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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 A. Guan, K. N. Han, J. J. Kellar, D. A. Boyles

Metal ions associated with effluent streams pose an increasing environmental problem for the mineral industry. Various techniques currently in use to combat this problem including bioremediation, chemical precipitation, and ion exchange are reviewed, and their relative advantages and disadvantages discussed. An alternative technique for metal ion removal, adsorption on surface modified alumina substrates is presented. Alumina surfaces were modified by adsorption of organofunctional silanes, and metal ion removal occurs by chelation of the ion by the adsorbed silane molecules. Experimental data is presented for the removal of cupric ions by this method and is compared to cupric ion removal by adsorption on alumina without prior surface modification.

Jan 1, 1994

By Donald G. Foot, Jeffrey D. Mckay

Flotation columns have been readily accepted for use in most sulfide flotation plants: however, recently columns are being used in many other areas. Recent improvements in design methodologies have overcome many operating problems and led to improvements in metallurgy. In addition. Physical improvements in column design have simplified their operation while leading to better control. The Turbo-Air External Bubble Generator has provided a method for bubble size control and variation in air holdup and carrying capacity. These have enabled commercial operations to improve grades and recoveries by optimizing performance.

Jan 1, 1989

By H. T. Mulryan

Talc is used as an essential ingredient in a variety of plastics applications ranging from polyester body patch compounds through polypropylene automotive, appliance and household furniture components to high performance parts made from liquid crystal engineering resins. This paper focuses on polyolefin applications, the three-tier market for talc in polypropylene, the effects of various tales in typical compounds and trends in each market segment. Emphasis is given to emerging markets, examples of which are polypropylene compounds that mimic higher cost resins, and polyethylene films. Customer requirements for tales for these purposes are discussed.

Jan 1, 1994

By Don Stainbrook

Over a period of many years a highly automated computerized system of ore control has been developed at the Newmont Gold Company, (NGC). It is the purpose of this paper to review the development of this system, describe the setting in which it functions and to mention some of the future developments and enhancements. Discussion of the evolution of the system in a historical perspective helps to understand its present status and illuminate some thinking about future directions of development.

Jan 1, 1989

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 Richard M. Crowell, Laurie M. Tahija, Keith D. Dagel

Echo Bay Mines Ltd. operates a gold heap leach in Round Mountain, Nevada, U.S.A. In the past two years, the mine has expanded operations from 13.5 kt/d (15 kst/d) to 41.0 kt/d (45 kst/d), making it the world's largest gold heap leach operation. The expansion is a separate system from the previous 12 year old plant, yet very similar. The flowsheet contains open circuit primary, secondary, and tertiary crushing with interstage screening. A leach pad stacker loads reusable asphalt leach pads. The process plant features carbon adsorption, pressure strip, electrowinning, and electrorefining.

Jan 1, 1990

By James L. Parks

This paper describes improvements in SAG and AG mill liner designs and their cumulative effect on wear life and mill availability. Routine procedures used by many SAG and AG mill operators to improve liner life are reviewed. Guidelines are provided for estimating the time required to replace worn liners along with practical methods to reduce downtime for liner replacement. Finally, the effects of mill operating conditions on liner wear life and breakage are considered.

Jan 1, 1998

By Raimo J. Leimala, Heimo U. A. Saarinen, Matti Seilo

Processes for hydrometallurgical treatment of crude nickel hydroxy carbonate and impure high grade ferronickel to produce cathode nickel and cobalt hydroxide are described. Outokumpu nickel refining process originally developed for nickel matte has been adapted to the mentioned new raw materials. Both new process routes contain the Outokumpu cobalt removal and nickel electrowinning stages but leaching and solution purification stages differ from the industrial process in operation in Harjavalta.

Jan 1, 1979

By William J. Kohan

Milling has traditionally been considered more art than science. In the last 10 years, significant improvements in process equipment have been made and we are finally taking significant steps toward approaching grinding as a science. Two machines have been at the center of this development. These are the roll press and the high efficiency separator. The former can be considered as a new technology or adaptation of existing i.e. roller mill. The latter is clearly an improvement of existing technology. Other machines have been introduced to a lesser degree and later. Among these are the CKP and Horomill. The purpose of this paper is to provide an over- view of the currently available modifications for operating systems and options for new milling circuits with some comments on their application and history.

