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By R. J. Pruett, P. I. Prescott

Ground calcium carbonate (GCC) is used in the paper, plastics, paint, rubber and caulks and sealants industries. The favorable properties of GCC include high whiteness and brightness, low hardness and outstanding rheology in water systems. The quality of calcitic GCC ores, which includes chalk, limestone and marble, is dependent on calcite purity and the nature and quantity of the impurity minerals. Wet and dry grinding are used in the processing of GCC. Ore processed by optical sorting, flotation and/or particle-size classification has higher brightness and lower abrasion characteristics. GCC markets are a function of the product's properties, purity and cost.

Jan 1, 1997

By Scott K. Palm

The initial intent of the Hazard Communication Standard (HCS) was to improve worker health by providing more information about the hazards of chemicals used in the workplace. However, the impact of the HCS goes well beyond worker right-to-know. There are direct costs associated with compliance. In addition, labelling and hazard communications can provide a competitive advantage to producers of minerals that have not been identified as hazardous. Often, the lack of hazardous information about a substance is due to the lack of scientific study, rather than an indication of product safety. Currently, industry and regulators sometimes give known hazards greater weight than unknown risks.

Jan 1, 1991

By Jonathan J. Owen

We will describe modifications to air-sparged hydrocyclones (ASH) that enhance collisions and reaction of wastewater contaminants with sparged gas. These new ASH-based reaction chambers are combined with flotation tanks that are designed to optimize separation of bubbles and particles from water. In combination, these systems have achieved unprecedented removal of contaminants from industrial wastewater and process water while requiring smaller footprints with lower capital and operating costs. Real-world examples of chemical and nonchemical water treatments that demonstrate the outstanding flexibility and applicability of these systems are shown. Design enhancements that resolve the operational problems of traditional ASH are discussed.

Jan 1, 1999

By K. N. Han, P. B. Queneau, Bruce W. Cavender

Measures of metallurgical performance, such as recovery rates or mass balances, are frequently based on point estimates of operating conditions in the system of interest. Because the processes being measured are dynamic, a range of uncertainty accompanies each measurement; this uncertainty is reflected in the accuracy with which the calculated result describes the true metallurgical performance. In stochastic modeling, a range of probable values is used in place of a point estimate to describe each variable. The calculated result takes the form of a distribution, delineating both the magnitude and probability of potential outcomes.

Jan 1, 1993

By Ugo Preti, Gianfranco Ferrara, Mark C. Williams, Thomas P. Meloy

Theoretical and experimental lockedness profile curves are the same when the model assumptions are met. They appear different because of the way the data is presented. Continuous theoretical lockedness profile curves present all the data, including the wings of the curves giving them the deep U-shaped configuration. Experimental lockedness profile curves, because of the measurement methods, are discretized, obscuring the wings. If the continuous theoretical curves are discretized, they are similar to the experimental curves. When a float sink test is used to measure an interval of locked particles, the integrated averaging of the separation process obscures the wings of the continuous theoretical curve. To disclose the wings with experimental data, narrow density or measurement intervals must be used.

Jan 1, 1992

By G. Bezuidenhout

The newly developed Bateman Flotation Machine has proven its versatility in roughing and cleaning flotation circuits. This mechanical flotation machine has the dual performance capability of suspending solids and dispersing air at relatively low power inputs without compromising these two important fundamentals. This new development has been successfully marketed to a wide cross section of concentrator mineral processes. The mechanical design of the flotation mechanism has been optimised to reduce operational costs and to lower manufacturing costs. Production process environments were utilised for verification of the scale-up of each cell volume size rated mechanism. These thorough investigations produced performance data which could be accurately quoted. This paper is a historical account of the Bateman Flotation Machine. Technical details of the development are covered with descriptions of the operational applications.

Jan 1, 1995

By Leonard Harris, Rosa H. Harris

An important part of doing business today in the mining industry, especially overseas, involves community assistance programs for the people who live around the mining areas. The purpose of such a program is to build mutual cooperation and respect that will allow the company and its neighbors to live and work in peace. To do this, it is necessary to form associations or foundations and work in a joint venture fashion. The authors discuss in some detail the outline for setting up such programs and the important role that women, in particular, can play in them.

Jan 1, 2001

By A. G. Wylie

The dimensions and shape both airborne and bulk amphibole-asbestos fibers are different from those of both airborne and bulk of cleavage fragments of the amphiboles. These differences are related to the mineralogical properties unique to the habit of asbestos, including the fibrillar structure, small fibril widths and distinctive crystal-lographic faces of fibrils. Criteria for distinguishing amphi-bole cleavage fragments from amphibole-asbestos include mineralogical properties observable in bulk samples and the dimensions of particles collected on air filters. It would be it very helpful to the mining and mineral industry lf these properties were recognized in the regulation of asbestos.

