Search Documents

By Henry Kreisinger, L. P. BRECKENRIDGE, WALTER T. RAY

The investigations of fuels conducted by the technologic branch of the United States Geological Survey had their inception at the Louisiana Purchase Exposition in 1904. By an act approved Febru- ary 18, 1904, Congress authorized the work of analyzing and testing at the Louisiana Purchase Exposition the coals and lignites of the United States, under the supervision of the Director of the United States Geological Survey. An appropriation of $30,000 was made for this purpose. In the general deficiency bill dated April 27, 1904, the sum of $30,000 was added to the appropriation. To carry out these investigations the Director of the Geological Survey appointed a committee consisting of E. W. Parker, statistician of the Geological Survey; Joseph A. Holmes, State geologist of North Carolina; and Marius R. Campbell, a geologist of the Geological Survey. Under the first act authorizing this work all of the machinery and coal for the tests was to be furnished the Government free of charge. The buildings containing the testing apparatus were all paid for out of the first appropriation. After the close of the Louisiana Purchase Exposition every Congress made an appropriation for continuing these fuel tests. These subsequent appropriations permitted the purchase of appliances better adapted for the testing work.

Jan 1, 1912

By S. Abu-Samra

By virtue of its complex nature, the construction industry comprises a wide spectrum of interrelated variables and factors. This multifaceted character of the construction industry puts the use of engineering modeling tools and techniques on top of project management necessities. This research introduces a macro-level earthmoving management system using Genetic Algorithms (GAs) to reach the optimum allocation of earthmoving equipment. The Earthmoving Equipment Management System (EEMS) functions through four integrated modules: (1) A Central Database containing information about projects and available equipment; (2) An Equipment per Segment Selection module that calculates the cut and fill quantities, plots the Mass Haul Diagrams, and selects the equipment types to be used for each segment; (3) An Equipment Pool module which determines the production and cost for each available equipment, based upon the project site conditions; and (4) An Optimization Engine equipped with a GA optimization solver. This engine formulates the optimum earthmoving cost for all projects, by changing the number of allocated equipment. The Optimization Engine takes into account the number of available equipment and calculates the weekly equipment allocation. The EEMS model was implemented on an earthmoving company conducting five different projects on hand. The model proved to be an effective tool in providing decision makers with optimum equipment utilization on a multi-project scale to minimize the earthmoving cost. The results were then compared with the company?s existing micro-level management system, demonstrating better performance on the level of savings, amounting to 13% of total earthmoving cost.

Aug 1, 2013

By H. Memarian

In the last few decades, many developing countries have tried to expand and improve upon higher education, which is acknowledged to be the leading factor for development. In this respect, develiping countries have significantly increased the number of tertiary institutions and their students. These rapid expansions, along with all the benefits, have drawbacks as well. An example is the status of mining engineering education in Iran. Presently, the number of active mining engineering departments in Iran (27) is more than the sum of similar departments in Canada, Australia, the United Kingdom, and South Africa (23 altogether). Also, the number of annual mining graduates in Iran (645) is more than the cumulative graduates of the United States, Canada, the United Kingdom, and Australia (613). The expansion of mining engineering education in Iran has coincided with the closing or merging of similar mining departments, as well as a decline in the number of interested students in the industrialized world. The present study shows that the need for development and the excessive number of high school graduates, resulting from high population growth in the early 1980s, are the two primary factors influencing the significant expansion of mining engineering education in Iran.

Jan 1, 2007

By B. F. Dickerson

STRATEGIC METALS! Recently, this money accented cry has been heard in such diverse locales as Mining company boardrooms, Banker's offices, Stockbroker's quarters, Swindler's dens and Congressional committee rooms. (In some cases, these locales are one and the same). Is the strategic metals rush for real? Should it be? Our paper attempts to give a very generalized view of the subject for a few metals, points to a few potential, but generally overlooked sources of these metals, and offers conclusions based on our studies.

