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By James R. Aggson, Verne E. Hooker, Dennis R. Dolinar

The stability of underground openings and mining systems is closely related to the in situ stress field. This paper presents a short discussion of the three-component borehole deformation gage and overcoring technique which the Bureau of Mines uses to measure in situ stresses, and a summary of stress data that the Bureau has gathered in the process of evaluating ground control problems. Specific ground control problems and stress distributions are discussed as examples.

Jan 1, 1982

By Sylvain Duchesne, Claude Bazin, Robert Grant

Grinding simulators are now widely available to assist in the selection of circuit operating conditions or flowsheet designs that yield a given product size distribution. These simulators do not inform of the impact of the grinding product size distribution on subsequent flotation stages. This paper presents a method to predict the effect of fineness of grind on a flotation bank operation. Application of the method is illustrated with data from two Canadian concentrators.

Jan 1, 1995

By Jerome C. Motz

Los tipos, tamaños y número de trituradores empleados en un sistema completo de reducción varían con factores tales como: el volumen de mineral que debe ser procesado, tamaño de la mina, tamaño máximo del todo-uno, dureza del mineral y de su roca soporte y tamano requerido para el producto final. Básicamente, sólo existen tres tipos distintos de equipos de trituración para la etapa primaria. Estos son: machacadoras de mandíbulas, trituradores giratorios y molinos de impactos, y cada uno tiene unas características operativas propias. Las trituradoras de mandíbulas operan por aplastamiento de las rocas entre dos paredes, una fija y otra móvil, en una cavidad determinada. Han sido ensayadas variaciones en la caída y movimiento, pero la mayoría de las máquinas del tipo Blake tienen un ángulo de trituración de aproximadamente 27° entre las mandíbulas fijas y móviles. El principio de trabajo del triturador giratorio es muy simple. Si un cono es montado en un eje vertical y la parte superior del eje se sitúa estacionaria mientras que la parte inferior gira excéntricamente, el cono tendrá también un movimiento excéntrico. Si el cono se coloca en una carcasa conveniente se movers aproximándose y retrocediendo de las paredes que lo contienen a la vez que gira. Si el cono y las paredes de la carcasa son suficientemente robustas y pesadas, cualquier cosa apresada entre ellas será triturada. Al lado de los incrementos de la eficacia desarrollados por las continuas acciones de trituración y el curvado de las caras de trituración, los trituradores del tipo giratorio tienen las siguientes ventajas: 1. La gran abertura de alimentación disponibles en comparación con trituradores de otro tipo. 2. El alto rango de tamaños y capacidades, que se encuentran entre 600 y 6.000 toneladas por hora. 3. Generalmente no es necesario control en la alimentación. Dumpers de 150 a 200 toneladas descargan directamente en las actuales instalaciones.

Jan 1, 1982

By M. J. McPherson

The legislation that prohibits the recirculation of air in coal mines was formulated because of the fear that concentrations of airborne pollutants would rise to dangerous levels. This paper undertakes a simple analysis of the effects of a controlled recirculation system on the gas concentrations in headings. It is shown, through an algebraic formulation and a numerical example, that a properly planned system of controlled recirculation leads to a reduction in the maximum general body gas concentration that occurs in a heading.

Jan 1, 1988

By Stavros A. Argyropoulos

The strides that have been made in recent years in applying Artificial Intelligence to pyrometallurgy, are reviewed. The computer reproduction of the way in which a human being reasons and calls on past experience and stored knowledge when faced with problem will be extremely helpful in pyrometallurgy. It is expected that Artificial Intelligence will be applied in all areas of human endeavor. Areas of pyrometallurgy that are most promising for expansion into A1 in the near future are presented.

Jan 1, 1990

By Robert C. Bates

Background is given on the various equations used to describe diffusion and convective flow of radon in porous media. Bureau-developed equations for modeling diffusion and Darcy flow through multilayered porous media are described briefly, and examples of their use are given. Analysis results discussed include: The transient effect of pressure changes in different length models, time dependent flux changes in multi-layered models, and radon flux through pinholes in sealants

Jan 1, 1980

By Peter D. Warwick

Recent investigations conducted by Federal, State, and industry organizations suggest that significant coalbed gas resources may exist in the Cretaceous and Paleocene-Eocene coal beds of the Gulf of Mexico Coastal Plain. Exploration efforts have focused on three areas which are in south Texas, north-central Louisiana, and south-central Mississippi (Figure 1). Coal-bed gas production is currently underway in south Texas and in north-central Louisiana. In Mississippi, several test wells have been drilled but no data are available on their production potential.

Jan 1, 2005

By P. Petropoulakis

Computer technology in the mining activities of our company has been applied in the last decade. In this presentation the experience gained by applying this computer technology in mining spescific applications are reported. Attention is given to the problems phased out and to the methodology used for software selection, centralized and decentralized development, data processing personnel and end users training and support. The paper concludes with a report of the first results obtained and a look at the future developments of the system.

Jan 1, 1989

By J. J. Schwoebel

Resource Enterprises Inc. (REI) is exploiting the coalbed gas resource by working in unison with active underground mining operations. At REZ7s pilot project at the Soldier Canyon mine, Carbon County, UT, RE1 has drilled nearly 15.25 km (50,000 ft) of horizontal in-seam and slant boreholes during the initial two years of drilling activity. Produced gas has been sold to a natural gas transmission company on a continuous basis since mid 1983.

