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By D. E. Gorse, R. G. Anderson

"Indusmin's history dates back to 1937 when they developed the Blue Mountain Nepheline Syenite deposit at Nephton, Ontario, and began supplying material for the glass, fiberglass, paint, ceramics and rubber industries.Since then, as a subsidiary of Falconbridge Nickel Mines, Indusmin has expanded the Nephton operation, diversified into the aggregate quarries for the construction industries, with operations at Acton and Halton, Ontario, established silica plants at St. Canut, Quebec and Midland, Ontario, to supply the glass, carbide, ceramics, cleanser and concrete products industries, and the purchase of a foundry, Fahramet Limited, Orillia, Ontario, supplying steel and alloy castings to the mining, construction cement and petrochemical industries.Indusmin also has a Technical Resource Centre and Head Office facilities in Toronto.As this paper deals with Indusmin's experience with dust abatement, and although dust control is a concern at the Nephton, St. Canut and Orillia plants, we will be confining this paper to the experience gained at the Badgeley Quarry and Midland plant of the Ontario Silica Operation."

Jan 1, 1980

By Clifford Britch

"Kaiser Resources Ltd. has completed feasibility studies resulting in approval of $277,500,000 for the construction of the Greenhills Surface Coal Mine, located 35 km north of Sparwood, B.C. The mine is designed to produce 1,800,000 tonnes per year of metallurgical coal over a 20-year period by conventional truck /shovel methods.The project is in the detailed design phase, with some preparation work being carried out on the site. The major construction activities are scheduled to commence in the spring of 1981. Mine development and pre-stripping will commence in July 1981, with first coal production scheduled for mid 1983.This paper will be a general description of the project and will include a discussion of the geology, reserves, mine planning, coal handling and processing, surface facilities and related topics.IntroductionProject DefinitionThe Greenhills Project is designed to produce, by conventional truck I shovel surface mining methods, 1,800,000 clean tonnes of metallurgical coal per year for twenty years . The production/ life constraints were chosen as being meaningful for planning and evaluation purposes after appraisal of the market potential and are not limited .by economic reserves. Substantial additional strippable reserves are available which would facilitate expansion of the proposed mine life and/ or capacity. In fact , all the facilities are designed so that they can be expanded in the future to accommodate a doubling of annual coal production, and certain portions of the coal processing facilities are being installed with an annual capacity of 3,600,000 tonnes. The mine will also produce approximately 2,400,000 clean tonnes of oxidized thermal coal, mostly in the first decade."

Jan 1, 1981

By Archie Richardson

The trona mines in the Green River Basin, commonly known as the "trona patch," present an interesting set of rock mechanics issues stemming from mining in a unique underground environment. Like other minerals occurring in tabular deposits, trona is mined using high-productivity room-and-pillar and longwall methods. However, trona does not behave quite like other evaporites and behaves far differently than coal. In this paper, the following key issues in trona patch rock mechanics are discussed: material properties, in situ stress field, water and gas pressure effects, creep characteristics, pillar behavior, roof span stability, floor stability, underground tailings storage, longwall mining, two-seam mining. and solution mining. Many of the existing trona producers are entering potentially more difficult mining conditions, and much consideration is being given to "new" technologies such as longwall mining and solution mining. In analyzing 20 years of experience with trona patch rock mechanics issues the authors have identified key comparisons and contrasts with conventional tabular deposit rock mechanics that will help illuminate what has been learned as the trona patch enters the 21" century.

Jan 1, 1999

By Donald A. Bruce

The paper reviews aspects of the construction and performance of prestressed ground anchors installed in soils and weak rocks. Attention is focused on good practice for drilling, tendon fabrication and handling, grouting, stressing and testing. Regional variations - not always logically justified - are described. The performance of anchors in a variety of geological conditions is illustrated with reference to recent full scale test programs. 1. Introduction In the United States there has been steady growth in the use of prestressed anchors in materials other than competent or hard rock, in the years since their introduction in the late 1960's. This expansion has to a large extent been driven by specialty geotechnical contractors who both imported foreign developments and conducted their own basic researches, in locally prevailing conditions. With such data and experience, these engineers have had the confidence to promote "alternative solutions" for difficult earth support problems to receptive designers and owners. In turn, being engaged in the details of design and performance monitoring has given these parties the close exposure necessary for the real transfer and understanding of the technological concepts, and this knowledge has generated positive feedback for the contractors.

