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By . M. Muskat

A THEORETICAL consideration of the mechanics of various water-flooding systems with the viewpoint of comparing their relative merits involves the study of two fundamental properties of such systems. On the one hand, it is important to determine the efficiency of the flood as measured by the percentage of the total area that is swept out by the encroaching water before water actually reaches the output wells. This is really a measure of the regional tendency of the water to "bypass" the oil. On the other hand, the various systems must be compared from the viewpoint of their resistances which determine the rate of fluid production obtainable for given pressures maintained at the water input wells. The first of these questions has been studied and very definite answers have been obtained by means of simple electrolytic models.1 These models showed that, in an ideal system, the percentages of the areas flooded out before water reaches the output wells are about 57 per cent for the direct line-drive flood (the input and output wells being equally spaced and placed in alternate parallel lines), 74 per cent for the regular five-spot network, and 79 per cent for the seven-spot network. With respect to the efficiency of the usual flooding arrangements, they are, therefore, given quite accurately by the above numbers. With regard to the resistances of the flooding networks, electrical conduction models have also been used successfully2 and are well adapted to the problem of determining experimentally the pressure distribution and streamlines, or over-all resistances of specific flooding networks. However, such models do not permit readily a study of the effect of changing dimensions or configuration within a network, since a new model must be made up for each set of dimensions considered.

Jan 1, 1933

By R. L. Kidd, T. H. Miller

"INTRODUCTION This paper is the seventh of a series of yearly reviews started in 1921 and pre¬sents information gathered in a cooperative investigation undertaken by the United States Bureau of Mines and the University of Utah. It is the purpose of this report to make available flotation—reagent consumption data and other milling information in such a manner as to be of value to the milling industry and to the manufacturer of flotation reagents.These data have been compiled from a survey of about 300 concentration plants in the United States. Much additional information has been obtained from the various offices of the United States Bureau of Mines. Many of the plants covered in the survey made complete reports of their operations, but others were apparently unable to supply this information in sufficient detail to meet the requirements of this report. As a result, some sections of the report are more complete than others. In general, however, the mill reports were much more complete than in previous years, and for the first time it has been possible to calculate average mill recoveries in the treatment of certain classes of ores. As in the past, every effort has been made to conceal individual plant operations.ACKNOWLEDGMENTSIt is realized that the publication of this information is possible only through the assistance of the mill operators, and the authors wish to express their appreciation of this cooperation. Thanks are also due the various field offices of the United States Bureau of Mines, division of mineral statistics, for assistance in collecting this information."

Aug 1, 1931

By Manuel Retamozo

El presente texto señala cómo el ejercicio físico adecuado y la dietética mejoran la producción y disminuyen el absentismo laboral en la empresa minera BHP Billiton Tintaya S.A a través de un política de prevención de salud. Entre los objetivos principales está determinar la frecuencia con que realizan ejercicio físico adecuado los trabajadores del área de mina, señalar si existieron cambios en las costumbres alimenticias de los trabajadores del área de mina después de la educación alimentaria, delimitar si existe asociación entre el aumento de la producción en el área de mina con la práctica del ejercicio físico adecuado y la dietética, así como entre la disminución del absentismo laboral en el área de mina con tales prácticas.

Jul 31, 2003

By Dale S. Preece

"Detonation delay timing has been an important aspect of quality rock blasting for decades. Detonators that enable delay timing have improved over the years especially with the recent advent of precision electronic detonators. The positive effects of precision delay timing have been observed repeatedly in the field with improved fragmentation, heave and overall blast control. Three-dimensional computational capabilities in terms of software, material models and computer speed have recently made possible the computer simulation of multiple blast holes in a bench configuration with precise delay timing between holes. Some of the key physical phenomena enabled by precise delay timing include: 1) collision and interaction of stress waves produced by adjacent blast holes, 2) reinforcement of stress waves from multiple holes as they reflect from the bench face and ground surface, 3) reflection of stress waves from “dynamic free surfaces” created by previously detonating holes, and 4) deformation induced fracturing, cracking and fragmentation. Simulating rock blasting in 3D has shed light on the physics involved and is resulting in an evolution of our understanding of fragmentation mechanisms. Routine use of these 3D computational tools will result in a much better understanding of the complex physics set in motion by the rock blasting process and allow predictionof improved blasting."

