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By None None

This month, Mining, Metallurgy & Exploration (MME) is launching with a special issue on mineral and metallurgical processing in honor of the 90th birthday of Prof. Emeritus Douglas W. Fuerstenau. Headed by a special review article by Prof. Fuerstenau, this special issue contains 22 papers by the top experts in the field.

By James E. Gingrich

The new Track Etch* technique for uranium exploration has been utilized in several survey programs conducted during the last few years. The results from these programs have been very encouraging, and new uranium ore bodies have been discovered by using this new technique. The Track Etch method is being used in several exploration programs in various locations around the world. The Track Etch exploration technique utilizes small pieces of special radiation-sensitive plastic film to detect the presence of radon gas which is released by uranium ore bodies. Because of the selectivity and sensitivity of the technique, ore bodies not normally detected with other surface or airborne monitoring methods are found. Since no large equipment or special training of personnel is needed, the Track Etch technique is easily used in field operations. The basis for the Track Etch method, its application in field exploration programs, and the results obtained to date in locating uranium ore bodies is discussed.

Jan 1, 1974

By Dalva L. Moellenberg

Introduction Hard rock mine closure (often referred to as decommissioning), mined land reclamation and financial assurance requirements are receiving considerable attention by governments and organizations around the world. In the United States, federal agencies and the states continue to consider and make changes to laws governing mine closure and mined land reclamation, most of which were originally enacted in the mid-1970’s through the mid-1990’s. Internationally, a number of prominent groups and various countries currently are considering new laws, regulations and policies for mined land reclamation. For example, the European Union has conducted a review of existing European laws concerning mining wastes and mine water and is considering new directives concerning mine waste and mine water management and liability schemes that are likely to significantly impact mine closure and mined land reclamation. Many countries, particularly those outside of North America, Europe, and Australia, have recently adopted or are considering new mine closure and reclamation legislation and regulations. These include significant hard-rock mining countries such as Chile, Peru and South Africa. This paper identifies recent developments in hard-rock mine closure and mined land reclamation laws in the United States, focusing on several of the more significant and controversial developments. It also discusses some of the more significant international efforts to consider mine closure and mined land reclamation laws and policies and some of the notable conclusions and trends from those efforts. The focal issues discussed in this paper include requirements for the reclamation of open pit mines, including backfilling; consideration of and measures to address the mining of sulfide ores and potential for acid mine drainage; and new requirements for the estimation of closure and reclamation costs and for financial assurance for closure and reclamation.

Jan 1, 2005

By Alfred A. Roetzer

In several sections of the country new demands are being brought bar cement users. Among these the demand' for truck shipments; and palletized loads present new problems that do not lend themselves to sample solution. In fact these demands have far-reaching effect in the way bagged cement might be marketed. Early solutions of palletized truck loads filled from existing packing and loading facilities have resulted in' slowdown in packing, additional labor and space for palletizing, considerable experimentation in type and construction of pallets, and usually far from optimum truck handling and loading methods.

Jan 1, 1961

By L. B. Rothfeld

Two new coal use technologies are on the verge of commercial acceptance by the utility industry: atmospheric fluidized bed combustion (AFBC) and gasification combined cycle (GCC). Generating plants under construction or in planning will replace older pulverized coal (PC) boilers or substitute for new PC boiler capacity. This paper reports recent developments in the commercialization of AFBC and GCC, emphasizing the potential impact on the coal mining industry. The influence of coal quality characteristics on fuel selection is explored by means of preliminary economic calculations for different coals and competing fuels.

Jan 1, 1987

By L. Alan Weakly

Coal mines and power plants utilize different methods to control dust for the safety of their workers and to protect their installations. The methods that they use are limited by the Environmental Protection Agency or the states in which they operate. Now there is a new technology for controlling dust at conveyor transfers! The Passive Enclosure Dust Control System utilizes several proven technologies to mitigate fugitive dust. This new system has been proven to be four times more effective than standard enclosures utilizing bag house collection and is considerably less expensive to install and operate.

