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By Pieter Hoekstra, Jim Hild, Mark Blohm

In the Basin and Range Province of Nevada, geophysics is used to assist exploration for bulk minable gold deposits, particularly over pediments. It is employed for mapping thickness of alluvium and Tertiary valley fill, for mapping covered structures, and for identifying alteration zones. In addition to potential field and seismic methods, three different electrical and electromagnetic methods are frequently used, resistivity-induced polarization, controlled source audiomagnetotellurics, and time domain EM. A review and comparison of the principles of these methods, illustrated by case histories, is the topic of this paper.

Jan 1, 1989

By James P. Dorian

Like Russia and Ukraine, Kazakhstan is one of a few former Soviet republics well-endowed in mineral and energy resources (Fig. 1). Kazakhstan is the second largest newly independent Commonwealth state. It possesses major fuel and power centers, including 20 electric power facilities that operate on the more than 300 kt (330,000 st) of coal extracted daily. These power stations supply Central Asia, the Urals and Western Siberia with much needed electricity. Kazakhstan plays a critical role in Central Asia as it serves as both the regions' economic and political hubs. While Kazakhstan already contains a robust and diversified minerals industry, the government is actively pursuing foreign investment to boost production capacity and improve efficiencies in operations. A primary objective of the Kazak government is the expansion of metal processing facilities to improve the country's long-term export potential. Since 1991, international mining companies have found the investment climate of Kazakhstan relatively favorable. This is due to tremendous efforts by government officials to create sufficient investment legislation and a national minerals policy, while eliminating bureaucratic bottlenecks common to most other former Soviet republics.

Jan 1, 1993

By Karl H. Gehring

According to the increasing importance of boom type roadheaders in tunnelling essential problems occuring in the application of these machines are dealt with. Based on a chart including the various stages for decicion finding the excavation method of underground cavities, both the technical limits and economic criteria are discussed in order to determine the range of applicability of roadheaders. Giving examples-the numerous developments in the fields of pick and cutting technology, performance data of boom type roadheaders in hard rock, safety technology and increase in the machines' degree of utilization, research and development of VA is illustrated. Two topic operation examples show partial aspects of the various tendencies of development.

Jan 1, 1981

By S. B. Gaidhani, V. A. Mandlekar, R. L. Sonolikar

Column flotation technique is applied for the depression of the magnetic material by the application of an axial magnetic field from chalcopyrite ore. It is observed that an increase in the intensity of magnetic field from 0 to 316.8 oersteds decreased the magnetic content in the froth from 25 to 2 %. . This might be due to retention of magnetic material in the magnetizable zone and the diffusion of nonmagnetics through it. The effect of air velocity increased the magnetic content in the froth and total froth content also. At low gas velocity the tiny bubbles are formed whereas at high gas velocity these coalesce into big bubbles and slugs formed breaks the magnetizable zone. This study opens a new field called 'Magneto-flotation'.

Jan 1, 1988

By M. K. Patel, K. C. Wade, M. Cross

In the past decade a good deal of effort has gone into the computer simulation of the heat distribution of pellet induration systems. The major uncertainty in the analysis of such systems is the gas flow distribution and, in particular, the role of leakage. Evaluation of the leakage into or out of a zone has proved to be very difficult, as has the cross-flow from one zone to another when adjoining zones have gas flows which change direction from up draft to down draft for example. This paper describes an initial model to calculate the gas flow distribution in a variety of practical situations of interest to those involved in pellet induration. The model is based upon a multiphase CFD code called CASCADE which is used in conjunction with the pellet induration simulation INDSYS.

Jan 1, 1990

By J. J. Davis, D. G. Osborne

The Australian coal industry is characterised by efficient fines recovery, and the climate does not dictate the use of thermal drying. With the increasing trend to underground mining and hence finer ROM coal, and market pressures for reduced product moistures, dewatering issues are assuming increasing importance in the Australian coal industry. The greatest potential gains in dewatering performance undoubtedly lie in the treatment of finely sized material. This paper examines the dewatering issues which have been recognised by the Australian coal industry, and describes current Australian research in this field.

Jan 1, 1995

By Tracy E. Chantson, Brian R. Green, Kenneth G. Ashurst

Work that has culminated in the manufacture and testing of a old-selective resin on a pilot-plant scale is dcscribed. Following a brief discussion about the nature of commercially available resins which identifies them as poor candidates for a gold extraction application, the improved properties of the new type of resin are illustrated using results from comparative loading tests. Further results from continuous countercurrent extractions using synthetic leach liquors and elution work using thiourea as the eluant demonstrate the superiority of the new resin over commercial resins and hence, its potential for use in a resin-in-pulp process for gold.

