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By K. Valta

This paper presents an approach for developing a Sustainable Development Indicators (SDIs) framework tailored to the Greek Industrial Minerals sector, due to its importance for the national economy. To achieve this goal, an overview of the Greek mining and minerals, and especially the Industrial Minerals sector, from a technological and a financial perspective, is presented. In addition, a brief description of the global initiatives to this direction is given. The proposed indicators are based on those presented in 2006 by the Greek Mining Enterprises Association (GMEA) adjusted for the sector of industrial minerals by taking into account economic, environmental and social issues, known as the Triple Bottom Line (TBL) approach.

Jan 1, 2007

By Lothar Anheuser

The appearance of very large shielded softground TBM's, of 14 m (46 ft) O.D. and more, as needed for two-lane highway tunnels, calls for a thorough search of overall stability and new solutions for front support during maintenance operations in the cutting chamber. The paper deals with the development of a shield for the planned 4 th tunnel crossing under the river Elbe in Hamburg. Specific problems arise from the high water head, the shallow overburden of loose soil and the stone-bearing mixed ground. The choice of the tunneling method and the different features provided to overcome the problems are discussed.

Jan 1, 1995

By George D. Tikkanen

The world supply of zinc and lead is reviewed. The nature of zinc and lead deposits, production constraints, current production and reserves, new developments, possible future developments, and closures are considered. Lead sup- plies for the future are adequate. Zinc supplies are expected to tighten in the longer term due to growth in zinc consumption and orebody depletion.

Jan 1, 1986

By S. Gopalakrisbn, J. D. Miller, M. Misra

Pilot-scale tests indicate that effective concentration of fine gold from Colorado River sands can be achieved by flotation with the air-sparged hydrocyclone. The fine sands (55% -400 mesh and 0.01 opt*) from gravity concentration were processed with a 5-cm air-sparged hydrocyclone (capacity ~1.0 t/h dry solids). Concentrate grades as high as 5.0 opt were produced in a single stage at a recovery of 75%. The separation efficiency was significantly better than that achieved in conventional batch flotation experiments.

Jan 1, 1987

By R. L. Grayson, M. P. Miano, S. Yuan

Matching the productivity gains of continuous mining machines with the increasing performance levels achieved by longwall units has required creative thinking to assure that development is completed in time for uninterrupted longwall production. By using management information systems to coordinate support operations, the most productive planning decisions can be made. This paper focuses on the role of computer technology tools in achieving improved productivity from both longwall and continuous miner sections. The primary emphasis is on the planning process and the methodology developed to guarantee the best allocation of management and manpower resources.

Jan 1, 1995

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 R. L. Grayson

Compliance standards for respirable dust, which are reduced because of high quartz concentrations, have become an industry-wide problem. Research on the physical and chemical character of quartz-classified particles in respirable coal mine dusts indicates that they may exist in intermixed layers or may he coated by clay or coal material. The relative amount of intermixing varies with the coal seam being mined. If most of the quartz particles of a mine dust are "pure," then the dust may have a high fibrogenic risk potential because of truly free silica and the compliance standard should he lowered. If, however, the quartz is locked inside another material matrix, or coated, a reduced compliance standard may not he appropriate.

Jan 1, 1991

By G. Jeffrey Taylor

The environment at the lunar surface is drastically different from the one we are used to on Earth. The Moon has one-sixth of Earth's gravity, virtually no atmosphere, a surface bathed in radiation and micrometeorites, large temperature gradients, low seismicity, and a dusty, rubbly surface. To successfully mine and process materials on the Moon and to mitigate degradation effects in the hostile lunar environment, these factors require new designs for equipment and development of new techniques and technologies.

Jan 1, 1990

By Frank Matter

Production of ultrafine powders of industrial minerals has been a problem in the past. In recent years new wet and dry grinding stirred ball mill systems have emerged which have been commercialized Two such systems are the TRZK mill with double step air classifier for dry grinding and the NRZK mill for wet grinding The primary features of these mills are feed entering from top and the product along with the grinding media leaving from the bottom, and a media separation and recycle system A detailed description of the NRZK mill for grinding coal is presented

Jan 1, 1983

By Rock M. Poulin, Bruce G. Moulton, Daniel E. Nowak, David T. Cass

The Yacambu Irrigation Tunnel Project of 34 km, 5 meter diameter circular and horseshoe section, has been under construction since the early 1970's. Notable among the excavation challenges is high ground cover of 3,000m creating large lithostatic pressures in the tunnel alignment with subsequent plastic flow of the ground in the tunnel walls. The tunnel may converge from small amounts to 1 or more meters of diameter over long sections. Several excavation techniques have been attempted but all without desired results. The paper proposes a new machine concept that uses the history of ground experience as its basis for design.

Jan 1, 1995

By Thomas W. Healy, David V. Boger, Yee-Kwong Leong, Lee R. White, Peter J. Scales

The concentration of mineral slurries by conventional thickening devices is discussed. The role of additives on the compression of mineral slurries is also examined. Results for a range of flocculation conditions are presented. The compression of flocculated mineral slurries is found to be highly dependent on the fundamental particle-particle interaction forces and hence, the rheology of the particulate fluid. It is demonstrated that a detailed knowledge of the properties of both the mode of operation of the thickening device and of the solid/liquid interface is required for improvement in the rate and in particular, the extent of dewatering.