Jan 1, 2000

By Iga Trisnawati, Fitria Puspita, Himawan Tri Bayu Murti Petrus, Gyan Prameswara, Idi Amin, Andi Nurfaadhilah Ulfah

Laterite ores, rich in essential metals like nickel, iron and cobalt, are a crucial resource for modern technology. However, the extraction of nickel from laterite ores is a complex process due to their intricate mineral compositions and low nickel concentrations. This paper presents the results of a study to understand the leaching behavior of preroasted laterite ore and the impact of roasting on leaching kinetics. The ore was subjected to roasting at 280 and 610 °C for a duration of three hours, followed by leaching in sulfuric acid (H2SO4) under atmospheric conditions. The results show that preroasting the ore at 610 °C significantly improved the recovery of nickel during leaching, with recovery rate of up to 93 percent, and the leaching process of the preroasted ore was primarily controlled by diffusion through the ash layer. The activation energy values were found to be 20.97 kJ/mol for the ore roasted at 280 °C, and 18.97 kJ/mol for the ore roasted at 610°C. These findings suggest that preroasting can enhance the leaching performance of laterite ore, potentially paving the way for more efficient and sustainable nickel extraction processes.

Aug 1, 2024

By S. R. LaBrooy, J. Avraamides

Thermal reactivation of eluted carbon is an essential part of most carbon-in-pulp gold recovery plants. The effectiveness of the reactivation procedure depends on the nature and level of contaminants adsorbed on the carbon, the efficiency of the elution and the temperature, residence time and atmosphere within the kiln. The most commonly used kilns are evaluated in terms of their operating parameters and performance. Data obtained both in the laboratory and in the field emphasize the importance of carbon feed moisture content, kiln atmosphere and carbon conditioning on the activity of the kiln product.

Jan 1, 1998

By V. R. Voller

The WTBAL computer program for evaluating material balances for minerals processing flowsheets was developed at the MRC and has been in general use for a number of years. This paper reports on two enhancements to the basic MTBAL routine. The original program accounted for errors in the process measurements and used estimates of measurement variability to calculate stream weights. Unfortunately, the estimate of measurement variability was fixed over all streams. In the enhanced version of MATBAL, named IMTBL, the program equations and their solution procedure have been modified to allow the estimated variability in a process measurement to vary from stream to stream. The .second enhancement involves making MTBAL interactive. As such, the user now prescribes his information in an easy-to-use fashion in a conversational mode via a terminal. Finally, an assessment of the feasibility of implementing IMTBL on microcomputer systems will also be reported.

Jan 1, 1982

By Young C. Kim

In the past, underground coal mine planning has traditionally focused on the mine design n aspects concerning safety and efficiency in the quest to produce low cost coal. Very little attention has been given to coal quality control aspects of mine planning at most of the underground coal mines within the U.S. With the enactment of the clean air act of 1970, the generally high sulfur content of coal has become a major concern for the coal-fired power plants in the east. Similarly, the ash and the BTU contents of coal are of equal importance from boiler efficiency standpoint. Thus, the time has come when the coal mine planning must incorporate the coal quality control aspects as well as the traditional safety and efficiency aspects.

Jan 1, 1983

By L. Bomvisinho

As a result of today?s requirements for larger mills with higher power demand, and in order to cope with maximizing throughput, and optimize grinding efficiency, the minerals industry is increasingly relying on the robust Gearless Mill Drive (GMD) solution. This paper describes the new features introduced with the revolutionary ABB drive controller for Gearless Mills, and explains the benefits this can bring to the operation. Extensive surveys have been performed with GMD users to gather suggestions and understand the market wishes. As a result the new driver controller capabilities and functionalities focus on safety, high availability, operational flexibility and remote diagnostics.

