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By D. Bienstock

In connection with air-pollution studies, the Bureau of Mines is cooperating with the U.S. Public Health Service in investigating the use of solids for removing sulfur dioxide in concentrations of less than 0.5 percent from combustion and waste gases. Removal of sulfur dioxide at flue-gas tempera¬tures would no longer result in the cooling of scrubbed gas, which is inherent to liquid scrubbing processes used exclusively in industry today. Results are reported of extensive investigation, using metallic oxides as absorbents, adsorbents, and oxidation catalysts at 130° and 330° C. (temperatures at which flue gas may be treated in powerplant practice). The most active absorbents tested were the oxides of manganese, cobalt, copper, and alkalized alumina; 23 to 33 grams of sulfur dioxidn were removed by 100 grams of absorbent at 130° C., while scrubbing more than 90 percent of the sulfur dioxide from a simulated flue gas, and 19 to 61 grams of sulfur dioxide were removed at 330° C. A more detailed study is reported on absorption and regeneration, using manganese oxides and alkalized alumina. Adsorption of sulfur dioxide on activated carbons and molecular sieves at elevated temperatures is considerably less efficient than removal by absorption--a maximum of 7 to 8 grams of sulfur dioxide could be removed with 100 grams of adsorbent at 130° C. A potash-promoted vanadium pentoxide is effective in converting sulfur dioxide to trioxide; complete conversion in a simulated flue gas containing 0.35 percent sulfur dioxide was obtained at 365° C. Pilot-plant and cost studies are being made by the Bureau to determine the economic feasibility of removing on an industrial scale the sulfur dioxide present in gases in low concentrations.

Jan 1, 1961

By Richard P. Walters

This Bureau of Mines report reviews and assesses the technology for preparing electrodeposited coatings of the platinum-group metals from molten alkali metal cyanide baths. Methods are described for the preparation and purification of the cyanide electrolyte. Vacuum drying, fusion, and purity of the cyanide salts are discussed. Use of a sodium borosilicate test tube as a sodium-ion-conducting membrane for the addition of the desired platinum-group metal is described. The optimum plating parameters of potential and current density for Pt, Pd, Rh, Ru, and Ir coatings that result in the best deposits are given. A method for producing platinum-rhodium alloy coatings of predetermined composition is also described. The importance of careful substrate surface preparation is illustrated. While problems still remain with respect to coating porosity, careful application of the methods described permits the preparation of adherent, coherent electrodeposited coatings of the platinum-group metals.

Jan 1, 1984

By S. A. Shoop

Vibrations from thirty-seven blasts were monitored using three seismographs. Data analysis showed that square root, cube root, and site-specific scaling predicted ground motion with equal reliability. Imprecise prediction is caused by geologic and blast variability, particularly inaccurate delay times. Vibrations at some mines were consistently lower or higher than vibrations reported in the U.S. Bureau of Mines studies. Regulations based on USBM data could then be too conservative or lenient. Predominant vibration frequencies were generally less than 50 Hz, but several blasts had significant energy up to 125 Hz. In some cases energy was concentrated at frequencies corresponding to delay intervals.

Jan 1, 1983

By Thys B. Johnson

Operations Research techniques for determining optimal shipping schedules and production and product allocation are discussed. A hypothetical mining operation model is formulated by the Bureau of Mines, and optimal production and product allocation are determined. The technique of sensitivity analysis is discussed and is used to illustrate the effect of the variability in a mining operation on the optimal production and product market plan.

Jan 1, 1969

By Camilo A. Alvarez, Stephen K. Harris, Brian R. Zuckerman, Philip J. Meymand, Danielle M. Steinmetz