Jan 1, 1989

By S. Dixon

The objective of any business is to maximize the value derived from the commodity produced. There is a point where additional expenditure does not return a value sufficient to justify the additional expense. The treatment of high acid consuming copper ores is a perfect example of this principle in which the relationship of acid consumed to the percentage of Copper extracted is vital to the economic value of the final product. This paper describes a method of evaluating column leach test data to determine the economic optimum conditions for leaching high acid consuming copper ores. The effect of acid consumption on the net economic value of the Copper extracted is very significant in the case of high acid consuming ores. The focus of this paper is the relationship of acid concentration in the raffinate, and acid cure dosage to the economic value of a leach cycle.

Jan 1, 2004

By H. Ouellet, J. Paraszczak

The pneumatic jackleg drill remains a widely used tool in development and production drilling in many small-scale and narrow-vein underground mining operations in North America. Several drawbacks of this technology (unsatisfactory drilling rate, noise, vibration, presence of oil mist, etc.) and the successful introduction of water-powered jackleg drills in South Africa have stimulated the interest of many mine operators. The performance of both drill types have been tested in a mine site in Northwestern Quebec, Canada. Results of the testing of penetration and advance rates as well as environmental aspects are presented. They show a superiority of water-powered drills, even though the difference in performance is less significant than that reported from South Africa. Further research avenues are proposed to better evaluate the potential of water drilling technology in North American metal mines.

Jan 1, 1995

A form of column flotation cell is described in which the contact between the feed and the air stream is made in a mixing device at the top of a vertical downcomer. The air-liquid mixture flows downward to discharge into a shallow pool of pulp in the bottom of a short cylindrical column. The bubbles disengage and rise to the top of the column to overflow into a concentrate launder, while the tails are discharged from the bottom of the vessel. The main advantages of the device described are that the overall height of the column is reduced to about 1 m (3 ft), and the column can be self-inducing with respect to the air supply. Experimental results are given from tests on a feed stream to a conventional zinc cleaner circuit. Using wash water to reduce gangue entrainment, the column gave high concentrate grades and high recoveries.

Jan 1, 1987

By Don Minard

Management support systems are extremely important to mining management to enable them to operate their company as a business. Management must give attention to the financial, maintenance, materials, and other reporting and control systems that are necessary to successfully operate a mining company. This subsection describes the management support systems that are critical to most mining companies. In this introductory review, the major objectives and functions of these management support systems will be introduced. The following topics will expand on the functions and key concepts as well as other considerations in each of these systems areas. Additionally, this introductory review will touch upon the unique environment that mining companies find themselves in from a management and personnel standpoint and the effect of this environment on management systems. Additionally, specific keys to successful systems installations and acceptance in the mining industry are discussed.

Jan 1, 1979

By A. Cavero, M. Diaz

The annual rainfall at Minera Yanacocha's gold mining operations in northern Peru averages 1.2 meters. The influx of water into the operations is higher than losses to evaporation and by ore absorption which results in a positive water balance. To minimize water intake and maintain a balance, some special operating procedures are required, and a system involving diversion ditches, storm ponds, heap skirting and detoxification and treatment of excess water is practiced. An operation background is also reviewed at the beginning of the paper.

Jan 1, 1998

By W. Trask

The state of the art in crawler transporters for loads to 3 kt (3300 st) is sufficiently advanced to allow compilation of job cost figures showing the economics of tracked vehicle use under a wide variety of circumstances. Initial costs, cost per ton of capacity, and operational and maintenance expenses are presented. Data is derived from participation by the Neil F. Lampson Co. in more than 3 Mt - km (2.05 million st - mile) of crawler operation during the past 16 years. The effects of economics on future design trends will be examined with particular reference to versatility, portability, and capacity.

Jan 1, 1987

By Bill Reid

Coal companies mining the seams in the Appalachian region appear to be optimistic. Although some older mines are closing, newer mines are expanding. Money is being spent on new equipment and research to increase mining productivity, as well as improve safety. Coal has been produced from the rich Appalachian seams for about 200 years with no end in sight. Many equipment manufacturers have substantial backlogs of orders for new equipment. Some of the innovations being monitored by the Appalachian underground coal operators include au¬tomated longwall mining, continuous haulage systems and methane drainage. Appalachian coal was a major ingredient in the steel that culminated in the Golden Spike ceremony at Promontary Point, UT, where the final link in the transcontinental railroad was closed. This occurred on May 10, 1869, according to a history published by Union Pacific Coal Co. It stated that "rails and fastenings for track construction were purchased in Danville, Scranton, and Johnstown, PA and Troy, NY." Ever since, coal from the eight Appalachian states has contributed in no small measure to geographic expansion and economic growth of the United States.

