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By H. J. Kelly

[This investigation of the refractory properties of seven Pacific Northwest chrome ores and concentrates has shown that five of the ores and one of the concentrates are suitable for making refractories and that all may be used in combination with high-grade chromite. The specific objectives of the investigation were to determine the inherent physic al and chemical characteristics, to shapes using each of the chrome ores and concentrates, to compare the refractory qualities of the laboratory-prepared with commercial chrome refractories. As far as possible, standard tests were used as criteria.]

Jan 1, 1952

By E. V. Daveler, Frank L. Antisell

CERTAIN physical and chemical properties of copper are so intimately related that a change in variation of the physical properties indicates a certain chemical change. The standard specifications of copper of the American Society for Testing Materials are based upon physical characteristics with one exception, namely, the copper contents. Certain phenomena of the surface indicate the adaptability of the metal for forging or rolling. The writer believes that it is much simpler to produce shapes that are metallurgically correct than those that are mechanically satisfactory. The appearance of the surface of the copper when cooled is considered as to its "pitch," or the general contour of the surface, and the "set," or the decail appearance of the surface of the shape. The set of the copper is, in a very large measure, directly related to the pitch; and so intimately are these characteristics connected that they are often used as synonymous terms by the refiner when he is speaking of well-refined copper. Oxygen is often spoken of as a medicine for copper, it being used to regulate the pitch.

Jan 1, 1920

By David Heyl

"El presente texto señala la evolución de los modelos genéticos de geología económica del yacimiento minero Tres Cruces. Dicho yacimiento se encuentra localizado en el noreste del Perú, adyacente al distrito minero de Quiruvilca. A partir del año 1995 se le reconoció como el mayor productor de oro a través de un programa de exploración en la Formación volcánica Calipuy. Posteriormente, el yacimiento fue visitado por variosgeólogos que postularon diferentes modelos genéticos del yacimiento para así estimar su potencial económico -en tanto se incrementaron los datos geológicos del yacimiento. Por ello, el texto presenta el modelo genético de Tres Cruces, como el más adecuado, aunque la evaluación de su potencial econornica está aún en progreso."

Apr 26, 1999

By Andy Schroeder

Located in Hamilton, Ontario Canada, Berminghammer Foundation Equipment, is a manufacturer of advanced foundation equipment with 30 years of experience. The company is represented in more than 20 countries world wide, maintains an extensive Research and Development team, and has earned a reputation for finding the most practical solutions to the most challenging projects. The vertical travel lead, referred to as "VTL" system, was first developed and patented by C.W. Bermingham in the 1970's. This lead system was developed in response to the fundamental limitations of either a fixed lead or hanging lead system. The fixed lead system is well suited to level job sites with few obstructions and has the advantage of faster positioning of the lead, the hanging lead is very adaptable to different elevations and batter piles but takes much longer to position. Therefore the Vertical Travel Lead was developed to combine the advantages of fixed leads, fast and accurate positioning, with the ability to adjust the height of the lead base up or down. The VTL lead is connected to the boom by a sliding connection which allows the lead to be elevated or lowered below grade. The advantages of the VTL system were recognized by many foundation specialists and they have become the Industry standard in Canada , US Railway Construction , and many parts of the USA.

Jan 1, 1997

By William J. Campbell

This study was a part of two programs: The first, to develop and evaluate high-temperature refractories; the second, to investigate reaction-rate kinetics and phase equilibria in the sinter step of the lime-soda process for the recovery of alumina. High-temperature X-ray diffractometer techniques are to be used extensively in both programs. This paper summarizes developments in the field of high-temperature X-ray diffractometers through 1959, evaluates various furnace designs, and describes briefly the X-ray diffraction facilities of the Federal Bureau of Mines. A more detailed description of the equipment and its calibration is planned in a future paper on thermal expansion and phase inversion of rare-earth oxides.