Jan 1, 2010

By Andrew Torok

Activated bleaching clays, so called because of their ability to remove color bodies from bleach fats and oils, are produced from clays of bentonitic origin. Activation is achieved by subjecting these clays to physical or chemical alteration to increase selective sorption capacities (1) . The future of activated bleaching clays depends upon the ability of producers to recognize the new areas of applications which are arising, and their skill in developing sophisticated active clays to meet new and stringent requirements. The major portion of activated bentonites are produced for decolorization of oils. New techniques of activation will improve these clays for broader spectrum use. General properties expected to result from present activation methods are: 1. Modification of hydrophobic-hydrophilic properties and increased available surface area in non-aqueous systems, thereby improving sorption capacity and ability to remove color bodies from oils. The following additional properties will be expected from future activated clays: 2. High purity of the active clay with interfering impurities totally removed. 3. Increased selective sorption capacity in aqueous systems. 4. Selective chemical reactivity, such as oxidation or hydrolysis. This property is required for removing

Jan 1, 1971

By T. A. Moss

The installation of equipment and structures at mines often requires the evaluation of unique loading and operating conditions. Consideration of these unusual features is required throughout design and construction and into operation. The necessity for employing sound civil, structural and mechanical engineering techniques to the design of structures and equipment is well understood. However, the influence of geotechnical factors on the overall behavior during construction and operation of these facilities is less appreciated. Mine operators routinely perform exploratory drilling for the purposes of defining ore deposits. These exploration activities can be extensive and often include provisions for assessment of subsurface conditions as they relate to the mining operation, i.e., requirements for ground support. All of these factors are important to the economics of the mine and are well justified. Surface facilities are provided to access and service the mine and they play an important role in the successful development and operation of a project. Headframes, hoist foundations and shaft collars, in particular, are examples of unique installations encountered at underground mine sites. The design and above surface behavior of these facilities can be analyzed with the usual fundamental engineering practices employed throughout the engineering professions. This requirement during the project development is understood and adopted. Unfortunately, near surface exploration for the purposes of assessing soil and rock conditions for foundations are often given a reduced priority and less consideration. This paper is aimed at providing an outline into the benefits and importance of performing such explorations and to provide a brief discussion of the merits of such an approach. References in the paper relate particularly to shaft headframes, hoists and shaft collars but the issues raised apply equally well to other installations of a similar nature, e.g. milling equipment.

Jan 1, 1992

By John N. Murphy, Edward F. Fries

The availability of fast, low-cost computer hardware and advanced software is opening new opportunities for minerals extraction and processing. Programmable Logic Controllers (PLC's) are currently used extensively in the minerals industries; this paper looks beyond PLC's and that vintage of “computer control”--it looks toward what the authors see as new in the next five years. Topics covered include expert systems, neural networks, intelligent signal processing, and hierarchical controllers as applied to mining and mineral processing operations.

Jan 1, 1993

By S. S. Nadgauda, A. J. Hathaway

Typically, as long as the coal quality is within the specified range, electric utilities have used delivered cost of fuel per million Btu as the primary criteria for qualified coals when making coal-procurement decisions. Such an approach may not fully address the total cost of using different quality coals at a given plant. A practical and easy-to-build model is described for estimating plant-specific utilization costs for coals of different qualities. Examples are included to illustrate the modeling results for plants operated by two utilities. While the model has certain limitations, it does represent an improved method for evaluating coal bids, and, consequently, reducing generation costs.

Jan 1, 1990

By Sukumar Bandopadhyay

In recent years, research in the field of artificial intelligence (AI) has had many important successes. Among the most significant of these has been the development of powerful new computer software known as the "expert systems". Expert system programs designed to provide expert-level consultative advice in mineral exploration (Duda et al, 1981), scientific (Feigenbaum, Buchanan and Lederburg, 1971) and medical (Shortliffe, 1976) problem solving are generally acknowledged to be among the forerunners of this research. As the decision makers virtually in all fields face a more complex and involved world within which to operate, the need for some decision support is also becoming urgent. Thus applications of expert systems continue to spread out reaching problems that, because of their dimensions or particular aspects, set more demand on the decision methodologies. To meet these new requirements, many activities which were performed in the past by the domain expert or engineer must become automated. Furthermore, previous research (Dawes and Corrigan, 1974; Dawes, 1979) has shown that automating an expert's decision rules often provide better decision than the expert does. For large systems it would be very useful (or even necessary) to have formal tools, allowing one for example, to automatically discover inconsistencies, contradictions or redundancies, or to identify the possibilities of wrong lines of reasoning in the decision process.