Jan 1, 2009

By T. K. Perkins, L. R. Kern, R. E. Wyant

Many factors influence the results of hydraulic fracturing to stimulate well productivity. Most of these factors have been studied and their effects discussed in the literature. However, the movement of sand through the crack during fracturing has received little consideration. Exactly where the sand goes in the fracture, how it gets there, and how this might influence results have not been studied, judging from published reports. To get an answer to some of these questions we have studied sand movement through a simulated crack segment in the laboratory. Although the work is preliminary, we have answered some questions about sand movement in a semiquantitative sense. We are reporting our results at this time in the hope of stimulating interest and further study in this important aspect of fracturing. LABORATORY EXPERIMENTS Fig. 1 is a schematic diagram of equipment used in this study. A segment of a vertical crack 0.25-in. wide was formed between two Plexiglas plates, and movement of sand in fluid through the crack was observed under various conditions. Sand and fluid were injected into the crack at constant rates. The top and bottom of the crack were closed so that the fluid flowed horizontally. Because of gravity most of the sand settled to the bottom before moving very far through the crack. If the fluid velocity exceeded a certain critical value, then all the sand injected was washed on through the crack even though it had settled to the bottom. When the fluid velocity was less than this value when sand injection was started, most of the sand which settled in the crack remained in place until enough of the area open to fluid flow was blocked by the settled sand to increase the fluid velocity to the critical value.. At this point all injected sand moved on through the crack even though it settled to the lower portion of the moving fluid section. All sand previously settled remained in place. When fluid velocity was increased at this paint by increasing fluid injection rate (without also increasing sand injection rate), some of the previously settled sand was washed out until enough area was open to flow that the velocity dropped to the critical value. Conversely, when the fluid velocity was decreased by decreasing the fluid injection rate (without changing the rate of sand injection), additional sand would settle until the critical velocity was again attained. In short, the critical velocity is an equilibrium value which the system will automatically seek, if possible. The equilibrium (or critical) velocity was measured under several conditions. The results of these measurements are shown in Pig. 2 where the equilibrium velocity is shown as a function of the amount of sand injected per minute. The points falling in the shaded band shown in Fig. 2 were obtained with water. The higher viscosities were obtained by adding CMC (carboxymethylcellu-lose). Data indicate that the equilibrium velocity is not very sensitive to sand size or transport fluid viscosity, or to sand injection rate (except at very low rates). Points connected by the solid CUrve in Fig. 2 were obtained with water and 20- to 40-mesh steel shot. The equilibrium velocity is apparently fairly sensitive to difference in density between particle and fluid. Only one run was made with a gelled fluid and that was gelled water at zero sand injection rate as shown in Fig. 2. (Measurements of equilibrium velocity at zero sand injection rate were made by filling the crack

By A. Ebrahimabadi

Roadheaders are very versatile excavation machines used in tunnelling, mine development, and mine production for soft to medium strength rock formations. Performance prediction is an important factor for successful roadheader application and generally deals with machine selection, production rate and bit consumption. Among many different parameters, brittleness is also one of the material properties related to breakage characteristics and can be used as a cuttability parameter from a mechanical excavation point of view. The main objective of the research study is to contribute the brittleness of rock excavated to construct a new empirical equation for predicting the performance of roadheaders in different material and operational conditions. In this regard, a new performance prediction model for medium duty roadheaders based on a brittleness index (BI) is presented. In this study, rock mass brittleness index (RMBI) is defined in order to investigate the influence of BI on roadheader performance. RMBI is an index which can be used to relate the intact and rock mass characteristics to machine performance. Results demonstrated that RMBI is highly correlated to instantaneous cutting rate (ICR) (R²=0.94). Moreover, through the further analysis and normalization, the pick consumption index (PCI) was introduced as a parameter having a good relation with pick or bit consumption rates (PCR) (R²=0.79). Finally, the new predictive models for ICR and PCR showed very good correlations with the actual measured values. Keywords Performance prediction, roadheader, brittleness index, mechanical excavation.

Jan 1, 2011

By E. T. C. Spooner, Ioannou S. E.

