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By R. M. Carland, F. F. Aplan

The ion-exchange capabilities of natural zeolites from the western United States, representing the species chabazite, clinoptilolite, erionite and mordenite, have been studied because of their potential use in environmental remediation and in hydrometallurgical processes. These raw zeolite samples were found to contain Na+, K+, Ca+2 and Mg+2 as exchangeable cations, and all of these, with the exception of Na+, were found to seriously interfere with the exchange of Cu+2 from solution. Placing these zeolites in the Na+ form was found to increase their cation-exchange capacity, often massively. In addition, the elution of Cu+2 from the Na+ pre-exchanged zeolite is greatly facilitated when the deleterious K+, Ca+2 and Mg+2 have been largely expelled. The relative influence of these deleterious ions on the uptake and elution of Cu+2 was determined.

Jan 1, 1996

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 John C. Braithwaite

Gold production commenced in New Zealand during the gold rush of 1861, and recovery to date is over 900 tonnes, almost 60% of which was alluvial. New Zealand pioneered development of bucket line dredges during the 1880's. The advent of the modern hydraulic excavator and increased gold price led to a resurgence in alluvial production with about one hundred plants in operation in 1988. The processing plants are mainly floating, with throughputs of 50-100m3/hr fed by backhoes of 20-40 tonne operating weight. Some larger plants with more sophisticated recovery systems have commenced over the last few years, with the largest using a 180 tonne backhoe.

Jan 1, 1989

By Kerry Spickelmier

With the dissolution of the former USSR and a welcoming of foreign, minerals expertise by a host of developing countries, a "new," more international, world of minerals is open to the mining industry. However, even in the new frontier, the old laws of nature still apply. For those attendees of the 98th annual Northwest Mining convention, the adage "survival of the fittest" commanded particular attention. Miners, engineers, geologists and other unique species traveled to Spokane in December to learn of adaptations they can make to assure, or at least prolong, their place in the mineral industry's land of the living. You have heard the tales of the spotted owl and the desert tortoise, but add to this endangered list the North American mining industry. During a session on international investment criteria, D. Silver of Balfour Holdings (Littleton, CO) blamed excessive environmental regulation, 1872 Mining Law revision and the anti-mining-and-business attitude of our government for migrations from and extinctions within the domestic mining population. "We've been on a death curve for some time," Silver said, "with a lower birth rate and a higher death rate. In the last four years, we've lost 60% of the gold producers in North America, and we're down to 110 companies. The entire industry has lost about 400 companies and is now down to 2800." Unreasonable regulation founded on emotion rather than scientific fact has been the chief cause of death, according to many of the convention speakers. B.J. Kennedy, president and chief operating officer of FMC Gold (Reno, NV), emphasized, "We have accepted a regulatory environment - but we oppose being strangled to death by unreasonable regulations."

Jan 1, 1993

By Thomas P. Meloy

As the importance of particle shape in mineral processing is increasingly recognized as an major variable in predicting the behavior of both individual particles and particle systems, whether it be in dense media, froth flotation, comminution or the flow of particles, new method of shape characterization are being developed, particularly for use on image analyzers. These shape characterization methods may be broadly classified into the analytical, empirical and physical formation methods. Discussed are approaches and the strengths and weakness of each of these methods. Moreover old and new shape measuring techniques are reviewed, particularly the new image analysis methods techniques such as Fourier, Haar, Fractal, Walsh and Delta as well as a variety of other techniques such as tabling, the Cascadograph, settling and L/D ratios. Also discussed are the problems of doing shape research, current progress and the future of the field.

Jan 1, 1990

By S. Saklar, i. Bayraktar

The effect of the feed size distribution on the kinetic parameters in pyrite flotation was studied. The kinetic parameters of the particular sizes were determined as a function of whether other particle sizes were present. From the data, a relation between the pyrite flotation rate and the particle size distributions was obtained. It was shown that the flotation rate constant (k) is a function of the size modulus (dt) of the Gates-Gaudin-Schuhmann distribution, and its variation may be expressed as k = a • exp(b . d,) for either individual size fractions or composite feed. Parameters a and b are dependent on the particle size distribution of the feed. Specifically, parameter a increases linearly as the distribution becomes coarser. The above relationship was also tested under conditions in which the collector (KAX) dosage was varied from 130 to 278 g/t. It was shown that the established relation was not dependent on the collector dosage.