Jan 1, 1961

By D. A. Reynolds

[A few studies on the relationship of the fusion temperature of the ash of coke to that of the corresponding coal have been made on commercial high-temperature cokes. R. J. Rose3/ in 1921 compared the' fusion temperatures of the ashes of 10 coals and. the cokes produced from them and concluded tat they were in such close agreement that either figure could be used. More recently, Quarfort4/ found that the ash of coke fused at a somewhat lower temperature than that of the original coals As the ash of a coal and that of the coke produced therefrom have the same origin their chemical composition should be identical, provided that carbonization has not altered the inorganic, or ash-forming, constituents of the coal, and such alteration seems highly improbable. However, it has been shown5/ that coke is liable to contamination by iron during crushing and preparatory to sampling. Pieters6/ found that coke ash was cantaminated in this manner up to 0.4 percent. extraneous iron would lower the ash-fusion temperature because such iron may form ferrous silicate, which is readily fusible,7/ These results provide a basis for the prediction that the ash of coke will fuse at a lower temperature than that of the corresponding coil., especially if the fine grinding of the coke was done by rubbing surfaces of iron, as in a disk pulverizer or bucking plate.]

Jan 1, 1940

By R. L. Castro

Block caving methods, when operated under favourable rock mass conditions, can achieve higher production rates and lower operating costs than other various existing underground mining applications. For this reason, it has been considered the preferred method for the mining of deep and large orebodies in current and future operations around the world. One of the key aspects in the design of block caves is the selection of the production level layout, which, among other parameters, is based on the gravity flow characteristics of the caved rock. This is because gravity flow has a large impact on total ore recovery and the amount of dilution in a caving operation. Today, there are a number of computer based methods which aim to emulate the gravity flow pattern of the caved rock. In this paper, the authors present the development of FlowSiman improved model of gravity flow based on the cellular automaton approach, to estimate dilution entry, mixing and ore recovery. As part of the model development, flow simulations were conducted and subsequently compared to full-scale data collected at two mine sectors operated by Codelco Chile. The results indicate that by using proper calibrated parameters, good correlations between simulated and measured grades as well as dilution entry are obtained. The potential use of the numerical tool to evaluate drawpoint spacing in terms of recovery and dilution for block/panel caving operations is also presented.

Jan 1, 2009

This report presents the results of a study of Kennecott Copper Corporation?s Chino leaching dump at Santa Rita, N. Mex. The stability studies described herein were performed on only one cross section of the leach dump, utilizing data obtained from drilling, sampling, and testing, which was limited in nature. The first part of the report contains a discussion of site geology and seismicity, pertinent information on the waste material disposal system and leaching method, a discussion of the waste embankment characteristics, a summary of the engineering analyses, and a bibliography. The second part (appendices) contains basic geologic and engineering data supporting the discussions in the first part.

Jan 1, 1974

By W. A. Calhoun

This investigation of low-grade bauxites as potential sources of aluminum by caustic desilication and alumina extraction was undertaken by the Bureau of Mines to develop extractive methods for winning alumina from domestic deposits of low-grade bauxites. This report is the second of a series covering the work by the Bureau of Mines' Rolla, Mo., and Bauxite, Ark., laboratories. The first report published in the Journal of Metals, December 1951,3/ and dealt with kaolin and halloysite. The present investigation is concerned with low-grade bauxites only. The purpose of these investigations is to increase the domestic supply of aluminum ores. With eventual depletion of high-grade deposits, aluminous materials, such as low-grade bauxite, clays, shales, and high-iron laterites, will become our principal domestic sources of aluminum. The development of extractive processes for winning alumina from these low-grade materials is one of the many national security measures undertaken by the Bureau of Mines. A method has-been developed in the laboratory for successfully treating high-silica bauxites from domestic deposits. In this process the bauxite was calcined at 980° C. to form amorphous silica and alumina. The calcine was then leached by percolation with 15-percent sodium hydroxide solution at 940 to 96° C., removing 67 to 77 percent of the silica with a loss of 4.1 to 5.0 percent of the alumina. The sodium hydroxide in the spent liquor used in desilication was 95 percent recoverable, and comparable desilication results were obtained with 100-percent reclaimed liquor, The indicated cost of reagents, for sodium hydroxide and lime used in the desilication and regenera¬tion of spent liquor, was about $4.00 per ton of calcine treated.