Jan 1, 1995

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. Duvris

The main objective of this work was to quantitatively investigate exhaust emission levels relative to maintenance (service) intervals during the operation of diesel-powered equipment at an underground bauxite mine in Greece. Such emissions depend on a great number of parameters, including the type of engine (technology) and its tuning, the type of work performed (as related to the engine workload), the suggested maintenance intervals, the altitude, the temperature and humidity of the atmosphere in the underground mine, the properties of the fuel and the operator's training and experience levels. The necessary ventilation quantities were calculated based on exhaust gas-concentration measurements and site-specific relationships between pollutants and adjusted air-quality indices. Diagrams comparing the necessary and recommended airflow for several equipment groups, featuring two engine types and different maintenance intervals, are presented.

Jan 1, 2000

By Thomas J. Feeley

The US Department of Energy (DOE) is supporting the engineering development of three advanced physical coal cleaning technologies: selective agglomeration, advanced flotation and advanced cycloning. Each is capable of significantly reducing the pyritic-sulfur content of US coals. The objective is to provide the coal and electric-utility industries with a cost-effective option for addressing the SO, emission reductions required by the 1990 Clean Air Act Amendments (CAA). A secondary objective is to evaluate the potential of advanced coal cleaning for removing trace elements that are precursors to the formation of hazardous air pollutants (HAS). The proposed National Energy Strategy (NEE) and the 1990 CAA lay a foundation for a more efficient and environmentally sustainable energy future (1991). The need to use energy resources in an environmentally sound manner presents critical challenges and opportunities for coal preparation during the next decade, particularly regarding the control of SOS and HAY emissions. The principal challenge is the development of cost-effective coal preparation approaches for sulfur and HAY precursor removal.

Jan 1, 1993

By Hugh R. Wilson

Echo Bay's Waste Management Program for its Lupin Mine was developed in response to the terms and conditions of the water license issued to the mine in 1981 by the Northwest Territories Water Board. The gold mine, located about 80 km (50 miles) south of the Arctic Circle, commenced production in 1982. The Waste Management Program was based originally on the total containment concept, contingent on future treatability testwork results indicating the best treatment method to ensure pond discharges would be in compliance with stated Northwest Territories Water Board discharge criteria. To assess the various treatment technologies, an investigative program was established to determine the most effective means for treating the tailings pond water. In the course of milling, about 850,000 m3 (11 million cu yd) of tailings are produced annually that require appropriate management to protect the environment. This annual tailings stream consists of about 175,000 m3 (229,000 cu yd) of solids and 675,000 m3 (883,500 cu yd) of water. Following the completion of the required waste management studies, a two-ponds-in-series concept of tailings impoundment was developed. To attain this concept, the tailings impoundment area would require modification and construction to enable the use of such a system.

Jan 1, 1991

By Mario E. Rossi

The concept of entropy is classical in thermodynamics and information theory. Its potential use as a measure of the ordering of a spatial system is discussed. Although entropy has been discussed previously in the framework of spatial statistics and for univariate distributions, a bivariate data-based estimator has not until now been defined. Different statistical distributions maximize entropy, depending on the univariate, bivariate, or n-variate constraints applied. For bivariate distributions, with a known mean and known covariance, it can be shown that the distribution that maximizes the entropy of the system is the bivariate gaussian. A nonparametric bivariate entropy estimator is introduced, derived directly from the experimental cumulative frequency distribution. Assuming that this experimental bivariate distribution is representative of the population distribution, then a measure of departure from gaussianity can be introduced as a relative entropy estimator. Practical applications for the entropy estimator are discussed, and an example developed.

Jan 1, 1992

By Henry E. Bakkila

Introduction United States Steel Corporation's, Texas Uranium Operations operates in-situ mines located approximately 70 miles north of Corpus Christi near the town of George West in Live Oak County, Texas. In 1977, Texas Uranium Operations became the operating entity for the Burns Ranch mines 100% United States Steel ownership and also operates the Clay West mines a 50150 joint venture of United States Steel Corporation and N M Uranium, Inc. Until mid-1982, Texas Uranium operated eight (8) satellites where uranium was captured on resin and two central plants where the loaded resin was eluted, acidized, precipitated and dried to yellowcake. At present, the Clay West Central Plant is operating, as are four (4) satellite plants in a mode designed to optimize results while depleting remaining reserves. United States Steel's Texas Uranium Operations, as have some other uranium producers, managed to continue successful production during the plunge to the recent floor price of $17. Despite the fact that United States Steel does not intend to continue as--a uranium producer beyond the life of its present reserves, we naturally hope the recent trend to the pre- sent price of $24 will continue to increase.

Jan 1, 1984