Jan 1, 2002

By Douglas W. Fuerstenau

This paper concern the specific adsorption of sulfate anions on nonmetallic minerals and its role in flotation. The specific surface affinity of sulfate ions in various systems has been observed in the results of electrokinetic measurements that show conditions under which sodium sulfate can reverse the sign of the zeta potential. The electrical double layer model provides a means for interpreting the results and for estimating the free energy of adsorption of sulfate ions. Because of their surface activity, sulfate ions not only can function as a depressant in the flotation of oxide minerals with physisorbed anionic collectors but also can function as an activator for flotation with physisorbed cationic collectors. Their role in depressing or enhancing the flotation of the sparingly-soluble mineral barite is also explained in terms of the double layer model.

Jan 1, 2005

By M. B. Díaz Aguado

Traditionally, the practical evaluation of a mining project for a potential investment has been made considering mainly technical aspects. But the concept of sustainable development has introduced significant changes in the factors analyzed to make the final decision. This paper proposes an empirical evaluation of a project considering not only technical, economic and financial parameters, but also associated risks and other intangible aspects, such as political considerations, stability in the legal frame, social factors and environmental issues. The proposed methodology is practical and easy to apply for project management. Among its main advantages, the following could be quoted: using this evaluation two different projects or locations of a same project can be compared, future behaviors could be predicted, the index incorporates a new approach to specific mining projects and this perspective could also be applied to other projects with environmental and social impact, such as civil works or industrial projects.

Jan 1, 2007

By S. Chander

Neutralization of acidity by addition of alkaline materials is a commonly used method to treat acid mine drainage. However, this procedure requires large amounts of reagents based on acid-base accounting. The potential use of organic additives in preventing or ameliorating acid mine drainage was investigated in this research. The tests were conducted in weathering columns using refuse samples from a coal cleaning plant. Both cationic and anionic compounds were tested. For a comparison, tests were made in the presence of limestone and lime. The results show that some of the reagents substantially retarded the rate of oxidation whereas others even enhanced it. The suppression of the rate of pyrite oxidation was ascribed to surface chelation. Formation of surface compounds prevented the pyrite particles from further oxidation. Such a treatment required only small quantities of reagents since the reaction was confined to the surface.

Jan 1, 1992

By K. G. Colman

Este texto intenta facilitar al operador y contratista 10s datos básicos para dimensionar las cribas vibrantes que deban ser utilizadas en las plantas de trituración. Las capacidades básicas, factores que la modifican .... etc., utilizados en el cálculo de la superficie requerida, se han desarrollado empíricamente y modificados sus valores hasta el presente con 10s datos de las aplicaciones prácticas Hay que señalar que el cribado tiene mucho más de arte que de ciencia exacta; sin em- bargo, la información aquí presentada proporciona una razonable seguridad cuando se aplica al cálculo de cribado de minerales metálicos.

Jan 1, 1982

By Winfield G. Wright, Greg P. Meeker, Philip L. Verplanck, Douglas B. Yager, Dana J. Bove, M. Alisa Mast

A really extensive acid sulfate-altered and mineralized rock in the southeast Red Mountains area is noted for its association with naturally occurring and mine-related acidic and metal-rich waters. Integrated geologic and aqueous geochemical studies demonstrate that the degree of metal mobilization and acid production in natural waters correlates well with the type of hydrothermally altered rock and structural features in which these water interact. Quartz-sericite-pyrite, quartz-alunite, and argillic alteration assemblages are associated with some of the most naturally acidic, high-metal waters in the study area; calcite-bearing propylitic rocks are related to the most pristine waters and buffer sulfate-rich, acidic waters produced by pyrite oxidation. Trace metals in natural waters are mostly derived from enargite, zinc-rich tetrahedrite and sphalerite. Pyrite oxidation contributes very little with respect to base-metals in these natural waters.

Jan 1, 2000

By Charles D. Litton, Margaret R. Egan

In order to reduce the number of nuisance fire alarms in underground mines that use diesel-powered equipment, the U.S. Bureau of Mines has developed a diesel-discriminating fire detector (DDD). It was designed to discriminate between smoke produced by a fire and the smoke-laden exhaust of a diesel engine. Welding and cutting with arc or flame can also produce combustion products capable of triggering nuisance alarms. In this report, the response of the DDD to the emissions from diesel exhaust, arc welding, and flame cutting are compared to the response of conventional smoke and carbon monoxide (CO) detectors. The data show that when the DDD is set at an alarm threshold of 0.05 v, it will reliably detect a developing conveyor belt fire while remaining insensitive to other sources of nuisance combustion products. The alarm times of the three types of detectors were also compared. The DDD alarmed first in response to a smoldering conveyor belt in two of four experiments.