Jan 1, 1954

By D. P. Roberts

This investigation aimed to simulate the experiments performed by Nic Gay (Gay, N.C. 1976. Fracture growth around openings in large blocks of rock subjected to uniaxial and biaxial compression. International Journal of Rock Mechanics and Minining Sciences and Geomechical Abstracts, vol. 13. pp. 231-243) on fracture growth around openings in blocks of rock subjected to uniaxial and biaxial compression, using the Elfen discrete element code. The results of the physical experiments indicated a number of trends that were successfully replicated in the numerical simulations, including crushing ahead of the face, the formation of a sub-vertical tensile fracture at centre-span, the formation of groups of fractures originating from the crushed face zone, the formation of large corner-to-corner fractures which precede sample failure, and linking of slot corner and sample corner fractures leading to sample failure. In addition, other features were apparent that were not reported by Gay. It is believed that these took the form of conjugate shear fractures (as reported by Gay in a previous paper) and other features that may have been altered or inhibited by the presence of pre-existing structure in the physical samples. It was found that the samples, though nominally made up of the same rock type, must have had significantly differing properties. The presence of pre-existing structures may have contributed to this discrepancy. Strain measurements from the physical experiments were reasonably well matched, except where the gauge lay directly in the path of advancing fractures.

Jan 1, 2012

By Siavoljub D. Maksimovic

The Bureau of Mines, through a cooperative agreement with Duquesne Light Co. of Pennsylvania, field tested a method of using pneumatic stowing of crushed limestone to construct seals in long-abandoned mine openings that were part of an active mine closed shortly before sealing. A total of 13 openings at 11 sites were backfilled. In pneumatic stowing, material is conveyed through a pipeline and into the mine opening under low air pressure. The stowing equipment consists of a power sup-ply, a blower, a feeder to inject material into the pipeline, and a nozzle for directing the placement. Material is ejected from the nozzle at high velocity, creating a high-compaction fill upon impact. The fill material used was well-graded limestone aggregate up to 1-1/2 inches in diameter, with sufficient fines. This fill was modified at five locations by the addition of portland cement, expansive cement, and/or bentonite. The pneumatic stowing method is safer and faster than conventional methods, is cost competitive, and eliminates or reduces the exposure of workers to possible hazards since the nozzle can be kept outside the mine opening. The equipment is mobile, but some modifications in the technique would improve performance. The technique was used at remote locations where other methods could not be used without disturbing the environment.

Jan 1, 1982

By Donald O. Capstick

The U.S. Bureau of Mines conducted an inventory of the prospects and mineral resources in the Scodies RARE II area (No. 5212) in 1982. No mineral production is recorded from the area, and no mines are being developed. The Scodies RARE II area is comprised primarily of light colored granodiorite with minor inclusions of mafic granitic rocks. Late stage differentiates of magmas resulted in quartz veins and pods. Metasedimentary rocks which have been mineralized in some parts of the Sierra Nevada were not observed within the study area during this investigation but small inclusions have been reported.

