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By B. Boryczko, J. Norwisz, Jose Escobedo Bocardo, Z. Kolenda, A. Holda

"Classical thermodynamic analysis of any thermal and chemical process is usually based on the first law of thermodynamics. Such an approach is not sufficient when deeper understanding of the nature of each elementary process is required. The use of the first and second law of thermodynamics together is necessary to solve practical process more effectively. Enthalpy and exergy balances allow to enhance our understanding of thermal processes especially when cumulative consumption of energy and exergy is calculated. To ensure reliability of such an analysis the least squares method for adjustment of mass balances of principal chemical elements has been applied and described in detail. Numerical analysis has been carried out to compare two different processes of copper production – shaft furnace and flash smelting.IntroductionClassical thermodynamic analysis of any technological process is usually based on the First Law of Thermodynamics in the form of energy (enthalpy) balances. Such an approach is useful in engineering practice as it makes analysis easier in the global scale neglecting modeling of the elementary processes, allows calculation of the thermal efficiency and makes possible to control quality of the measurement results. Additionally, graphical presentation of the energy balance is simple in the form of Sankey diagram.In the case of aluminum electrolysis process, design of the new electrolyzer or its modernization is always based on the enthalpy balance.However, deeper thermodynamic analysis leads to the conclusion that such an approach is not sufficient. The First Law of Thermodynamics guarantees the exact equivalence of the various forms of energy (allowing all forms to be measured in the common unit such as joules) but it does not guarantee interconversibility. Thermal energy (heat) is in a peculiar and unique position, for whereas all other forms can be completely converted into thermal energy, the reverse process id impossible, only a portion of the heat can be converted into mechanical energy. Explanation comes from application of exergy balances. As we know exergy expresses the amount of mechanical work necessary to produce a material in its specified state from components common in the natural environment, in a reversible way, heat being exchanged only with environment [1]. Consumption of exergy connected with the fabrication of some considered product appears not only in the plant manufacturing the product, but also in all plants delivering raw materials for the final production process"

Jan 1, 2008

By Emilia Visileanu, Eftalea Carpus

"Due to the demographic explosion and development without precedent of the consumer society, the capacity to destroy the ecological balance the entire planet life depends on, acquire new dimensions. In this context new approaches on society development are imposing as well as special responsibilities for stopping and preventing Earth destruction and repairing the damage already done. The zero waste is a call to action that has as an aim the changing of current mentality of human society. ”take, use, throw away”. The zero waste is a policy, a way, an aim and represents a new approach planned for the XXI century that include the resources preservation principles, pollution reducing, increasing of the opportunities to create new work places and providing the highest degree of the.1. INTRODUCTIONThe zero waste is a call to action that has as an aim the changing of current mentality of human society. ”take, use, throw away”. The zero waste is a policy, a way, an aim and represents a new approach planned for the XXI century that include the resources preservation principles, pollution reducing, increasing of the opportunities to create new work places and providing the highest degree of the economy stability.2. ECOLOGICAL CONCEPTSA long-living Romania means:The closing of the production cycles, by waste reusing and recycling; the reducing of the use of fossil fuel; the improving of the material qualities, for extending the economical life of the products made by these materials; the reducing of the transport traffic.In this context, ecology, the star science with the ability to conserving and renewal of the environment is making its way, having the following principles:•,everything is bind by everything – is referring to the importance which the environment has for a great number of allied fields;•,everything leads to somewhere – the principle of the indestructible property of material (in nature, there must not exist wastes);•,nature does it the best – ecology becomes the responsible science with the governing of the strategic laws between man and nature, man takes advantage of the natural resources which he cannot create by himself and nature must feel guarded and not destroyed by this alliance;•,nothing is for free – the polluter pays.The protection of the natural environment means:•, its strong knowledge and that of the interactions between the social economic system and the natural system, the foreseen of the most close and most distant consequences of these interactions;•,the rational usage with maximum economical character of the natural resources not depending on their origin;•,preventing and direct fighting against as well on the degradation of the environment caused by man, as on those produced by natural causes;•,the ability to harmonize immediate interest of the human society on long and permanent term, using the natural factors of the environment."

