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By Raymond M. Stateham

Infrared and displacement studies were made of an unsupported roof in Kaiser Steel Corp.'s York Canyon coal mine, Raton, N. Mex. Monitoring of the roof continued until the roof over the area was caved. Loose slabs in the roof, about 6 inches thick, were detected by means of associated thermal anomalies, using remote-sensing infrared instruments. Displacement measurements taken during the study indicate that roof movement was cyclic in nature; the cycles appear to have been related to the mine work cycle (work days to idle days).

Jan 1, 1974

By Georgene Renner, William R. Yernberg, Steve Kral

Allmand exhibited its LSC 100Light Sequence Commander, the mining industry’s first automatic lighting and command control system. The system is available with all of Allmand’s portable light towers. The LSC100 uses a preset photocell sensor that allows the light tower to be automatically turned on or off. At dusk, the sensor engages the power unit and then activates the light. At dawn, the sensor automatically shuts off the light. The unit also features an eight-event digital timer that allows eight separate sequences daily. The LSC100’s sequenced light control ensures that the engine is started before the lights are turned on or off. This prevents possible generator damage that can occur if the unit is powered down under load. Also, a low-fuel shutdown sequence helps protect the generator from damage by automatically shutting down the unit when the fuel level reaches 10 percent. And the LSC100’s smart circuitry senses engine water temperature during startup, determines the glow-plug time requirement and schedules repeat intervals, if necessary, to start the diesel engine.

Jan 1, 2004

By Wen Songlin

This paper presents an experimental program to investigate the behavior of a pile with wings under horizontal loads in sand at laboratory. The work focused on evaluating the lateral resistance behavior and the geometric effect of wing board on the horizontal resistance. Based on the measured data and observed phenomenon, the following behaviors have been observed: 1) A pile with wings is not only a powerful means to improve the horizontal bearing capacity of a pile foundation but also economy and feasibility; 2) The horizontal bearing capacity of a pile with wings increases with increasing of it?s wing board?s area; 3) The pile lateral capacity is also influenced by the wing board?s geometric shape. Under a certain soil and pile condition, there is a critical embedment depth of the wing board, which will yield the maximum horizontal bearing capacity. It was further observed that when the displacement of the pile head increases, part of the horizontal bearing capacity of the pile is developed by the so-called shaft?s anti-pulling capacity.

Jan 1, 2007

By J. Werfling, J. R. Kiehl

SUMMARY: The effects of blasting on structures are assessed on the basis of the maximum amplitudes of the occuring vibration velocities. If the standard values in the German Standard DIN 4150 are not exceeded, damages to structures are not to be expected. The estimation of the maximum vibration amplitudes is usually based on experience or on emperical formulae. However, a comparison of expected with measured values shows that these estimations are not conservative, particulary in case of small distances between blasting locations and structures. More reliable predictions are possible on the basis of numerical analyses, which simulate the three-dimensional propagation of waves with consideration of the geomechanical and geometrical conditions. In addition to the expected velocities, these analyses also allow the determination of stresses resulting from dynamic loading. If the dynamic stresses are known, the effects of blasting on structures can be predicted. ZUSAMMENFASSUNG: Die Auswirkungen sprengbedingter Erschütterungen auf bauliche Anlagen werden in der Praxis auf der Grundlage der Maximalamplituden der auftretenden Schwinggeschwindigkeiten beurteilt. In der DIN 4150 werden Anhaltswerte angegeben, bei deren Einhaltung Schäden von Gebäuden nicht zu erwarten sind. Die Abschätzung dieser Schwing-geschwindigkeiten erfolgt meist auf der Grundlage von Erfahrungswerten oder empirischer Formeln. Der Vergleich der prognostizierten Werte mit Meßergebnissen zeigt jedoch, daß diese Ansätze insbesondere dann, wenn die Abstände zwischen den Sprengorten und den Gebäuden gering sind, nicht konservativ sind. Zuverlässigere Prognosen sind auf der Grundlage von numerischen Berechnungen möglich, in denen die räumliche Ausbreitung von Erschütterungen unter Berücksichtigung der geomechanischen und geometrischen Verhältnisse simuliert wird. Mit derartigen Berechnungen können die zu erwartenden Schwinggeschwindigkeiten und die aus der dynamischen Beanspruchung resultierenden Spannungen ermittelt werden. Dies ermöglicht Aussagen über die Auswirkungen sprengbedingter Erschütterungen auf Bauwerke. RÉSUMÉ: Les conséquences de vibrations résultantes d'explosions pour des bâtiments sont estimés dans la pratique à partir des amplitudes maximales des vitesses d'oscillation. Dans la norme allemande DIN 4150 des valeurs d'orientation sont données, avec l'observation desquelles de dommage à des bâtiments n'est pas à présumer. Ces vitesses d'oscillation sont estimés généralement à partir de valeurs d'expérience ou de formules empiriques. La comparaison des valeurs prédits avec des résultats de mesures montre cependant que ces hypothèses ne sont pas conservateurs, en particulier si les distances entre les lieux de sautage et les bâtiments sont petites. Des prédictions plus fiables sont possibles à partir de calculs numériques, dans lesquelles la dissipation spatiale de vibrations est simulée en considération de la situation géoméchanique et géométrique. Avec tels calculs les vitesses de vibration à présumer et les contraintes résultantes de l'effort dynamique peuvent être établies. Cela permet de constater sur les conséquences de vibrations résultantes d'explosions pour des bâtiments.