Jan 1, 1992

By K. A. Natarajan, J. M. Modak, P. Anand

A microbial survey of Jamnagar bauxite mines in Gujarat, India, revealed the indigenous presence of a variety of autotrophic and heterotrophic bacteria and fungi associated with the ore body and water ponds in the vicinity. Among these, bacteria belonging to the genera Thiobacillus, Bacillus and Pseudomonas are implicated in the weathering of aluminosilicates; the precipitation of iron oxyhydroxides; the dissolution and conversion of alkaline metal species; and the formation of alumina, silica and calcite minerals. Fungi belonging to the genus Cladosporium can reduce ferric iron and dissolve alumina silicates. Biogenesis thus plays a significant role in bauxite mineralization. Various types of bacteria and fungi, such as Bacillus polymyxa, Bacillus coagulans and Aspergillus niger, were found to be efficient in significant calcium solubilization and partial iron removal from bauxite ore. Probable mechanisms in the biobeneficiation process are analyzed. Biobeneficiation is shown to be an effective technique for the removal of iron and calcium from bauxite ores for use in refractories and ceramics.

Jan 1, 1998

By M. Shen, T. D. Wheelock

The important characteristics of a gas-promoted oil agglomeration process for cleaning coal particles in an aqueous suspension were determined. Numerous agglomeration tests with scale-model mixing systems of different sizes with controlled amounts of air were conducted. The tests were conducted on high- and mediumvolatile bituminous coals using either i-octane or hexadecane as an oily agglomerant. The performance of the system was characterized by employing the minimum time required to produce spherical agglomerates (tE), the mean agglomerate diameter (dp), coal recovery and product ash content. Among these parameters, tE was found the most useful. It is a key parameter in the scale-up of an agglomeration mixing system. This parameter was found to depend on a number of system and operating variables. By controlling these variables and conducting further agglomeration tests with mixing systems that varied in size, an appropriate size scale-up rule was established.

Jan 1, 2002

By Armstrong

This is a world of change and has been from the beginning. There are constant efforts on the part of natural forces to wear down the high spots and fill in the low spots. Wind and water over eons of time tunnel through obstacles and build windways and waterways to make movement of air and water easier and more efficient. It is a natural, never ending, ever changing continuing effort. Man in his struggle to survive, and to progress, has had to adapt the terrain of the earth to fit his needs the best he could. First, he used natural caves to protect him from the elements; then he learned how to build earth and rock-moving tools from antlers, bone, rocks, and sticks and adapted his cave to increase his security and provide better protection from heat and cold and from his predatory enemies. As his numbers increased, so did the necessity of further adapting his environment to accommodate his needs. Water was usually not available when and where needed, especially in the desert areas where civilization developed, and long tunnels were drilled to intercept ground waters and lead them to underground caves carved out of soft limestone. Most of the tunnels of early man were to bring water from where it was to where man needed it. Then, as now, as man increased his chances for physical survival, he turned to the quality of life -- and this reflected in the concern for life after death. This lead to the elaborate shafts and tunnels for the protection and prservation of the more affluent noblemen and pharaohs of the early Egyptian civilization. Man used the underground for the stable temperature and for protection and safety.

Jan 1, 1974

By F. F. Aplan

Mineral process engineering is a small but important part of the nation's raw material industry. Minerals are usually processed in large plants of high capacity, at low cost, using few engineers and operators, and at an ever-increasing level of plant sophistication. The magnitude of the mining industry is huge, with about 4 Gt (4.5 billion st) of ore, coal and industrial minerals mined annually in the United States. Industries such as construction, manufacturing and power generation rely heavily on a strong US resource base to maintain a competitive edge. Though rooted in classical chemistry, geology, physics and mathematics, a mineral process engineer must be trained in the science and engineering required to process raw materials. A modern mineral processing program still stresses the traditional aspects of the profession. But it also emphasizes particle technology, applied surface chemistry, chemical processing of ores, solid-fluid separations, process and equipment modeling and optimization, materials handling, personnel management, maintenance and environmental and health aspects. In such areas as particle technology and some aspects of applied surface chemistry, mineral processing academic programs have taken a leadership position in supplying specialists to a variety of other industries. The objectives of a mineral processing program are: • to furnish personnel to support the basic raw materials industries (undergraduate programs); • to provide a research and development base for industry (graduate programs); and • to provide expertise in particle technology, applied surface chemistry and environmental programs for other industries (undergraduate and graduate programs). In the United States, mineral process engineering programs have historically been associated with mining and metallurgy departments. The recent movement of metallurgy programs away from primary processing towards materials science has created the need for a new accommodation.

