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By I. E. Lewis, W. R. Hopkins

Flowsheet improvements, such as series/parallel SX plant configurations, discontinuation of plant sumps and improved filter pumping concepts, the use of in-settler baffle systems, and the Krebs and combined mixer-settler designs offer opportunities to reduce SX plant cost. Today's plants employ permanent cathodes and mechanical stripping, and the increased capital cost can be offset by labor savings and higher current densities. The wider use of HDPE and new cell construction materials also reduce capital cost. The "Portelex" type of relocatable design embodies such new, cost-saving measures in a simple basic plant. Organic inventory and losses are reduced by new, fast-settling, hybrid organic reagents with improved kinetics and selectivity.

Jan 1, 1991

By Jed H. (Original by) Mosgrove

Good mine ventilation starts at the drawing board. A coal mine will either be adequately ventilated or not, depending upon how good a job was done in the planning. Poor planning will not only result in inadequate ventilation, but may also lead to low productivity. A mine foreman cannot achieve high productivity while trying to maintain 4.2 ma/s (9000 cfm) of air at his last open crosscut.

Jan 1, 1981

By Gary Schaffer, Anthony Stentz

Surveying of mines is a necessary step in coal mining to assemble maps which are used for tracking progress in the development of the mine and to plan future coal removal. A first approach for automatically building high-resolution two-dimensioml maps of underground coal mines is presented. The technique assembles laser rangefinder scans obtained from several locations within the mine into a consistent global map of the mine. Each range scan comprises thousands of data points collected in one second, thereby achieving higher resolution and much faster measurement compared to a human using a transit. The raw data (range scans) are processed to fuse them into a consistent representation. This paper describes a first approach to automated surveying and presents initial results of merging range scans. Improvements to the scan-merging algorithm are proposed.

Jan 1, 1993

By Bobby J. Timmons

A few years ago during a Southeastern Geological Society field trip, a professor from a Florida university and a trip leader commented at one of the stops, "... and for those of you interested in the geology ...." More recently, in the spring of 1992, a geology faculty member at another southeastern university remarked, "Field geology is obsolete." An interviewee for a potential assistant position stated that he had never had a field class. This would-be assistant was to receive his Master's Degree in-Geology within a few days from yet another southeastern university. A regional illness? Certainly not, but symptomatic of the general health of Geology. Capitulation to Environmental Sciences seems to be in vogue with Geology becoming a four-letter word and the mention of mining is verboten regardless of the company. These trends permeate our profession while the demands for earth materials increase, often exponentially. Efficiency, a word lost on government, is routinely expected of business--our business--the industrial minerals geologist and producer. Our stage shrinks but the responsibilities expand. Are we meeting the challenge? Stay tuned!

Jan 1, 1995

By Rudrajit Mitra, Wesley B. Johnson, Erik C. Westman

The ability to understand stress redistribution within a mine allows greater extraction efficiency with reduced safety concerns. Stress redistribution has been examined at the laboratory scale using ultrasonic tomography and numerical modeling using PFC3D. A data acquisition system was built to obtain tomograms as samples are loaded in uniaxial compression. Limestone samples were loaded to failure. Three-dimensional tomograms of the samples correlate to various stress distributions. The tomograms are compared to analytical and PFC3D results.

Jan 1, 2005

By R. H. Seraphim

The name is derived from an Egyptian myth, "A beautiful lone bird which lived in the Arabian desert for 500 or 600 years and then consumed itself in fire, rising renewed from the ashes to start another long life." HISTORY This account of the first history is gleaned from old reports and documents which are listed in the Bibliography and from discussions with old-timers of the district. Prospectors were active in the vicinity of Greenwood in 189 1, and in that year staked the Mother Lode, Crown Silver, and Sunset. Henry White staked the Knob Hill claim in Phoenix on Jul. 15, 1891, and by the end of the year, other prospectors had staked most of the claims covering the valuable ore bodies in the camp. Much surface work done in the early years indicated that the values in copper, gold, and silver were low. Large capital investments were required to develop the ore bodies and build smelters. The discovery that the ore was practically self-fluxing greatly enhanced the value of the deposits. A map of the area showing the geology is given in Fig. 1. The bedded Brooklyn conglomerate is shown in Fig. 2.

Jan 1, 1991

By K. H. Al-Rawahy

Appreciation and awareness of the unique nature of mineral investment and ultimate development of a mine are crucial in promoting sustainable development. Special characteristics of mineral development include high capital intensive, long pre-production period, high risk, and the unavoidable ?economic? depletion. This paper examines ways to integrate these unique attributes of the mineral industry into the educational process, so that a properly advised and knowledgeable culture in terms of a sustainable mineral industry can be developed. Specific approaches are investigated in order to achieve this objective. These include a stochastic evaluation of a mineral investment proposal, adding a premium to the cost of capital that is used for valuation process, and internalizing incidental costs to the private cost function, thereby realizing the true (vs. apparent) marginal social cost of the proposed development. Undoubtedly, a total evaluation of any mineral project that accounts for both tangible and intangible parameters will contribute to sustainable development objectives. By incorporating the practical application of apparent theoretical topics such as risk, probability, and externality, and their relevance and impact on mineral lifecycle (prospecting, exploration, development, exploitation, use, and ultimate disposal) into the educational process, it is hoped that a generation of technocrats and decision makers that are familiar with and concerned about sustainable development will emerge.