Jan 1, 1981

By J Safarian, M K. Kar

Bauxite residue is one of the most important by-products from the alumina industry with no commercial use till now. The utilisation of bauxite residue through pelletising with different lime additions, hydrogen reduction, and smelting has been studied in this work. Three different types of green pellets were made with varying calcite-to-bauxite residue ratio and subsequently sintered at elevated temperatures. The sintered pellets were isothermally reduced at 1000°C under hydrogen gas followed by smelting of the reduced pellets in argon at 1500°C. Smelting of the reduced pellets leads to the recovery of metallic iron and the formation of a leachable calcium aluminate slag. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterise the phases and microstructural analysis. The iron produced in the smelting process has a high purity, above 99.5 wt per cent. While the iron content of the slags is quite low, and the slags shows variations of krotite (CaAl2O4), gehlenite (Ca2Al2SiO7), and perovskite (CaTiO3) phases based on the variation of calcite addition. It was found that the more calcite addition in pelletising yields higher percentage of krotite phase as compared to lower calcite-containing pellets. Employing quantitative XRD analysis, the krotite phase fraction was found approximately 85 wt per cent for higher calcite-added pellet, and around 74 wt per cent for lower calcite-added pellet. FactSage™, ver 8.1 (Thermfact and GGTTechnologies) thermodynamic software was used to evaluate the obtained experimental data, they both revealed that the

Jun 19, 2024

By J. Frederick Stampfer

Current certification testing of self-contained breathing apparatus includes tests with human subjects wearing the apparatus while exercising. During these tests, certain apparatus variables are measured during rest periods. Because of concerns that the present tests may not accurately simulate the stresses to which an apparatus is subjected in the field, the Bureau of Mines proposed new human subject tests. It was also felt that different measurement techniques would supply more reliable data on the apparatus response to these stresses. The Los Alamos National Laboratory was asked by the Bureau to evaluate the proposed tests and monitoring techniques. The major conclusions derived during this study are these: (1) The proposed tests are not too physically demanding. (2) As long as human test subjects are used, a minimum subject weight should be required for certification tests. (3) Important apparatus variables are the breathing resistance, temperature, and carbon dioxide and oxygen concentrations of the inhaled gas. (4) Continuous monitoring should be used, rather than monitoring only during rest periods. (5) New pass/fail criteria based on realistic estimates of the user's physiological requirements, as tempered by present and future engineering limitations, are needed. (6) When available, breathing machines, rather than human subjects, should be used for most certification testing. (7) A more realistic ergonomics test than that proposed is needed. (8) A gas leak test for the system and a facepiece leakage test are also needed.

Jan 1, 1983

By Jr. Brown, A. Calderara, A. L. Antozzi

"The result of extensive research into fundamental mixed metal oxide catalyst morphology has produced a next generation all titanium Dimensionally Stable Anode (DSA ®). This new DSA ® anode, patent pending, is tailored for electrowinning of non-ferrous metals (copper, nickel, cobalt, zinc) by means of this new coating technology.These DSA ® anodes are characterized by a hanger bar with vertical distributor bars, having primary titanium mesh attached by weldments. The active mesh is provided with noble-metal electrocatalytic coatings, consisting of iridium and/or ruthenium oxides, obtained by thermal decomposition of precursor solutions applied to the titanium substrates. The catalytic activity of state-of-the-art DSA ® anodes is increased by controlling the crystallite size of the noble-metals without decreasing the decomposition temperature. It is known that below a certain value (typically 400°C) the stability of these oxides, and associated lifetime, is seriously compromised. A highly active DSA ® anode, consisting of a quasi-amorphous phase, is obtained at high temperature (above 450°C), therefore not compromising lifetime performance. Through optimization of these design parameters, the manufacture of these novel anodes was identified.DSA ® anode performance advantages include: lead-free ' green' all titanium anodes, true leadfree cathode quality, energy savings of 0.3 to 0.55 V can be realized depending on the EW application when compared to industry standard lead-alloy anodes, eliminate need for cobalt sulphate addition required for lead anodes, sustainability designed into long-life recoatable anode structures, increase plant cathode output through increased current density operations, improve plant on-stream production, no sludge generated or removed, and improve current distribution producing smooth high efficiency cathode.Introduction of ProductThere are many factors to consider when engineering a high performance DSA ® electrowinning anode. Half of the anode's performance is derived from the physical attributes of the electrocatalyst and methods employed when applying this catalyst to the titanium anode structure. The other half of the performance benefits relate to the proper structural design of the anode. In this paper, we will highlight the anode development program in which De Nora has invested to provide the Electrowinning marketplace with a high performance anode product."

