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By V. J. Matta, A. A. Pincheira, I. A. Reghezza, Ch. J. Vergara

The growth of solvent extraction in Chile has been astonishing during the last years and has been established as a very successful technology. However, there are still limitations that must be improved, mainly, the problem of carry over from one phase to the other and the losses of organic reagent associated with the crud formation. These are problems that our company has been taking care, solving them with high efficiency and low costs, allowing important increases in the copper output of our plants and capital savings by means of the optimization of the use of nonproductive units in the SX plants.

Jan 1, 1998

By R. Venugopal, T. C. Rao, J. P. Barnwal, K. Udaya Bhaskar

The performance characteristics of a multigravity separator for the recovery of heavy minerals of lead, zinc, copper and silver from a lead rougher-flotation concentrate were studied. Factorially designed experiments were carried out on three operating variables, i.e., the amount of wash water, the drum inclination and the drum rpm, of a multigravity separator. The experiments were carried out at two levels of each variable. With the experimental data, regression equations were developed for different metal grades and recoveries. The analysis revealed that drum speed has a major influence in determining the heavy-metal grade and recovery. Drum inclination is the next most important variable, with the amount of wash water being the least important. A concentrate containing 40% lead, 9.4% zinc, 1.5% copper and 1,400ppm silver was obtained with recoveries of 74.8%, 65.9%, 64.1% and 53.2%, respectively. Finally, the predicted values of grades and recoveries at intermediate levels are compared to actual experimental data to test the validity of the equations developed.

Jan 1, 2000

By D. Ince

Flotation of dolomite from apatite was investigated, using dodecylamine hydrochloride or sodium oleate as the collector, with and without inorganic modifiers such as sodium chloride. Separation of dolomite from apatite was anticipated from the single mineral experiments under various pH and collector concentration conditions. Flotation selectivity in the mixtures, however, was found to be limited. Attempts to control the flotation response of these minerals by addition of salts such as NaCl and KCI indicated that selectivity is possible. The presence of sodium chloride was determined to depress apatite flotation using sodium oleate, leaving dolomite flotation unaffected (Moudgil and Ince, 1989). In this paper, conditions for optimum separation and the effect of major parameters on the desired selectivity are discussed.

Jan 1, 1992

By A. K. Haines, M. W. Godfrey, D. M. Miller, P. C. van Aswegen

The Bacterial Oxidation [(BIOX)] process for the pre-treatment of refractory ores for gold recovery developed by Genmin, the mining division of Gencor, has been operating successfully at the Fairvew Mine since October 1986. The continuous operation of a pilot plant at Genmin Process Research has resulted in further process developmenst to improve plant operating efficiencies. These new developments, which include a higher solids content of the pulp feed to [BIOX], lower retention times, higher operating temperatures, lower power utilizaton for oxygen dispersion and reduced nutrient addition, have all been successfully implemented on the Fairvew plant. It has furthermore been confirmed that the arsenic precipitate formed in the neutralization of effluent solutions complies to the United States of America EPA standards. Contineous cyanidation pilot plant work conducted on [BIOX] product has indicated that cyanide consumption can be drastically decreased if a continuons flowsheet is implemented in preference to a batch leaching system.

Jan 1, 1992

By F. L. Wilke, J. Fabian, D. Oravec

The task of production planning in ore mining is primarily con¬cerned with the removal of ore blocks within planning periods spread over the life of the mining operation. The investigation of this problem in the past resulted in the introduction of computer based optimizing techniques for production scheduling and se¬quencing. Although these techniques succeed in computing an "optimal" mine output for one planning period, they usually fail in composing a practical and feasible mine plan over the periods in concern. This paper describes conventional production planning based on operations research and the capabilities of a knowledge-based approach. An example of a planning system for the Slovak under¬ground iron ore mine Nizna Slana will be presented. By combina¬tion of these two techniques this system should improve the qual¬ity of planning procedures.