Jan 1, 1995

By W. T. Gorton

Bonds are required by state and federal law to address reclamation when the permittee defaults. Under various principles of law, a bonding company may propose to perform the obligations of the permittee, however, the negotiations with the regulatory agencies, surface and mineral owners and other interested parties can create a very complicated scenario that requires an understanding of the law regarding environmental protection, bankruptcy and surety ship, along with technical expertise in land reclamation. This paper presents the engineering professional with a framework regarding areas of law that pertain to surety reclamation projects and negotiations with state and federal agencies and related parties. Though presented in the context of the coal industry, the principles discussed are generally applicable to the mining industry as a whole.

Jan 1, 2003

By S. L. Zhu, Brij M. Moudgil, J. L. Pinault

Prompt neutron activation probe (PNAP) was evaluated to determine chemical composition of phosphate rock slurry in-situ. The technique was able to precisely analyze Ca, Si and H using a 252Cf source. Direct measurement of P and Mg was not accurate due to interference by the rare earth elements associated with the Florida Phosphate Rock. The solids loading, particle size distribution and flotation reagents present in the slurry had no significant effect on the accuracy of the measurements. The technique was found to be reliable also under industrial conditions.

Jan 1, 1993

By Robert M. Rowe

Among the increasing operating costs affecting today' s processing facilities are those necessary in meeting the continually growing requirement for safe and environmentally sound materials- control and handling procedures. Of particular interest are materials listed as hazardous, the need to maintain accurate records of their acquisition, consumption and disposal, and the obligation to employees and the community to have information available regarding such materials. Some requirements affecting modern operating facilities are reviewed in this paper, and potential methods for dealing with complex handling and documentation requirements, including computer automation, are discussed.

Jan 1, 1991

By A. S. Dremukha

The problems of geological exploration are discussed on the basis of computerized modeling of, complex orebodies, as well as the task of data authenticity evaluation. The theoretical baseof modeling is solving the problem of determining the parametres of orebodies sizes distribution along random intersections by exploratory workings. The relationship is established between univariate distribution moments in the intersections and the moments of the orebodies sizes distribution in three dimentions. It is suggested to use the obtained results for compyter modeling of the orebodies accumulations and for imitation modeling of their exploration. The computer experiments with the models make it possible to establish the optimum parametres of exploration networls.

Jan 1, 1989

By A. I. Arol, I. Iwasaki

Clay minerals adversely affect the selective flocculation of iron ores. The effect of montmorillonite on a hematite-quartz mixture was studied. Montmorillonite, particularly in the presence of Ca++, caused indiscriminate dispersion of the pulp. Three possible mechanisms were postulated, namely, card-house structure formation, adsorption of dissolved species from montmorillonite, and montmorillonite- hematite interaction. It was determined that hetero- coagulation of montmorillonite on hematite was responsible for the behavior. Flocculation tests, montmorillonite abstraction tests, starch adsorption tests, zeta potential measurements, and surface analysis techniques were used to ascertain the montmorillonite-hematite interaction and to account for the manner in which it affected selective flocculation.

Jan 1, 1987

By Brij M. Moudgil, Ivan U. Vakarelski, Yakov I. Rabinovich

Polymer and surfactant dispersant are widely used to disperse filler particles within a medium. Sur- faces active dispersants form self-assemble structures at the solid-liquid interface. The mechanical properties of the surfactant structures have been determined to strongly influence the dispersion behavior. In this study the atomic force microscope (AFM) is used to determine the elastic modulus and yield strength of a steric dispersant layer adsorbed to a rigid non-deformable surface. To interpret these values a model for elastic body contact based on a modified Hertz theory is applied. The results from this method may aid in the design of application-based dispersant systems.

Jan 1, 2003

Magnetic separators are commonly used as an effective and low-cost method to concentrate paramagnetic or ferromagnetic minerals. These versatile separators are often used in multistage circuit configurations to further improve concentrate recovery and/or grade. Although these circuits are generally very efficient, field studies suggest that the layout of multistage circuits can be less than ideal for many industrial operations. To illustrate this shortcoming, a theoretical analysis has been conducted to compare different circuit configurations for magnetic separators. The resulting knowledge base has been used to establish generic engineering guidelines for the layout of multistage circuits. The potential improvements in separation efficiency that may be realized through the application of these guidelines have been demonstrated using a simple case study.

Jan 1, 2004

By J. D. Raulerson, R. P. Farias, G. A. Gruber

A flotation process has been developed to successfully treat ore from the Santo Domingo phosphate deposit in Baja California Sur. The ore contained less than 4% P2O5 with quartz, silicates, and carbonates as gangue minerals. Flotation of the low- grade feed in seawater required that the conventional Crago process, comprising direct anionic flotation, deoiling, and inverse cationic flotation, be augmented by an anionic cleaner flotation step, phosphate depression, and a calcite flotation step.

Jan 1, 1988

By Lawrence A. Ph. D. Hansen, J. David Deatherage

Laboratory testing programs were conducted to investigate the performance under compression loading of several types of geomembranes and geotextiles proposed for use in heap and dump leach projects. Synthetic liners of several thicknesses were sandwiched between representative subgrade soils and cover materials, thus modeling in the laboratory the actual installation conditions expected. Performance was evaluated by visual inspection and vacuum testing. Several testing procedures and equipment were used to investigate the effect of these testing parameters on the predicted performance.

Jan 1, 1987