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By J. Iannicelli

A variety of domestic bauxites have been beneficiated to meet refractory grade standards by use of high intensity, high gradient, wet magnetic separation. Besides reducing the iron content to less than 2%, the Ti02 content of the bauxite was also reduced. The beneficiation can be accomplished by means of a simplified wet process flow sheet with an estimated cost comparable to that of water washed, filler grade kaolin. The process has been carried out on a small pilot plant and then scaled to produce 25 tonnes of calcined refractory bauxite meeting National Stockpile Specifications.

Jan 1, 1984

By Donald J. McKee

The product sizing and tonnage from a grinding circuit are the end result of a series of linked size reduction stages which always involve: fragmentation in mining; degradation in transport of ore; crushing and finally grinding. A case study is presented which illustrates the substantial effect on autogenous mill throughput of different mining practice. It is shown that it is possible to model each of the size reduction steps of fragmentation, degradation, crushing and grinding. The way in which this predictive capability is used is dependent on the operating constraints of each mine-mill combination.

Jan 1, 1998

By Gopalan Ramadorai

This paper presents a review of halogen solvents used in the processing of precious metals. Reagents of widely varying chemical structures, such as chlorine gas, calcium and sodium hypochlorite, chlorine dioxide, iodine and bromine have been used for precious metal extraction. None of these chemicals are a replacement for cyanide: however, each of these chemicals present an opportunity for use in processing a specific type of ore. The ore and chemical must be matched to each other for success. Recovery of metal from the leach solutions also offers challenges.

Jan 1, 1994

By V. L. Zajakowski, J. D. Gargulak

The current political climate has forced multinational cement manufacturers to consider technology that minimizes GO, emissions. Along with this environmental issue, individual manufacturing facilities are under constant pressure to increase productivity and lower costs. The use of processing or functional additions can help address these difficult demands by maximizing the extender content in blended cements. Recently, cement standards have been modified such that additions can be employed to improve quality. By using these "cement performance enhancers," the cement manufacturer can maximize extender content of cement thus optimizing plant economics, while meeting local quality standards and minimizing greenhouse gas emissions.

Jan 1, 2003

By W. R. Dearman, N. Turk

The theoretical relations between the strain and stress Mohr circles make it possible to establish a relation between the internal friction angle [ ] and the Poisson's ratio (v) of rocks. The internal friction angle is related to the Poisson's ratio as Sin [-] = (1 - v)/(l + v). This relation gives lower friction angle values than the triaxial Mohr envelopes and higher values than those given by surface sliding friction tests.

Jan 1, 1986

By S. K. Mukherjee, M. M. Singh, N. I. Jayaramn

In underground mining operations, ventilation and water sprays are the common methods of controlling dust. In recent years, there has been a proliferation of technical literature dealing with water sprays for dust control. However, guidelines for the design of an effective water spray system have not been presented to the mining industry. This paper recommends guidelines for water spray systems to control dust in underground mining operations. These guidelines suggest type, number, location, and orientation of nozzles; desirable operating water pressure; and associated filtration system.

Jan 1, 1987

By L. Evrard, M. Van Camp, J. Y. Yen, R. G. Reddy, D. Mantha

Viscosities of two industrial lead blast furnace slags have been experimentally determined as functions of composition and temperature. A Brookfield viscometer with alumina rods and crucibles were used. Experiments were carried out between 1200 and 1573 K in an argon atmosphere with up to 5% addition of FeO, MgO, and SiO2 to the slags. Results showed that 1) the viscosities of two slags decreased with increase in temperature; 2) addition of FeO decreased the slag viscosities; and 3) addition of MgO and SiO2 increased the slag viscosities. Use of the above slag compositions with the addition of FeO is recommended for successful lead smelter operation.

Jan 1, 2005

By S. Su, S. Natansohn

This report describes a process for tungsten recovery from Searles Lake brines and upgrading its concentration to useful levels. The method consists of a combination of a liquid-solid and liquid-liquid extraction step and results in a product stream containing more than l00g W03/1. This technique is also effective in substantially reducing the concentration of objectionable impurities in the tungsten product. An ion exchange extraction mechanism is postulated.

Jan 1, 1983

By A. I. A. Salama

A computationally efficient technique for generating a balanced set of density or size separation data is developed. The technique proposed utilized minimization of a modified form of error squares to generate the optimum estimates of outputs mass yields (splits) and balanced direct mass distributions of feed and outputs. The estimated separation data set satisfies mass balance conditions of the streams mass distributions around the separator. The technique proposed avoids the generation of small negative values for the estimated feed and outputs direct mass distributions. Actual data are used to demonstrate the technique proposed.

Jan 1, 1996

By Z. Kowalski

Landfilling of waste causes the degradation of natural environment, not only due to land occupation, but also due to pollution of air, water and soil. The flotation waste from zinc-lead industry also poses such problem. There is a need to find the way to utilise substantial amount of these wastes and backfilling seems to be a good solution. Recently, in Poland only sand was used for backfilling. However, it will be more beneficial to substitute the sand with the industrial solid waste, especially flotation waste. The tests were performed in the laboratory to examine the use of flotation waste as a main ingredient for backfilling. The use of flotation waste is possible only when it is combined with other waste with specific bonding properties, especially regarding the prevention of leakage. The outcome of tests shows that flotation waste combined with cement and fly ashes can be used as a backfilling material. This paper presents the preparation of flotation waste for using it for backfilling.