Jan 1, 2003

By Neil J. Mansfield, Setsuo Maeda

The purpose of using experimental subjective and/or perception methods is: (a) to understand human subjective impressions of the physical characteristics of vibration; (b) to determine the relationship between the subjective perception of some aspect of the vibration and an evaluation index of the physical vibration characteristics; and (c) the establishment of target values for design of vibration environments in terms of human sensation of vibration characteristics. In order to understand the relationship between a physical measure of the mechanical vibration and the subjectively perceived aspect of the vibration environment, experimental methods shown in Table 1 have been used1. [ ] The constant measurement methods of Table 1 are mainly used for measurement of the threshold of human sense. The subjective scaling methods are mainly used for obtaining subjective (or proportional) scaling between the perceived quantity and physical quantity. In this review, the fundamental approach of experimental methods for obtaining the target values used in the design of vibration environments, and the different findings between the subjectively perceived methods for evaluating human response to vibration characteristics and the physical quantity of the vibration environment are summarized. Fundamentals of Subjective Scaling The relationship between the experimental psychological methods for providing target values in the design of the vibration environments and the physical quantities is illustrated in Fig. 1. Vehicle mechanical vibration can be characterized using many metrics, and these can be considered the ‘input’ to the human. In order to predict subjective responses to the vibration, it is necessary to link the characteristics of the source of vibration and human reactions, the ‘output’.

Jan 6, 2006

By K. Oraee

Mining of copper ore and the related industries play an important role in Iran?s economy. Copper ore production in Iran accounts for 75% of the total production in the Middle East. All activities related to copper, that is, exploration, production, refinement etc are owned and managed by state owned companies. Decisions have been made to privatize all these activities. To assess the success of this privatization process, different components of the industry must be subject to economic analysis. In this paper, the cost estimation of all operations has been carried out. The total potential and attainable revenues have also been estimated using historical data available from the industry. Risk is a major factor in all mining activities and the copper industry of Iran has been subject to risk factors arising from many internal and external variables. These variables have been recognized and their effects evaluated. The effect of risk on the economic feasibility of the operations in the industry has also been analyzed.

Jan 1, 2011

By J. W. Adams

Two different techniques were wed to make measurements of the absolute value of electromagnetic noise in an operating hardrock mine, Grace Mine, located near Morgantown, Pennsylvania. Diesel-powered haulage equipment is used in this mine, and the electromagnetic noise environment it creates was measured to see how it differs from the environment created by electric-powered haulage equipment. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. Data are recorded using broadband analog magnetic tape and are later transformed to give spectral plots. The other technique records noise amplitudes at several discrete frequencies for a sufficient amount of time to provide amplitude probability distributions. The specific measured results are given in a number of spectral plots and in amplitude probability distribution plots.

Jan 1, 1974

By V. Eloy Román

El presente trabajo evalúa la adición del oxígeno puro al circuito de cianuración, con la finalidad de incrementar el porcentaje de recuperación de oro y plata, así como su efecto sobre el consumo de cianuro de sodio. En ese sentido, la mayoría de las plantas mantienen un alto nivel de concentración de cianuro, en lugar de un alto nivel de oxígeno disuelto en la solución. Como consecuencia de ello , operan a niveles de cianuro de modo que la disolución del oro depende del nivel de oxigeno disuelto. Por ello, es más fácil mantener un nivel alto de cianuro, que un nivel alto de oxígeno disuelto en la solución, principalmente si se utiliza aire en lugar de oxígeno.

Sep 12, 2005

By Allan E. Martin

As part of a comprehensive investigation of tae mechanism of desulfurization of iron and steel by slags, the Blast Furnace Studies Section, Metallurgical Division, Bureau of :lines, in cooperation with the Institute of Technology., University of Minnesota, has made a study of the forms in which sulfur occurs in blast-furnace slag. This report presents data on the three sulfides most important in iron smelting, namely, ferrous sulfide, manganous sulfide, and calcium sulfide. The tendency of these sulfides to form colloids in the molten slag was determined by an examination of quenched samples with an ultramicroscope. Vogt5/ conducted experiments on sulfide silicate melts and examined synthetic blast-furnace slags in a partly crystallized condition. His conclusions were that FeS, CaS, and MnS, or isomorphous compounds, such as (FeXCay)S and (MnxCay)S, were precipitated from the melt, depending on the composition of the slag. In all specimens sulfides were visible and were spherical.