Jan 1, 1988

By S. Behl, S. Mathur

It was previously reported that dolomite samples from different locations showed varying flocculation behavior with poly(ethylene oxide) (PEO). In this study, a Florida dolomite sample was examined, and it was determined that palygorskite associated with dolomite was responsible for its flocculation with PEO. A detailed characterization of dolomite samples from different locations was made by electrokinetic, XRD and FT-IR analyses, and the relevance of these characteristics to flocculation with PEO is discussed.

Jan 1, 1996

By John A. Herbst, William T. Pate, A. Edward Oblad

Dynamic optimization is a cost-effective means to increase production or improve product quality in a plant. Several model-based approaches to dynamic optimization of mineral processing operations have been developed and implemented in plants. This paper reviews the phenomenological models that are the basis for dynamic optimization and the alternative methods of mathematical optimization. These methods range from theoretically complex and costly to implement to intuitively comprehensible and readily implemented.

Jan 1, 1990

By W. Z. “Ben” Wu

The investigation provides a method of efficiency evaluation among several kinds of tools employed to cut different types of rocks. A ballistic test stand incorporated with a modified Hopkinson bar was used to simulate a percussive drilling tool. An Apple IIe microcomputer was employed for high speed data acquisition and numerical analysis. A newly developed method for remote monitoring the rock-tool interaction, including contact force, bit penetration and energy transmission,is presented in the paper. Theoretical predictions and experimental results appear in faily good agreement

Jan 1, 1986

By Daniel P. Coughlin, Robert C. Thomas, Christopher S. Romanek, Kristian W. Paul

Two separate constructed treatment wetland (CTW) systems receiving the same metal contaminated, acid sulfate water over different lengths of time and at different rates were evaluated for metal attenuation. Both wetlands are the alkalinity generator portion of a succesive alkalinity producing system (SAPS). Sequential extractions are employed to determine phases of metal removal. Results indicate that Fe, Al, Zn, Ni. and Cu accumulate in the organic substrate over time. Manganese accumulates initially, but is not retained in the system over time.

Jan 1, 2000

By Ian H. Clark

A series of numerical experiments were performed in order to elucidate the stress distribution, fracture strength and mineral liberation potential in single specimens of rock during crushing. Fracture strength was shown to reduce under eccentric loading conditions. Similarly, the presence of inclusions, both hard and soft, reduced the fracture strength. The predicted crack paths indicate that mineral liberation is unlikely to be preferential.

Jan 1, 1992

By G. Tapia, R. J. Kelley

Empresa Minera de Mantos Blancos S.A. successfully commissioned two copper SX-EW plants in late 1995. The design of these solvent extraction plants is such that chloride tenors of 30-35 g/l can be tolerated in the leach solution with no contamination of the electrolyte. The design was carried out in conjunction with Bechtel-ARA engineers and was based on the successful application of the available technology in the market; this mainly focused on decreasing the aqueous entrainment in the organic phase. This entrainment can reach 20,000 ppm in conventional plants.

Jan 1, 1998

By Roman Pyrih, Jim V. Rouse

Because cyanide is a naturally-occurring chemical, geochemical and biogeochemical mechanisms exist to retard or attenuate the movement of cyanide and its compounds in the subsurface and to degrade such compounds into low-hazard reaction products. The attenuation capacity of subsurface earth materials can be measured, predicted, and enhanced by simple and inexpensive procedures. The paper describes methods of testing the geochemical and biogeochemical attenuation capacity of the subsurface and offers general suggestions for methods of enhancing such capacity. It also presents examples of data which documents such attenuation.

Jan 1, 1991

By Jeffery L. Kohler

The characteristics of mine airstreams, such as their magnitude in the time and frequency domain and their spatial distribution, as defined by isovels, must be considered when making a measurement. The possibility for erroneous measurements is greatly increased when fixed- point sensors for mine monitoring systems are used. However, an a priori understanding of the airstream characteristics can be used to reduce the possibility of erroneous readings. This paper describes the problem, presents data to illustrate the nature of the problem, and provides recommendations for alleviating the problem.

Jan 1, 1987

By Ruth A. Maurer, Steven L. Capt. Van Drew

Coal preparation for a company having several sources of coal and several contracts for sale of coal was modeled. The objective was to minimize wash loss by selecting the quantity of coal to be supplied from each source and the appropriate washbox specific gravity setting to yield contract quality for a given shipment. constraints inposed by silo and stockpile sizes, plant and rehandling capacities, and varying coal quality specifications were included in the model. Solution is by iterative linear programming on an Apple II.

Jan 1, 1987

By Leo J. Laughlin

In recent years, heavy mining applications have put an increasing demand on conveyor pulleys. This has resulted in the increased usage of turbine pulleys. The designs of these pulleys are often based upon the failures seen in the conventional welded designs, overlooking the interaction of pulley-shaft system components as the profile of the disc is modified. This paper will focus on the development of balanced design philosophy using case studies of turbine pulleys in heavy mining applications, evaluated with FEA.

Jan 1, 2002

By J. P. Savely, D. E. Nicholas, R. D. Call

Slope stability is a probabilistic phenomenon and as such should be analyzed with probabilistic methods. Fracture orientations alone, insufficiently model the rock mass. Other parameters describing the fracture set characteristics are required with distributions that can be sampled to fit mathematical stability models. Important considerations are length, spacing, dip, waviness angle, and overlap. These parameters are of major concern in design and are difficult to measure. Reasonable estimates of the characteristics can be used to provide distributions.

Jan 1, 1977