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This report is the 24th in a series summarizing research on coal and related investigations3 by the Bureau of Mines. The coal programs of the Bureau of Mines include a wide range of theoretical and applied studies--such as fundamental studies of coal structure and properties, the development and evaluation of new mining techniques, and work toward more effective processing and utilization of coal. The scope of these programs is indicated, in topical outline, by the table of contents. These investigations are integrated into a broad but coordinated effort to develop information on coal that will benefit the coal mining industry and the coal consumer while promoting the wise conservation and utilization of our national coal resources. Any attempt to summarize in one volume the progress in all of the program areas indicated must necessarily be limited to a brief review of developments, without detailed reporting of the data. However, while the brief discussion in each section will present only the highlights of the Bureau's work during the year, details of many of the operations or investigations described here can be found in the publications cited throughout the text. Other work, reported here for the first time, will be covered in greater detail in later publications.

Jan 1, 1962

By TvS. von Moltke

Steel is a highly versatile material due to its low cost and good mechanical properties, but typically needs some or other form of corrosion protection due to its tendency to corrode when exposed to atmospheric conditions. In the case of organic coatings, the corrosion protection and functionality of the final product is critically dependent on the adhesion of the coating to the surface of the steel. In this work the effect of contaminants and the nature of the surface layers present on industrial steel products are investigated by means of paint adhesion tests, Auger electron spectroscopy (AES), and X-ray Photoelectron spectroscopy (XPS). It was found that the presence of sodium species on the surface is very detrimental to paint adhesion under wet conditions, while satisfactory adhesion may be obtained even in the presence of silicon and carbon residues. It was also found that the nature of the Fe-O layer, formed under wet conditions is labile and different from that formed in dry air, and that subtle changes in process conditions, such as changing the oxygen content of the quench water, may change the adhesion of paint to the surface of the steel. Lewis acid-base interactions are discussed as a mechanism that may determine the bonding between the steel and polymer coating.

Jan 1, 2003

Lime and Marble Limited was founded by the late T J McKee OBE and his family in 1935. The Company had its base in the high grade marble deposits on Takaka Hill, and was also shipping crushed limestone to the Auckland glass works, and supplying burnt lime for industry.

Jan 1, 1998

By Alexander Filotti, Stanley Merjan

"Abstract. The paper shows the benefits and accomplishments of this relatively new but established product on the pile foundations market in the United States. The first part of the paper describes general aspects of the design, construction, and geotechnical capacity (designed and in situ) of Tapertube piles. The qualities resulting from the design and manufacturing of the Tapertube pile will be presented first.The second part of the paper describes the installation of Tapertube piles for an addition to Terminal One at JFK International Airport and The Edge development. A carbon print analysis for both projects is developed using the EFFC-DFI carbon print calculator. For the JFK project the benefits of using BIM in redesigning the project for Tapertube piles are explored.General description.The tapertube pile consists of a tapered tubular bottom section attached to a conventional pipe extension. The 50 ksi steel for the taper is mechanically folded into a polygonal cross-section (usually 12-sided) with a longitudinal welded seam. The tapers are fabricated in many sizes with bottom diameters varying from 8 to 14 inches, top diameters from 12 to 20 inches, lengths from 10 to 35 feet, and steel thicknesses from 3/16 to 1/2 inch. A conical steel shoe or a flat plate is welded to the bottom of the taper and the top of the taper is circularized to match the outside diameter of the pipe extension. The inclination of the tapers is generally between 1.5% and 2.5%.The pipe extension is fully butt welded to the taper and has the necessary length for the pile to develop the requisite capacity. Concrete fill for the piles is generally 4,000 p.s.i. or more. Typically the piles are shopassembled and shipped to jobsites in lengths to 80 feet."

Jan 1, 2014

Provide improved permanent stoppings designed specifically for use in mines with large cross-sectional entries. Approach The large entry sizes in many mines, such as oil shale, salt, and limestone, make the conventional stopping construction techniques used in smaller opening mines unacceptable. The Bureau of Mines and Colorado Mining Association jointly sponsored a contract to design and test new or modified stopping concepts for these mines. The most promising concepts were then tested in an oil-shale mine having 30-foot-high by 55-foot-wide mine entry openings. All stopping designs tested were evaluated in terms of cost, air tightness, and resistance to blast damage.