Jan 1, 1941

Cyclonic Separation Effect of Metallic Ores in Cyclonic-Static Micro-Bubble Flotation Column

Sep 13, 2010

By X Yang, B Wang, L Liu

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Huoqiu iron ore field in north-west Anhui province is located in the south-east margin of the North China Craton and hosts large iron resources. Orebodies are hosted in Neoarchean amphibolite facies metamorphic rocks, forming silicon-iron bands from north to south. The area is dominated by an Early Precambrian basement consisting of Neoarchean grey gneisses, amphibolites and metasediments. The gneisses are similar with assemblages of Trondhjemite-Tonalite-Granodiorite in compositions and intercalated with amphibolites. Igneous zircons from gneisses and amphibolites have U-Pb ages of 2.86 and 2.75 Ga respectively, which are interpreted as the crystallisation ages of their protolith. Zircons from amphibolite and gneiss have eHf(t) values of 2.4–15.5 and -3.0–1.5 respectively. The tDM2(Hf) model ages of the gneiss range from 2.87 to 3.14 Ga, which is consistent with tDM1(Hf) ages of amphibolite (2.84–3.16 Ga). The U-Pb-Hf isotopes thus confirm that the gneisses were generated by partial melting of amphibolite. Two granites produce two group Hf isotopic compositions. The older one (1916 ± 42 Ma) has eHf(t) values and tDM1(Hf) ages of -9.4–3.4 and 2.24–2.71 Ga respectively, whereas the younger one (1823 ± 41 Ma) shows a large variation in eHf(t) values of -18.1–12.5 and tDM1(Hf) model ages of 1.73–2.92 Ga. Geological and geochemical characteristics indicate that the Huoqiu banded iron formations are a Superior-type iron formation rather than an Algoma-type as previously considered.CITATION:Yang, X, Liu, L and Wang, B, 2015. Study on the Huoqiu banded iron formation, West Anhui Province, East China , in Proceedings PACRIM 2015 Congress, pp 649–656 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Two concentrates from Palabora, in South Africa, containing 0.056-0.068% undesirable Cu and 0.8 or 2.2% Ti, were chlorinated with air:chlorine ratios of 10:1, 15:1 and 20:1 at temperatures between 1 200 and 1 329 K. The resulting volatile chlorides were condensed and the solutions analysed for Cu, Fe and Ti. Recovery of Cu was less than 25% at low temperatures and short reaction times, but at 1 258 K almost all Cu was removed from the magnetite at all ratios of chlorine to air. At higher temperatures, the increased carrying over of iron as FeCl3 could be minimised by decreasing the partial pressure of chlorine. No titanium was detected in the volatile products and the percentage of Cu recovered was independent of Ti concentration in the concentrates, though as a function of Cl2 vol%, more Cu was recovered at 1 200 K from the low-Ti than from the high-Ti concentrate. In a fluidised-bed reactor, Cu recovery was 58-90% and iron carry-over less than 10 ppm

Jun 21, 1905

By Robert Hopler

Some few years ago, when the cruiser “Brooklyn” was passing through the fairway to the southwest of the Battery, the ship being fully equipped with stores, etc., and therefore at her maximum draft, she grounded quite heavily upon some obstruction, and received injuries which necessitated her docking at the Brooklyn navy yard, where extensive repairs had to be made on her damaged bottom.

Jan 1, 2007

By Martin G. Castro, Renato G. Bautista, Morton Smutz

During the last 25 years, multistage mixer-settlers have been used extensively for liquid ion exchange work. The mixer-settler has the advantage of being a compact device in which a large number of stages can be assembled in a relatively small area. They are particularly advantageous for the separation of rare earths. Most of the adjacent rare earths have separation factors which are near one, which means that a large number of stages are needed to produce a good separation. When two elements (m, n) are extracted simultaneously, the separation factor (ßm, n) is defined as: [ ] where Ym, Yn are the molarities of the respective elements in the organic phase and Xm, Xn, are their molarities in the aqueous phase at equilibrium. The industrial consumption of rare earth oxides rose to over 6800 tons in 1968, an increase of 33% over 1967.1 The increased production and demand for rare earth and lanthanum chlorides for petroleum cracking catalysts was one of the principal factors in this increased consumption of rare earths. In 1968 approximately 59% of the rare earth oxides produced were used for gasoline cracking catalysts in the form of rare earth and lanthanum chlorides. There was also an increase in the sales of lanthanum oxides for use in optical lenses and in fiber optics. The future looks good for the rare earth industry. The rare earths can be expected to be used in many new products which are being developed. Until the late 1950's tributyl phosphate (TBP) was the principal solvent used in rare earth liquid ion exchange. In 1957 Peppard3 reported the use of di (2-ethyl-hexyl) phosphoric acid (D2EHPA) as a solvent for separating the rare earths. Rare earth separation factors of up to 2.5 were obtained in nitrate and chloride systems while the maximum separation factor using the

