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By A. Fahimifar, H. Soroush

Abstract: In order to develop non-destructive methods in studying physical and mechanical properties of rock and replacing them with difficult and expensive static methods, several ultrasonic tests were carried out on cylindrical rock specimens in accordance with the ISRM suggested methods and velocity of P and S waves were determined. Also, density, porosity, water absorption, uniaxial compressive strength and indirect tensile strength were determined for each specimen in accordance with ISRM suggested methods. According to above tests static and dynamic elastic constants were calculated After statistical analysis of data obtained from tests, the relationships between velocity of elastic waves and physical or mechanical parameters were determined and some equations were obtained. Also similar analyses were performed on static and dynamic constants and some equations were extracted. Using these equations, the physical and mechanical parameters of rock and also static elastic constants can be estimated by conducting simple and quick tests (i.e. ultrasonic tests). Abriß: Um zu entwickeln, die zerstörungsfreien Methoden für Studieren die physischen und mechanischen Eigentümer von Steinen und auch ist für Ersetzen diese Methoden mit schwierigen teuren statischen Methoden, mehrere altrasonic Prüfungen auf zylindrischen Steinproben gemäß ISRM anregenden Methoden und den Geschwindigkeiten von S und P Wellen bestimmt worden sind durchgeführt worden. Außer der Dichtheit und der Porosität betonen Wasser Aufnahme und monoaxial Widerstand und dehnbaren indirekten Widerstand jeder Probe betreffend der erhaltenen Ergebnisse die atmosphärische Aufladung sind bestimmt worden und die dynamischen Faktoren der Steine sind kalkuliert worden. Nachdem statistische Analyse die Korrelation der Ergebnisse zwischen der Geschwindigkeit elastischer Wellen und mechanischer und physischer Eigentümer der Steine erhalten worden ist, und mehrere Verhältnisse sind vorgeschlagen worden. Eine ähnliche Analyse ist auf atmosphärischer Aufladung und dynamischen Faktoren durchgeführt worden und einige Verhältnisse sind erhalten worden. Mit Hilfe dieser Verhältnisse die physischen und mathematischen Eigentümer von Steinen und auch können die Statistik Faktoren durch einfachen und schnellen altrasonic Prüfungen erhalten werden. Resume: Puor le development des method non-destructive et evaluuation des propietes physical et mechanical des rock et superseding avec les methods dificzle et cher statique, c‘ est fait plusieur essayes ultrasonique sur les echantillons cylinrique et par a port le proposale TSRM et le vittesse des ondes P et S et densite et porosite et absorption des eaux le resistant de pression uniaxial et resistance de chaque echantillon est determinee. A la fin en base des resultat obtenue les constant statique et dynamique des roches sont calcule. Apres les analyses statistiquc sur les resultat obtenue du les essaybs, c‘ etait produit les relation entre les viptesse les ondes elastique et les proprietes physic et mechanicue des roches et c est propose quelque relations. Aussi le meme enterpretation sur les constant statique etdinamique. En possezon de ces relations, les spesificatio physique, aussi on peut trouver leur constant statique, avel les essayes sample et raptid a d ultrasonique.

Jan 1, 2003

The Black Hills Mineral Atlas briefly summarizes all important data available on the mines and mineral deposits in the Black Hills that have been explored, developed, mined, or located. The purpose of the atlas is threefold; First, from available data the general potentialities of the Black Hills region can be determined, although it is not possible to calculate actual ore reserves; second, it will provide the necessary basic information regarding a given property or commodity for further detailed study; and third, the compilation is a comprehensive directory of Black Hills deposits.

