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By J. S. Dunning

One Federal Bureau of Mines research goal, to minimize requirements for domestically scarce mineral commodities through conservation and substitution, can be accomplished by utilizing more abundant elements such as iron, molybdenum, and titanium. An example of this research is the study of precipitation-hardening, iron-base alloys containing molybdenum and titanium, as substitutes for the high-tonnage stainless steels that are high in imported nickel and chromium. The precipitation hardened iron-base alloys are strengthened by a dispersion of the ternary Laves phase, Fe2 (Mo, Ti). Aluminum and chromium additions changed the solid solubility limits of molybdenum and titanium in a-iron and affected the composition of precipitating phases. A baseline composition of Fe-7Mo-2Ti was selected to study the effects of aluminum and chromium additions on the precipitation-hardening mechanism and microstructure and was also used in studies of mechanical properties and oxidation resistance. The study yielded workable, precipitation-hardening alloys, with elevated temperature strengths equivalent to or superior to types 304 and 316 stainless steels. Chromium and aluminum additions in combination were more effective in providing oxidation resistance than either addition was alone.

Jan 1, 1980

By Z X. Zhang

Ground vibrations from the blasts of the LKAB mine at the Malmberget town had reached 18-19 mm/s from year 2000 to 2002. From 2004 to 2010 the maximum vibrations had been reduced to 9 mm/s and most vibrations lowered to about 5 mm/s, indicating that the technical measures used in the mine are effective in vibration control. The major measure that has always been used in Malmberget mine is the method called Changing Initiation Sequence (CIS in short). Another method named Dividing Ring Blasting (DRB in short) is often applied to some special blast rings in the mine. Both methods have been proved to be successful in vibration reduction, and they do not need any additional costs. Because of the two methods, both maximum vibrations and average ones have been reduced by around 50% since 2004.

Jan 1, 2012

By Masaki Kitazume, Yoshiaki Kikuchi

"Abstract Pile foundation is one of fundamental techniques to improve the bearing capacity and settlement characteristics of superstructures. Wide varieties of piles having various shape, size and material were developed and have been applied to a lot of construction projects throughout the world. The deep mixing method, an in-situ admixture stabilization method, was developed in 1970s in Japan and the European countries, and has been frequently applied to many construction projects for various improvement purposes such as increasing bearing capacity and horizontal resistance, reducing ground settlement, preventing liquefaction and so on. The design methods, execution procedure and quality control and assurance (QC/QA) of the method are standardized or specified in many countries. These standards, specification and/or technical manual have been a remarkable contribution to spread the techniques throughout the world. The QC/QA is one of the major concerns for clients and engineers who have poor or no experience of the technologies. In order to assure the high quality of deep mixing work in the global market, it is necessary to establish the concept of QC/QA and correlate the output of different procedures. Upon the request by the organizing committee of the DFI-EFFC International Conference on Piling & Deep Foundations, the authors conducted survey of the specifications and standards on the piling and deep mixing technologies in Asian countries. In this manuscript, the results of survey are briefly introduced by comparing these specifications and standards.IntroductionThe pile foundation is one of fundamental techniques to improve the bearing capacity and settlement characteristics of superstructures. Wide varieties of piles having various shape, size and material were developed and have been applied to a lot of construction projects throughout the world. The design method, execution procedure and quality control and assurance of pile foundations are standardized in many countries based on the accumulate research results, laboratory and field experiences. In Japan, steel pipe piles are mainly constructed by hammer driven in port construction. On the other hand, precast pre-stressed concrete piles or cast-in-place piles are mainly used in on land construction. When precast pre-stressed concrete piles are constructed, piles are usually set by inner excavation method because of preventing noise and vibration problems. More than 50 years ago, noise and vibration problems had not been serious problem in Japan, but around 50 years ago, they became serious and now less noise and vibration construction methods are used for pile construction on land in Japan. In Asian countries, though piles used for construction have a lot of variety, precast pre-stressed piles are commonly used. In this report, execution controls of construction methods of steel pipe piles and precast concrete piles are mainly considered."