Jan 1, 1987

By I. J. Brown

Paper prepared for presentation at Industrial minerals and the environment, held in Leeds, 24-35 September 1990. The need to submit an environmental statement (EIS) has certainly increased the workload of those concerned with both its production and assessment. However, there is now good evidence that the system is enhancing public confidence in the minerals industry in particular and improving relationships between the developer, planning authority and those consulted such as statutory bodies, parish councils, civic societies, nature conservation interests and ramblers

Jan 1, 1991

In the course of work being carried out in the Lubricants and Bearings Section of the Council lor Scientific and Industrial Research on the production of copper4ead 'bearings for 'use in aircraft, it has been found necessary to develop special metallographic methods. For proper control of the production of steel-backed copper-lead bearings it is necessary to adhere to rigidly controlled conditions, and it is essential that a method of examination be adopted which will readily detect actual defects or any variations in quality. Some defects can be observed with the naked eye, whilst others are detected by radiographic examination. This latter method is invaluable as a rapid, reliable test in the production of aircraft bearings, but it is necessary to observe the structure of the alloys under the microscope, both to be able to interpret the radiograph correctly and to determine what has occurred to the metal during and after solidification. The use of a sound metallographic technique is'particularly important in developmental work and research connected with these bearings.Polishing TechniqueCopper and lead are practically immiscible in the solid state, but whilst they are miscible only in certain limited proportions in the liquid state; consequently "alloys" of copper and lead consist of a mixture of the constituent metals. The metallographic difficulties are obvious. Copper is a relatively tough metal, although it readily scratches, whilst lead is extremely soft and easily deformed. It wouId be expected if any normal polishing technique were applied that the lead would be readily torn out of the surface being prepared, and, in addition, that the lead would tarnish very easily.Grange(2) has described a method by which these difficulties can be overcome. The method involves an etch-polish procedure using "chrome regia" as an etchant for the copper. The chrome regia was a solution of chromium trioxide and hydrochloric acid in water. This type of etchant has been adopted, but it was found necessary to make certain changes.The method now adopted in this laboratory is as follows: The specimen (which is usually mounted in bakelite) is wet ground in a series of successively finer Hydro-Durexsil emery papers down to 60.0· grit paper.The specimen is then etched in the chrome regis, etchant (the composition of this etchant will pe discussed later) for approximately five seconds.Most efficient etching is obtained by swabbing the surface of the specimen...

Jan 1, 1944

By James R. Wait

The present final report constitutes the total productivity of a series of contracts from the U.S. Bureau of Mines and the Institute for Telecommunication Sciences over the period 1971-1979. The emphasis on the research has been analytical. In this "executive summary" we give a succinct description of each phase of the investigation. In the first phase of the investigation that was stimulated by the National Academy of Engineering, we concentrated on the analytical studies of techniques relevant to mine rescue. Several specific procedures for locating a buried source were analyzed. In the next, but overlapping phase of the investigation, we dealt with the fundemental character of how electromagnetic waves propagate in mine tunnels. At the outset we allowed for the finite conductivity of the tunnel walls and the presence of axial conductors such as cables, pipes, and tracks. The third phase of the investigation was devoted to the analyses of various specific geophysical engineering problems. The related fourth phase dealt with the general subject of non-destructive testing of wire ropes such as used for mine hoists.

Jan 1, 1980

By Paul Miranda, Corby Anderson

"The Center for Advanced Mineral and Metallurgical Processing (CAMP) has recently obtained a Mineral Liberation Analyzer (MLA). CAMP has utilized the technology for several projects with excellent results. The MLA is able to both analyze size and quantify mineral phases. Therefore, the MLA is becoming the Sherlock Holmes of the mining and metallurgical industry. For this presentation, four projects have been evaluated and data was collected using the MLA. The first project involved tungsten mine. Previous mining practices have yielded poor tungsten results and recoveries. By using the MLA, tungsten mineral phases, along with possible contaminants, were verified and the results used to try to increase overall tungsten recoveries. The second project evaluated a molybdenite/chalcopyrite concentrate with surprising results. The third project is a silver project. Initial flotation scoping tests were performed by attempting to separate silver from gangue material. Because of the poor recovery results (less than 5%), MLA was used to determine possible scenarios for increasing silver recovery. Finally, the last project involves gold evaluation in tailings. For all projects, MLA application results will be presentedand discussed.INTRODUCTIONThe Center for Advanced Mineral and Metallurgical Processing (CAMP) has recently received a software add-on to a scanning electron microscope (SEM) located at Montana Tech. The Mineral Liberation Analyzer (MLA) technology was developed by Dr. Ying Gu of the JKTech Center of the University of Queensland. Since August 2006, CAMP has received and processed over 50 samples. These samples include a total mineralogy of tungsten ore samples, gold tailings, lead zinc tailings pile, molybdenite concentrates, copper concentrates, as well as others. During analysis of these received samples, the technology allows the samples to be quantified mineralogically with some surprising results.For analysis, the samples were initially sieved between 170 to 200 screen sized mesh. This ensures that received samples mineral size is fairly uniform. The samples are then placed into epoxy and allowed to harden. Next, the samples are polished and carbon coated for MLA analysis."