Jan 1, 1955

By H. W. Gillett, E. L. Mack

"This report describes the trend of developments in electric brass-furnace practice in the last two years, and supplements Bureau of Mines Bulletin 202, ""Electric Brass-Furnace Practice"", which was published in 1922. In that bulletin it -as pointed out that some of the lines on which electric brass-furnace progress would take place were clear, but others were less so.Developments in foreign countries.Foreign brass-melters have not yet adopted electric melting to an extent comparable to its use in the United States. It is doubtful Whether all foreign countries combined use 100 electric brass furnaces; of these about 35 are of American make (Ajax, Detroit, Baily) and are operating in Canada, Mexico, England, France, Japan, Sweden, Switzerland, Spain, Norway, Germany, Argentina and Czecho-Slovakia.`The Rennerfelt furnace finds some use in Sweden (1)c, notwithstanding its high metal loss on alloys high in zinc, Two German firms are reported(2) to be using the Rochling-Rodenhauser induction furnace on bronze, the average energy consumption being given as 400 kw.-h. per ton. No comment is made on any trouble from the ""pinch effect"", A firm in Switzerland is reported (3) to use three 600-lb., direct-arc furnaces of its own design to melt babbitt, antimonial lead, coinage silver, nickel, copper, and brass. The metal loss on yellow-brass turnings is high. Use Of a direct-arc furnace in England, with precautions aimed to prevent surface overheating, vas abandoned (4) in favor of an Ajax furnace."

Apr 1, 1924

By W. T. Adams

The production of natural abrasives var¬ied in quantity and value compared with 1975. Output of tripoli-type materials and garnet increased in both quantity and value; special silica stone products decreased in quantity and increased in value; the production of emery decreased. The production and value of manufactured abrasive materials increased for all types. [ ]

Jan 1, 1978

By George S. Rice

The major purpose of this bulletin, as indicated in the preface by Dr. John W. Finch, Director of the Bureau of Mines, is to give a critical review of the coal-mining methods used in the principal producing countries of Europe, to describe the reasons underlying the adoption of these methods, and to contrast them with coal-mining methods employed in the United States. The report includes discussions of various subjects intimately related to coal mining, such as geology of the principal coal fields; production and resources of the several countries; mine safety and health research; Government mining regulations; mine inspection and rescue procedure; safety lamps; fixed lighting methods under-ground; testing electric motors, mining machines, and mining explosives for permissibility; and special mining hazards, such as explosions of gas and coal dust, mine fires, instantaneous gas outbursts, ground movement and surface subsidence, and bumps. Commercial, economic, and labor problems of European coal mining, including miners' output, wages, and social-insurance schemes, as well as cost of mining, prices of coal, etc., are briefly described. It will be noted that data on most subjects are not given for Russia, which has become an important coal-producing country, owing to the lack of reliable published information concerning Russian coal mining.

Jan 1, 1939

By D. T. Bergado

The uppermost subsoil profiles of the Bangkok plain can be divided into four layers, namely: weathered clay, soft clay, stiff clay, and dense sand layers. The soft Bangkok clay is a normally consolidated marine clay with built-up preconsolidation effects and overlain by a weathered crust. Up to the present, a large number of full-scale tests on excavations and pile foundations has been made by numerous investigators. Based on these results, the available data are reviewed and evaluated. The results show that for test excavations, the excess pore pressures were overpredicted by the existing theories. The vertical and lateral movements in the excavations can be predicted by the bilinear and non-linear finite elements using appropriate modulus values. Relationships among probability of failure, safety factor, and safety margin of the excavation were also obtained. In the case of pile foundations, good agreement between the measured and predicted ultimate pile capacities were obtained for long piles. The adhesion factors ranged from 0.4 to 1.0 while the average skin friction factor was found to be 0.33. The ultimate capacity of the pile was also predicted successfully by using the Dutch cone data. For lateral deflection of piles, Davisson and Gill's theory predicted well in the low deflection zone while Poulos' theory agreed well in the high deflection zone. From the probabilistic analysis of ultimate pile capacity, the probability of failure was related to the central factor of safety. The piles usually used in Bangkok area are mainly precast concrete piles

Jan 1, 2010

By E. D. Gardner

Ore and concentrate are transported on, the surface at western mining districts by (1) railroads, (2) surface trams, (3) aerial trams, (4) trucks, and (5) wagons, and (6) on the backs of animals. The daily and ultimate tonnage to be moved is the principal factor governing the selection of the method of transportation. Railroads are preferred when large tonnages are to be hauled over relatively long distances. The mine-haulage system may be extended or surface trams built to the mill or shipping point if a practical track grade is possible and if the distance is relatively short. Aerial trams have a special field of usefulness for transportation over steep or excessively rough terrain.