Jan 1, 2007

By R. K. Mehta, G. T. Adel

A review of the literature reveals that methods for simulating the coupled behavior of size reduction and liberation are limited to binary mineral systems containing one composite particle class. The aim of this paper is to describe the development of a mathematical model to simulate such behavior for binary and ternary systems containing multiple classes of composite particles. A modified Levenberg-Marquardt algorithm and a finite difference Jacobian are used in conjunction with the developed model and a set of constrained equations to estimate all kinetic parameters. This estimation scheme is validated far a binary ore (sphalerite-dolomite) with five composite particle classes using experimental data.

Jan 1, 1991

By Bern Klein, Richard W. Lawrence, Scott Frostad

A laboratory study was conducted to evaluate the effects of various kinetic test protocols on sulfate production, NP depletion and time to acidity. Six test protocols were evaluated including standard humidity cells, non-aerated cells, tall cells, shaken cells, simulated precipitation cells, and NP depletion columns. The study indicates that test protocols which disrupt the oxidizing environment, such as extreme wetting and drying cycles, shaking the cells, or the high addition of acidic water will create an unnatural environment that affect the results. Trickle leach and non-aerated test protocols create an oxidizing environment that more closely represents field conditions and are therefore recommended.

Jan 1, 2000

By Dilip K. Sinha

In the paper some interesting cases of applications of Operations Research and Computer Methods as worked out by the author and accepted by the management of some of the newly formed Indian mining organisation for implementation are highlighted. The main emphasis on the application cases was to use simple techniques and methods which yield the result in shorter time period, The case problems mainly deals with the production system optimisation in unit mines, areas/divisions and at the corporate levels. Also the management decisions regarding reorganisation of transport and distribution system of material and mineral are attempted to be optimised. Further, the case of management system development with computer aided decision making worked out for single large Iron Ore Project captive to a steel plant is outlined. Finally, the case of a large mining company having decentralised units and divisions geographically dispersed throughout the country, computerised management decision-information system designed on the basis of inputs and outputs of decision models relevant for different levels of management in the organisation is depicted.

Jan 1, 1986

By E. H. Ahrens

This paper deals with the responsibilities of an operating geologists and the relationship of operations to exploration. It should be of interest to those soon to enter the profession, those new to pining geology and as a review to more experienced geologists. Subjects discussed include detailed geologic mapping, sampling, core logging, assaying, selection of proper map scale, posting geological and assay data, section preparation, identification of ore controls, delineation of development drill targets and geologic hazards, models and the very important topic of salesmanship. Methods and ideas, proven valid in vein, pyrometasomatic replacement and porphyry copper deposits are presented. Hopefully, these will smooth the path for new members of our profession.

Jan 1, 1992

By Raj K. Rajamani, Ilesh M. Shah

Maintaining pH, a routine requirement in many industrial processes, is by no means trivial. The control is troublesome because of the inherent nonlinearity and frequently changing process dynamics. Many researchers in the past have investigated advanced on-line estimation and/or adaptive control techniques to overcome these difficulties. Most methods require the development of a complex mathematical model. The present work deals with the use of a simple and elegant method for pH control, based on the use of fuzzy logic. First, a standard fuzzy-logic controller is discussed, followed by a self-organizing controller. The latter algorithm generates a set of rules based on observation of the process. Thus it is a learning algorithm. The development and application of the algorithms to a laboratory acid-base neutralization experiment are presented. This elegant technique is powerful and deserves attention in mineral pro- cessing.

Jan 1, 1990

By D. J. McKee, D. M. Wiseman

The usefulness of simulation as a technique for metallurgical process design and optimization studies has been greatly extended over the last few years by the development of a number of general purpose simulation packages. The packages, or simulators, all have the common objective of presenting the mathematical models and simulation methods in a form which is readily usable by plant engineers and metallurgists. To date, most simulators have been concerned with steady state simulation, but packages capable of dynamic simulation are now becoming available. The paper outlines the essential features of versatile steady state and dynamic simulators. Typical applications are presented by considering examples of design and optimization studies. Limitation on the use of simulators are also presented.

Jan 1, 1991

By Juan P. Camus

One of the most important decisions in mine development is the selection of the mining method. Open pit or underground methods are selected depending on the shape of the deposit, and its position with respect to the surface. When the decision is not clear or evident, then the common rule is to compare underground and open pit projects to choose the one which yields the maximum return. However, in some circumstances' the best alternative is to start-up the operation with an open pit until a point where mine operating costs make more convenient to employ an underground method. In this case, the final pit limit is not directly related with commodity prices and its position is a funtion of capital and operating costs associated with both methods. The goal of this paper is a mans of establishing the proper ultimate pit considering a potential underground mine. The methodology is quite simple and can be implemented to work with a variety of available routines for pit optimization, such as Lerchs-Grossmann, floating cone, network flow and the Lemieux moving cone optimizing algorithm, which is the tool used by the author.