Jan 1, 2007

By S. Jennings

The Red Dog zinc-lead-silver deposit is located in the DeLong Mountains of the western Brooks Range in northwest Alaska. The region is located 145 km(90 miles) north of the village of Kotzebue (Fig. 1).Red Dog’s current resource base is 143 Mt (157 million st) averaging 16.1% zinc, 4.3% lead and 83g/t (2.4 oz/st) silver. It is contained in four structurally separate deposits— the Hilltop, Main Deposit, Aqqaluk and the newly discovered Paalaaq deposit. Recent exploration for the Aqqaluk and the Paalaaq deposits has contributed to Cominco American’s understanding of the detailed structural geology of the district and its role in the placement of individual ore bodies.

Jan 1, 1999

By M. I. Brittan

Cyanide leaching of two West African gold ores was studied in multiple laboratories to provide process-engineering data for plant design purposes. Unusually slow leach extraction kinetics were observed using routine cyanide leach test procedures with pregnant solution monitoring. Carbon-in-leach testing, however, showed normal rapid kinetic behavior, with the same ultimate gold extractions being reached in much shorter elapsed times. Kinetic curves based on washed solids assays also exhibited more typical leaching characteristics. The results bore all the hallmarks of some equilibrium inhibition of the leaching. It was surmised that ore gangue components were responsible for weakly adsorbing gold-cyanide complex reaction product, thereby holding up soluble gold in the solid phase. The term ?preg-borrowing? was coined to describe the reversible phenomenon and distinguish it from irreversible preg-robbing. The two ores investigated may represent an extreme form of a more general effect that in most instances might pass unnoticed. The effect can lead to misinterpretation of kinetic leach curve data and underestimation of calculated ore head grades.

Jan 1, 2008

By Michael A. Piepenburg

The East Side Access (ESA) Project will extend Long Island Rail Road (LIRR) into midtown Manhattan via 11 km of tunnels, a new terminal station and associated support facilities. In addition to the hard-rock tunneling currently underway in Manhattan, soft-ground tunnels in Queens will traverse beneath Amtrak?s Sunnyside Yard and Harold Interlocking, the busiest rail interlocking in North America. This paper details ESA?s coordinated approach to interfacing with both Amtrak and LIRR with regard to the planned tunnels, shafts and related construction beneath or adjacent to the operating railroads. This interface includes integration of railroad staff, extensive presentations, reviews and agreements with the railroads regarding settlement mitigation, real-time automated geo-instrumentation monitoring, ground improvement, and geotechnical/environmental controls.

By James Westfield

Drilling for roof bolting has created a new dust problem for the coal-mining industry. Drilling is inherently dusty, and control of dust produced by drilling vertical or nearly vertical holes is much more difficult than control of that produced by drilling flat or down holes.4/ Also, the dust produced by roof drilling differs in composition from that produced by drill-fur, or cutting the coal face because it contains a significantly greater amount of free silica and therefore presents a greater potential hazard of silicosis. Roof bolting has been practiced successfully in the mines of the St. Joseph Lead Co. in southeastern Missouri for over 20 years, but it was not until 1947 and 1948 that large-scale roof-bolting experiments were conducted in coal mines.5/ Although the need for dust control in conjunction with roof drilling was recognized from the beginning, the development and acceptance of roof bolting progressed so rapidly during 1949 and 1950 that solution of the dust problem lagged behind other engineering phases of the technique.