Jan 1, 2014

By M. Reza Saberi, T. Ted Miyake

Driven piles are a common tool in any engineer’s toolbox for supporting large structures over very soft ground, especially in high seismic risk zones. Challenges include achieving sufficient vertical and lateral load capacities within the constraints of pile spacing and geologic conditions. This was the case for a project in Orange County, California with a state-of-the-art, $180 million plant for biosolids processing, biogas management and energy recovery located in marshland next to an existing waste water treatment plant. The new construction for the Irvine Ranch Water District included a 70-foot (21 m) tall building and three closely spaced, 90-foot (27 m) high, 65-foot (20 m) diameter, egg-shaped steel digester tanks. The lower 35-feet (11 m) of the tanks were constructed below ground level. The site was underlain by up to 45 feet (14 m) of highly compressible peat and organic clays with standard penetration test (SPT) blows as low as 2 blows/ft (30 cm). Some of the peat layers had measured in-situ dry densities of less than 30 pcf (480 kg/m3) with moisture contents of over 250 percent. The soft clays and peat were underlain by a dense layer of sand and gravel at depth. Groundwater was very shallow. While nearby sites were designated by others as seismic site class “D”, this site was clearly class “F” (SF) which required site specific seismic hazard and time history analyses. Six recorded time histories were selected from the 1994 Northridge, 1989 Loma Prieta (California) and 1999 Chi Chi (Taiwan) earthquakes for the ground motion analysis considering the magnitude of the earthquake, distance to the source, characteristics of the earthquake source (i.e. type of fault displacement), peak ground acceleration, local site geology, station type (i.e. free-field or small structure stations), and spectral content that was similar to the period range of interest. Following ASCE’s Guideline Document 7-05, a site-specific horizontal acceleration response spectra (ARS) was developed for the maximum credible earthquake (MCE) associated with the site.

Jan 1, 2018

By Keith L. Harris

The performance of the world economy improved significantly in 1984. Real world output!/ grew 4.3% (compared with 2.6% in 19831, the highest since the 4.4% increase recorded in 1978 (table 1). The output of industrial nations rose 4.9%, while that of the developing nations rose 3.7%. The United States and Japan had the largest increases in output of the major industrial nations, with respective increases of 6.8% and 5.8% (table 2). The components of real output with the most significant growth in the industrial countries were gross fixed investment (9.2%), consumer expenditure (3.1%), and public consumption (2.5%) (table 1). Industrial output, as measured by industrial production indices, has returned to about the 1980 level for most of the major industrial nations (table 2). Exceptions to this were industrial production in Japan and the United States; Japan's industrial production rose steadily throughout the 5-yr period and is now more than 16% above the 1980 level, and the industrial production index for the United States reached 11 1.2 (1980=100.0). Real total domestic demand grew at 8.7% in the United States, more than double the rate of Japan, which, at 4.0%, had the second-largest growth. Average demand for all industrial countries was up 5.1%. During 1984 the U.S. dollar showed great strength on international markets, contributing to large current-dollar negative net exports of goods and services and even larger negative net exports of the merchandise sector. While growing U.S. imports helped spread the benefits of the recovery, they also led to a widening of current account imbalances and growing trade tensions throughout the world.3/, 4/

Jan 1, 1985

By Sushil Bhandari, S. S. Rathore

Controlled drilling and blasting continue to be an important method of block production and for block splitting. Drill and blast technique has disadvantage that sometimes, it produces cracks in uncontrolled manner and also produces micro cracks in the block as well as in remaining rock, if not carefully carried out. Recovery by this method is low compared to other methods. Therefore, attempts have continued to develop controlled growth of crack in desired direction. In this paper a series of tests are described using detonating fuse in marble. Economics of different methods is also compared. In comparison to conventional use when holes are lined with inexpensive cardboard or plastic liners with a slit, the cost and damage is the least and development of crack is in desired direction.