Jan 1, 1983

Pese a tener cajas sólidas en su estructura, algunas vetas desarrollan un relleno frágil, ocasionando problemas futuros de sostenimiento para el "corte y relleno" de los mismos. Por ello, se utilizó el método de los "Square Sets", donde además de ser costoso, implicaba eliminar una proporción de la roca encajonante y diluía el contenido metálico de los filones. En ese sentido, el objetivo del texto es señalar la viabilidad del "método Cornish"como método alternativo, económico, de rendimiento óptimo y que no presenta riesgos para el personal o la labor realizada. Este método es aplicable en aquellas vetas uniformes no falladas, que tengan desde una potencia pequeña hasta aquella que sea posible apuntalar, así como en aquellas que requieran sostenimiento del techo en la veta mima o donde se realizen Shrinkages. El proceso del método se basa en la preparación de los tajeos, luego en la explotación(perforación y disparos), enmaderado, relleno del tajeo, recuperación de madera, las variantes en la preparación del tajeo y la recuperación del mineral. La única desventaja que ofrece este método es su peligrosidad, dado que si se aplica en zonas inadecuadas o sin la supervisión que garantice el cumplimiento de las normas preventivas, es preferible el uso de los "Square Sets". Sin embargo, la aplicación del método resulta mucho más productiva en rendimiento teórico puesto que alcanza de 7 a 10 toneladas por tarea de 8 horas y responde satisfactoriamente siempre y cuando las condiciones de las vetas lo permita.

Jul 20, 1957

By M. N. Rubin

This report summarizes the work performed under USBM contract J0100018. The purpose of this work was to document the currently available noise control techniques that can be incorporated into new coal preparation plants during the design stage. This was accomplished by reviewing the related experience of the contractor and subcontractor (Bolt Beranek and Newman Inc.), conducting an extensive literature search, visiting operating coal preparation plants, and contacting various equipment manufacturers. The treatments addressed include equipment substitution, changes in plant layout, and retrofit treatments for existing equipment.

Jan 1, 1982

By Ji-He Wei

Keywords: stainless steel, AOD refining, side and top combined blowing, mixing characteristics, water modeling The fluid mixing characteristics in the bath during the side and top combined blowing AOD (argon-oxygen decarburization) refining process of stainless steel have preliminarily been investigated on a water model unit of a 120 t AOD converter. The geometric similarity ratio between the model and its prototype (including the side tuyeres and the top lances) was 1:4. On the basis of the theoretical calculations for the parameters of the gas streams in the side tuyeres and the top lances, the gas blowing rates used for the model have more reasonably been determined. The influence of the tuyere number and position arrangement, and the gas flow rates for side and top blowing on the characteristics has been examined. The results demonstrated that the liquid in the bath underwent vigorous circulatory motion during gas blowing, without obvious dead zone in the bath, resulting in a well mixing effectiveness. The gas flow rate of the main tuyere had a governing role on the characteristics, a suitable increase in the gas flow rate of the subtuyere could improve mixing efficiency, and the gas jet from top lance could make the mixing time prolong. Corresponding to the oxygen top blowing rate specified by the technology, a roughly equivalent and good mixing effectiveness could be reached by using six side tuyeres with an angle of 27 degrees between each tuyere, and five side tuyeres with an angular separation of 22.5 or 27 degrees between each tuyere. The relationships of the mixing time with the gas blowing rates of main-tuyeres and sub-tuyeres and top lance, the angle between each tuyere, and the tuyere number have been obtained.

Jan 1, 2005

By H. Sevim

Three transportation systems in surface coal mines: 1-Truck Haulage, 2-Belt Conveying, and 3-Coarse-Coal Slurry Transportation are compared from the operations and cost point of Views. Computerized design and cost models were developed and cost data banks were compiled for each system. These models can be used to evaluate transportation systems and layouts that are practiced in most of the U.S. surface coal mines. A typical midwestern area strip mine was considered for illustration purposes. Sensitivity analysis on critical parameters such as production rate, transportation, distance, etc. was conducted and the outcomes are presented.

Jan 1, 1990

By Lester M. Adams

In 1980, the Bureau of Mines surveyed a group of mine seals in Randolph County, WV, to evaluate their effectiveness for reducing toxic pollutants in mine water discharges. The survey focused on 11 block wet mine seals, but mine seals of several other types were also examined. The seals were installed in 1966 and 1967 in abandoned drift portals by the Federal Water Quality Administration (FWQA), a predecessor of the Environmental Protection Agency (EPA), in cooperation with the Bureau of Mines and other Federal and State agencies, in a project known as Elkins Mine Drainage Pollution Control Demonstration Project. The seals were designed to prevent air from entering the mine portals while allowing mine water to flow out. It was believed that by preventing air from entering inactive or abandoned mines, the formation of toxic pollutants and acid mine drainage (AMD) could be reduced. Evaluation of the seals was based on water flow measurements, water analyses, and visual observations. The Bureau's 1980 data were compared with past data collected by the EPA. Several leaks and failures were observed in the clay seals, as evidenced by apparent blowouts and the absence of vegetation where the mine water surfaced. Analyses of the 1980 data indicated some improvement in the quality of water discharged from many of the wet air seals.