Jan 1, 2012

By T. Klemetti, W. H. Su, M. A. Van Dyke

Entry stability in coal mines is dependent on geologic conditions and engineering controls. Most engineering controls in ground control are predictable and standardized for typical geologic conditions. However, geologic anomalies may exist that are difficult to detect with traditional core hole drilling. Borescopes offer a cost-efficient way to gather more geologic data between core holes. Additional data obtained from borescope results provide a clearer picture to enhance detection of hazardous conditions due to geologic anomalies. The equipment, methods, and analysis of borescope results provide geomechanical engineers with a clear understanding of strata behavior and the best information to implement roof control plans and supplemental support to enhance miner safety and health. INTRODUCTION Borescope technology has changed very little since its inception. However, the idea to use borescopes to examine roof strata started with the U.S. Bureau of Mines in 1979 with the production of a fiber-optic borescope (FitzSimmons, et al., 1979). The first documented use of a borescope in the coal mining industry began during the 1980s in Australia by researcher John Shepherd. Shepherd’s idea was to use a borescope to collect a series of data points from the roof lithology and compose a geologic cross section. The cross section was then used to identify key features that suggested the beginnings of roof failure. The features Shepherd identified were bedding plane separations in the roof and low angle, extension, and tensile failures. Shepherd also suggested that the borescope findings could be used for geologic mapping for lithological variation, fracture distribution, and determining if supplemental roof support was needed (Shepherd, et al., 1986). In the United States the first publication about borescope usage for coal mine stability assessment was by Su and associates in 1999, who specifically related the combination of using borescope, geophysical, and corehole data to produce geologic hazard maps (Su et al., 1999). This work directly linked the usage of a borescope with the design of supplemental roof support. The use of borescopes in mining was adopted industry wide by the 2000s. Operator case studies were being published using borescopes to aid in supplemental support recommendations and hazard mapping. An Australian study published in 2007 based the optimization of secondary support after each longwall pass on the results of borescope data. The study stated that the borescope was an invaluable tool for understanding roof behavior (Black, et al., 2007). In 2009, a publication by the National Institute for Occupational Safety and Health (NIOSH) took the concept of borescoping one step further. The work centered around creating a roof quality index (RQI) for limestone mines based on borescope data. The RQI attempted to assign a ranking to establish the nature of the roof and its stability (Ellenberger 2009). In theory, this would have been a very useful tool, but the RQI system has not been widely adopted in the industry.

Jan 1, 2019

By Reginald Dias

Mining equipment life may be extended through preventive maintenance and the proper application of quality lubricants. There are several practices mine operators should consider implementing to preserve their equipment. An exercise in review — Begin by reviewing original equipment manufacturer (OEM) recommendations regarding servicing and maintenance intervals for each part of the equipment, especially the engine. And the verdict is — If the manufacturer’s recommendations have been followed, good. If not, owners/operators should begin periodic service work on equipment, to help minimize equipment downtime and extend engine life.