Jan 1, 1951

By P Clark, P A. Kirsch, R Tapia Rivera

Community members’ sources of information about companies’ social investments are often influenced by the messages in a variety of communication channels, such as newspapers, television and social media. In this sea of communication channels, corporate communications may not always have the desired effect in influencing community perceptions. This paper explores the efficacy of communication between mining companies and communities in Chile through content analysis of corporate sustainability reports and newspaper reporting.Chilean media reporting between 2005 and 2013 is examined to identify community perceptions of corporate social investments made by mining companies. Content within the Chilean newspapers El Mercurio (national) and Soy Chile (regional) is contrasted with content from corporate sustainability reports published by The National Copper Corporation of Chile (Codelco) and Barrick Gold Corporation, Canada (Barrick) for the same period. The objective is to identify differences in the way that corporate social investments are reported by companies in sustainable development reporting and by media in newspapers.Overall, the study demonstrates that the media’s framing and reporting of corporate activities was more negative than positive. Moreover, media outlets tended to focus upon the ‘negative impacts’ or ‘damage’ to communities brought about by mining developments. Conversely, companies’ public communications were largely focused upon direct improvements in livelihoods (health, education, etc) of neighbouring communities. This preliminary study provides a baseline for the development of new formats of effective communication with neighbouring communities. The paper advocates for an increase in participatory mechanisms with affected parties, which could lead towards a greater mutual understanding of the impacts and draw parties closer together.CITATION:Tapia Rivera, R, Kirsch, P A and Clark, P, 2014. Challenging Perceptions? Sustainability Reporting, the Media and Mining, in Proceedings Life-of-Mine 2014 , pp 413–426 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By S. Read, G. Cook

The Hoek-Brown failure criterion is often applied to a wider range of rocks than the isotropic rock masses to which it is strictly applicable. This paper evaluates the patterns of defects in rock masses using spherical projection contour plots of samples of randomly-generated orientations and datasets from mapping of New Zealand closely-jointed greywacke rock masses. Two indices from the contour plots - the area within the 1% contour (A1%) and maximum concentration (Cmax) are introduced for distinguishing uniform (isotropic), random or regular defect patterns. The indices provide a potential extension to current guidelines on the use of the Hoek-Brown failure criterion. The paper also outlines kinematic checks to assess the influence of defect clusters on rock mass strength. Das Hoek-Brown Bruchkriterium, das strikte nur fuer isotrope Gefuege gilt, findet oft einen viel weiteren Anwendungsbereich. Diese Arbeit bewertet diverse Dispersionsmuster der Defekte einer Gesteinsmasse. Wir vergleichen in sphaerischer Projektion (1) Beispiele zufaelliger Orientierung von Defekten und (2) Felddaten ueber neuseelaendisache engstaendig geklueftete Grauwacken. Die Projektionen werden durch die Indices A1% (Flaechenanteil des 1%-Bereichs) and Cmax (Hoechstkonzentration) gekennzeichnet, welche isotrope, zufaellige und regulaere Muster unterscheiden und die aktuellen Richtlinien zum Hoek-Brown Kriterium ergaenzen. Wir testen ferner Defektgruppen der Gesteine kinematisch auf ihren Einfluss auf Massenfestigkeit. Le critère de rupture de Hoek-Brown est souvent utilisé sur une variété de roches plus étendue que les masses rocheuses auxquelles il est strictement applicable. Ce travail évalue la distribution des défauts au sein d'une masse rocheuse en utilisant une projection sphérique des contours d'échantillons d'orientations générées aléatoirement et de données de cartographie provenant de greywackes à joints rapprochés de Nouvelle Zélande. Deux indices de cette projection - la zone des contours en dessous de 1 % (A1%) et celle de concentration maximum (Cmax) sont introduites pour distinguer les répartitions uniformes (isotropes), aléatoires ou régulières. Ces indices fournissent une extension potentielle aux règles d'utilisation du critère de rupture de Hoek-Brown. Ce travail utilisent également les contrôles cinématiques pour évaluer l'influence des groupes de défauts sur la résistance de la masse rocheuse.