Jan 1, 1996

By Alfred W. Hefferan

A longwall face conveyor system serves the primary function as all material handling systems; i.e., to transport material between the source and its destination. However, the conveyor system must provide many other functions as opposed to the traditional belt conveyor system. In this paper, we will attempt to contrast the longwall face conveyor system with a belt conveyor system. In addition, the unique problems encountered along with the solutions to these problems will be covered. Table 1 lists the characteristics required of each conveyor system. The table demonstrates the contrast in the two systems. Both must be designed specifically to encounter its unique problems. The balance of this paper will explain how the longwall face conveyor is designed to address its requirements.

Jan 1, 2000

In late 1993, Inco Ltd. completed a $600-million environmental improvement project at its Sudbury, Ontario operations -the largest single environmental project ever undertaken by a Canadian corporation. Efficient new facilities and innovative technologies installed during the course of the project have also significantly improved Inco's productivity and competitiveness. In early May 1994, a panel of 18 Inco authors contributed to a Technical Forum, "Environmental Programs at Sudbury," presented at the 96th Annual General Meeting of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) in Toronto. Their papers have been published in CIM's Toronto `94 Proceedings Volume, pp. 62-77. The following report draws primarily on discussions of Inco's milling and smelting operations published in the Proceedings Volume. The Proceedings Volume also includes papers on the acid and oxygen plants and on engineering, construction and commissioning of the project. The 222-page Proceedings Volume is available from CIM, $C27 plus shipping. To order, contact: V. Ward, CIM, Xerox Tower, 1210-3400 de Maisonneuve Blvd W, Montreal, Quebec, Canada H3Z 3B8; phone 514-939-2710, fax 514-939-2714. Lane White, Publisher.

Jan 1, 1994

By Klados. T.

MSC.Software assessed the performance of the drive end and non-drive end bearings on a ball mill using the finite element method. The assessment included the effect of mill and pedestal deformation on the performance of the bearings. Oil film thickness, oil pressure distribution and power requirement were of interest. A solution approach coupling a structural solver to a Reynolds equation solver was specifically developed for the project. Results showed that the deformation of the bearing surfaces had a significant influence on the performance of the bearings. For example, for the non-drive end bearing, the minimum oil film thickness computed for the deformable bearing surfaces was significantly lower than calculated for the non-deformable case. The results also showed that cavitation was likely in both the drive end and non-drive end bearings (severe negative pressures were obtained in both bearings). Other design variations were also assessed, e.g. a case with a modified radial clearance which improved the results.

Jan 1, 2006

By V. I. Ryaboy, V. A. Luknitsky, V. V. Zuyev

The action has been studied of three types of reagents used as intensifiers in grinding copper-molybdenum, sulphide-sheelite, polymetallic and other types of ores, namely N-donor, dispersant, and surface-acting agents. It has been proved that, depending on the type of ore treated, the C (N-donor) and C-170 (dispersant) reagents increase the yield of the principal size fraction of 0.074mm by 8-16% (relative). Consequently, the specific mill capacity improves by 13-21 %. The C and C-170 reagents activate the subsequent flotation stage and are thus beneficial to the mineral recovery. The surface-acting reagents affect the mineral grinding process to a lesser extent. The intensifying action of the reagents is attributed to the effective crushing energy decrease (lower crack-resistance factor) or else to the slime-dispersing effect of the reagents. The pilot-plant test results for the C reagents are given. Both C and C170 reagents are commercially produced and recommended for use at a number of concentrators in Russia, Uzbekistan and Kazakhstan.

Jan 1, 1995

By T. van Sandwijk, G. Van Weert, E. Molleman

This paper reports on test work that explored the dissolution/precipitation reaction: ZnS + 2HCl - ZnC12 + H2S, which is part of a process used in the production of pure ZnS. The research focused on the influence of proton activity on the dissolution of zinc concentrates obtained from the Brunswick Mine No. 12 in Canada (Brunswick Mining & Smelting); the Red Dog deposit in Alaska (Cominco Ltd.); and the Tara deposit in Ireland (Outukumpu Zinc). A comparison between the results of the experimental dissolution as a function of pH and the dissolution predicted by thermodynamics suggest that the three concentrates contained sig¬nificant amounts of the more reactive mineral wurtzite, although XRD analysis showed mainly the presence of the mineral sphalerite.