Jan 1, 1936

By B. Benmokrane, G. Ballivy

"RésuméLe mécanisme de transfert des charges et le processus de décohésion le long des scellements d'ancrages scelles dans des massifs rocheux sous des charges de tensionnement peut être examine par instrumentation de l'ancrage à l'aide de jauges de déformation. Dans ce contexte il est présente ici les résultats d'une étude, en vraie grandeur sur chantier, ayant porte, d'une part sur des essais d'arrachement conventionnels et d'autre part sur des essais déflagrée barres d'ancrages instrumentées et scellées à l'aide d'un coulis de ciment dans un massif rocheux sain et compètent. Les résultats décrits ici, particulièrement les profits de contraintes de cisaillement le long de l'ancrage, obtenus à partir des valeurs de déformations relevées sur les jauges, ont permis de préciser le niveau de chargement correspondant à la décohésion initiale du coulis de scellement, d 'examiner l'effet de la décohésion sur la distribution des contraintes et de caractériser le fluage du système barre d'ancrage/coulis de scellement.ABSTRACTThe load transfer mechanism and the debonding process along grouted rock anchor, subjected to tention loads, can be examined through the instrumentation of the anchor with the aid of strain gauges. In this context, the resultsof a full-scale site investigation including classical pull out tests and creep tests are presented in this paper. These tests were performed on instrumented bars which were cement grouted in a competent rock mass. Results presented in this paper concern, among others, shear stress pro/ties along the grouted anchors which were determined from strain values obtained from the strain gauges. These results have been used to: (1) predict the load level corresponding to initial debonding of the grout; (2) study the effect of debonding on shearstress distribution along the anchor; and (3) characterize the creep behavior of the bar anchor/cement grout system."

Jan 1, 1991

By K. -C. Han, S. -Y. Kim

This study was carried out in a bid to survey Ganboke gold mine in Pala, Mayo-Kebbi Province, southwestern Chad. The Ganboke mine is now being prepared for investigation and development, and the research sought to perform rock properties tests of relevant rocks through its geological survey, rock mass evaluation, and in-situ and laboratory tests and analyze the stability by the means of limit equilibrium method, thereby suggest appropriate methods to design the pit slope and individual benches in Ganboke mine. Targenting GS1-GS1' section with the depth of 180 m and GS2-GS2' section with the depth of 150 m in the survey area, we set the height of the bench at 10 m and 15 m, and the angle of bench at 60o and 70o, respectively, and then reviewed the stability for dried condition and saturated condition. The result of examination indicated that it would be appropriate to set the bench height at 10m and the bench angle at 60o in developing the mine slopes concerned. Cette étude est réalisé dans le but de faire des recherches sur Ganboke mine d'or dans Pala, Mayo-Kebbi Provence, Tchad sud-ouest. La Ganboke mine est actuellement en train de étre disposé à la investigation et le développement, et la recherche a cherché à accomplir les tests de la propriétè des roches par l'intermédiaire de la étude géologique, la évaluation de la masse rocheuse, et in-situ et les tests de laboratoire et à faire l'analyse de la stabilité au moyen de la méthode d'équilibre limite, de ce fait à proposer le methodes propres à faire le plan de la pente et les gradins individuels dans la Ganboke mine. Concernant la section de GS1-GS1' avec la profondeur de 180 m et la section de GS2-GS2' avec la profondeur de 150 m dans l'aire d'étude, nous mîmes l'hauteur du gradin à 10 m et 15 m, et l'angle du gradin à 60o and 70o, respectivement, et alors nous avon reconsidéré la stabilité pour la condition sèche et la condition saturé. Le résultat d'examen a indiqué que il pourrait être propre de mettre l'hauteur du gradin à 10m et l'angle du gradin à 60o en développant les pentes de la mine concerné. Diese Forschung wurde um das Gold Bergwerk zu überschauen in Pala, Mayo-Kebbi Provinz, der Südwesten Chad ausgeführen. Das Ganboke Bergwerk ist jetzt zur Erforschung und Entwicklung vorgebereiten worden, und die Forschung suchte zu ausführen die Prüfungen der Felseigenschaft durch geologischen Überblick, Felsmassewertbestimmung, und In-situ und Lavorversuch auf, und analysieren die Stabilität mittelst der Grenzegleichgewichtsmethode, da-durch schlug die angemes-sen Methoden zu entwerfen die Böschungen und die einzelnen Bänke im Ganboke Bergwerk vor. Für den Abschnitt GS1-GS1' mit der Tiefe von 180 m und GS2-GS2' mit der Tiefe von 150 m in der Überblickfläche, wir setzten die Bankhöhe an 10 m und 15 m, und das Bankwinkel an 60o und 70o, beziehungsweise, und dann zurückblickten die Stabilität für die getrockneten Bedingungen und die gesättigten Bedingungen. Das Ergebnis der Untersuchung anzeigte daß es würde angemessen sein zu setzen die Bqnkhöhe an 10m und das Bankwinkel an 60o in der Entwickelungen vom Bergwerk be-teiligt.