"Abstract- The Dixie Zone Au-Ag deposit is a low sulfidation (adularia-sericite) epithermal system located 1.4 km from the producing Ken Snyder mine (7.0 M oz Au equivalent reserve/resource), Midas Mining District, north-central Nevada. This WNW striking, steep south dipping, fault system is hosted by mid-Miocene (17 Ma to 14 Ma) felsic volcanic rocks that were erupted from a vent(s) to the northeast. The system was mineralized by approximately 250 ± 20°C (n = 86), near-neutral pH, ascending fluids of predominantly meteoric origin [volatile corrected salinity = 0.52 ± 0.35 eq.wt% NaCl (n = 86)]. Bulk analytical fluid inclusion gas chromatography identified a mineralizing fluid volatile composition of 99.68 ± 0.18 mole % H2O, 0.16 ± 0.09 mole % CO2, 0.11 ± 0.05 mole percent N2, 0.05 ± 0.04 mole % CH4, and 0.01 ± 0.01 mole % CnHn+i (n = 7). Sulfur species were not analyzed due to absorption within the chromatography system; however, a H2S concentration of 16 ppm to 160 ppm molar is estimated. The volatile content contributes approximately 50% of the microthermometrically measured freezing point depression. Cl- concentrations up to approximately 9000 ppm suggest an additional, probably magmatic, fluid component.Ascending fluids were channelled along approximately NW striking faults related to the same primary extension (17 Ma to 14 Ma) responsible for Nevada basin and range physiography. Boiling induced by CO2 effervescence led to precipitation of Au and Ag over a 150 m vertical interval. At the time, this interval was about 460 m below the water table (approximately 38 bars), but because of erosion, it is now within 90 m of the surface. A Ag:Au ratio of 25:1 has been calculated for the Dixie Zone."

Jan 1, 2000

By C B. McCampbell, R W. Jr Bickes

Sandia National Laboratories has developed a semiconductor bridge (SCB) igniter for the ignition of a variety of explosive materials. When subjected to a low-energy current pulse, the bridge bursts into a plasma causing rapid ignition of the explosive material pressed against the bridge. Despite the low energies required for ignition, SCB components have proven to be explosively safe, meeting both no-fire and electrostatic discharge (ESD) safety requirements.

Jan 1, 1991

By Michael Valencia, Alonso Marchena, Fredy Arcos, Miguel Chumbe

Cobrepampa es un depósito de cobre ubicado en Acarí (Caravelí-Arequipa). La mineralización se emplaza en pórfidos dioríticos pertenecientes al intrusivo Cobrepampa (Superunidad Linga) y está constituida por bornita, calcosina, covelina y calcopirita y en la zona de oxidación cuprita, crisocola, malaquita y hematita. El magmatismo es calcoalcalino con alto K. El intrusivo Cobrepampa evoluciona por fraccionamiento y contaminación en una corteza más delgada que la superunidad Linga. Petromineralógicamente se tiene epidotización con diseminaciones de calcopirita, pirita y bornita, gangas de cuarzo y calcita con hematita acicular. Las inclusiones fluidas muestran temperaturas de homogenización de 165.5 - 266.43 °C y salinidad 3.5 - 16.8 % eq. peso NaCl de un mesotermal o epitermal, pero que por sus características geomineralógicas sería un mesotermal. Por tanto, Cobrepampa presenta más de un evento de mineralización: una con magnetita y actinolita, y otro mesotermal de vetas de cuarzo con sulfuros.

May 22, 2019

By Ron Glowe

This paper shows the potential of a new computer model, using the Glowe-Tech (GT) Tonnage Analyzer program to compare drilling and blasting results. This model uses the crushers and conveyors as measuring tools in aggregate quarries in the USA and Canada. All data is collected using commercially available kilowatt transducers and an analog input/output automation module. There are two areas of measurement used to compare results. The first area is the tonnage moved by key conveyors to show the split in products produced and the actual rate of production. If belt scale readings are not available then the Glowe-Tech Tonnage Analyzer can be used to convert kilowatts from the conveyor motor to tonnage. The second is the tons of rock crushed per kilowatt hour of energy consumption by the primary and secondary (optional) crushers. This modeling process works best if blasts are mucked and crushed in sequence. There are many other variables such as crusher types, crusher settings, screen sizing and actual geology in the pit that can influence the results, however if variables can be standardized then definite trends can be seen when comparing drilling and blasting results

Jan 1, 2005

By Thomas J. Albin

U.S. Bureau of Mines research has found that maintenance of surface mining equipment is involved in slightly more than one-third (34.1 pct) of all surface mining accidents. Two groups of machines, haulage trucks and power shovels, accounted for over one-half of all surface mining mobile equipment maintenance accidents in 1978-84. Maintenance work-time histories for these machines were compared with accident records to identify the most hazardous-to-maintain systems within the machines. Recommendations to reduce the accident risk associated with maintenance of these hazardous systems are presented.