Jan 1, 2003

By H. R. Cooper

Beginning from the point of view that process control of ore flotation can be approached by on-line analysis of processing behavior, an equation was developed which has characteristics useful for a multi-variable feedback loop. The application of this equation to optimizing control with a data acquisition system will be discussed in Part 11. OBJECTIVE OF CONTROL The purpose of developing a feedback method for concentrator control is to provide a means for determining ore processing behavior in order that data describing the ore can be used to make appropriate changes in control conditions while the ore continues to flow through the flotation circuit. In absence of simple linear relationships between pairs of variables in the flotation process, attention is directed to the need for a generalized relationship which possibly would incorporate all pertinent variables. It would be possible to apply such an equation to the control of variables in a concentrator in real time according to operational requirements as ore gradually changes in quality and processing behavior. To meet this objective, it is necessary to define relationships describing flotation performance in terms of performance variables capable of being measured on-line, either with on-line instruments and analyzers or with manual methods lending themselves to quick determination of meaningful information. Relationships derived to meet this objective form a model for the flotation process. The evaluation of flotation parameters of the ore and the execution of control on the basis of the derived information while the ore is continuing through the process would constitute a feedback control system. Data for the following control and performance variables can be made available: 1) ore feed rate, 2) collector addition rate, 3) lime addition rate, 4) pulp density, 5) assay or multiple assays in feed, tails, or concentrate sufficient for material balancing, 6) particle size distribution in flotation feed, 7) froth height, and 8) frother addition rate. Other process variables, such as flotation air input and mechanical agitation intensity, are usually not considered as control variables and were not taken into account in this analysis. Other data, such as that describing the ore, would be useful for concentrator process control. However, information of this type (such as ore hardness, grain size of the mineral, chemical species of the mineral, and ore surface properties) being not presently measurable in the on-line sense, has the effect of causing disturbances in the system which can be detected only indirectly. The process control system being sought must recognize disturbances by their effect on measured performance followed by determining control changes to compensate for them in meeting the objectives of improved performance (perhaps higher throughput, maximum return, etc.). A suitable model for the process having capability of recognizing the effects of ore disturbances should provide the means for introducing proper compensation through control changes. This would be done by processing on-line data with the model to calculate coefficients reflecting ore characteristics. This procedure can only be applied in a typical flotation system when on-line data can be processed at faster rates than the usual rate at which the ore in flotation feed takes on significantly different characteristics. For example, material balance data can be accumulated in approximately 5-min intervals using on-line X-ray fluorescence analysis. The flotation system time constant might be 15 min including grinding. Ore changes having time constants longer than 1 hr could be accommodated using on-line feedback control by this procedure. FORM OF A FLOTATION MODEL A suitable form for mathematical expression of the flotation process is an equation involving rates, when each of the components entering into the separation can be treated independently by a rate equation. A first-order, kinetic rate equation can be written on

Jan 1, 1967

By J. Drelich, J. Pletka

Lost foam casting patterns are foamed polystyrene shapes glued together into the shape of the part to be cast and are coated with a refractory material consisting of a mineral mixture and binders. Prior to casting, a significant number of the patterns are damaged and inevitably land-filled. In this study, a process is developed for the recovery of foamed polystyrene from the coating and glue contaminants. The process consists of shredding, impact comminution, size classification and density separation. It is successful in separating up to 97% of the contaminants, while recovering 95% of the polystyrene.

Jan 1, 2001

By Magued G. Iskander

The deterioration of concrete, steel, and timber is a serious hindrance to construction in marine and corrosive environments. Composite materials such as fiber-reinforced polymers (FRP) can offer performance advantages for construction in these environments. In the last decade, piling made of FRP composites has been used experimentally throughout North America. However, composites face obstacles because they do not have a long track-record of use in civil engineering structures. A comprehensive review of the current experience in research, testing, design, and practice of composite piling is presented in this paper.

Jan 1, 2002

By Mohammad Djavid

The one-pass tunneling pipe jacking method has often been the most schedule and cost efficient method for the pipe line installation. The main challenges in jacking pipes larger than 108 inches and for longer runs are: transportation and logistics, requiring high jacking forces, keeping line and grades, control of ground surface settlement, providing adequate external lubrication, and the potential of damaging the joints and pipe spigots. In recent years, 144" diameter pipes have been jacked for short runs of up to only 300 feet. In this article design and construction of installation of up to 1,000 linear feet run of 144-inch internal diameter, reinforced concrete pipes without intermediate jacking station in Chicago O?Hare International Airport are discussed. The article also presents discussions regarding the subsurface saturated silt formation, shallow cover, dewatering, jacking and receiving shafts, jacking forces, lubrication and settlement data.

Jan 1, 2008

By Y. M. Jiang

A users friendly PC Computer Program has been developed to implement a systematic design of the powered support. The required input data are: (1) thickness, RQD, and compressive strength of the immediate roof; (2) mining height; and (3) type, thickness, and tensile strength of the main roof. Several important parameters for support selection under a given geological condition are generated through the implementation of the program, including type of support most favorable for the geologic condition, minimum inclination angle of the legs with respect to the horizontal axis, suitable setting load ratio of the front to rear leg for the 4-leg supports, optimum setting load, and support capacity.

Jan 1, 1989