Jan 1, 2006

By Dennis L. Boley, Francesco Gallavresi, Donald A. Bruce

The authors describe novel aspects of ground reinforcement and treatment as related to soft ground excavation for tunnels throughout the world. Insitu reinforcement for cut slopes (soil nailing), as underpinning (reticulated micropiles), and as direct tunnel support (infilaggi) is introduced. Ground treatment focuses on new aspects of permeation grouting (by the tube'a manchette system), and on jet grouting-a very powerful and positive new technique. Recent developments in equipment, materials, methods and instrumentation are reviewed, with special reference to major tunnelling projects in Italy and Singapore.

Jan 1, 1987

By Andrzej M. Wala

The purpose of this paper is to describe a data-acquisition system for mine ventilation surveys that was developed by the author. The system is composed of "off-the- shelf" components integrated through a custom- designed software package to form a user- friendly data acquisition system capable of operating as an unmanned base station or as an operator-triggered roving station. To demonstrate the applicability of the developed system, the author will present data collected during an experimental ventilation survey, which was performed in one of the underground coal mines of eastern Kentucky.

Jan 1, 1993

By M. Kyzeridi

The paper presents a study on the reclamation of two mined-out bauxite open pits in the area of Kefali, Itea, Greece. The mining area has been reclaimed partially in the past, but its proximity to the town of Itea and a national road with tourist traffic, rose the interest to examine various scenarios for improving the landscape and the aesthetics of the site and introducing alternative land-use for recreational activities. Geospatial data were modelled using a Geographical Information System (GIS) that made it possible to study alternative proposals in terms of final landscape profiles, volumes required to be moved and the associated costs.

Jan 1, 2002

By J. Devon, D. L. Ewart

Long-term coal mining plans are often based on attainment of an average cost of coal. This is achieved by blending low- and high-cost coal production. Coal that is beyond the economic limit of the reserve is mined in a misguided effort to improve reserve recovery. Long-term contracts should be least cost-based and generate the best net present value from the economic reserve within the context of a rational mine plan. The selected economic reserve should he mined on a low- to high-cost basis to benefit from the time value of money.

Jan 1, 1996

By George H. Klein, B. Kent Merritt, Anthony Crisci

During the past decade, over 114-km (71-mi) of 0.25-m (10-in) to 3.7-m (144-in) finished diameter tunnels have been driven below Metropolitan Houston as part of a major program of water and wastewater improvements. This large effort has seen the introduction of midwestern technology with over 18-km (11-mi) of man-entry pipe jacking and European and Japanese technology with over 21-km (13-mi) of microtunneling. Owing to the high water table; a stratigraphy consisting of stiff fissured clays containing numerous layers, channels, and lenses of water-charged sands and silts; and active faults, many challenges existed for designers and contractors alike.

Jan 1, 1991

By J. Kulczycka

Poland in time of transition had been dealing with the remnants of the previous regime ? particularly in the field of environmental protection. The burden left was tremendous and there was a need for fast and effective tools for improving the environment. The idea of environmental protection had been supported by the introduction of a new environmental policy that underlined the importance of sustainable development in industry in the beginning of 1990s. This policy introduced high environmental fees and fines ? a concept not very popular in Europe in that time ? and good only for a country in transition to boost the protection of the environment. While this policy had its role to play, its role is now completed. It is time to move forward, especially when these environmental charges affect the international competitiveness of industries so much, and at the same time have virtually no influence on environmental protection investments any more.

Jan 1, 2005

By Luis Dr. Sobral

In this study, the removal of zinc, cadmium and copper from an aqueous sulphate solution, derived from the biomass desorption process, was examined by using a reaction system with a three-dimensional high surface area electrode (RNiF). This reaction system was found to be extremely effective in reducing metal concentrations to the ppb range. The effect of cathode potential and flow rate were studied for three different nickel foam porosities. In addition, current- potential curves were recorded, at a rotating vitreous carbon electrode, to deter- mine the possibility of depositing the aforementioned metals separately.

Jan 1, 1998

By Risto Lindsberg

A wide concept of flotation equipment and technologies is presented in this paper. The basis for the presentation in Outokumpu's world-wide experience in mineral processing and other related areas, and continuing research and development work done in Finland as well as abroad by Outokumpu's subsidiaries (and customers). It is understood that flotation equipment selection for a certain process stage is becoming more complicated. It is obvious that flotation equipment in grinding circuit needs different design from a multistage cleaning process. In this paper, column flotation is compared with other flotation methods. Thus three areas of flotation are discussed in this paper: 1. Flotation in the grinding circuit, Skim-Air machines 2. Rougher-scavenger flotation, conventional cells vs columns 3. Cleaning flotation, columns

Jan 1, 1988

By Jindrich Fiala, Jirí Kout

The paper contains knowledge that have been achieved when the problem of airflow temperature and humidity changes prediction in mine airways was investigated. The substance of physical processes has been consistently applied. The methods of dry-bulb and wet-bulb temperatures calculations can be applied in any type of mine airway. The exceptionality of auxiliary ventilated airways is in the original solution of so called losing air flowing when a ventilation pipe is leaky. The combination of aerodynamics and thermodynamics solutions enable to determine climatic conditions on projected workplaces with a sufficient accuracy.

Jan 1, 1991

By Kenneth R. Dickson, I. Michael Gowring, Gary M. Davey

The Kemano Power Tunnel is currently being constructed by a joint venture of Atkinson, Kiewit, and Commonwealth. The 5.73 m diameter, 16.1 km long tunnel is part of the Kemano Completion Project in British Columbia, Canada which is being developed by Alcan Smelters and Chemicals Limited. The discussion includes the refurbishment and development of Robbins TBM 189-229 previously used at Calaveras (RETC Proceedings, 1987), the logistics of conducting a tunneling operation in a remote area with adverse weather conditions, in addition to a description of the work and the performance details in the various geological conditions encountered to date.

Jan 1, 1991