Jan 1, 2003

By H. Willenberg, J. S. Coggan

ABSTRACT: Although individually both continuum and discontinuum numerical analyses provide useful means to analyze rock slope stability problems, complex failures typically involve mechanisms related to both existing discontinuities (i.e. discontinuum) and deformation and brittle fracture of intact rock (i.e. continuum). One such example is the 1991 Randa rockslide in the southwestern Swiss Alps, where failure involved several complex mechanisms, which require the consideration of progressive failure and rock mass strength degradation. This paper presents results from a series of hybrid finite-/discrete-element models directed towards the explicit modelling of brittle fracturing in natural rock slopes, enabling the modelling of progressive failure, from initiation, through to the development of catastrophic failure, transport and deposition. RÉSUMÉ: Si les modélisations numériques de type continu ou discontinu fournissent des outils utiles pour l’analyse de problèmes de stabilité de pentes rocheuses, elles montrent de sérieuses limitations lorsque des mécanismes de rupture complexes impliquent des processus liés autant aux discontinuités préexistantes qu’au développement progressif de nouvelles fractures. Ceci se retrouve typiquement dans l’exemple de l’éboulement de 1991 à Randa dans les Alpes suisses du sud-ouest, où la rupture a impliqué plusieurs mécanismes complexes nécessitant la prise en considération de la fracturation progressive ainsi que de la dégradation de la résistance des masses rocheuses. Cet article présente des résultats provisoires d'une série de modèles hybrides orientés vers la modélisation explicite de la fracturation de pentes naturelles, permettant la modélisation de fractures progressive de leur initiation jusqu’à leur développement, leur rupture catastrophique, leur transport et leur déposition. ZUSAMMENFASSUNG: Obwohl numerische Kontinuum- und Diskontinuum-Berechnungen einzeln nützliche Ergebnisse zur Stabilitätsanalyse von Felshängen liefern, sind komplexe Felsrutschungen typischerweise mit Mechanismen verbunden, die sowohl durch bestehende Trennflächen (s.a. Diskontinuum-Ansatz) als auch durch die Deformation und das Versagen intakter Felsbereiche (s.a. Kontinuum-Ansatz) bedingt werden. Ein Beispiel für einen solchen Sachverhalt ist der Bergsturz von Randa 1991 im südwestlichen Teil der Schweizer Alpen, bei dem die Rutschung mehrere komplexe Mechanismen umfasste, so dass “progressive failure” und Verminderung der Gebirgsfestigkeit in Betracht gezogen werden müssen. Dieser Artikel beschreibt vorläufige Ergebnisse einer Reihe von hybriden Modellrechnungen (Finite-/Diskrete-Elemente). Diese haben zum Ziel, explizit das bruchhafte Versagen natürlicher Felshänge zu modellieren, wobei das progressives Versagen im ganzen modelliert wird, von der Anfangsphase über die Entwicklung zum katastrophalen Versagen und den Transport und die Ablagerung der Rutschmassen.

Jan 1, 2003

By D. T. Randall

The burning of coal without smoke is a problem that concerns the Government directly because of the advantages of smokeless combustion both in public buildings and on naval vessels. In addition, smoke abatement is a factor in conserving the fuel resources of the United States. Hence, as part of its general investigation of the best methods of utilizing the coals of this country, the Bureau of Mines, which is in charge of the fuel-testing work formerly carried on by the United States Geological Survey, has made extended tests to determine the conditions necessary for the smokeless combustion of bituminous coal in boiler furnaces. Bulletin 39,¢ a preliminary report, treats the smoke problem from a theoretical point of view, detailing the steps that are being taken by municipalities, manufacturers, and citizens to abate smoke, also showing the possibility of a clean city. The present bulletin not only shows that bituminous coals high in volatile matter can be burned without smoke, but also that large plants carrying loads that fluctuate widely, where boilers over banked fires must be put into service quickly and fires forced to the capacity of their units, can be operated without producing smoke that is objectionable. Proper equipment, efficient labor, and intelligent supervision are the necessary factors.