Jan 1, 1991

By Manuel Rapiman, Ricardo Sepulveda

The feasibility study of Escondida Norte (ENorte), recommended a slope angle design for the Final Pit. But, according to the experience obtained with the slope adjacent to the West wall of ENorte, in which Compañia Minera Zaldívar (CMZ) gained in its phase 4, a slope of similar geotechnical characteristics will be exposed in the West Wall of Phase 1 (Premine) and of the Final Pit, with an interramp angle 53º and with very good stability results. In this regard, Minera Escondida Ltd. (MEL) performed a study of the slope angles for the phases mentioned and according to this delivered the results of this evaluation, the recommendations and/or the necessary conclusions in the design to ensure that the slopes are stable enough and may enable safe operational management of them.

Jan 1, 2006

By W. Tom Witherspoon

Many Engineers are skeptical and cautious about skin friction factors for the portion of drilled piers where temporary casing is used. This has led Texas engineers in many cases to eliminate skin friction values for the cased section, which necessitates deepening the drilled shaft to compensate for the loss in the cased section. This paper has provided field test data that supports inclusion of skin friction in the temporarily cased hole section as a contributing factor in total axial capacity as comparable to open hole shafts of the same diameter. Reasons for the resultant friction values are provided including; remolding of the cased clay section and the increased pier circumference necessitated by the oversized casing required for adherence to the engineers shaft diameter specification.

Jan 1, 2009

By Brigitte Lacouture, Yeen Shien Hwang, David Lin

"A baseline survey of the partially open lead regrind circuit at Red Dog Mine indicated poor regrind efficiencies for the three parallel 450 HP tower mills. Driven by the high energy cost and the potential metallurgical gain brought by improved mineral liberation, the Red Dog lead regrind circuit was optimized in two stages.In the first optimization stage, different circuit layouts were evaluated in two plant trials. In June 2003, the regrind circuit was changed to a fully closed circuit. This reduced the tower mill requirement from three to two mills. The circuit modification payback was 11 days through power savings alone.The second stage of optimization was the evaluation of reagent addition. To improve pyrite depression, sodium cyanide was added to the feed of the lead regrind tower mills and tested in a series of plant trials over several mill feed stockpiles. Galena selectivity against pyrite was found to improve in these plant trials. Due to environmental sensitivities, no net increase in cyanide addition to the plant occurred and thus no increase in the cyanide concentrations in the tailings pond or the environment will result.The lead regrind optimization work improved the overall lead metallurgical performance and reduced energy and reagent costs. Economic analysis showed that annual profit increased by as much as US$3.0 M."

Jan 1, 2005

By A. C. Richardson

The mine of the Porter Coal Co. is located at the town of Porter in the northwestern part of Jefferson, County, Ala., about 20 miles west of Birmingham. The operations in this mine are confined to the middle and bottom benches of the Mary Lee bed. The coal from the Porter mine is handpicked and washed before being placed on the market. The handpicked lump coal and the washed egg and nut, coal are sold chiefly as domestic and steam-raising fuel. The coal finer than 1 inch is washed in 2-compartment jigs and utilized in the manufacture of metallurgical coke. The coal company has found that, when coal ranging in size from 1 to 0 inch is washed in jigs, a considerable amount of high-ash material finer than 3/16 inch remains in the washed coal. This paper gives the results of an investigation which was conducted for the purpose of determining the washing characteristics of the through 316-inch raw coal and the extent to which the ash might be reduced by means of coal-washing tables. This investigation has been made in connection with an. extensive study of the coal-washing problems now being conducted by the United States Bureau of Mines and the University of Alabama, with the cooperation of the coal-mining companies of the State.

Jan 1, 1933

By J. B. Hadaway

The current limit to power transmission for grinding mills through one mill pinion is approximately 7,500kW. Above this power rating either twin pinion arrangements or Gearless drives are required. The SMTP concept was developed to overcome this limitation by using two pinions with a single large drive motor. The SMTP mill drive offers major advantages in capital cost and greatly simplifies plant layouts, while using an innovative adaptation of industry-proven single helical gearing. Through the use of a single motor, provision of variable speed drive is greatly simplified. The SMTP can also be used for significant power upgrades on existing mills.

Jan 1, 2001

By D. O. Kennedy

"INTRODUCTION During the recent war attention was directed to prevent the destruction of American industries by sabotage. By Executive order of Lay 19, 1942, the Bureau of Mines was required to conduct investigations and make recommendations that would prevent loss of production of essential war minerals. The Health and Safety Branch of the Bureau of Lines was able to extend its activities with minimum loss of time to include security surveys of the important mineral facilities in the United States.A Mineral Production Security Division was established in the Health and Safety Branch with funds appropriated for that purpose by Congress in April 1942. From July 1942 to July 1945 engineers of this division, under the direction of D. Harrington, Chief, Health and Safety Branch, and J. J. Forbes, Chief, Mineral Production and Security Division, conducted investigations of 1,560 metallic and nonmetallic mines and associated facilities in accordance with the requirements of the Executive order.PURPOSEAn analysis of losses in the production of minerals shows that failure or destruction of equipment either from deliberate or accidental causes produces essentially the same result. Maximum production is insured by the prevention of subversive activities, fires, and industrial accidents."