Jan 1, 1972

By Arturo Ressi di Cervia

From the times when men in lacustrine environments drove wooden piles into the mud to elevate their dwellings, until the beginning of the twentieth century builders reacted to the conditions found in the location of their proposed structures by attempting to distribute their loads in ways that could be supported by the foundation's soils; or, if those were unsuitable, by moving the structure, whenever possible. While many major structures were built on stable ground (the pyramids were founded on rock), others were built on [ ]

Jan 1, 2000

By James Westfield

Bureau of Mines activities for safety and health in the mineral industries were reorganized during the fiscal year to provide direct supervision by the Assistant Director -Health and Safety. On December 19, 1954, the field offices conducting these activities were designated as district health and safety offices reporting to the Assistant Director. The functions of determining the causes of accidents and injuries in the mineral industries and recommending measures to eliminate them were continued, with satisfactory results in improved safety records. The inspection of coal mines and enforcement of the Federal Coal Mine Safety Act of 1952 were conducted as directed by the Congress, and safety conditions in the mines were notably improved. One coal-mine explosion classed as a major disaster occurred during the year. The causes of that explosion and means for preventing a recurrence were still under investigation because of the extreme difficulty in recovering several portions of the mine. Basic research on the nature of certain hazards and ways of eliminating them is continued. Training of individual workmen and supervisors in this knowledge is a major part of the work.

Jan 1, 1956

By T. Klemetti

Moisture deterioration of clay-rich roof rocks causes high numbers of roof falls in coal mines in humid summer months. Rocks with high moisture content are generally weaker and can further deteriorate when subjected to wetting and drying cycles. As a result, it is important to evaluate the moisture-sensitivity of roof rock prior to mining. The National Institute for Occupational Safety and Health (NIOSH) has evaluated three moisture-sensitivity index tests on roof rocks from 23 U.S. coal mines. The three tests were the University of Kentucky Weatherability test (Weatherability test), the Consol Energy Water Sensitivity test (Water Sensitivity test), and the NIOSH Immersion test (Immersion test). Of these three tests, the Weatherability and Water Sensitivity tests are more reliable in classifying the moisture-sensitivity of roof rocks. Disclaimer: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By Frances Badelow

This paper describes a design process for piled raft foundations supporting high-rise buildings. The design process comprises an initial stage of geotechnical site characterization using the results of investigation boreholes to prepare a subsurface model and derive geotechnical parameters for raft and pile design from empirical correlations. Following this a preliminary analysis is undertaken using a combination of elastic theory and allowances for non linear behaviour of the piled raft system to assess the viability of such a foundation system and any potential advantages of a piled raft over conventional fully piled foundation systems. Finally, a detailed analysis is undertaken using the GARP8 computer program. Case studies where this design process has been successfully used to design a more efficient piled raft system that has resulted in significant cost and time savings compared to conventional bored pile foundation options are also described.

Jan 1, 2006

By J. A. Flinn

Phelps Dodge’s Morenci copper mine has had six drills, six track-dozers, 16 shovels, two loaders, and 90 haul trucks equipped with either Caterpillar, Aquila, or Modular GPS systems for nearly three years. The Caterpillar Computer-Aided Earthmoving System is an open-architecture system, which allows for inputs to enhance orientation solutions and system functionality. This system has begun a new phase that leads to an intelligent mining system. Optimization techniques of the current system and inputs are reviewed. In addition, some practical issues of implementing new technology in a mining environment have been identified to aid in this new phase.

Jan 1, 2000

By Roy E. Peterson

The Bureau of Mines conducted bench-scale research to evaluate materials which showed potential as low-cost reductants for use in the ironmaking industry. These materials were lignite, subbituminous coal, coal char, tree trimmings, refuse--derived paperboard, used crankcase oil, and peat. To compare their effectiveness, the materials were tested in the reduction roasting of nonmagnetic taconite and, except for oil and peat, in the reduction of iron oxide pellets to metallized pellets. Reduction was conducted in a 18-cm-diameter, rotary drum, which was externally heated in an electric furnace. Over 92 pct of the iron was magnetically recovered from a nonmagnetic taconite after roasting with any of the reductants, but greater quantities of reductant were required to achieve this when the waste materials were used. The fossil fuels were also more effective for metallizing pellets, although metallizations above 90 pct were also obtained with tree trimmings and refuse paperboard. However, refuse paperboard had to be frequently recharged to the furnace because it depleted rapidly.

Jan 1, 1983