Jan 1, 2002

By Brad McBain

Agenda ? Accurassay Laboratories and Automation ? History and experience ? Features and benefits of automation in the lab ? Tata Steel Minerals Canada (TSMC) Iron Ore Laboratory ? State-of-the art systems and design ? The integration of fusion systems and XRF units ? Meeting deliverables: quality, reliability, safety

Aug 1, 2013

By . Jaime G Tapia Aguirre

La Unidad Minera Rosaura del Grupo Glencore fue considerada la mina subterránea más segura del país durante los años 2005, 2006 y 2007. Sin embargo, cuando el Grupo Glencore adquirió la concesión de Rosaura, el panorama minero era de una mina marginal, de bajas leyes. Por esta razón, el único metodo a ejecutar para hacer de Rosaura una mina rentable era el de utilizar un método masivo. Em ese semtido, el presente texto señala la operación de mina cone el análisis y conocimiento de causa raíz en la prevención de caída de roca.

Sep 12, 2011

By S. Narasimha Rao

Bored cast in situ piles are highly susceptible to construction defects like necking, discontinuity in concreting, poor compaction of concrete, improper end bearing condition due to inadequate cleaning of bore hole, exposure of reinforcement, segregation of concrete etc. There is a necessity to understand the behavior of piles so as to design effective foundation system. In this paper investigations of two field cases were discussed to bring out the effect of defective piles. In one case improper end bearing has been discussed for a concrete pile of length of 45m and diameter equal to 1.2 m and is reinforced with 32 no's of 28mm diameter steel bars and in another case necking of the pile has been discussed. Further model piles with preformed defects have been tested in laboratory to bring out the influence of defective piles.

Jan 1, 1996

By John K. Alley

Despite the extensive use of fluorphlogopite, investigators do not agree as to its exact melting temperature. Data on other fluormicas and on related fluorsilicate systems are largely nonexistent. A knowledge of the melting temperature is necessary for the effective synthesis and use of fluorphlogo¬pite or other fluormicas. The increasing use of two- and three-mica systems to yield polycrystalline ceramics has made more urgent the need for melting temperature information concerning these other fluormicas. This report is part of a program by the Bureau of Mines to synthesize large-size or large-crystal fluorphlogopite and develop a usable reconstituted fluormica sheet. The melting temperature of fluorphlogopite, K2Mg6A12Si6020F4, was found to be 1,383° ±2° C. This temperature was found by studying single crystals of fluorphlogopite, heating behavior of glass of fluorphlogopite composition, and the actual crystallization of fluorphlogopite from a melt that had been heated above 1,430° C. The formation of forsterite or norbergite was directly proportional to the loss of volatiles during the experimentation. Many trials revealed that the only reliable seal was a thick platinum sheet with welded seams. If no volatiles were lost, neither norbergite nor forsterite were formed; fluormica was then the only product. Excellently formed crystals of forsterite with an optical sign different from ordinary forsterite were obtained during the single crystal melting experiments. These crystals resulted from a slow loss of volatiles. A congruent melting of fluorphlogopite is indicated by the data of this report; however, incongruency within a small temperature range is not precluded. A more refined method using phase equilibria-quench methods would be necessary to settle the question absolutely.

Jan 1, 1962

By D. E. Wolfson

As a part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report.2/ The inherent suitability of coal for metallurgical use depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, as well as the available reserves, are considered in selecting coals for carbonization tests. According to the estimate of reserves by Dowd,3/ the recoverable coal in Floyd County in beds 28 inches or more thick, in thousand tons, is as follows: [ ]