Jan 1, 1992

By Ron L. Schmiermund

The Ferris-Haggarty underground mine was abandoned circa 1910, and portal discharge has since resulted in degradation of a trout fishery in the receiving waters of Haggarty Creek. Although tunnel discharge varies dramatically in volume throughout the year due to infiltration of snowmelt, compositionally it is a nearly constant low-TDS, pH-neutral, low-sulfate, copper-silicate dominated water. Between infiltration events, components of ARD accumulate in unsaturated, oxygenated environments within upper workings and are delivered to the main haulage level by the subsequent annual snowmelt flush. Mixing with non-ARD mine waters results in neutralization, dilution, and precipitation of amorphous copper carbonate and silicate phases. These mechanisms, combined with variations in the water balance, control the composition of the portal discharge. Understanding the chemical and hydrologic control mechanisms was critical to the design of a passive treatment system to decrease effluent copper concentrations.

Jan 1, 2000

By Thomas H. Holley

This presentation will describe the underground excavation at the Bad Creek Pump Storage project. It consists of approximately 3,650 m of various size tunnels ranging from 4.2 m to 9.0 m finished diameter, a powerhouse cavern 45 m high by 135 m long by 22.5 m wide, and 422 m of 9 m diameter shaft. A total of 350,000 m of rock will be excavated, hauled, and placed in a submerged wier. Temporary rock support consisting of shotcrete and/or rockbolts is installed as required.

Jan 1, 1987

The Mining Foundation of the Southwest will hold its 15th annual American Mining Hall of Fame Awards banquet on Saturday, Dec. 6,1997 in Tucson, AZ, preceeding the Arizona Conference of SME. The Mining Foundation's Hall of Fame, located in Tucson, recognizes outstanding contributions to the mining industry by individuals and industry partners. A permanent display of honoree vitae is located at the Arizona Historical Society at 949 E. Second St. in Tucson. Each year, one living award recipient and up to two honorees from mining history are chosen by the Hall of Fame committee and the board of governors of the Mining Foundation. In 1989, the Mining Foundation also initiated a Medal of Merit to recognize outstanding individual technical and professional contributions to the mineral industry. And in 1995, an award was instituted to recognize contributions made by companies and organizations in partnership with the mining industry. This year's inductee is James R. Moffett, chairman and chief executive officer of Freeport-McMoRan Copper and Gold Inc. He will be present as guest of honor and featured speaker. The Hall of Fame will induct John V. Dorr, metallurgist and chemical engineer. Also inducted will be Frederick L. Ransome, a geologist. Medals of Merit will be awarded to Hugo T. Dummett, senior vice president, Exploration BHP Minerals, and Spencer R. Titley, professor in the Department of Geosciences at the University of Arizona. An Industry Partnership Award will be presented to the Colorado School of Mines for its continued support to the mining industry through education and research. The banquet will be held at the The Westin LaPaloma in Tucson beginning with cocktails at 6:30 p.m. Tickets are available from Clare A. Roscoe, manager, Mining Foundation of the Southwest, telephone 520-577-7519, fax 520-577-7073.

Jan 1, 1997

By Jan M. Mutmansky, David R. Kalasky

Computer simulation continues to be one of the most successful analytical applications of computers in the mining and mineral processing industries throughout the world. Through simulation, managers and engineers can explore the impact of new technologies, equipment designs, plans and operating strategies to improve their operations. It is not uncommon for a single simulation application to provide a quick payback of analysis expenses (within weeks or months) yielding long-term financial and operational dividends. The paper will present a summary of the types of software systems that are available for use on PCs and other computer systems. Support software for curve fitting, statistical analysis, and optimization of simulation models will also be presented. Methods of leveraging simulation efforts through networking and coupling of software systems will be discussed. Finally, the trends in simulation in the mineral industries will be analyzed. Areas of strength and weakness of simulation will be discussed along with the usefulness of commercial general-purpose and custom-writ- ten simulation packages. The future possibilities for simulation in the mineral industries will be outlined and predictions on trends for the future will be presented.

Jan 1, 1996