Jan 1, 2008

By R. Padilla

Enargite (Cu3AsS4) occurs normally associated with copper sulfides, mainly chalcopyrite. When the enargite content in chalcopyrite concentrates is high, direct smelting of the concentrate presents problems related to environmental pollution and contamination of the final metallic copper. Leaching processes are viable alternatives to treat copper concentrates with high content of enargite. Consequently, in this paper, the pressure leaching of enargite in sulfuric acid-oxygen system is discussed. The leaching rate was studied in the range 160 to 220 °C and partial pressures of oxygen of 74 to 200 psi. The enargite dissolution increased substantially with temperature increase. Complete dissolution of enargite was obtained at 220°C, and 100 psi of oxygen pressure in 90 min. The shrinking core model controlled by surface reaction was used to analyze the kinetics of enargite dissolution. Activation energy of 70 kJ/mol was obtained for the temperature range 160 to 220 oC.

Jan 1, 2008

By Michael Gauna

An evaluation and analysis of a coal pillar bump in a West Virginia mine indicated that the pillar bump occurred because of the unique combination of controlling factors. The pillar?s development stability factor of 2.6, based on Mark-Bieniawski strength and tributary loading, would typically indicate an adequate pillar size for long-term main entries. A combination of multiple-seam mining geometry and geological conditions resulted in stress concentration leading to the coal pillar bump. No high extraction mining had been performed in the area and the overlying works appeared to have adequate stability factors. However, it was interpreted that long-term flooding had softened the overlying pillar system and rendered all but the largest pillars ineffective. Contributing factors include large overlying pillars transmitting stress through the approximately 60 ft of interburden and the failed pillar?s location at a transition in the immediate roof from shale to hard, massive sandstone. Other contributing factors include sandstone channeling forcing the development section to mine the pillar smaller than surrounding pillars in an attempt to avoid the channel, the relatively high overburden of 1,100 ft, and the pillar?s position in the bottom of a trough within the coal horizon. Pillars subjected to similar conditions on the other side of the section did not fail where the roof was composed of shale, even though the roof exhibited evidence of high stress concentration. An analysis was undertaken to determine appropriate pillar size for future mining. The conditions were evaluated by investigating mine historical conditions, assessing pillar bearing pressures, and using Lamodel 2D coupled with traditional Mark-Bieniawski pillar strength and tributary area loading stability factors to determine the stress levels for the pillar. Recommendations for future pillar sizes were based on the critical load bearing capacity identified by the analysis. To date, no further pillar bumps have occurred.

Jan 1, 2008

By P. Kolettas

The development of novel methods for the investigation of the subsoil contributes to the improvement of geotechnical research, enhances the obtained geotechnical characterization and may reduce the investigation cost by reducing the number of required tests. Non-destructive testing methods, performed either in situ (i.e. electrical tomography, seismic refraction, etc) or in the laboratory can provide initial data and perhaps estimates of rock/soil properties. This study focuses on the development of rock material properties and/or characteristics based on non-destructive laboratory testing of a number of stones, ranging from porous (bioclastic) limestones to impervious marbles. Seismic velocity measurements as well as attenuation signals were digitally recorded using a digital oscilloscope. Data were processed using a novel technique of spectral analysis available through special Matlab packages employing Fourier transform methods. More specifically, the NFFT (Non Equispaced Fourier Transform) transformation was applied to seismic waves traveling through the subsoil using the Autosignal program (by Seasolve) and the Specgramdemo program included in the Signal Analysis toolbox of Matlab 6.5 (Mathworks). Results indicate a definite relationship between the frequency content of the signal and the rock type as well as the degree of saturation of the specimen.

Jan 1, 2008

By John A. S. Green, J. Gilbert Kaufman, Subodh K. Das

"The aluminum industry is a leading proponent of global sustainability and strongly advocates the use of recycled metal. As the North American primary aluminum industry continues to move offshore to other geographic areas, such as Iceland and the Middle East, where energy is more readily available at lower cost, the importance of the secondary (i.e., recycled metal) market in the U.S. will continue to increase. In the past, the recycling industry had been synonymous with the collection of aluminum beverage cans. However, as the opportunities for aluminum recycling have multiplied in motor vehicles, building and construction, and aerospace, these market are getting additional scrutiny for optimization of recycling strategies.Accordingly, the secondary industry can now draw upon a much wider range of product forms and alloys for its raw material, but this in turn brings issues of alloy sorting, impurity content, and control as the material is remelted and recycled into new product forms. The purpose of this paper is to take an integrated, industry-wide approach to look at the recovery of material from demolished buildings, shredded automobiles, and aging aircraft, as well as from traditional cans and other rigid containers. Attempts will be made to assess how the different alloys used in these separate markets can be recycled in the most energy efficient manner.IntroductionIn his recent book “Aluminum Recycling”[1], Mark Schlesinger points out that in traditional extractive metallurgy, the raw material used to produce a metal is mined from the earth and then is separated from other gangue minerals and impurities. In aluminum recycling, however, the ore body consists of scrap metal found on the ground, rather than in it. He further notes that scrap comes with its own variety of gangue and impurities such as painted coatings, other metal attachments, and even dirt and other contaminants. So, while the recycling process still requires some refinement and expenditure of energy, the effort and energy involved is much less than traditional mining."