Jan 1, 2004

By A. J. Kwitowski

Remote control for mining machines ordinarily means the operator is not seated on the machine, but is located within direct view of the machine and work area Thus, remote control operators are exposed to the hazards of roof/rib falls and dust/methane explosions. The U.S. Bureau of Mines has developed a method to disassociate remote operators from these hazards. Off-board, computer-based "tele-operational" systems are utilized that station the operators one-hundred meters or more distant from the working faces. Details are provided for tele-operated systems for thin-seam extraction and haulage equipment in highwall and deep, room-and-pillar coal mines.

Jan 1, 1992

By G. W. Barton

Process Systems Engineering (PSE) can be defined as the integrated usage of computer-based design and analysis tools. As such, PSE is becoming increasingly important in the chemical and petrochemical industries. This paper shows how a range of PSE techniques have been applied to the zinc electrowinning process. Topics discussed include model development, parameter estimation, steady-state and dynamic model applications, steady-state optimisation and neural network modelling.

Jan 1, 1994

By R. A. L. Drew, G. Mendoza-Suarez, J. Filipi, R. Vintila, J. A. Kozinski

Economics and environmental considerations along with the increasing demand of hydrogen encourage development of novel technologies such as plasma processing of hydrocarbons and thermal cracking of natural gas. Plasma discharges, either in thermal or non-thermal regimes are expected to allow low temperature and fuel flexible on-site hydrogen generation. The main drawback of thermal plasma reformers is the high-energy consumption resulting from high-temperature operation. On the other hand, non-thermal plasma, generated by dielectric barrier discharge (DBD), is able to simulate the chemical reactions employing much lower energies than those required by thermal treatment processes. The non-thermal plasma process allows for instance, a direct conversion of methane into hydrogen and carbon black with no CO2 release. The focus of this research was on the GHG-free method of H2 generation in compact non-thermal plasma reactors using low, medium and high permittivity dielectric ceramics. A stable, non-thermal plasma was generated by placing a dielectric ceramic between two electrodes with a 25 thou gap and applying an alternating current of 1-5kHz and voltages of 4-8kV. In order to ensure energetic efficient plasmas, experiments were conducted to analyze the behaviour of different permittivity ceramics. It was found that the dielectric properties of a ceramic, when used in a DBD reactor, have a strong influence on the discharge characteristics, which in turn influence the power consumption. Higher dielectric constant resulted in higher conversion rates of methane (higher yield of hydrogen and carbon). At the same time, the mechanical properties of the dielectric material, which are closely associated with its processability, influenced its resistance to electron bombardment, as well as thermal and mechanical damage. Therefore a reliable ceramic should have good dielectric properties, in addition to good thermo-mechanical stability.

Jan 1, 2004

By J. S. Hansen

In support of its objective to conserve mineral resources by minimizing premature failure of materials, the Bureau of Mines conducted a cooperative study with the U.S. Department of Energy on the erosion and abrasion resistance of hard materials for valves in coal conversion systems. This report describes a newly developed erosion-testing apparatus and presents data on the erosion resistance of over 200 materials. Erosion resistance of most metals was comparatively low. In contrast, ceramics and cermets such as B4C, WC, SiC, Si3N4, and TiB2, when fabricated to minimize porosity, displayed greater than five times the erosion resistance of metals. Coatings such as boron diffused into Mo and WC, chemical-vapor-deposited TiCN, and electrodeposited TiB2 were highly erosion resistant if applied in thicknesses ranging from 60 to 75 µm. Erosion resistance of cemented carbides was inversely related to metal binder content.

Jan 1, 1979

By Barry A. Hillman

The rapid evolution of computer and field sensor technology is now providing the ability to integrate mine and office operations. Digital maps and mine plans as well as CAD and GIS can be transferred to ruggedized field computers for development of real-time mine surveys and real-time GPS machine navigation and monitoring. Surveyors can insure that their surveys are accurate before returning to the office. Engineers and surveyors are also able to upload field computer-based surveys to mine planning software and directly to mine equipment including shovels, drills, and dozers providing the operator of the equipment with a real-time view of their work space. Production information can be transmitted through dispatch and/or centralized mine servers to update mine plans with mining progress and production data. Static mine models then become a dynamic element of operations, providing greater use of information that emphasizes the spatial aspects of the mine by providing real-time maps, productivity charts, and graphs. This information can be disseminated through various mine communication systems to provide operators and management with real-time feedback as well as daily and weekly reports. Integrated systems now being used in extensive trials are reporting productivity increases of 4 -7% or more thereby providing rapid payback to the mine.