Jan 1, 1958

By K. M. Phamotse, A. S. Nhleko

"*Paper written on project work carried out in partial fulfilment of BSc (Mining Engineering) degreeSynopsisLiqhobong Mining Development Company (LMDC) has been experiencing problems with boulders after blasting where the fragment sizes exceed the maximum of 800 mm as per mine standard. As a result, the mine has employed various methods to improve the fragmentation. The goal is to produce a run-of-mine (ROM) feed that does not choke the crusher and cause delays in production. In order to achieve this goal, fragmentation distribution within the fines and coarse envelope must be optimized through effective planning of blasting activities and accurate execution.The mine determined the fines-coarse envelope within which the entire crushing system can handle fragments using Split Desktop software. It is expected that both the predicted and actual fragmentation curves lie within that envelope for optimal fragmentation. The Kuz-Ram model with blast design parameters of 2.6 m for burden, 2.8 m for spacing, and 127 mm hole diameter was used to predict the fragmentation. The results show that the blast design parameters may need altering to achieve optimum fragmentation. Furthermore, the execution of the drilling and blasting may be the cause of the fragmentation problems. The mean fragmentation size (X50) differs greatly, unlike the uniformity index (n)s values which are relatively close to each other (0.6 to 2.2). The mean squared error (MSE) values have a large range. A proposed solution is a modified burden, spacing, and hole diameter. It is concluded that blast design parameters need to be reviewed in order to obtain correct predictions. IntroductionFragmentation has an impact on the mine production cycle which comprises, inter alia, drilling, blasting, loading, hauling, and crushing. Correct fragmentation as set by the plant design is important as it reduces the time lost due to secondary blasting and/or loading difficulties. In this paper we analyse blast results at Liqhobong Mining Development Company (LMDC) in Lesotho for a period of six months. This project was undertaken to observe the trends from the blasts and to identify whether any discrepancies exist in the overall blast information. The period under study included 16 blasts."

Jul 1, 2019

By Afrânio Márcio Costa

Placas lingotadas continuamente, não obstante atendam a requisitos como composição química, conteúdo de inclusões, aspectos macro e micrográficos, podem ser desclassificadas por falta de conformidade dimensional. Contrações térmicas, de solidificação e de transformações de fases são partes intrínsecas do processo e são afetadas por alterações na taxa de extração de energia da placa durante o processo. Este conjunto de contrações determina o Fator de Contração de operação, o qual é utilizado para determinar as dimensões do molde que irão resultar na largura especificada, onde o presente estudo determinará o fator de contração dos aços peritéticos. As variáveis identificadas que influenciam no fluxo de calor primário foram: frequência de oscilação, superaquecimento, velocidade de lingotamento e viscosidade do pó fluxante. Identificou-se que o resfriamento secundário e a conicidade utilizado no molde, também são critérios determinantes para obtenção de larguras especificadas. Assim sendo, uma equação de regressão foi desenvolvida para o Fator de Contração.

Aug 17, 2017

By John R. Hawley

"This paper is intended as a review of the progress that has been made in the Province of Ontario in the field of acid drainage waste treatment technology.Three years ago, at the Third Annual Meeting of the Canadian Mineral Processors, we presented a paper entitled ""The Problem of Acid Mine Drainage in Ontario"". At that time I was working for the Ontario Water Resources Commission. The paper turned out to be the very beginning of the Commission's acid mine drainage control program. In the intervening three years, the Ontario Water Resources Commission has been amalgamated with other government groups and has evolved into the present Ontario Ministry of the Environment. Today the Ministry is involved in running one of the most advanced acid mine waste control programs in the world.As a part of its mining program, the Ontario Ministry of the Environment has published three major reports which deal directly and specifically with the industrial waste disposal problems that may arise at a mining operation. In order of publication, these reports are as follows:(1) ""The Problem of Acid Mine Drainage in the Province of Ontario"".This 338-page report covers all aspects of the problem of acid mine drainage and includes detailed sections on acid flow detection, acid flow chemistry and acid flow treatment.(2) ""The Use, Characteristics and Toxicity of Mine-Mill Reagents in the Province of Ontario"".This report, 244 pages in length, gives the chemistry and toxicity of nearly all of the chemicals that find common use in the Canadian mining industry. Most of the toxicity figures quoted are the result of a comprehensive bioassay program that was initiated by the Ministry."

Jan 1, 1974

By R. V. Ramani

This report is volume 10 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation, and ventilation. This volume of the final report describes the Ventilation subsystem of the Master Design Simulator. The Ventilation subsystem has the capabilities to handle: (1) branches in parallel or series, (2) fans in parallel or series, (3) multiple fans, (4) methane, compressed air, or other injections into the system, (5) leakages and fixed quantities, and (6) calculations of absolute pressure at nodes. The program uses the Kirchoff's Junction and mesh laws, and the Hardy-Cross iterative technique to converge to the desired accuracy in solving fox the head quantity. A case study is included in the report illustrating the use of the model. The appendices of the report constitute a user's manual for the Ventilation subsystem, and include a program listing.