Jan 1, 1987

By M. Z. Dogan, M. S. Celik, G. Onal, O. Ozcan, I. Yildirim

A fluorite ore (51.85 % CaF2) containing high contents of calcite, quartz and iron oxides was upgraded by flotation using a new reagent, oleoyl sarcosine (OS). In addition, quebracho and sodium silicate were used as depressants for calcite and quartz, respectively. The effect of pH, collector and depressants concentrations on grade and recovery was determined with the aim of optimizing the flotation conditions. Application of the two-stage cleaning achieved a concentrate assaying 92.17 % CaF2 with 80.1 % recovery. The Si02 content (0.76 %) was below the required level of 1 % SiO2. The mechanism of interaction between OS and fluorite, as compared to oleic acid, is also elucidated based on the zeta potential measurements.

Jan 1, 1993

By M. Z. Rashad, H. A. El-Sageer

The intersections of numerous joint sets at the surface of tunnels of the Abu-Tartour project in Egypt create blocks of irregular shape and size in the rock mass. Although most of these blocks are unable to move into the free space of the tunnel, a few key blocks are capable of such movement. In addition, as soon as they move, some restrained blocks will be liberated. The aim of this work is to find the removable key blocks of the walls, floor, roof and corners of a portion of the tunnel under jointed surface rocks and then determine the best tunnel direction.

Jan 1, 1993

By Y. A. Attia, D. K. Sengupta, H. A. Hamza

Increased recycling of waste paper has been emphasized in recent years in both the United States and Canada for environmental and economic reasons. Removal of ink particles from waste paper pulp is therefore necessary. One of the most promising methods for ink removal is froth flotation. This study investigated the feasibility of a simplified flotation scheme and found that about 90% to 92% ink removal can be achieved. Also, a 95% to 97% ink removal is achievable if a hydrophobic polymer is used ahead of the flotation stage. Clean paper pulp recovery was over 90%. The effects of pulping pH, flotation pH and concentrations of flotation and polymeric reagents are discussed in the paper.

Jan 1, 1995

By B. J. Scheiner, D. A. Stanly, P. M. Brown

The Bureau of Mines has developed an equation that describes the dewatering of clay slurries with poly- ethylene oxide. This dewatering equation is: A[ ] = KC + b where n, k, and h are empirical constants and C is the concentration of polymer solution used for dewatering. The minimum amount of polymer required for dewatering, A, is determined by titration of the clay slurry with a polymer solution. In this report, the dewatering equation is applied to data obtained for a polyacrylamide dewatering sequence. Fundamental similarities between the dewatering properties of clays and the viscosity of polymer solutions were observed. These similarities were explained by correlating an equation describing polymer configuration in solution with the dewatering equation. This correlation showed that the amount of polymer required for dewatering and polymer solution viscosity are both the consequences of the frictional interaction of entangled polymer coils.

Jan 1, 1991

By F. M. Doyle

Metal removal kinetics and metal ion selectivity in ion flotation were studied from a thermodynamic perspective. Surface tension data could be used with the Gibbs adsorption equation to quantitatively predict the metal-ion removal kinetics in alkylsulfate-Cu systems. However, surface tensions predicted cation selectivity coefficients in the sodium dodecylsulfate (SDS)-Cu-Ca and SDS-Cu-Pb systems rather poorly, although the predicted order of the selectivity (Cu2+ < Ca2+ < Pb2+) was correct. Another thermodynamic selectivity model, which used the Grahame adsorption equation and a geometrical analysis, predicted cation selectivity coefficients that agreed very well with experimentally measured values.

Jan 1, 2002

By Maureen D. Carmen, Joseph L. Zaluski, Gladys Beck Green

The Federal Surface Mining Control and Reclamation Act (SMCRA) requires a surface mine operator to post a performance bond before a mining permit can be issued to that operator. Release of that bond is contingent upon the completion of all required reclamation, restoration, and abatement work on the permit area. This paper explores the requirements of each of the three phases of reclamation under SMCRA, as well as provisions of four exemplar state regulations of four states that have been granted "primacy" under SMCRA. Successful completion of these requirements is a condition pre cedent to the release of performance bond liability. Failure to secure a timely bond release will have an ad verse impact on an operator&apos;s other mine permitting activities throughout the United States.