Jan 1, 2008

By W. J. Schitt

Section 15 covers a loose collection of topics that involve water in some way. The chapters in this section include Dredge and Placer Mining (Chapter 15.1), Solution Mining: Surface Techniques (Chapter 15.2), and Solution Mining: In Situ Techniques (Chapter 15.3). The dredge and placer systems involve water in several forms. The segment on hydraulicking or hydrosluicing discusses the use of monitors to direct high-pressure water jets to move material. As such, this represents an alternative to mechanical breakage, loading, and hauling. This chapter also covers placer mining (except dry placering) where the water provides the medium that promotes the separation of minerals based on their density and other settling characteristics. Thus placer mining is generally limited to concentration of gold, tin ore, diamonds, and other heavy minerals that are already liberated and are contained in a less dense matrix. The third topic, straight forward dredging, as in sand and gravel operations, involves water only in an incidental way. Here water simply covers the minerals of interest. Thus the dredging system need only lift a payload from the submerged location to the surface for further processing or handling

Jan 1, 2008

By G. Argyris

A number of important studies, ongoing environment monitoring efforts and mining and road construction projects in the lignite based electrical power production area of Amyntaio ? Ptolemais in North West Greece require an accurate and up to date model of the topography. In recognition of the importance of such a model, a project was initiated by the Laboratory of Mining Information Technology and GIS Applications in the Department of Geotechnology and Environmental Engineering of the Technological Educational Institute of Western Macedonia. A massive surface triangulation model was generated from vector data using an optimized Delaunay based method. Combined with aerial and satellite imagery, the triangulation model provides a complete 3D terrain model of the area characterized by high levels of accuracy, detail and realism. The generated model is easy to modify with new data in order to improve its detail and keep it up to date with ongoing earth moving and development operations in the area.

Jan 1, 2008

By E. R. Bauer

Previous studies and research efforts have shown that noise-induced hearing loss (NIHL) is a problem in the U.S. mining industry. This is especially true in surface and underground coal and stone mining where large, noisy equipment predominate. Workers in coal preparation and stone processing plants have also been found to be subject to high sound levels that could potentially cause NIHL over prolonged periods of exposure. National Institute for Occupational Safety and Health (NIOSH) researchers have been conducting a cross-sectional survey of equipment noise and worker noise exposures in the mining industry to estimate the potential for NIHL within the mining community. One commodity recently surveyed was the extraction of sand and gravel from surface pits and by river dredging. Little is known about the noise environment and worker exposures in these environments, where processing and mining equipment similar to coal and stone are employed. To address the potential for NIHL in the sand and gravel industry, sound levels on and around the dredges and processing equipment were recorded to identify areas of high noise levels. Full-shift worker dosimetry, in conjunction with task observations, was documented to determine the relationship between exposure and source. This paper presents research examining noise on dredges, in several surface mine sand and gravel operations and in the processing facilities. The locations where workers are likely to be overexposed and were found to be most susceptible to noise overexposures are reported. Results indicate that there are areas on the dredges (crane, suction pumps, and diesel engines) where sound levels greater than 90 dB(A) are present. In addition, crushers and screens used in the processing of the sand and gravel also generate sound levels greater than 90 dB(A). Although no surveyed worker exceeded the Mine Safety and Health Administration (MSHA) Permissible Exposure Level (PEL) of 90 dB(A) TWA8, laborers, mechanics, oilers, helpers, pickers, and greasers are the workers likely to be exposed to hazardous sound levels and thus develop NIHL over time. Knowledge of the equipment noise, area sound levels, and worker dose levels is information that management and employees can use to reduce exposures. Exposures can be reduced in certain areas through administrative controls and through engineering controls applied to the noisiest equipment.