"The sleek new air traffic control tower at the San Francisco International Airport stands at 221 feet tall and is set to replace the existing air traffic control tower by 2016. This aluminum-clad, torch-like structure and three-story Integrated Facilities Building at the base are situated between Terminal 1 and Terminal 2 adjacent to the tarmac. Berkel & Company Contractors, Inc. and Simpson Gumpertz & Heger Inc. worked in conjunction with structural engineers from Walter P. Moore Engineers and Consultants, geotechnical engineers from URS Corporation, architects from Fentress Architects, and general contractors from Hensel Phelps Construction Company on the performance-based design of a foundation to support this critical facility, which is located in a high seismic zone and situated on the very soft soil of the San Francisco Bay margin. With the loading demands and performance criteria established and Young Bay Mud thicknesses ranging from 44 to 47 feet thick across the site, the design team employed a total of 214 24-inch diameter Auger Pressure Grouted piles, which were drilled into the underlying Franciscan Formation as deep as 148 feet below existing grade. Pile reinforcement included full-length confined cages.The piles were designed to resist Maximum Considered Earthquake axial demands as high as 1,400 kips in compression and 700 kips in tension. The performance-based pile design included verification of shear capacity under double-plastic-hinge flexural mechanisms, verification of pile ductility via non-linear moment-curvature analyses, and consideration of curvatures due to kinematic as well as inertial loading.The team implemented an extensive pile load test program including a full-scale static compressive load test on a sacrificial test pile and five non-destructive high-strain dynamic load tests, four of which were performed on indicator piles that were later used as part of the foundation system. These piles were monitored with extensive embedded instrumentation throughout their length, including strain gauges and accelerometers."

Jan 1, 2017

By Walter Loel

THE application of aerial photographs to all phases of geologic mapping is set forth, indicating the advantages to be gained in different types of country and under varying climatic conditions. Methods of field and office procedure are given from a geological point of view, as well as suggestions regarding the best methods of aerial mapping for different uses and under varying field conditions, including the study of submarine geology. Aerial photographs with accompanying geologic maps are shown to illustrate the appearance from the air of different geologic features under varying climatic and topographic conditions.

Jan 1, 1938

By Samir Kumar Pal, Rajasekar Rathanasamy, Gobinath Velu Kaliyannan, Moganapriya Chinnasamy, Sathish Kumar Palaniappan

The research examines the performance of uncoated and coated tungsten carbide-cobalt rock cutting bits. It aims to optimize process variables (cutting speed, depth, coating material) considering multiple output responses (cutting forces, specific energy, wear rate, material removed, angle of reaction forces). The study uses a hybrid optimization technique combining Taguchi design, grey relational analysis, and fuzzy logic. The optimal parameter combination was found to be cutting speed: 200 mm/s, cutting depth: 6 mm, and titanium aluminum silicon nitride coating.

Apr 24, 2022

By S G. Hagemann, M E. Barley

The Mt Tom Price deposit is a world-class high-grade hematite deposit in the Hamersley Province of Western Australia with an original resource of 900 Mt of almost pure hematite, averaging 63.9 wt per cent Fe. Petrological and geochemical studies at both the Southern Ridge and the North deposit at Mt Tom Price have identified three hypogene alteration zones between unmineralised BIF and high-grade iron ore: distal magnetite-siderite-stilpnomelane; intermediate hematite-magnetite-ankerite-talc-chlorite; and proximal martite-microplaty hematite-magnetite-apatite alteration zones.Fluid inclusions trapped in siderite within the distal magnetite-siderite- stilpnomelane alteration zone at the North deposit revealed primary high salinity (25.5 eq wt per cent NaCl-CaCl2) inclusions that homogenised between 107¦ and 142¦C into liquid. Fluid inclusions trapped in ankerite within ankerite-microplaty hematite veins in the intermediate hematite-ankerite-magnetite-talc-chlorite alteration zone at the North deposit revealed mostly H2O-CaCl2 pseudosecondary and secondary inclusions with salinities of 22.4 - 25.4 eq wt per cent and 22.9 - 25.9 eq wt per cent CaCl2, respectively. Pseudosecondary inclusions homogenised between 153¦ and 449¦C and secondary inclusions homogenised between 103¦ and 157¦C. Fluid inclusions trapped in apatite within talc-microplaty hematite veins in the intermediate hematite-magnetite-talc-chlorite-apatite alteration zone at Southern Ridge revealed that primary, medium salinity (7.0 - 9.0 eq wt per cent NaCl) inclusions homogenised between 181¦ and 257¦C and primary high salinity (22.8 - 25.9 eq wt per cent CaCl2) fluid inclusions homogenised between 118¦ and 257¦C into liquid. Microthermometric analysis of quartz from quartz-hematite veins from the Southern Batter Fault, Southern Ridge show a complex fluid inclusion history. Primary fluid inclusions consist of: low- and high-salinity H2O-NaCI inclusions trapped at temperatures of approximately 140¦ to 230¦C; vapour-rich inclusions of unknown compositions; and æcomplexÆ salt-rich (Ca, Mg, K and Na inclusions).Secondary inclusions consist of medium-salinity fluid inclusions trapped at temperatures of about 140¦ to 280¦C.A two-stage hydrothermal model is proposed for the formation of both the Southern Ridge and North deposits. Early 1a hypogene alteration involved the release of hydrothermal NaCl-CaCl2-rich (25.5 eq wt per cent) basinal brines (110¦ - 150¦C) from the underlying Wittenoom Formation and directed upward along normal faults and focused within the silica-rich rocks of the Dales Gorge Member, by the shales of the underlying Mt McRae Shale Member and overlying Whaleback Formation. Within the Dales Gorge Member hydrothermal basinal brines migrated laterally within large-scale folds with permeability controlled by shale bands and the NW trending dolerite dyke sets. Fluid rock reactions transformed unmineralised BIF to magnetite-siderite-iron silicate BIF, with subsequent desilification of the chert bands. Stage 1b hypogene involved an increase in temperature of the hydrothermal, CaCl2-rich saline (24 eq wt per cent) basinal brines (250¦ - 300¦C) resulting in formation of hematite-ankerite-magnetite-talc-chlorite alteration and the crystallisation of microplaty hematite. Late stage 1c hypogene alteration involved the interaction of low-temperature (~120¦C) basinal brines with the hematite-ankerite-magnetite mineral assemblage. At the Southern Ridge deposit this process was very intense (ie high fluid flux), therefore resulting in the almost total removal of ankerite and resulting in the increased porosity of the ore. Stage 2 supergene enrichment in the Tertiary resulted in the removal of residual ankerite and apatite and the weathering of the shale bands to clay.

