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By Lynton S. Land

Representative collections of recent dolomites, and of samples concentrated by leaching-out of coexisting magnesian calcites, provide grounds for appraisal of the compositions and cation ordering in recent dolomitized sediments. Unit cell volumes for near-stoichiometric compositions exceed those of ordered dolomite and increase as the departures from regular cation order became more pronounced. Infrared absorption maxima of disordered examples occur at perceptibly lower frequencies. Stable isotope ratios indicate that best ordered examples formed in highly saline environments. Present observations are qualitatively reconciled with data from synthetic products described by other authors.

Jan 1, 1972

By G. K. Roset, L. R. Woodland, J. A. Stevenson, G. J. Hodges

The Stillwater Mining Co. (SMC) is a partnership of Pittsburg & Midway Coal Mining Co. and Manville Corp. Since the summer of 1990, SMC has operated a precious metals smelter at Columbus, MT for further upgrading of concentrates from its platinum-palladium mine. The facility's gas-cleaning system utilizes "oxidation/dilute-mode," dual-alkali scrubbing technology to capture sulfur oxide gases from the process gas streams. This paper describes the rationale for selecting the dilute-mode, dual-alkali system and summarizes the design parameters. Also discussed are the startup problems encountered and their solutions.

Jan 1, 1993

By D. K. Sitler

Continuing advancements in manufactured diamond materials as used in rock cutting tools have created a new generation of high production tools for mining. This paper reviews the three major manufactured diamond product types available in the mining industry as supplied by General Electric Co., Specialty Materials Dept., and examines the ways these materials are used. As an integral part of this examination, the economic impact of manufactured diamond tools is evaluuted. Time and again, one will find that the premium price for these tools is economically justified when compared to traditional tools.

Jan 1, 1988

By Harold L. Kike

Until recently sulphur uses were so broadly based that economists used sulphur consumption to measure industrial activity. However, sulphur use patterns are changing and the manufacture of phosphate fertilizers presently accounts for approximately 65% of the world's sulphur consumption compared with only 25% in 1960. This has encouraged the development of new agricultural and industrial uses for sulphur. Major emphasis has been placed on its use as a fertilizer and in the manufacture of paving materials, specialty concretes and coatings. Some of these uses could have a significant impact on future sulphur usage.

Jan 1, 1986

By Isiah M. Warner, Philip Oldham, John Kennedy, Bennett D. Lass

A new method for determination of residual flotation oils on beneficiated kaolin clays has been developed The method, which yields qualitative information, is based on fluorescence measurements employing a spatially resolved, polychromatic illumination source for excitation, and a two-dimensional detection scheme using a silicon-intensified, video imaging device The method was used to identify residual oils on a beneficiated, Washington County, Georgia, crude clay The results were compared to a similar qualitative analysis performed via capillary column gas chromatography using a flame ionization detector The video fluorometry was the preferred method of analysis

Jan 1, 1983

By N. T. Rempe

The underground voids that result from mining provide opportunities for deep geologic waste disposal (DGWD). Such disposal could solve many environmental problems. DGWD takes careful planning, technology transfer and true partnership between waste generators and mine/repository operators. The US government is now planning on using specially mined excavations to dispose of radiotoxic and mixed waste. Using the experience gained from the domestic projects that are now in preparation and from foreign repositories that are now in operation, US mines can claim their rightful share of the growing market for DGWD.

Jan 1, 1998

By A. Arik

The accurate estimation of mining-block grades continues to be a challenging task for ore reserve practitioners. The estimation method used and the variability of the mineralization in the deposit are two factors that affect the accuracy of the estimates. The objectives of this study are to determine how different estimation methods perform on a given deposit and to determine the impact that the nature of the mineralization has on the results. A comparison of several estimation methods for prediction accuracy is performed based on conditional simulation results.

Jan 1, 2002

By N. T. Rempe

The underground voids that result from mining provide opportunities for deep geologic waste disposal (DGWD). Such disposal could solve many environmental problems. DGWD takes careful planning, technology transfer and true partnership between waste generators and mine/repository operators. The US government is now planning on using specially mined excavations to dispose of radiotoxic and mixed waste. Using the experience gained from the domestic projects that are now in preparation and from foreign repositories that are now in operation, US mines can claim their rightful share of the growing market for DGWD.

Jan 1, 1997

By L. Alan Weakly

Coal mines and power plants utilize different methods to control dust for the safety of their workers and to protect their installations. The methods that they use are limited by the Environmental Protection Agency or the states in which they operate. Now there is a new technology for controlling dust at conveyor transfers! The Passive Enclosure Dust Control System utilizes several proven technologies to mitigate fugitive dust. This new system has been proven to be four times more effective than standard enclosures utilizing bag house collection and is considerably less expensive to install and operate.

Jan 1, 2000

By A. M. Abouzeid, R. Hogg

Materials transport is involved in all phases of mineral processing. Bulk transport is necessary for moving materials between unit operations and through processing devices such as grinding mills. Differential transport is a primary mechanism for most separation processes. The basic mechanisms of transport and flow in particulate materials are reviewed and their role in materials handling and storage and in the performance of processing operations such as grinding and separation are discussed. Specific examples are used to illustrate current understanding of these transport phenomena and to indicate important research needs and opportunities.

