Na2O+K2O) and base metal alteration indices are the best practical lithogeochemical vectoring tools at this deposit. Sommaire - Le gîte de 12.1 Mt de sulfures massifs de Zn-Pb-Cu-Ag Brunswick No.6 est localisé entre deux formations volcaniques felsiques sous-marines situées près de la base du Groupe de Tetagouche d’âge Ordovicien Moyen. Le mur consiste en roches pyroclastiques rhyodacitiques (Formation de Nepisiguit Falls) tandis que le toit consiste en une séquence de coulées, de brèches et d’hyaloclastites de composition rhyolitique (Formation de Flat Landing Brook); la différence d’âge entre les deux est de moins de 3 m.y. Le gisement Brunswick No. 6 est un gîte autochtone proximal comprenant un corps de sulfures massifs clairement zoné ainsi qu’une zone cuprifère basale qui passe progressivement à un stockwork de filonnets de sulfure en profondeur (feeder). Les sulfures massifs sont abruptement surmontés d’une unité laminaire de chert et de magnétite dont l’extension par delà le gisement est régionale. Le gisement affecte la forme d’une quille (fourreau) résultant d’un patron d’interférence F1F2. Plusieurs des structures épigénétiques du stockwork et des patrons d’altération de l’encaissant ont été transposés par la déformation ductile hétérogène ainsi que par le métamorphisme régional au faciès des schistes verts. L’altération hydrothermale est beaucoup plus importante, tant verticalement qu’horizontalement, dans le mur (quelques 100 m) que dans le toit (<100 m). Les anomalies situées plus haut dans le mur semblent être reliées à des systèmes d’altération indépendants associés aux dômes de rhyolite. Les unités les moins altérées du mur une altération kératophyrique (en albite ou en adulaire) ainsi qu’un faible enrichissement en Mg (chlorite). Une altération en mica (séricite et chlorite magnésienne) plus intense est présente autour de la séquence du mur. Les sulfures du stockwork de filonnets transposés consistent typiquement en chlorite ferrifère (± séricite, ± silice) accompagnée de pyrite, de pyrrhotite, de chalcopyrite, d’arsénopyrite et de sphalérite. L’indice d’altération (Fe2O3T+MgO)/(Na2O+K2O) et l’indice des métaux usuels sont les outils d’exploration les plus appropriés dans ce gisement."

Jan 1, 2006

By Celso Sotomarino Chávez

Ante la necesidad de reestructurar la deuda externa y adquirir incrementos sustanciales de la producción exportable, el Perú requiere una producción nacional que genere 1000 millones de dólares más por año, los cuales deben ser obtenidos a través del sector minero(70%) y un 30% de otros sectores. En este sentido, el presente estudio refiere las posibilidades de inversión en el Perú a través del incremento de producción del petróleo y cobre, asi como de la ampliación de la pequeña y mediana minería, producción del oro, valor agregado a la producción nacional del zinc, la planta de molibdenita de la Southern Perú y la inversión que comprende el destino del producto y su utilización en el extranjero.

Nov 20, 1978

By A. Policard

The bodies of mammals possess a very efficient mechanism for ridding themselves of inhaled dust. When the lung is healthy this mechanism works very well, and dust is quickly and completely expelled from the lung either by the respiratory tract or the lymphatics. The mechanism, however, is easily upset, and slight alterations in the condition of the ciliated epithelium or the circulation of lymph are sufficient to interfere with it, therefore the second mechanism comes into play and the dust is fixed and immobilized in some part of the lung. This, however, is not a real cleansing process, since the lung becomes a dust-trap, and may become'pneumokoniotic. The mechanism is protective at first, but later, when the accumulation of dust is considerable, it gives rise to trouble. The lung cannot become, so to speak, a physiological dust-trap, and still retain its normal structure and function; pneumokoniosis begins, which is essentially a disease due to the mechanical presence of large amounts of inert foreign material.

Jan 1, 1947

By Jorge Olivari Ortega

El presente texto señala la relación del inca Huayna Cápac con las arenas auríferas de Chuquimayo. Huayna Cápac, hijo de Túpac Inca Yupanqui y Mama Ocllo, fue el décimoprimer inca gobernante del Tahuantinsuyo (¿1493- 1527) que ordenó construir una estatua de oro puro, similar al del cuerpo de su madre ya muerta,en Mullucancha. Asimismo construyó adoratorios para los dioses Inti, Huiracocha e Illapa, a los cuales dotó de tierras, ganado y personal de servicio. Luego se casó con Cusi Rimay y retorna a Quito y Cuzco. Posteriormente muere Cusi Rimay y se casa con Rahua Ocllo, futura madre de Huáscar. Inicia una nueva campaña militar hacia el Collasuyo, llegando a la región de los Charcas, pasa a Chile y regresa a Cusco. De otro lado, en uno de los viajes de reconocimiento a tierras peruanas de Francisco Pizarro, Yupanqui se informa y ordena el traslado de los españoles a Tumibamba. En ese contexto, Diego Palomino, uno de los españoles en llegar, realizó un croquis de la zona yacimientos auríferos de importancia, ubicados en el territorio de los Pucamurus, son los de Tomaque, Aconipa, Picorana, Quipe y Santa Agueda, que no son explotados actualmente por falta de recursos hídricos.