Jan 1, 1984

By H. A. Dierks, H. B. Link

The purpose of this investigation was to develop a practical feeder apparatus to introduce comparatively large pieces of coal and similar material into a pipeline under pressure in connection with the vertical hydraulic transportation of solids , termed " hydraulic hoisting . " This method of hoisting the precrushed run - of - mine product of an underground mine has been given unusually wide attention abroad and could be of considerable significance to the U.S. mining industry in its search for operating improvements and cost reduction . A lock-hopper assembly was developed after a series of sinking velocity tests were made by dropping anthracite in a column of water . The system functioned reliably as an automatically operated feeder apparatus .

Jan 1, 1964

By P. C. Holloway, A. Tshilombo, T. Xue, M. J. Collins, R. Lopetinsky, I. Mihaylov, I. M. Masters

The Voisey’s Bay deposit contains a trace amount of cadmium, which reports to solution during pressure leaching of the nickel concentrate at Vale’s Long Harbour Hydrometallurgy Plant, and must be removed to produce high quality nickel cathode. In 2006, Vale approached Sherritt Technologies to collaborate on the development of a process for removing cadmium to low levels (<1 mg/L) in the nickel raffinate. Following successful bench scale and pilot plant testing at Sherritt’s laboratories, the cadmium removal process was then moved through engineering and construction, culminating in the successful commissioning and startup of a cadmium removal circuit at the Long Harbour Hydrometallurgy Plant in 2017. This paper presents the results of this collaboration and the challenges that were encountered through each stage of development, as well as current results from operation of the commercial cadmium removal circuit. INTRODUCTION Vale’s Long Harbour Processing Plant, with a nameplate capacity of 50,000 t/y nickel, began operation in 2014. In addition to electrolytic nickel rounds, the plant also produces electrolytic cobalt rounds and copper cathode. The Long Harbour Processing Plant uses a unique hydrometallurgical process developed by Vale Base Metals Technology Centre, as shown in Figure 1, to treat a nickel sulphide concentrate produced at the Voisey’s Bay mine and mill located in northern Labrador (VBN concentrate) (Stevens et al., 2009).

Jan 1, 2019

By Siavash Mahvelati, Alireza Kordjazi, Joseph Thomas Coe

Deep foundations are often constructed as end bearing members with a significant amount of their capacity derived from bedrock. Sites with highly variable bedrock conditions therefore present a unique challenge when attempting to estimate the design elevation of deep foundations. Typical subsurface characterization techniques such as drilling, standard penetration testing (SPT), and cone-penetration testing (CPT) may fail to adequately establish top-of-rock elevation in geologic settings prone to karst and/or significant amounts of residuum, saprolite, and deformed bedrock. Seismic surface wave geophysical methods have been increasingly used to map bedrock topography in such settings. However, the current standard of practice for these methods introduces resolution limitations in spatially variable subsurface conditions due to averaging effects from the analytical framework used to process the acquired data. This study explores the use of a tomographic approach with full waveform inversion (FWI) to map top-of-rock elevations at a numerically simulated site representative of highly variable bedrock topography. Comparisons are made with seismic refraction (SR) and a dispersion-based multichannel analysis of surface waves (MASW) approach as more commonly used in geophysical subsurface investigations. The results highlight that FWI provides a superior estimate of top-of-rock topography than SR and MASW at a cost of a significant increase in the required computational resources and time.

Oct 1, 2021