Jan 1, 1989

By Robert C. Bates

Published information on costs of radon-daughter control in uranium mines was analyzed to develop estimates of the cost per ton for any level of radiation exposure control. All data were converted to 1967 cost of living index to provide a common analysis base. Results of the analysis show that the cost per ton increases exponentially as the radiation level is lowered. A linear relationship with the cost of living index is assumed, and equations and graphs are provided to estimate control cost per ton for any exposure control level and cost of living index.

Jan 1, 1981

By G. Banini

A plug-flow model is described for the reactor mass balance of a typical AARL gold elution process. The model is in the form of a hyperbolic differential equation and was transformed using the method of characteristics. The transformed model was then solved simultaneously with models dependent on intraparticle surface diffusion and film transfer parameters. The solution was found to represent the experimental data for a modified form of the AARL elution. Correlation between the experimental conditions and the film transfer parameters estimated by the model are also presented.

Jan 1, 1998

By Eric Forssberg, Benny Andreasson

The paper describes experiments to stabilize mineral processing waste materials for use in construction. Fine mineral processing wastes from various mines have been mixed with binders and compacted. As binders blast furnace slag and other materials have been used. Experiments have been made in laboratory scale and in large scale. The results have been evaluated by means of determinations of compression strength and the modulus of elasticity. The paper also describes some experiments in laboratory and large scale to use stabilized mineral processing wastes for back filling in cut and fill mining.

Jan 1, 1992

By S. K. Kawatra, T. C. Eisele

Under normal conditions, a significant amount of pyrite is recovered in the froth during flotation of high-sulfur coal. To reduce this pyrite recovery, it is first necessary to determine the primary recovery mechanism, because different measures are required for reducing entrainment, locked particle flotation or true hydrophobic flotation. In this paper, evidence is presented that suggests that hydrophobic flotation is not the major mechanism for recovery of liberated pyrite; instead, the bulk of the recovered pyrite results either from simple entrainment or from being physically locked with floatable coal particles.

Jan 1, 1993

By B. K. Parekh, R. H. Mehta

The handling of fine coal is an important issue for both the coal and utility industries. Reconstitution of fine coal in the form of pellets or briquettes would be desirable if it could be done economically. This paper evaluates the effectiveness of three binders, asphalt-emulsion, corn starch and Brewex, informing pellets of ultrafine clean coal. It was found that asphalt-emulsion and corn starch were not effective binders. However, the use of Brewex resulted in pellets that exceeded all of the minimum quality requirements for coal pellets.

Jan 1, 1997

By W. R. Penney, J. M. Richardson, J. Y. Oldshue

Introduction The mining industry has for years underrated the value of mixing in mineral processing unit operations. In present-day operations where leaching is playing an ever increasing role in the total profit picture, the need for good mixing is becoming more obvious. The engineer in the research laboratory and in the operations is by necessity becoming more familiar with the concepts of mixing. This section is designed to provide the engineer with mixing data and correlations sufficient to assist in the general planning of simple mixing systems.

Jan 1, 1985

By R. P. Moran, B. C. Lewis

The objective of this article is to discuss the fundamentals for determining the value of a limestone reserve or operation. The general step-by-step procedure, while prudent, is subject to the various site-specific issues that influence the valuation calculation. The most common methods for determining fair market value of mining lands are: comparable sales, operational analysis, and royalty analysis. An overview of typical eastern limestone mines (both quarries and underground) is presented. Specifically, properties in West Virginia and Alabama are reviewed and the sample methodologies and valuation calculations are presented.

Jan 1, 1991

By Vanessa M. Torres, Lafayette C. L. Freitas, Evandeo C. Silva

This paper shows two applications of artificial intelligence models in process development. In the first application, a heuristic fuzzy correlation can predict flotation behavior in bench scale based on feed characteristics for a high variability copper ore, as well as to predict plant performance for a feasibility project evaluation, minimizing its risk. The second case study shows the use of neural networks to model the iron ore sintering, correlating ore characteristics and operational parameters with sinter properties. With this application, CVRD aims to establish a new step on iron ore product evaluation and customer support.

Jan 1, 1998

By S. Chander

The effect of pretreatment potential on the response of a gold electrode for Eh measurements in sulfide solutions was examined in terms of measured Eh values and electrode response time. The electrode response time is defined as the time required for the electrode to reach a steady-state value. The relationship between measured Eh values and the hydrosulfide ion concentration is established. The effect of pH, the reversibility of the gold electrode in the sulfide solutions, and the reproducibility of measurements are also investigated. A mixed potential theory is proposed to explain the observations.

Jan 1, 1989

By Håkan Tyni, Jan Björkman, Per-Olaf Samskog, Irving Wigdén

Process automation can provide better utilization of capital investments. Furthermore, it is a necessity for securing the high demands of product quality. In this paper, process automation in underground mining as well as in the beneficiation plant will be discussed. The development of reliable broadband communication systems for real-time transfer of image, audio and data have enabled remotely controlled LHDs and drilling rigs. In the beneficiation plants, model-based expert control systems far on-line dynamic process optimization and control have been installed in unit operations such as grinding, flotation and induration.

Jan 1, 2000