Jan 1, 2005

By A K. Raina, V M. S R Murthy

Rock mass response in blasting is an important element to determine the performance of a blast along with its other outcomes. The near-field monitoring for rock mass response analysis is vital for determining the behaviour of a blast; however, due to costly and cumbersome methods involved in such measurements the subject has received scant attention so far and the publications on this account are perfunctory in nature. This paper presents a non-destructive method to monitor the blast-induced pressure in the rock mass at a distance from a blasthole. The methodology of monitoring and a few examples of actual field monitoring are detailed in this paper. The responses of the rock in the near-field of a blasthole under dynamic loading have been documented to predict fragmentation and throw. The proposed method has also been used in limited cases earlier by the author to predict flyrock using a semi-empirical method and trajectory equation. The pros and cons of the method are discussed while throwing light on the actual response and the prediction of fragmentation and throw of blasted rock.CITATION:Raina, A K and Murthy, V M S R, 2015. Measurement of blast-induced pressure in bench blasting and deciphering explosive performance through rock mass response analysis – a methodology, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 501–508 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By PHILIPP HARTLIEB, Peter Schimek, Thomas Seidl, Pablo Segarra, José A. Sanchidrián, Juan Navarro

This paper develops a new Blastability Index to assess hole-to-hole fragmentation in bench blasting based on a new Rock Factor exclusively obtained from drill-monitoring data, that can provide an automatic assessment of rock structure, strength, and waste/ore, the effective energy factor of the explosive and the delay time per blasthole.

Feb 1, 2020

By B. R. Johnston, K. D. Streeter

"ABSTRACTCoal Mountain Operations is the newest of Fording Coal’s operations although it is the oldest in terms of its historical production. In October, 1994, Fording purchased the former Corbin Creek/Byron Creek Mine. The mine is located in southeastern British Columbia, approximately 150 air kilometers from Calgary, Alberta. It was first developed in 1905 and has gone through a variety of owners in its 90-year history.This paper will deal with the remobilization strategy and the mining plans for the operation which are being implemented to make this operation competitive in the world export coal market. IntroductionIn October 1994, following a due diligence process, Fording Coal Limited purchased Coal Mountain Operations from Corbin Creek Resources, an employee group which had previously owned the mine. The purchase awarded Fording Coal Limited with 100% of the assets, and control of all the coal leases at Coal Mountain.The mine is located in southeastern British Columbia, southeast of Sparwood at the hamlet of Corbin, (Fig. 1).Rehiring of laid-off employees started in November 1994, with mining activities also recommencing in November. The coal preparation plant was restarted in December with one shift, went to two shifts in January 1995, and had four-shift, full-time operation in April 1996."