Jan 1, 1918

By R. A. Beall

This bulletin reviews the historical background of the cold-mold arc-melting technology, with specific references to the development that led to homogeneous zirconium ingots. Descriptions are given of modern production arc-furnaces for vacuum melting of troth exotic and conventional metals. Besides zirconium, specific data are given for production of chromium, thorium, and copper. The development of the skull-casting technique for titanium is detailed, and the application of the technique to such refractory metals as molybdenum and tungsten is described. Factors of operation of the apparatus and furnace design are considered.

Jan 1, 1968

For its Hellyer project, Aberfoyle sought to establish a high degree of confidence in all aspects of the feasibility study. Accurate capital and operating cost estimates were an integral and essential part of the study. They were crucial to the evaluation of investment returns and competitive cost position. Both the capital and operating cost estimates were based on the comprehensive data available from exploratory mine development, pilot plant operation, detailed engineering design, and Aberfoyle's experience in the area. One of the principal project objectives was to maximise operating productivity and efficiencies and this created capital cost alternatives which needed thorough cost-benefit assessment. The estimated capital cost for construction and development was $90 million, and the project was completed virtually on time for $80 million. The first year's experience indicated that operating costs would settle to well within 10% of the estimates.

Jan 1, 1990

By Arno C. Fieldner

This is the fifth of a series of annual reports4/ of technologic investigations conducted by the Bureau of Mines on the occurrence, properties, mining, preparation, and uses of coal. The research of the Bureau is carefully coordinated with the requirements of the producing and consuming industries, with a view to conservation of resources of coal in mining and use, and conservation of the health and lives of workmen employed in these industries. Such coordination is facilitated by the wide range of specialization of the several groups on engaged in studies concerning coal. Here are reported correlated studies ranging from paleobotanic analysis of the formation of coal as it occurred some millions of years ago to the effect of mechanical methods of mining on present-day employment in mines. As this is a summary of the current work of the Bureau of Mines, so the Bureau likewise has provided a condensed review of the outstanding current work of others on research and technology of coal 5/.