Jan 1, 1990

By Valentín Choquenaira Bombilla

El presente trabajo describe el proceso de automatización de la planta concentradora BHPBilliton deTintaya desde el punto de vista del usuario final y así proporcionar una visión global sobre los aspectos relacionados con la automatización de nuestro proceso a través de sistemas de control distribuido (Distributed Control Systems, DCS) e inteligencia artificial (Sistema Experto).También se describe la arquitectura del control, las formas de conexión (Hardware) y la función que desempeña dentro del sistema cada uno de los componentes del sistema de control distribuido instalados en la planta concentradora de sulfuros de BHPBilliton Tintaya S.A. así como algunos conocimientos básicos de manejo del sistema composer y conductor NT (Software) para realizar las funciones de configuración, monitoreo y control del proceso desde unidades remotas y estaciones de trabajo.

Sep 12, 2005

By Kim Wiwchar, Elizabeth Mbaja, Lynne Dang, Jim Furey, Anita Marks

"Suncor Energy Inc., located north of Fort McMurray, Alberta, commenced pilot scale operation using a CPT 4’ diameter flotation column in March 2003. This larger scale trial follows two previously successful flotation column bench scale tests. They included an April 2002 trial with a 2.4” inner diameter column from the University of Alberta and a 20” diameter CPT column in August 2002. The column receives middlings stream feed from one of Suncor’s deep cone separation cells and is operated in parallel with a set of WEMCO flotation cells. The recovery, tails losses, and concentrate quality are being compared between the two systems. The column, to date, has been tested with all types of run of mine ore grades. Variables such as wash water flow and temperature, sparger nozzle size and location, sparger air/water flow rates, and column residence time has been adjusted to achieve better recovery and final product quality.Used in many mineral processing applications, column flotation is primarily used for the final stage of sulphide cleaning and flotation of phosphate or iron ore. As well, mechanical cells are often used in combination with a column to retrofit an operation and to produce a cleaner product.Initial results prove that this is the first successful application of a flotation column in an oilsand application. If viable, it will be an inexpensive process for recovery of bitumen from a middlings stream and able to produce a final product suitable for froth treatment.INTRODUCTIONSuncor’s oilsand is surface mined from the Athabasca Oilsand deposit north of Fort McMurray, Alberta. The oilsand is then mixed with hot process water (HPW) and the bitumen is slurried in a pipeline. Large separation cells as shown in Figure 1 float off the bitumen product, which is then steam or static deaerated and sent to Secondary Extraction for further cleaning. The tails stream from the cell is sent to the Final Tails Pumphouse (FTPH) for processing. The tailings flotation froth product gets recycled to the separation cell oilsand feed. The tailings are pumped from the FTPH to tailings ponds. The middlings stream is drawn off the separation cell approximately 9’ from the froth overflow level. It runs down, by gravity, to the scavenger banks for bitumen recovery. It was from this stream off of the Line 6 Separation Cell that the feed to the Canadian Process Technologies Inc (CPT) flotation column was taken."

Jan 1, 2004

By Thomas Gales

Longwall mining has a high potential for producing bulk production from a single face. Production is interrupted for a considerable time when it is necessary to move the equipment to a new block of coal. The frequency of such moves can be reduced by increasing the dimension of the block to be moved. Merely doubling the tonnage in a block to be mined may increase production by more than 21,000 tons per year. The time taken to move the equipment can be reduced by careful preplanning, industrial engineering analysis, and specially designed equipment. Reducing its move time from 30 days to five days can increase production by more than 25,000 tons per year. Increasing the panel dimensions and reducing the move time can give an increase in pretax profits of more than $600,000. A comprehensive bibliography is included.

Jan 1, 1977

By Charles Merguerian

In medium- to high-grade metamorphic terrains such as found in New York City(NYC), rock mass texture and mineralogy are important factors in predicting TBM penetration destiny. Integration of data from over two decades of traditional field and tunnel mapping suggest that hard-rock TBM penetration in the NYC area depends upon textural, mineralogic, and structural control. The bedrock of NYC consists of many different lithologic units of varying age, composition, texture, and metamorphic grade including many varieties of intrusive rock. In addition, brittle faults of numerous orientations cut the polydeformed crystalline bedrock, producing zones of highly fractured and disturbed ground and high water inflows. Pre-bid compilation of published bedrock data, drill core analysis by geologists to establish lithologic and mineralogic trends, integrated surface geologic mapping along a proposed alignment, and targeted petrographic and geotechnical investigations to characterize the rock mass conditions together constitute an important prelude to successful subsurface bidding and tunneling. A carefully planned program of as-built geological mapping, structural analysis, fracture class mapping, and monitoring of machine performance data provide important information for adjusting to changed conditions. In complex terrains, a clear understanding of the structural geology of any proposed tunnel line is the simplest and most cost-effective method to mitigate losses encountered during TBM tunneling.