Jan 1, 1997

By Pedro Jorge Walburga Keglevich de Buzin

Steel production process generates waste, among which is the electric arc furnace dust (EAFD). This waste has varying amounts of zinc, which is principally contained in the minerals zincite (ZnO) and franklinite (Fe2ZnO4). The presence of Zn is capable of economically motivating the recycling of this residue and facilitating the co-processing of the remaining material. The zinc content in EAFD and the presence of zincite, however, have significant influence on the application of hydrometallurgical recovery processes (economic alternatives to the Waelz process). In this study, based on the computational thermodynamic tool FactSage, theoretical considerations are made on the conditions for the formation of zinc-containing minerals found in EAFD. Through thermodynamic analysis, the best conditions for obtaining a high fraction of ZnO were analyzed, which favor the hydrometallurgical processes for EAFD treatment. A classification of dust depending on the phases present in the EAFD is suggested as a guide for the feasibility analysis for the use of a hydrometallurgical process.

Jul 30, 2018

By Rongjie Kong, Shiwei Wang, Dongjiao Gui

Metal cations have significant effects on the flotation of coal and minerals. In this study, the effects of monovalent cations ( Na+ and K+) on the flotation of low-rank coal (LRC) were investigated using flotation and particle–bubble attachment experiments and through X-ray photoelectron spectroscopy (XPS) and molecular dynamics simulations. Oleic acid (OA), methyl linoleate (ML), hexadecyltrimethylammonium chloride (CTAC), ricinoleic acid (RA), and kerosene were used as flotation collectors. The flotation experiments revealed that the flotation yields of LRC improved when OA, ML, RA, CTAC, and kerosene were used in pure deionized water. However, flotation was suppressed for these collectors in the presence of K+ and Na+ ions. In contrast, when using CTAC, the flotation yield increased in the presence of these ions. Specifically, the flotation yield increased from 41.24 to 87.03% when 2.0 kg/t CTAC was used in 10 mmol/L NaCl solution. Particle–bubble adhesion experiments and XPS revealed that the hydrophilic groups of CTAC were adsorbed on the LRC surfaces by electrostatic forces, whereas the oxygen-containing functional groups of OA, ML, and RA formed hydrogen bonds with the LRC surface in pure water. Finally, the simulating result revealed that the hydrophobic ends of the OA, ML, and RA collectors hinder the flotation of LRC by adsorbing monovalent cations, whereas the adsorption of monovalent cations on the hydrophobic end of the cationic surfactant (CTAC) promotes flotation via strong electrostatic interactions.

Jan 31, 2024

By Reinaldo J. Villa, Joshua C. Adams

The I-395/SR-836/I-95 reconstruction project is an $818-million design-build construction effort that includes construction of viaduct, segmental and signature bridges in Miami leading into Miami Beach in Florida. Based on the load testing performed during the design phase, the design-build team determined that conventional driven pile and drilled shaft foundations were not feasible for support of segmental and signature bridges. Due to the weak limestone formation and successful use of auger cast-in-place (ACIP) piles in the Downtown Miami area on commercial developments, ACIP piles were selected as a foundation system to support bridges. This is the first time in history where the bridges will be supported by ACIP pile foundations in an interstate highway in the State of Florida. The design build-team worked closely with the Florida Department of Transportation to develop requirements for the load test program. The paper will provide an overview of the geotechnical data collected, results of dynamic/bi-directional load testing performed on test piles, data collected, installation of piles, and lessons learned. The load test program included a total of fifteen test piles with dynamic, bi-directional, and lateral load testing on 30 and 36-inch diameter ACIP piles and instrumented with thermal integrity profiling wires.

Sep 8, 2021

By Wilder D. Foster

In the method used in the Health Branch of the Bureau of Mines for petro-graphic identification of the minerals in a rock, the sample is crushed, ground to a fine powder in a mortar, the powder is put on a slide, a drop of index oil and a cover slip are added, and the slide is ready for examination. The rock should be ground fine enough so that most of the particles consist of only one mineral, otherwise identification is difficult. Finally, the amounts of the minerals present in the sample are estimated to the nearest 5 or 10 percent. When quartz grains are mixed with some claylike minerals) of which by far the most common example is quartz and kaolinite in a shale, grinding in a mortar does not always separate the quartz from the kaolinite; instead, the quartz grains become coated with the kaolinite and are not visible, even after careful search. Talc acts Similarly, but muscovite and pyrophyllite do not. In evaluating the possible silicosis hazard of breathing dust from a shale, it is essential to be able to see and identify all of the quartz grains, as the other minerals present are relatively innocuous.