Jan 1, 1940

By R. M. Spang

Abstract Between the German city of Dresden and the Czech capital Prague a 4-lane highway is under con-struction. At the outskirts of Dresden it will cross the narrow and deeply eroded Weißeritz Valley by a bridge. Two twin tube tunnels under oblique angles join the bridge out of the rocky valley flanks. The different geotechnical conditions of these 4 tunnel portals, their design and construction are described within this publication. The two southern portals of the tunnel Dölzschen are situated within a vertical 65 m high former quarry slope, 25 m above the valley floor. The slope proved instable due to toppling failure and exposed serious rockfall risks. Systematic anchoring, scaling, rock bolting, netting and filling under extreme access conditions eliminated these risks. Tunnel excavation started from the slope surface without any pre-cut or conventional portal construction. The opposite northern portals of the tunnel Coschütz are situated in more gentle rock slopes. After removal of debris, excavation of the eastern tunnel started in a 30° slope striking oblique to the driving direction, without any precut, too. Because of the gentle slope inclination the cross section was not earlier completely covered by rock than 30 m behind. The western tunnel started from an optimized short, narrow and steep precut. Its flanks were stabilized by reinforced shotcrete and rock bolts. Because of the small distance between the tubes rock bolts were drilled into the cross section of the neighboring tunnel. Tunnel excavation was made by drill and blast operation, preliminary support consisted of steel arches, reinforced shotcrete and radial rock bolts. Thorough survey of the bolt’s coordinates and direction prevented them from meeting each other. Rock bolts were of the permanent type to prevent the final lining from being obliquely loaded. Systematically arrayed measuring devices checked deformations of slopes and tunnels. Zusammenfassung Der Neubau der Bundesautobahn A 17 wird Dresden und Prag miteinander verbinden. Die vierspurige Autobahn quert westlich von Dresden das enge und tief eingeschnittene Tal der Wilden Weißeritz mit einer Brücke. An beide Brückenwiderlager schließen mit schiefwinkligem Anschnitt doppelröhrige Tunnel an, deren Portale in den felsigen Talflanken liegen. Die unterschiedlichen geotechnischen Verhältnisse, die Überlegungen für einen jeweils optimalen Entwurf und der Bau der portalnahen bergmännischen Tunnelabschnitte sind Gegenstand dieser Veröffentlichung. Die Südportale des Tunnels Dölzschen liegen in einer vertikalen, 65 m hohen Felswand, 25 m über dem Talgrund. Die Felswand erwies sich als global kippgefährdet, außerdem lagen flächig verteilte erhebliche Steinschlag- und Felssturzrisiken für Bau und Betrieb vor. Die Kippgefahr wurde durch ein Systemraster aus vorgespannten Felsankern, die Steinschlag- und Felssturzrisiken durch bergsteigerisches Beräumen mit dem Brecheisen, Felsnägel und Steinschlagschutznetze eliminiert. Der Tunnelausbruch begann von einer Vorschüttung direkt in der Felswand ohne Voreinschnitt im Schutz einer kurzen Luftbogenstrecke. Die gegenüberliegenden Nordportale des Tunnels Coschütz befinden sich in wesentlich flacheren Hängen. Nach dem Aushub einer mehrere Meter dicken Abraumhalde begann der Tunnelausbruch der östlichen Röhre asymmetrisch mit einer Luftbogenstrecke in einer spitzwinklig zur Vortriebsrichtung streichenden, 30° mit dem Vortrieb steigenden Felsfläche, ebenfalls ohne Voreinschnitt. Wegen der flachen Neigung der Böschung war der Tunnelquerschnitt erst nach 30 m vollständig überdeckt. Für den Vortrieb der westlichen Tunnelröhre mussten erst eine zwischen den Röhren vorhandene Felsnase teilweise abgetragen, die westlich anschließende zurückspringende Felswand vertikal gestellt und gesichert und Felsaushub in der rechten Flanke getätigt werden. Der damit entstehende Voreinschnitt wurde so kurz wie möglich und ohne seitliche Arbeitsräume ausgeführt. Die Sicherung der Böschungen erfolgte mit bewehrtem Spritzbeton und Felsnägeln. Wegen des geringen Abstands der beiden Röhren wurden die unteren Lagen der radialen Ausbruchsicherung durchgeankert. Der Tunnelvortrieb begann im Schutz eines geankerten Portalkranzes und ebenfalls von einer Luftbogenstrecke aus.

Jan 1, 2003

By J. P. Josien, J. F. Noirel, F. Lahaie, P. Bigarre, M. Al Heib

ABSTRACT: In June 2001, a fatal rockburst affected a longwall face in the Houillères du Bassin de Lorraine (HBL), France. Subsequently, a large operation of in situ stress measurements by overcoring was carried out with two main objectives: providing input data for the back analysis of the dynamic event and characterising the stress field in the next panels to be mined for identifying other potential high-risk zones. This paper makes a synthesis of the results of the overcoring tests performed and discusses those results in connection with the mining context, numerical model predictions, laboratory rock test results and microseismic activity. KEY WORDS: Mine, rockburst, stress, overcoring, measurement. ZUSAMMENFASSUNG: Im Juni 2001 hat ein Bergschlag eine Kohlengrube des Houillères du Bassin de Lorraine (HBL, Lothringen, Frankreich) schwer beschädigt. Nach diesem Unfall sind Spannungsmessugen durch Überborung durchegeführt worden, mit zwei Hauptziele : 1/ Daten zu liefern für die Retro-analyse des dynamischen Gebirgsschlag und 2/ die Spannungen in den zukünftigen Ausbauen so gut wie möglich zu charakterisieren, um eventuele andere Risikozonen festzustellen. Dieser Artikel stellt eine Synthese der erzielten Ergebnisse vor. Er diskutiert diese Ergebnisse in Verbindung mit dem gesamten Kohlengruben Zusammenhang, mit den Ergebnissen von numerischen Modellierungen, mit der Labor-Charakterisierung und mit der microsismische Überwachung. SCHLÜSSEL-WÖRTER: Kohlengruben, Bergschlag, Spannung, Überborung, Messung. RESUME: En Juin 2001, un coup de terrain a gravement affecté une longue taille aux Houillères du Bassin de Lorraine (HBL) en France. A la suite de cet accident, une importante campagne de mesures de contraintes par surcarottage a été réalisée, avec deux objectifs majeurs : fournir des données d’entrée permettant la rétroanalyse du phénomène dynamique et caractériser au mieux le champ de contraintes dans les futurs panneaux exploités afin de détecter d’éventuelles autres zones à risque. Cet article présente une synthèse des résultats obtenus, et discute ces résultats en liaison avec le contexte d’exploitation, les résultats de modélisation numérique, de caractérisation en laboratoire et de surveillance microsismique. MOTS CLES: Mine, coup de terrain, contrainte, surcarottage, mesure.