Jan 1, 1990

By Richard M. Tinlin

The mining industry needs to assure compliance with the Federal Water Pollution Control Act Amendments of 1972 (Public Law 92-500). Congress has enacted this legislation with the intent of preventing, reducing, and eliminating pollution of the nation' s surface and groundwaters. Recognized sources of pollution such as seepage from tailings ponds, waste dumps, and contaminated effluent from mine dewatering operations pose a serious threat to adjacent groundwaters. In addition, technological innovations being implemented by the industry such as in situ leaching of low grade ore deposits may also lead to ground- water contamination. An adequate monitoring methodology designed to meet the needs of the mining industry is needed. Monitoring and control methodology devised for other man- caused sources of ground- water pollution - e. g., landfills - offer considerable promise for adaptation to the problem. The prediction of deleterious effects on groundwater quality usually requires extensive geohydrological data in addition to a thorough analysis of the mining activity that is underway or projected. If the avail- able data are adequate, mathematical models of surface and groundwater flow can be constructed that will help to predict effects on water quality. Data are inadequate to allow a realistic interpretation of pollution potentials. These data can be supplemented by computer simulation as a method to explore a number of possible environmental effects and also to develop a minimum-cost approach to identifying and gathering the additional necessary supporting data. Incorrect assessment of the important environmental considerations may, in many instances, prove to be the weakest link in analyzing the financial feasibility of a mining operation.

Jan 1, 1973

By J. A. Ehler

Speed and torque control of standard A.C. induction motors can be accomplished using a variety of devices ranging from mechanical, hydraulic, and electrical. Also, the motor can be specified as an A.C. wound rotor or D.C. motor using the associated controls. Normally, any one of these drive types can be adequately used to provide the torque control necessary to accelerate a conveyor belt system. The selection will depend on the economics, experience, and preference of the designer or end user. These drive types will be presented from a functional and performance viewpoint to assist in the understanding of the available technology.

Jan 1, 1998

By Ioannis Nicolaou

This paper demonstrates the method of approach for the optimization of such filters. This does not only incorporate the proven and simple recently developed equations for the calculation of the solids throughput, the residual moisture and gas throughput, but also introduces equations for the calculation of the specific product costs for both vacuum and hyperbaric filtration under consideration of the influences exerted by the filter compressor and a possible thermal drying. An easy-to-use method is offered which incorporates a special graphic representation concerning the plotting of the target parameters in dependence of the pressure difference with which the optimal process pressure difference can be established, independent of the specific cake permeability or product fineness. Finally, the optimization method is exemplarily demonstrated for a concrete application.

Jan 1, 1995

In parallel work, the cyanide/silver impregnated activated carbon system was studied for the purpose of developing an alternate cyanide removal system. It was found that free cyanide can be reduced from 20 ppm to below 10 ppb with a fixed bed of silver impregnated activated carbon, since such cyanide removal might be applicable to gold mill effluents, the investigation was extended to the cyanide/gold impregnated activated carbon (GIAC) system. Batch tests were conducted varying the gold content of activated carbon, carbon/CN ratio, stirring speed, pH of the initial solution, and the reaction temperature. The adsorption isotherm of cyanide/gold impregnated activated carbon system was also studied. The results of these batch tests show that the behaviour of the cyanide/GIAC system is very similar to the cyanide/silver impregnated activated carbon system variation of the gold content of the impregnated activated carbon has some influence on the cyanide adsorption rate. The latter is mainly increased, however, by increasing the GIAC/CN ratio. The activation energy was determined to be 3.12 kca1/mole (13.08 kj/mole) and the Au(CN)2 saturation at 194 µ M/g NORIT ROX O.B. The experimental results of reaction temperature and stirring speed show that the adsorption of free cyanide on such activated carbon is controlled by pore diffusion inside the activated carbon particle or by surface reaction. The adsorption isotherm follows the linear model and it is favourable for the cyanide/gold impregnated activated carbon system.

Jan 1, 1994