Jan 1, 1949

By WenJun Dong

This paper presents the stability assessment of the steel pipe piles that are used to support a deadman beam to anchor an adjacent bulkhead wall. Finite element analyses are performed to assess the stability of the bulkhead wall and determine the required tie-back force to the pile. The piles are relatively close to the bulkhead wall such that their soil resistance wedge zones are not fully developed but truncated by the bulkhead wall. The reduced lateral resistance capacity of the anchor piles is determined by applying the Coulomb wedge method on the truncated soil passive zones between the pile and wall. Both the conventional soldier pile stability (in terms of force and moment equilibrium) and Winkler soil spring (for soil-pile-interaction) analyses are used to assess the stability of the anchor piles.

Sep 8, 2021

By W. W. Cummings

The Mineral King Mine, owned and operated by Sheep Creek Mines is located in the Purcell mountain range of southeastern British Columbia. Production of lead and zinc concentrates commenced in 1954 some 60 years after the initial discovery. Low cost mining methods have been employed to extract 16,0C'O tons of ore monthly from large ore bodies formed by replacement in limestone. Extensive areas in the limestone are yet to be explored and success in the search for new ore bodies is anticipated.

Jan 1, 1960

By C. C. Clark

The national Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health, Ground Control Engineering Branch is investigating the use of shotcrete in weak rock mass mines with the objective of reducing fatalities and injuries resulting from rock fall accidents. When shotcrete is used as part of a multi-element ground support system, it is necessary to know when the material has developed a compressive strength of approximately 1 MPa (145 psi), the early threshold for safe re-entry of miner and machine into shotcreted mine workings at this value, the material has developed enough strength to be self-supporting and to allow for installation of other ground support components that require drilling of the shotcrete layer without degradation. NIOSH researchers have developed methods and portable test equipment to measure shotcrete strength on site in the first six hours after application using a partial beam test standard, a STM C 116-90 (1990). These advances were demonstrated in tests with five commercially available shotcrete mixes, sprayed as dry shotcrete using field expedient methods and equipment. The strength values from these tests allowed for real-time identification of the early strength threshold and were consistent with strengths reported using laboratory-type equipment. Measuring the early strength properties of shotcrete directly at the mine site can improve mine safety by identifying appropriate re-entry times and providing a convenient means of conducting on site quality control during shotcrete applications.

Jan 1, 2011

By H. D. Hess, C. P. Mabie

This report describes in detail the results of petrographic research conducted on 21 phosphate ores representing important deposits in southwestern Montana , southeastern Idaho , and northeastern Utah . The ores are described and categorized by mineralogical and chemical composition , thermal behavior of organic carbon , and textural constitution . Descriptive and genetic classification schemes applicable to western phosphate ores are discussed ; results from related studies made of the collophane mineralogy are also presented . The latter studies were centered on determining unit - cell dimensions and CO₂ , P2O5 , and fluorine content of collophane concentrates of 11 high - grade phosphate- rock hand specimens selected solely for this purpose . On the basis of this investigation , operational methods have been developed for quantitatively describing textural and compositional features that are likely to be significant in determining the response of phosphate ores to conventional beneficiation treatments ; systems for classifying the ores in relation to these features have been proposed . Studies to date point out distinct textural and compositional variations in the western phosphates and illustrate their importance in determining optimum beneficiation procedure .

Jan 1, 1964

By J. P. Gouvea, T. R. Stacey

A research project was carried out on a gold mine in the Vaal River region of South Africa (Witwatersrand Basin) to evaluate the effect of two particular aspects of rockbolt installation – the angle of inclination of the bolt relative to the orientation of the rock surface, and the protruding length of the bolt – on the mine’s gully support system. A keyblock analysis approach indicated that these factors do not have an adverse impact on the stability of the strike gullies. This was confirmed by extensive empirical data collected from the case study mine. While safety is the primary concern, cost saving opportunities can be realized through reconsidering historically inherited support standards that are perceived to be correct and appropriate. The research described in this paper sets forth a practical approach, that is easy to implement and repeatable, to evaluate the role of rockbolts in stoping gullies.

Feb 12, 2024