Jan 1, 1999

By Andrzej Wala, Waclaw Dziurzynski, Janusz Tracz

Recent advancements in computer hardware have led to the development of new ventilation planning software for PC's. These programs now can be run more quickly and can display their outputs with graphical techniques. Only a few of the existing programs have the capability to display the output data graphically on plotters. Graphical presentation of ventilation simulation data is essential for quick and sure comparisons of alternative analyses. Recently a noticeable growth has occurred in the application of graphics for display and interpretation of the data that have been developed by simulation procedures. The process of mine ventilation network analyses used for planning and design can benefit from this development. The authors describe and present graphics-assisted software that has been developed to work with a mine ventilation simulation program. This software has some of the following features: - graphic editor on screen, - graphical display of output data on screen (EGA, VGA), - graphical display on plotter or printer, - scaling capability (desired part of the entire schematic can be displayed), and - such values as flow, pressure loss, gas concentration for branches, and pressure and elevation at junctions can be presented as labels.

Jan 1, 1991

By Christopher Haycocks, Randolph Reed, Erik C. Westman

The industrial Source Complex (ISC3) model is the accepted standard used to predict emissions of particulate matter less tan 10µm in diameter (PM10) from industrial operations. This model, however, over-predicts PM10 emissions from surface mining operations, making permits harder to obtain. The over-prediction is likely due to the fact that the model applies emissions from mobile (dynamic) sources to stationary (static) areas. Utilizing a Gaussian dispersion equation, a Dynamic Component Program was created to correct the over-prediction of the model and results in a much more realistic modeling of actual conditions from mobile sources.

Jan 1, 2002

By E. Robert Kiehl

In the early days of the United States, gypsum was most commonly used for the manufacture of plasters with energy being used for quarrying, grinding, and calcining of gypsum rock. With the dramatic switch to gypsum-drywall construction after World War II, the energy usage per ton of rock processed increased more than threefold, and with the rapid growth of the construction industry, the total energy consumption in gypsum-board production alone increased eightfold during the period from 1940 to 1973. The gypsum industry was one of the first to recognize the need for energy conservation and has voluntarily reported its progress to the Federal Energy Administration for the past several years. Efficiencies in the use of energy have resulted in decreasing the unit consumption an estimated 10 percent during the past six years. Improved combustion efficiencies, optimum operating conditions, more liberal use of insulation, and heat recovery will all contribute to the gypsum industry's goal of using less energy. Gypsum products today are vital to over 85 percent of new housing construction in the United States.

Jan 1, 1978

By St. E. Deák

There is a large preoccupation concerning the development of expert tools (ET) in the mining industry, in order to minimize the impact from waste dumps and processing residues on the environment. In this paper, the authors present a new approach for the development of an expert tool for each area under study, in order to minimize production and disposal of mining wastes on the environment, by taking into account the DKRControl method as well as the Ecomining principles, regarding among others hazard identification, impacts and monitoring. Due to the complexity of this topic a reliable ET requires input from a number of interested stakeholders. The design and management of a mining waste disposal site over its entire life cycle is also considered very important.

Jan 1, 2008

By Charles Rubin

Mining is a capital- and labor-intensive business, and profitability often depends on the ability to squeeze maximum efficiency out of every piece of equipment to achieve safe production. This means keeping every mechanized drill, loader, truck and bulldozer operating at all times, and having a system to coordinate the movements of people and personnel. Mines often use wireless radios to connect equipment with management systems. But growth and changes in a mine?s profile over time can require upgrades to the wireless network. In its openpit gold mine near Carlin, NV, Newmont Mining Corp. has recently upgraded to microwave radio systems to increase bandwidth while maintaining round-the-clock uptime on its wireless network. For many of its operations around the world, Newmont uses Minestar, an operational control software system that allows administrators to dispatch equipment operators and use GPS to track the precise position of every piece of equipment in an operation. Each of the approximately 150 pieces of equipment at the mine has a radio on board. These radios connect to a network backbone that carries information between the equipment and the mine?s operations center. When traffic began to bog down on this network, Newmont upgraded to Exalt microwave backhaul systems to carry dispatch, inventory and control information throughout its operation.