Jan 1, 1975

Ontario Operaations Mining Garson Stobie Copper Cliff North Copper Cliff South Creighton Mcreedy East Milling Clarabelle Mill Smelting Smelter Matte Processing Anode Casting Refining Copper Cliff Nickel Refinery Port Colborne Cobalt Refinery

May 1, 2007

By R Lastra, J. A. Finch

An artificial standard material has been developed and used to examine the robustness of some of the procedures for correcting stereological bias. Different mineral liberation distributions were constructed from the standard material. The particles were mounted, sectioned and the sectioning data measured with an electron microscope interfaced to an image analyser. Four correction procedures were used and the corrected and true liberation distributions compared. It was found that the large-sections correction provided a simple, uncorrupted correction. Hill's fast approximation performed well except in cases of narrow liberation distributions; the sectioning data appeared to support the assumption that the locked section and locked particle distributions are identical. Barbery's correction performed well in most cases, having difficulty only with the very irregular liberation distribution. The PARGEN correction was able to provide a good estimate of the true amount of free material, but had difficulty in predicting the locked particle distribution

Jun 21, 1905

The history of the industry which recovers rutile and zircon from the heavy mineral beach sand deposits of Eastern Australia began with the initial discovery of zircon in 1895. Whereas a large number of small companies operated during the rutile boom of 1955-57, the industry is now controlled by a few large groups.Mining is mainly by suction dredging. Metallurgical practice is a two-stage process in which a bulk concentrate of heavy minerals, recovered by gravity methods, is separated into its constituent minerals by processes based mainly on surface, electrical, and magnetic properties.Various separating devices using these principles have been developed in the industry and combined in various ways in the operating plants.There is scope for future metallurgical developments.INTRODUCTIONThe existence of deposits of heavy minerals ("black sands") on the northern coast of New South Wales has been known for at least 90 years. The earliest metallurgical operations aimed at the recovery of gold, platinum, tin and monazite. Mainly because of the low grade of these deposits with respect to these minerals, but also due to metallurgical difficulties, such operations were abandoned by about 1895 (Whitworth, 1959). The presence of zircon was recorded quite early (Carne, 1895) but Raggatt (1925) appears to have been the first to report the presence of rutile.The economic exploitation of the deposits was initiated in 1928 when D. H. Newland, State Geologist of New York, made an examination on behalf of The Titanium Alloy Manufacturing Company of America. Developments were then delayed by the world-wide depression, and the first commercial separation of the heavy minerals was made at Byron Bay in 1934 by Zircon Rutile Ltd. using a froth...

Jan 1, 1963

By Alastair Grogan, Ron Elliott, Dale MacLean

Blasting for armour stone presents many unique challenges. Often, blasters get themselves into trouble when they assume that they can simply modify a production blast design to produce the required fragmentation size. They bid on the project using typical production blasting costs, and then find that they cannot produce the required fragmentation size and quantity with an acceptable waste factor. This paper outlines industry best practice guidelines for the production of riprap or armour stone. The paper examines the importance of initial geological mapping to determine the average in-situ block size, and the advantages to be gained from working with the geology to maximize production of the required block sizes. The paper also outlines the importance of proper explosives selection as well as blast designs that are unique to the production of riprap. The paper reviews challenges and experiences realized from multiple projects in differing rock types.

By E. R. Bauer

This report describes a U.S. Bureau of Mines investigation into the removal of gate road chain pillars in conjunction with longwall retreat mining. The research objective was to determine, through evaluations of the loads imposed on the gate road pillars and supplemental support elements in the entries, how the pillars, supplemental support, and entries were affected by the longwall abutment pressure. To achieve this goal, vibrating wire stressmeters and hydraulic flatjack pressure cells were installed in the support elements to monitor stress change caused by abutment pressure as a function of longwall face advance. The findings documented in this report are the result of information collected from instrumentation and observation at the mine. Pillar and support loading measurements and stability observations revealed that the roof and the sup- port elements remained stable during panel retreat, while the face progressed at a normal rate of advance. The ability to safely and efficiently mine chain pillars during panel retreat increases resource recovery and can provide several other benefits described in this report.

Jan 1, 1993