Jan 1, 2005

By Michael S. Wieland

"Toxic fumes cause fatal andnonfatal incidents in underground mining, where the working environment tends to trap the fumes, hindering the restoration of non-harmful conditions. Workers can underestimate the residual fume toxicity and return to the work site too quickly. The toxic fumes from charge explosions depend upon a number things: formulation ingredients, mixture uniformity, water resistance, hole contaminates, rock hardness, and dust interactions. Transitory hole-to-hole waves can cause partial desensitization, ruin the reaction kinetics, and worsen the fume toxicity.Traditionally the toxic fume hazard for a candidate explosive is resolved from a requisite tally of fume components. The resolution starts with the fume spectrum, a tabulation of specie concentrations, transformed to standard reference conditions and readjusted to remove the air dilution. The resultant influence, which is referred to as relative fume toxicity RFT, is deduced by a formula rule with some chosen constants and the requisite concentrations. The RFT result is normally compared to an RFT criterion that represents the worst-case (maximum) tolerable fume toxicity, as stipulated by regulations or otherwise."

Jan 1, 1997

Jan 1, 1961

By Miguel Rutti

El presente trabajo señala la geología, litología y mineralización del yacimiento minero El Tapado del distrito Yanacocha, situado al norte de Cajamarca. Este se encuentra conformado por diferentes depósitos auríferos epitermales de alta sulfuración, los cuales se desarrollan dentro de un vulcanismo calco-alcalino de composición andesítica a dacítica de edad Mioceno y son correlacionables con la Formación Porculla del Grupo Calipuy. La geología del depósito está conformada por rocas porfiríticas (intrusiones) y flujos piroclásticos tales como tufos de cristales, tufos líticos y brechas piroclásticas afectados por eventos eruptivos de brechas freáticas - freatomagmáticas. Todas estas rocas han sufrido posterior alteración hidrotermal con ensambles típicos de sistemas tipo ácido-sulfato. La mineralización económica está controlada por procesos hidrotermales y se encuentra asociada a sílice masiva y sílice vuggy ( 1-10 g/t Au y estructuras de hasta 136 g/t Au ) y en menor grado sílice alunita y sílice granular (moderada a baja ley).

Apr 22, 2003

By Shemek Oginski

The 5 km (16,194 lf) of 6.1m (20 ft) diameter TBM driven tunnel built by the J.F.Shea Co. will serve as sewage overflow storage. The TBM tunnel and four connecting tunnels excavated by drill and blast methods in hard granite will remain unlined. Based on the Geotechnical Baseline Report (GBR), the Contract documents provided a design with no required pattern of rock bolts, no probing, no pre-excavation or consolidation grouting, and lastly, no final lining of the tunnels was deemed necessary. This paper will provide a general overview of these topics with the emphasis on the actual ground conditions encountered versus the projected conditions provided in the GBR and how the GBR reflected the design of the project. Proposed modifications to the temporary and permanent ground support will be presented and the necessity of probing and pre-excavation grouting will be evaluated.

Jan 1, 2005

By Thomas M. Barczak

This report examines practical considerations in longwall support selection that have evolved from Bureau of Mines ground control research. The scope of discussion includes trends in support selection, analysis of shield designs, performance testing, and an examination of support and strata interaction theories and their relevance to in situ support loading. Application recommendations are made for two-leg shields. four-leg shields, and chock-shields. Two-leg shields account for 67 pct of the current active longwall installations and are used in a variety of applications. Automated control systems are likely to continue to grow in utilization. The next major change in shield design is likely to be the application of wider supports. The most effective method of performance testing longwall shields is by controlled displacement of the canopy relative to the base. Controlled force application does not control the load transfer through the shield and may not produce maximum loading in all support components. Theories of estimating support capacity based upon a detached roof block that must be maintained in equilibrium by the powered support are being challenged by concepts based upon the equivalent stiffness of the total ground supporting system.

Jan 1, 1990