Jan 1, 2003

By G. M. Kintz, Charles B. Carpenter, G. W. Jones

"INTRODUCTION At 9:12 a. m. on April 16, 1947, the ammonium nitrate cargo in hold 4 of the S. S. Grandcamp, a 7,176 gross-ton Liberty ship owned by the French Government, detonated at pier 0 of the Texas City Terminal Railway Co., Texas City, Galveston County, Tex.This detonation was the first of a series of explosions and fires that took the lives of approximately 600 persons, injured 3,000 other persons, and caused a property damage and business loss that will exceed $58,800,000. It has been estimated that the life, accident, and workmen's compensation insurance loss will be $8,200,000.At 1:10 a. m. on April 17, 1947, the ammonium nitrate cargo in hold 5 of the S.S. High Flyer, a 6,214-gross-ton Liberty ship owned and operated by the Lykes Bros. Steamship Co., Inc., detonated at pier L. This explosion materially increased the property damage caused by the first explosion, in between 50 and 100 persons, and is believed to have taken the life of only one person.The exact number of casualties resulting from the Texas City disaster may never be known. On June 22, 1947, 65 days after the explosions, the red Cross and the Texas Department of Public safety repoted:,""Identified dead, 405; unidentified dead, 63; believed missing, 100; injured, 3,000; hospital¬ized, 600; still in hospitals, 37."""

Feb 1, 1948

By D. Harrington

Dust diseases are much before the public at present, but little reliable information on the subject is readily available to the layman; even those rated as experts usually have a more or less theoretical conception of these diseases, their causes, remedies, and prevention. Until recently little attention has been given to prevention, and the usual attitude of the engineer, upon whom the main reliance for prevention ultimately must devolve, has been to let "sleeping dogs lie" or, more definitely, to "let well enough alone." However, the "laissez faire" attitude no longer is tenable; in the past few years numerous conditions have caused those engaged in industry, including mining, to study the subject with a view to ascertaining the facts upon which to formulate remedial measures, primarily preventive. This bulletin is an attempt to assemble information in convenient form on effects of breathing dusts, largely in the mining and allied industries. The literature on this subject is so extensive that no attempt has been made to include all published material or all types of dust diseases but only to assemble some of the more outstanding data on several aspects of the subject, especially with reference to silicosis.

Jan 1, 1937

By George K. Clement

Manual estimating method through use of equations, factors and curves for preparation of feasibility type estimates for capital and operating cost of mining and primary beneficiation in the United States and Canada of various types of minerals occurrences, except fossil fuels, using state-of-the-art technology. User should have basic estimating experience in the mining industry and/or related fields. Primary usage of this handbook will be for the preparation of preliminary estimate within a reasonable degree of accuracy with relative small amounts of hard input data. Output may be used to determine if a more finite type of estimate should be produced.

Jan 1, 1978

By W. F. RITTMAN, E. W. Dean

This report presents the results of an investigation conducted by the Bureau of Mines for the purpose of assisting in the establishment of a satisfactory standard method for the analytical distillation of petroleum, a problem of great importance to the petroleum industry. Experiments were performed for the purpose of studying the charac- teristics of methods typical of those in use; comparative studies were made of the efficiencies of the principal types of fractionation ap- paratus available to the petroleum chemist; and the characteristics of a type of apparatus that the results of the experiments seemed to indicate was best adapted to the purpose were investigated in detail. Also, some experiments were made to determine the effect of cracking as a factor in the analytical distillation of petroleum in still heads.

Jan 1, 1916