Jul 1, 2016

By Lewis Stansfield

A rotary displacement method was used to install permanent steel casings for bored piles through an asbestos tip. This method was chosen in preference to alternative driven systems because it was quieter and more versatile if obstructions were encountered. New equipment was designed and made specifically for the project, and stringent health and safety regulations had to be observed.

Jan 1, 2000

Beneficiation of Iron Ore - Washing with Surface-Active Agent The stability of the dispersed phase in 10 wt per cent slurry of iron ore slime and fines was studied at pH 5 and different concentrations of surface-active agents. The behaviour of the dispersed phase of iron ore slime and fines is different for different surface-active agents. The improvement of iron value of slime and fines in the presence of surface-active agent is best realized at pH 8, where the Al2O3/Fe and Al2O3/SiO2 ratios in the concentrates are appreciably reduced. The polar functional group like -COO- interacts with hematite surfaces and forms outer- and inner-sphere surface complexes depending on the suspension pH and adsorbate.

Sep 13, 2010

By Francisco Cabrejos

"El acopio de minerales a granel en pilas genera una forma de almacenamiento segura para grandes cantidades de minerales chancados gruesos o finos. En este sentido, el principal objetivo de los stockpiles es proveer una capacidad pulmón entre la mina y la planta de chancado, y asegurar un flujo de alimentación contínua, uniforme y controlada a los equipos aguas-abajo. Por ello, el presente trabajo describe el diseño y operación de los stockpiles en algunos yacimientos de Chile y Perú. El primer paso para el correcto dimensionamiento de un stockpile y su respectivo sistema de extracción de material, es determinar las propiedades de fluidez del mineral manejado bajo condiciones similares a las que será sometido el material en la mina, una vez que entre en funcionamiento el proyecto. Asimismo, se recomienda realizar ensayos de fluidez a varias muestras representativasdel mineral, las cuales deben ser cuidadosamente seleccionadas para que representen fidedignamente las condiciones que se encontrarán en la mina durante su vida útil, de forma que sus resultados permiten un correcto diseño y dimensionamiento del stockpile y su sistema de extracción de mineral. "

Sep 13, 2001

PRESIDENT AND DIRECTOR JOHN M. LOVEJOY NEW YORK, N. Y. PAST PRESIDENTS AND DIRECTORS HOWARD N. EAVENSON PITTSBURGH, PA. HENRY A. BUEHLER ROLLA, Mo. VICE-PRESIDENT, TREASURER AND DIRECTOR KARL EILERS NEW YORK, N. Y. VICE-PRESIDENTS AND DIRECTORS LOUIS S. CATES NEW YORK, N. Y. PAUL D. MERICA NEW YORK, N. Y. WILFRED SYKES CHICAGO, ILL. R. C. ALLEN CLEVELAND; OHIO HENRY KRUMB NEW YORK, N. Y.

Jan 1, 1936

By Frederick S. Fisher

Three spatially separate porphyry copper/molybdenum deposits are associated with the Tertiary Needle Creek igneous center in the southern Absaroka Mountains, Wyoming. In all three deposits a central zone containing disseminated copper and molybdenum is surrounded by a halo of small, discontinuous base and precious metal veins. Propylitically and phyllically altered rocks are common in all three mineralized areas, and potassically altered rocks are locally present. Fission- track age data from apatite and zircon indicate that mineralization occurred about 32-40 m.y. ago. Limited data suggest that the lead isotopes are nonradiogenic, similar to porphyry copper deposits elsewhere in the western United States. The complex igneous history of the Needle Creek center has involved several periods of intrusive and probably extrusive activity. lntrusive rocks are calc-alkalic and include andesite, granodiorite, diorite, quartz monzonite, dacite, and rhyodacite. Stocks (1-30 kmz in exposed area), radial dike swarms, and sills make up the presently exposed plutonic masses and constitute lower-level vent fillings in an old stratovolcano. The Needle Creek igneous center is located approximately midway along a northwest-trending belt of intrusive rocks extending more than 100 km along the central axis of the Absaroka volcanic field. The igneous and mineralized centers within this belt were probably localized at the intersections of northwest- trending Laramide and possibly Tertiary fracture systems and earlier northeast-trending Precambrian structures in the underlying basement rocks.

Jan 1, 2013

By Michael Gilbert

In the world of tunneling the glamour is in the large diameter, long tunnels, but perhaps the number of projects for small diameter and short length tunnels are greater and generally have higher risk factors. Reasons for these higher risks include both the ?boiler plate? contract provisions used on these types of contracts, the technical specifications related to the tunnel work (versus the pipeline construction), the bid practices including measurement and payment and the construction. This paper reviews and comments on some of the key issues the authors have observed in recent major pipe-line projects that involve a small percentage of tunneling footage of the total contract.