Jan 1, 2008

ME?s Arizona Conference was held at the Hilton El Conquistador resort in Tucson on Dec. 2 and 3, 2007. The annual conference is organized by the Arizona Conference Board of Directors, which represents SME sections in Arizona and adjacent areas. The conference provides an opportunity for individuals and corporations associated with mining in the region to get together once each year to discuss the status of the industry. The 2007 meeting featured a keynote address, a distinguished lecturer and more than 25 technical papers that were presented in seven sessions. The sessions included environmental, geology, safety, metallurgy, mining, new projects and a special session on Mexico. Topics covered included mine closure, sustainable mining, exploration methods, health and safety issues, mining equipment and drilling. Much of the discussion at the conference concerned major new developments in the region?s copper mining industry. For example, Freeport-McMoRan?s new Safford Mine and BHP Billiton?s Pinto Valley restart were the topics of technical presentations. There was also much discussion among the attendees on the current and future price of copper, community relations, education issues and recruitment concerns. At the time of the conference, the price of copper hovered around $3.30/lb, up considerably from the 61 cents/lb in late 2001, when the industry was being challenged by world market conditions and a weakened domestic economy. Since then, strong demand from China helped push copper prices to record levels that at one time reached as high as $4/lb. The general consensus among the attendees is that the current price of around $3.30/lb will continue through 2008. Most attendees also expect increased corporate investments in the industry to continue. Copper mining in Arizona has been a major industry since the 1800s. In 2007, Arizona was the leading copper-producing state in the United States and produced more than $5 billion worth of copper. The copper mining industry in Arizona also produces byproduct gold, silver and molybdenum. Arizona is the second largest molybdenum producer in the United States.

Jan 1, 2008

By Daniel N. Adams

The University Link project extends Seattle?s light rail from downtown to University of Washington (UW). It includes 5.0 kilometers (3.15 miles) of twin-bored, 6.4 meters (21 feet) excavated diameter tunnels, and two cut-and-cover stations. The Capitol Hill Station (CHS) requires an excavation 170.7 meters (560 feet) long, 22.6 meters (74 feet) wide, and 22.9 meters (75 feet) deep. The University of Washington Station (UWS) requires an excavation of about 238.4 meters (782 feet) long, 21.3 meters (70 feet) wide, and 33.5 meters (110 feet) deep. The project is within the glacially diverse soils of the Puget Sound region, below groundwater. This paper highlights major station and tunnel design elements, including the approach to support of excavation at both station boxes, and the site staging requirements.

Jan 1, 2008

By Scott Scovira, Ruilin Yang

This paper presents a non-waveform blast vibration model for the near-fi eld. The model uses the concept of a dominant charge augmented by other contributing charges estimated using a scaled time window. The model accounts for the effect of broken ground created by earlier fi ring holes, amplitude attenuation, effects of signal broadening with travel distance from frequency attenuation, as well as asynchronous propagation of different wave types due to the wave velocity difference, the delay time effect, and non-linear superposition of near-fi eld vibration. The model uses an effective distance defi ned from the broken ground screening, and determines a dominant charge contributing to the PPV at a monitoring station. Then the model uses a time window for each individual charge to determine if it contributes to the PPV. The time window has a variable width to model the effects of the signal broadening with travel distance. For modeling the signal broadening, a generalized rock quality factor Qd is proposed. The time window includes a weighting function that diminishes the contribution for charges fi ring further from the dominant charge and this accounts for contribution arising from the timing difference between a contributing charge and the dominant charge. The model uses a non-linear charge weight superposition technique that scales the charge weights within the time window to the same distance of the dominant charge and superimposes the scaled charge weight. The case study demonstrates that the model provides useful predictions for near-fi eld blast vibrations.

Jan 1, 2008

By Kenton W. Braun

Concourse B at the Anchorage, Alaska International Airport is currently being renovated while retaining the original building structure and foundations. Part of the renovation includes the installation of a new, permanent baggage tunnel system beneath the existing building. Installation of this cast in place concrete tunnel, beneath the existing structure, required installation of a steel retaining wall to support footing loads above the base of the excavation. Construction of this retaining wall presented challenging and unconventional design and construction methods. Detailed discussions of the design and construction techniques utilized for this project are outlined.