Sep 1, 1946

By R. D. Dukimo, M. V. Sevian

The nature of fracture and factors that control the extent of fracture in the tumble-drum and drop-tower tests have been identified. The product-size distribution, on which the standard strength indices for these tests are based, and the breakage rate constants depend on a number of factors other than the strength of the lumps. The standard indices and rate constants are meaningful only in a comparative context and for events whose loading mechanism is similar. The results of experiments on three Australian ores, from Yandi, Koolan and Mount Whaleback, are used in combination with fracture mechanics theory to explain why different tumble-drum standards have been found to be fully consistent. A more meaningful measure of strength could be the parameters of the Weibull function, scatter and average strength

Jun 19, 1905

By M. R. Geer

The Bureau of Mines surveyed the solid wastes that have accumulated from coal mining in Washington, Oregon, and Montana. Location, amount, character, and condition were determined, and both economic and environmental factors were considered. Areas covered by waste comprise 800 acres in Washington, 5 acres in Oregon, and 1,200 acres in Montana. In a few cases waste is being utilized, particularly cinder from burned refuse dumps, as fill in road construction and as a ceramic raw material. It is estimated that wastes deriving from coal mined for electric power generation by 1974 may amount to 3 million tons of washery refuse, 2.7 million tons of fly ash, and 1,000 acres of spoil banks.

Jan 1, 1969

As part of the Bureau of Mines program for conserving domestic mineral resources, a survey was made of the methods used for identifying scrap metals. Because of the large number of alloys currently being scrapped, correct identification of these materials is essential if they are to be recycled effectively. The methods and instruments used to identify scrap metals are described and evaluated. These include object recognition, color, density, magnetic testing, spark testing, chemical spot testing, thermoelectric measurements, eddy current measurements, and elemental analysis by chemical and instrumental methods. Other potential techniques are discussed also.

Jan 1, 1982

By Dennis Dolinar

In this National Institute for Occupational Safety and Health (NIOSH) investigation, numerical modeling is used to evaluate the degree the pillar strength is increased with a rectangular pillar over a square pillar. Three-dimensional models are developed with pillar sizes and geometries typical of underground limestone mines in the United States. Physical properties for the models are based on geotechnical surveys of nearly 30 underground limestone mines. To examine the effects of pillar length on pillar strength with the modeling, a parametric study was conducted where the pillar width was held constant while the length and height were varied resulting in width-to-height ratios ranging from 0.5 to 1.5 and width to length ratios ranging from 1 to 6. There are two aspects to pillar strength and failure. At relatively low stresses, pillars can fail as a result of geologic structure. At greater depths and sufficient extraction ratios, the pillars can also fail as a result of the vertical stresses exceeding the pillar strength. The effects of increasing pillar length regarding both strength aspects are presented in this study. Equations were developed for the increase in pillar strength with both height and length based on the model results. The results from these equations were compared to those from previously developed empirical equations for rectangular pillars. For the more slender limestone pillars with a width-to-height ratio below one, there is little increase in pillar strength for length-to-width ratios above 2 and almost no increase with length for a width-to-height ratio of 0.5. Only with the more squat pillars is there a significant improvement in strength with length. The gain in pillar strength with length for the pillars is explained by the change in the ratio of the area of the pillar affected by the ends to the area of the pillar. For the squattest pillar, the change in strength is also affected by an increase in pillar confinement along the central length of the pillar as the pillar transitions from a square to a long rectangular pillar. With geologic structure, added pillar length can significantly improve the pillar strength, depending on the strike of that structure with respect to the long pillar axis.