Jan 4, 2010

By I. Iwasaki, J. N. Orlich

The effect of slurry rheology and ball coating characteristics on the abrasive wear of grinding media and the rate of grinding were studied using -10 mesh quartzite in laboratory marked ball wear tests. Pulp viscosity was found to be closely related with both the thickness and physical characteristics of the coating affecting abrasive wear. The packing density of particles at the ball surface was the primary determinant of wear while the grinding rate was more dependent on viscosity and thus the ball coating thickness. The optimum grinding rate was achieved when the coating thickness was about twice the largest particle size.

Jan 1, 1988

By J. D. Miller, J. Hupka

Important aspects of kerosene penetration into tar sand have been investigated. The natural tar sand porosity was measured and used to analyze the performance of the hot water process. Subsequently, pretreatment experiments, using 20-kg tar sand samples (Asphalt Ridge and Whiterocks, Utah) and kerosene as a diluent were carried out at the expected summer temperature (26°C) and the expected winter temperature (-14°C). The natural tar sand porosity accessible by diluent has a crucial impact on the reduction of bitumen viscosity and influences the penetration time required for successful bitumen separation from tar sand by hot water processing. Thus, the tar sand porosity is a critical variable that determines appropriate operating conditions. Experimental results indicate that diluent penetration into the Asphalt Ridge tar sand (high porosity) is almost complete after 30 min, whereas for the Whiterocks tar sand (low porosity) the penetration process is much slower, being still incomplete after 15 hours regardless of the ambient temperature.

Jan 1, 1994

By Jaime Guzman

Mineral exploration decision problems involve the economic evaluation of upgraded geological information and the costs of obtaining it. This paper presents a valuation theory of risky projects applicable to the analysis of exploration investments. The valuation model is predicated on the Capital Asset Pricing Model (CAPM) from financial economics; its parameters can be objectively measured from publicly available information. Geostatistics is used to derive simplified random cash flow models which incorporate the impact of improved deposit knowledge in terms of reduced estimation variance. The application of the theory is illustrated by means of hypothetical exploration optimization examples.

Jan 1, 1986

By Saurabh Rastogi, Vikram Shishodia, B. Pitchumani

Comminution is a unit operation which consumes major part of energy in mineral processing industries such as fertilizer production. Ball mills are widely used for size reduction of a given ore to the liberation size that is required in further beneficiation processes. In grinding of materials much effort is concentrated on control of top size of the product and this results in production of fines, also creates secondary problems of pollution due to the difficulty in the collection of fine particles. The present work has been carried out to control product size distribution for rock phosphate grinding in an Industrial Ball Mill of 600 TPD. The plant data are taken for a given feed distribution and mill operating conditions. The information at various Ball Size distributions are collected. The comminution functions such as specific rate of breakage and breakage distribution functions are estimated by back calculation technique to solve the mass balance equation. A simulation program is written to study the product size distribution obtained for various ball size distribution.

Jan 1, 1993

By W. J. Pennstrom, J. R. Arnold

This paper focuses on solution-balance management around heap-leach operations. Experience has shown that increased leach recoveries can be achieved by utilizing various leach-solution recirculation techniques. The most prominent solution-recirculation technique is intermediate leaching. The net effect of intermediate leaching is to increase recovery plant performance by increasing solution concentration tenors, to increase metal recovery by increasing the total leach time and to decrease the overall capital expenditures required for metal-recovery facilities. The adverse effect on the flow of cash from increased metal inventories in the recirculating solutions is offset by increased metal recovery and lower operating costs per unit produced.

Jan 1, 2000