Jan 1, 1998

"Depletion of known ore reserves and increased demand for precious metals have caused a revolution in biohydrometallurgical processing technology for gold recovery. Known ore deposits and future discoveries are most likely to be lower grade sulfide ores that can be difficult to recover with current leaching technology. Future metal recovery operations will increasingly use bio-oxidation techniques.Bacteria are an integral part of mineral cycling and mineral transformation in nature. Although biological processes are recognized as part of the mineralization and oxidation reactions in some ore deposits, they have only recently been applied to enhancing metal recovery in hydrometallurgical procedures. This paper explores the traditional metallurgical application of biological leaching and oxidation reactions and reviews the complete range of bacteria available for metal recovery systems. Pre-treatment of ores with bacteria improves metal recoveries in tank leaching systems and shows promise for heap leaching methods.IntroductionThere is no longer any question that bacteria playa natural role in the on-going transformation of some ore deposits (1,2). As applied to sulfide ores, a few strains have been specifically identified that exhibit a natural leaching potential (3). These bacteria can be isolated from waters and soils in old mining districts where they contribute to continuing leaching and pollution problems in acid drainage and heavy metal solubilization. Sulfur and iron bacteria as well as many heterotrophic strains have also been found in ore deposits and sedimentary rocks at depths up to 2000 meters (4). Their presence in both ore deposits and processed ores shows the microbial association with natural leaching and the potential role that bacteria can play in the development of new leaching technology."

Jan 1, 1988

By Jessica M. Wempen, William G. Pariseau, Dallan J. Coons, Michael K. McCarter, Erik C. Westman

The abstract discusses the importance of proper pillar sizing in underground mining for safety and efficiency. It highlights the use of theoretical models, geotechnical measurements, and numerical modeling in predicting pillar behavior. The research focuses on using seismic tomography to image stress changes in a yield pillar at a longwall mine as the longwall face approaches. The study aims to compare the stress distribution imaged using tomography with theoretical models, geotechnical measurements, and numerical models.

Mar 18, 2022

By Ruilin Yang

Kinematic approach of blast modeling refers to using the velocity, strain, or displacement as controlling parameters to model blasting, rather than the stress and the material constitutive relations. The rock stiffness or constitutive relations is very hard or impossible to obtain due to the complexity of the rock mass property.