Jan 1, 2007

By Wilhelm Knickmeyer, Johannes Henneke

PREFACE For about 1 year Bergbau-Forschung GmbH, central research institute of the German Coal Mining Industry, undertakes full size tests for waterjet assisted tunnel¬boring in German coal mines (Fig. 1). These tests are performed with a tunnelborer of 2.6 m diam in an upper [ ]

Jan 1, 1979

By Robert G. Nisle

The classic theory of pressure build-up in shut-in oil wells as developed by Horner and van Everdingen is based on two-dimensional radial symmetry in the well-reservoir system. Such symmetry does not exist in the case of a well which parfiially penetrates the producing formation. As a result of this lack of symmetry the use of the classic theory in such cases become questionable. In this paper the mathematical theory has been extended to include the case of partially penetrating wells. Numerical solutions illustrating the up-dication of the equations are presented. The effect of partial penetration on pressure build-up is shown by a comparison of synthetic pressure build-up curves derived from the numerical solution of the equation for partially penetrating wells for various degrees of penetration. It is shown that partial penetration is detectable from the characteristic shape of the pressure build-up curve and that formation productivity may be calculated from the pressure buildup data in a manner identical to that described by the classic theory. INTRO DUCTION The use of pressure build-up data on shut-in oil wells is a well-established technique for the measurement of reservoir productivity. The work of Homer' and van Everdingen' is well known. Since the publication of their pioneering work, others"' have elaborated and extended the technique. These authors have dealt exclusively with the case of wells that completely penetrate he producing formation. Two-dimensional radial symmetry is achieved, thereby, and the problem is greatly simplified. This ideal situation is seldom encountered in practice. But, in spite of this, the technique is often employed anyway. The question, therefore, arises: how much confidence can be placed in the results of such calculations when the data are taken on wells that only partially penetrate the producing formation? It is the purpose of this work to answer this question. Only the single-phase fluid case will be considered. van Everdigen' has presented a rigorous solution of the two-dimensional case, but because of mathematical complexity, this solution has not proved to be particularly useful. Horner' utilized Kelvin's point source solution in two dimensions and showed that it is a sufficiently good approximation for oil reservoir studies. The geometry of the well and the producing formation is illustrated in Fig. l. Geometrically the formation may be described as an infinite slab. The infinite slab is defined as the solid (the porous medium in this case) bounded by two parallel planes. Thus, the slab extends to very great distances in both the positive and negative directions of two of the coordinate axes, but is finite in

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

Conservation and environmental issues are raising their profile with respect to both demand restraint and electricity supply options. In New Zealand, conservation pressures and energy efficiency need to be seen in relation to the supply system currently in place which has capacity for economic supply of electricity in quantities substantially in excess of the current market. Consequently, energy efficiency and conservation need to be interpreted in relation to the supply system as well as in relation to end use. The relationship between the environment and conservation is strongest when new generation is required. New Zealand's electricity supply system consists of a large proportion of hydro production and this has significant environmental benefits when considered in relation to concerns of global wanning and the greenhouse effect. However, environmental trade-offs in supply options need to take account of both the efficiency of electricity end use, the trade-off between hydro and thermal generation and the inter-regional effects of shifting development options from one region to another. The Electricity Corporation has a high level of consciousness with respect to environmental and conservation issues and this paper demonstrates its own moves to maximise energy efficiency and illustrate the environmental trade-offs for supply.

Jan 1, 1990

By Robert B. Hopler

Explosives, originally used only in fireworks and warfare, became legitimate contributors to human progress when miners in Eastern Europe began using them to break rock in the early 1600%. Since that time these powerful materials have had a dual role in the world: as agents of destruction in war, and as irreplaceable tools necessary to advance civilization. In the latter role, they serve as agents to enable mankind to produce metals, build roads, and drive tunnels. In other words, to provide those materials, services, and infrastructure without which the modern world could not exist.

Jan 1, 1997

By Stanley C. Rhoads

The Bureau of Mines investigated the complete ternary system K2 HfF6¬K2ZrF6-l.25 weight-percent HF at 40° C. In addition, solubility curves have been established at 25°, 30°, 500, 60°, and 70° C. These solubility data implemented a study of hafnium enrichment in feed solutions for liquid-liquid extraction processes.. Selected K2HfF6-K2 ZrF6-1.25 weight-percent HF mixtures were equilibrated in a constant temperature bath. Compositions of the equilibrated solutions and wet residues were established from combined hafnium and zirconium oxide and total fluorine analyses. All solubility curves were essentially parallel on triangular coordinates. At 40° C, the solid phase of the K2HfF6-K2ZrF6-1.25 percent HF system is a series of solid solution hydrates with K2HfF6-H20 and K2ZrF6.3H2O segments existing at the respective extremes. Since this system contains K2HfF6-H20 and K2ZrF6.3H20 segments, it is not ideal for simple separation of high-purity K2HfF6 from K2HfF6-K2ZrF6 mixtures by recrystallization. However, it would be useful for producing hafnium-enriched feed solutions from zircon concentrates for liquid-liquid extraction of hafnium from zirconium.

Jan 1, 1973