Jan 1, 1992

By P. Venkatraman, F. S. Knoll, W. S. Kow

Froth flotation is the most widely used technique for cleaning fine coal. This practice may change, however, with the development of enhanced gravity concentrators such as the Mozley Multi- Gravity Separator (MGS). The MGS is a flowing-film concentrator that utilizes centrifugal forces to improve the separation of flotation-size particles. In the present work, a pilot-scale test program was conducted to examine the effects of feed rate, feed solids content, wash water flow rate and drum rotation speed on the performance of the MGS. The test results indicate that the MGS effectively rejects high-density minerals such as pyrite, while ultrafine ash-forming minerals are removed less efficiently. A major advantage of the MGS is that high separation efficiencies can be realized without additional grinding, flotation reagents or heavy media. This article describes the working principles of the MGS and presents data obtained from recent pilot-scale test work.

Jan 1, 1995

By Kai Nielsen

In underground mining coarse muck and large boulders lead to ineffective utilization of costly mining equipment, and extra expenses and delays caused by secondary blasting. Cost analysis in some Norwegian mines shows that these extra expenses may amount to 10% or more of total mine operating costs. A computer model has been developed for sensitivity analysis of underground longhole stope blasting. The basic idea of the model is : When increasing the blasting energy input and fragmentation costs, the fragmentation will be better. This will lead to cost savings for loading, hauling, secondary blasting and primary crushing. The blasting design giving the lowest overall costs will indicate the optimal practice. The model has been used with data from several underground operations in Norway. An example run with typical costs shows that the costs for drilling, blasting and secondary blasting are the most significant parameters in the optimization process.

Jan 1, 1986

By Edward Marszalek, Boleslaw Firganek

The paper deals with a computer method and algorithm of optimization of the rescue routes for the endangered staff in the case of fire in a given place of the mine. The adapted method is based on the objective function and realizes the algorithm of the shorest path with weighers assigned to it. The objective function is so defined that it reflects possibly all the hazards and difficulties arising during a fire in the mine. The algorithm is enhanced by an empirical formula for calculation of the smoke zone as result of a mine fire. The presented results of computations of optimal routes for several simple examples using the canonical scheme of the mine network and simulated fires are satisfying and prove the method, the algorithm and the coded program to be correct. The program will be a part of the software library of the mine ventilation engineer. The data for the program will be updated on-line from the fire detection systems.

Jan 1, 1989

By M. G. Ayat

Engineers in the field of coal preparation are continually striving to increase the efficiency of various circuits used in preparation plants. Undoubtedly, one of the important factors concerning the processing efficiency of a coal preparation plant is improved analyses and control of the processing equipment. The necessary link between the performance criteria of a circuit may be provided through on-line determination of various parameters. Currently, there are a certain number of on-line instruments developed for measurement of ash content of coal (Watt and Sowerby, 1983; Kawatra, 1976; Fauth et al., 1984; Lyman and Chester, 1980), moisture content (Hall et al., 1969), and sulfur content (Stewart et al., 1974). In the case of coal separatory units, these parameters are often directly related to the quality of the product. In other words, the extent of misplacement of refuse in the product, or vice versa, would indicate the performance characteristics of any particular coal washing equipment. Partition curves are therefore established to predict the performance of coal cleaning operations. Conventional sampling and testing is currently the major tool with which partition curves are produced and the performance efficiency of the operation is assessed. While conventional analysis techniques are accurate, they are slow and time-consuming.

Jan 1, 1987

By H. K. Lin

Cyclic voltammetric and potential step chronoamperometric techniques were used to study gold dissolution in cyanide solution. Three distinct anodic peaks and one cathodic peak appear on the voltammogram between -0.50 and 0.80 V vs. SCE. The corresponding reactions were proposed to explain the peaks and the passivations. The proposed reactions were in agreement with the effect of pH and cyanide on the magnitude of the peak currents. Cyclic voltammetric tests, with various vertex potentials, were also conducted to examine the proposed reactions. Steady-state currents at various potentials were obtained by potential step chronoamperometric technique and were compared with transient currents obtained by the cyclic voltammetric technique.

Jan 1, 2002

By J. D. Miller, D. M. Catarious, F. L. Stanley

The quality of cleaned products from coal preparation plants is often variable due to natural fluctuations in the washability characteristics of the plant feed. To combat this problem, many modern plants have installed on-line analyzers that provide feedback for the real-time control of product quality via the adjustment of circuit cutpoints. Unfortunately, optimization studies show that this approach may actually lead to increased losses of saleable coal. This paper discusses the problems associated with the real-time manipulation of circuit cutpoints and suggests alternative modes of operation that are better suited for plant optimization. A case study involving an eastern U.S. coal plant has been used to compare the economic impacts of these different approaches for plantwide control.

Jan 1, 2000