Jan 1, 1991

By L. J. E. Hofer, L. F. Zeiler, D. A. Giardino

The Jones Trickett Ratio (JTR) is generally used in investigations of fires and explosions for the determination of the composition of the fuel. This paper takes a close look at the JTR and finds it unreliable and ambiguous for the determination of fuel composition. A new index is presented, termed the (H/C) Index which uniquely determines the fuel composition. The (H/C) Index is simple to use requiring only the results of a single gas analysis of the combustion products. Experimental data testing the (H/C) Index for methane, propane, ethylene and coal dust are given, showing that the Index unambiguously determines the composition of the fuel. The (H/C) Index is also applied to the gas analysis data of several mine fires, illustrating how the Index changes with the progression of the mine fire.

Jan 1, 1993

By Ronald J. Thomas

Prior to 1974, bauxite-producing countries were poorly informed about important aspects of the bauxite/alumina/aluminium industry. This placed them at a disadvantage in negotiations over the development of the industry with interested parties. Since the formation of IBA, its member governments have acquired a fuller awareness of the structure and operation of the industry. The role of IBA is to enlarge the relevant information base of member governments, to act as a forum for the exchange of information on the industry and to form a focal point for multilateral discussions on problems in the industry with corporate interests and with governments of consuming countries.

Jan 1, 1984

By Shouci Lu, Sun. Keji

Most phosphate ores in China are characterized by fine dissemination of the intergrown minerals and high content of carbonates. Therefore, in order to recover phosphorus minerals by flotation, some technological problems must be solved, such as fine particle flotation and separation of phosphate from carbonates. For effective flotation of finely ground phosphate ores and selective separation of phosphorus minerals from carbonates, S-series and L339 modifiers have been developed. A series of combined collectors with improved collector ability and selectivity have been developed and applied in several flotation plants in China. In this paper, CCLS, a combined collector for phosphates and PA-31 and a collector for reverse flotation of carbonates, are described. It has been found that some surfactants added with fatty acids function well in flotation at lower temperature, hence heating pulp in winter may be excluded. It is important for energy savings. The synergy mechanism of these additives in fatty acid flotation is discussed in this paper.

Jan 1, 1999

By P. Arell, D. Folkes

This paper presents the basics of EPA’s Hazard Ranking System (HRS), which is used to evaluate sites for possible inclusion on the Superfund National Priorities List (NPL). The paper describes the surface water, ground water, air, and soil exposure pathways and how they are applied to mining sites. Key factors contributing to the site score include the likelihood of a release, waste characteristics, and the targets for each pathway. Waste volumes, definitions of landfills versus surface impoundments, and background concentrations are of particular importance to mining and smelting sites. Because of the presence of metals, large waste volumes, and observable releases, mining and smelting sites often receive high enough scores to be proposed for the NPL based on a single path-way. Neverthess, owners and operators can take steps to reduce the risk of being scored, and to reduce the potential for high scores.

Jan 1, 2004

By E. Topuz, M. J. McPherson, I. M. Konduri

This paper describes experiments conducted to evaluate the effectiveness of jet fans for ventilating blind headings in under- ground mines. A laboratory model of a mine heading was built by using dynamic similarity criteria, and water as the fluid medium. In order to verify laboratory test results, field experiments were designed and carried out in a full scale mine model and in a coal mine in West Virginia. Using CO, as the tracer gas and in combination with a computerized gas monitoring system, tests were conducted to evaluate jet fan performance. The results highlight the flexibility and versatility of jet fans for ventilating blind headings. Numerical modeling of a jet fan in a typical coal mine heading was carried out to evaluate the potential of computational fluid dynamics.

Jan 1, 1997

By R. F. Hüttl

World-wide Germany is the leading lignite mining nation. Most of the lignite is produced in opencast operations. However, opencast mining causes enormous impacts on natural ecosystems and even on entire landscapes. The extensive production of lignite particularly in eastern Germany results in large devastated areas, which so far have been reclaimed only to some part. For the restoration of the post-mining area of more than 80,000 ha the major land use option is the reestablishment of forest ecosystems. However, adverse site conditions of the post-mining landscape such as extreme soil acidification and salt concentrations call for specific recultivation practices. Therefore, after the German reunification new reclamation and reforestation concepts have been developed for these brown coal areas of eastern Germany by the Collaborative Research Center (SFB 565) at the Brandenburg University of Technology at Cottbus (Germany). As a case study our comprehensive investigations into forest ecosystem development on terra nova in the Lusatian lignite mining district, south-east of Berlin, will be presented.

Jan 1, 2003