Feb 1, 2020

By Auhin Kumar Maparu

Metal oxide nano-particles are used as additives in various industrial applications such as pigments in paints, additives in adhesives, plastics, cosmetics, functional coatings, personal care and health care products, for antibacterial applications and more recently in heat transfer applications. In most of these applications, usually dry nano-particle powders are added to the formulations. However, often it becomes difficult to achieve a uniform and stable dispersion of nano-particles in the given formulation. Thus, a scalable and commercially viable process for in-situ production of stable nano-particles suspensions in the desired medium will certainly be more beneficial. Ultra-fine grinding in high energy mills (planetary mill, stirred media mill) has been used to produce fine particles (sub-micron size). However, in order to obtain nano-particles (particle size <100 nm), the choice of appropriate dispersant and solvent is crucial, since freshly generated nano-particles tend to agglomerate due to their high surface reactivity. We have employed molecular modeling (MM) based selection methodology to arrive at the most suitable solvent?dispersant combination for preparation of the given metal oxide nano-particles. Molecular modeling techniques are employed to compute the interaction energy of a given dispersant with surface of the metal oxide particles in the presence of the dispersion medium. The interaction energy helps identify a dispersant that has strong affinity for the metal oxide surfaces allowing for strong dispersant adsorption and hence a more stable dispersion. For example, in case of aqueous nano-titania suspensions, poly-carboxylic acids like citric acid provide better dispersion than mono-carboxylic acids like lauric acid, mysristic acid, and oleic acid. While in non-aqueous medium like ethanol, p-hydroxybenzoic acid and glycerol trioleate perform better. The suspension is produced in-situ by ultra-fine grinding of the metal oxide powder in the presence of the selected dispersant and dispersion medium in a planetary ball mill. By careful selection of various process parameters such as percent loading of powder, jar filling, grinding media to powder ratio, time and amount of dispersant addition, both aqueous and non-aqueous suspensions of metal oxide nano-particles with average particle size less than 100 nm are produced. The aqueous suspensions of alumina and titania produced in presence of citric acid dispersant exhibit median particle size of 83 and 62 nm, respectively. These suspensions have been found to be stable for nearly 3 years. The nano-particles thus produced are used in the preparation of nano-fluids?advance heat transfer liquids, which show enhanced heat transfer capabilities and unaltered stability and performance even after several heating-cooling cycles. The nano-particles are also utilized for making efficient photo catalysts, which are found to be highly effective under sunlight. Keywords: stability, nano-fluid, milling, grinding, thermal conductivity, nanocoolant, photocatalyst

Sep 1, 2012

By Y. Jeong, K. Kim

Excess water can lead to instability and even failure in tailings storage facilities (TSFs). Simply reducing the amount of water in TSFs could be the best way to ensure the safety of nearby communities. In this case study we investigated the effects of reducing the water content in tailings slurry at a copper-cobalt-zinc mine in Mexico. An environmentally friendly polymer was used as a drag reduction agent (DRA) to offset the increase in solids percentage. The potential effects of the increased solids concentration on the tailings transportation system were also assessed. A series of ‘what if’ studies was conducted to assess whether adding the polymer would allow the solids concentration to be increased without changing the pressure loss in the tailings pipeline. The studies entailed conducting pipe loop tests to investigate these changes under various solids/ polymer concentrations and then constructing a computational fluid dynamics (CFD) simulation model using the test results. The validated model was used to determine the optimal polymer percentages needed to maintain the same pressure loss under baseline (30% solids) conditions, and to assess the potential risks (clogging, increased erosion rates) to the pipelines. The potential water savings were found to be significant, varying from about 1.852 Mm3/a at 35% solids to 3.915 Mm3/a at 45% solids.

Dec 13, 2023

By E. J. Owen, A. Appah, I. C. Sanchez, K. T. Stafford, N. Hurtig, R. Otoo, N. A. Iverson, S. A. Moses, V. T. McLemore

New Mexico lies at the eastern edge of one of the world’s great metal-bearing provinces hosting numerous Laramide and Paleogene mineral deposits. Southwestern New Mexico contains Laramide porphyry Cu (±Mo, Au) and Paleogene Mo-W deposits. Porphyry deposits are generally large, low-grade deposits containing Cu, Fe, Mo, Au sulfides (and other metal sulfides) associated with porphyritic intrusions and exhibit characteristic alteration styles. Porphyry deposits can also be spatially and temporally associated with skarn deposits and polymetallic veins. All of these deposits have the potential to host various critical minerals, including Cu, Zn, Bi, Co, Ni, rare earth elements (REE), Te, and W. Critical minerals may be found as substitutions within ore minerals or as separate mineral phases. These deposits are constrained using 40Ar/39Ar dating into three ore-producing magmatic pulses: 1) ~78–71 Ma Laramide pulse, 2) ~59–50 Ma, Laramide pulse, and 3) ~40–30 Ma Paleogene pulse. New and historic whole-rock geochemical data have highlighted areas with critical minerals potential that require further study.

Feb 1, 2025