Jan 1, 1997

Aqueous pressure oxidation at low temperature, although desirable from a process engineering and operating point of view, presents unique problems when temperatures approach 160°C (320°F). In developing the pressure oxidation process for the Lone Tree Mine, elemental sulfur formation and agglomeration with pyrite proved to be a problem. This paper discusses some of the unique features of the Lone Tree sulfide deposit and its amenability to low-temperature oxidation. Problems encountered during pilot plant operation and their solutions are discussed.

Jan 1, 1995

By James K. Grunig, Rodney J. Anderson

A process consisting of leach, continuous countercurrent decantation, resin-in-column ion exchange, evaporative crystallization of beryllium sulfate, and decomposition of the sulfate was developed for Spor Mountain, Utah, ores. The process is metallurgically sound, has a minimum of process steps, and is applicable to a wide variety of beryllium ores. The most novel aspect of the process is a resin system of ion exchange which is highly selective for beryllium and which rejects substantially all impurities except for minor amounts of aluminum, magnesium, fluorine, and sulfate in addition to beryllium. The oxide from sulfate decomposition meets specifications of potential users.

Jan 1, 1983

By J. N. Economopoulos

The mining industry is becoming increasingly aware of environmental issues and has made big forward steps in the field of environmental management. Legislation, social pressure and competition introduced changes in the industry?s policies and practices in order to conform to the new standards of environmental performance. The paper addresses the need for an integrated and systematic approach to the issues of environmental management within the mining industry.

Jan 1, 2002

By I. R. McGowan, J. Tilk, J. I. Hershman, R. L. Lewis

The White Pine Mine is a large underground copper mine located in the Upper Peninsula of Michigan. A numerical ground water flow model of the White Pine Mine was constructed to evaluate potential engineering controls that would reduce the rate of mine-water discharge after closure. Of the passive controls evaluated, the placement of bulkheads within the mine workings was predicted to offer the greatest benefit, reducing the rate of discharge by as much as 35%.

Jan 1, 1998

By Y. Luo, S. S. Peng

Based on the concept of slope-stability analysis, a formula for determining an important parameter required in the mathematical model for the prediction of mining subsidence in hilly terrain is proposed. The slope geometry and the physical and mechanical properties of the soil at the surface of the natural slope can all be considered in the formula. Incorporation of this new formula into an existing mathematical model provides an integrated approach for the study of ground movement in hilly regions.

Jan 1, 2000

By R. L. Grayson, S. Yuan

A goal-programming-based, worker-scheduling model has been incorporated in the Mine Management Support System (MMSS) for assigning workers to prioritized jobs on a shift basis. In the model, the accomplishment of each regular and non-regular job is a goal, and the objective is minimization of the deviations from the goals. A number of coefficients are employed as premultipliers of the decision variables to address practical considerations associated with the utilization of workers and the requirements of jobs. This model is applied to a 41-worker problem.

Jan 1, 1992

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 Glenn Boyce, Paul Gribbon, Gary Irwin, Greg Colzani, Jim McDonald

This paper discusses the process utilized by the City of Portland Oregon’s Bureau of Environmental Services (BES) to procure and compensate Impregilo-SA Healy (I/H)for the West Side Willamette River Combined Sewer Over?ow (CSO) Project. The contract method is a three-phase process consisting of qualifications based contractor procurement, pre-construction phase design assistance/construction planning, and facility construction where the contractor is compensated on a cost reimbursable-fixed fee basis. The paper focuses on pre-construction phase lessons learned from the development of the contract general conditions, establishment of a construction budget and cost control program, incorporation of contractor recommended design changes, and development of a subcontractor procurement program for construction.

Jan 1, 2003

By Zbigniew Pokryszka, Eric Saraux, Christian Tauziède, André Carrau

This paper presents recent developments in the use of a CFD model for representing the flow of gases in the goaf of retreat faces. In France, it is of highest importance to optimize firedamp drainage in very gassy mines and nitrogen injection in faces prone to spontaneous combustion. Numerical modeling has been used to solve this problem. So the model developed has been first calibrated using a large quantity of field data and could then be used for various simulations. Though still in progress, this research has given promising results, many of them being already set into practice.

Jan 1, 1997