Jan 1, 2008

Newcrest Mining is one of the leading independent gold producers in Australia thanks in large part to its Cadia Valley operations. It is the largest gold and copper producer in New South Wales and one of the largest in Australia. This year Newcrest will expand its operations with a A$545-million expansion in the area. The Cadia Valley is approximately 250 km (155 miles) west of Sydney. The province presently includes the Cadia Hill opencut mine and the Ridgeway underground mine. With a significant mineralized system to the east of Cadia Hill and a mineral resource below Ridgeway, Cadia Valley has the potential to underpin Newcrest?s production for up to 30 years. In 2007, total gold production for the company in-creased to more than 50 t (1.6 million oz) and cash flow increased by 47 percent, according to the company?s annual report. The history of mining in the area dates back to 1851, but Newcrest?s history is young. In 1990, Newcrest commenced activities in the Cadia Valley. In 1992, Cadia Hill was discovered, with the discovery of Cadia East (1995) and Ridgeway (1996) following close behind. In 1998, the Cadia Hill openpit mine was commissioned. In 2002, the Ridgeway underground mine was commissioned and in 2007 the company?s board of directors approved an A$545 million development of the Ridgeway Deeps. The Ridgeway underground mine is located adjacent to Cadia Hill. The Ridgeway orebody has no surface expression but lies approximately 500 m (1,640 ft) below the surface and resembles an inverted teardrop. It measures approximately 450 m (1,476 ft) by 250 m (820 ft) and extends in excess of 850 m (2,788 ft) in depth. Ridgeway is a sublevel caving operation. Crushed ore from underground is delivered by conveyor to a surface stockpile, adjacent to the Ridgeway concentrator. Using similar processes to the adjacent Cadia Hill concentrator, gold and copper are recovered in a conventional flotation circuit to produce a copper concentrate containing elevated gold levels. Ridgeway concentrate is combined with the Cadia Hill concentrate before it is pumped to the filtration plant in

Jan 1, 2008

Barrick Gold Granny Smith Mine is currently undergoing conversion from an open cut operation to an underground mine at the Wallaby deposit. The underground project commenced in 2005 with the development of the reserves immediately below the pit and is now currently entering a production ramp-up phase for mining of these two initial surfaces below the pit. With increasing gold prices the owner has been forced to re-evaluate the underground project and has decided to investigate the potential of a deep level mine. This deep level underground mine presents a collection of challenges with the most notable being exploitation of a series of well separated near horizontal lodes ranging in thickness from less than 1 to 20 m. A variety of room and pillar mining methods are employed for extraction with careful consideration to resource recovery and pillar design for long-term stability. Compounding these deep level challenges is a need to accelerate mine level development to maintain the production profile of the mine. This paper describes the challenges, key learnings and outcomes of the studies undertaken to date associated with this project.

Jan 1, 2008

By K. G. Thorne, M. J. McLeod, D. Hoy

"Throughout the Paleozoic, a variety of gold depositional environments were created in the New Brunswick segment of the northern Appalachians because of the complexity of arc and continental plate collisions and subsequent erosion of the orogen. In southwestern New Brunswick, recent exploration and research has focused on deposits and occurrences that can be broadly classified as intrusion-related, generated by late- to post-orogenic felsic to intermediate plutonic rocks emplaced during the Early to Middle Devonian. This work has led to the establishment of models for gold mineralization and guidelines for exploration in this area, which might also be applicable elsewhere in the southern part of the province and, perhaps, throughout the northern Appalachians. The deposits in the vicinity of Clarence Stream in southwestern New Brunswick exemplify this deposit type, and highlight the emergence of a possible major gold district in the region. Durant le Paléozoïque, une grande variété d’environnements aurifères ont été créés dans le segment néo-brunswickois des Appalaches du nord en raison de la complexité des collisions entre arcs et plaques continentales ainsi que durant l’érosion subséquente de l’orogène. Dans le sud-ouest du Nouveau Brunswick, les travaux d’exploration et de recherche récents se sont tournés vers les gisements et les indices appartenant à la classe des gîtes associés aux intrusions, générés par des roches plutoniques felsiques à intermédiaires tardi- à post-orogéniques mises en place au Dévonien précoce à moyen. Ces travaux ont permis d’établir des modèles de mise en place pour la minéralisation aurifère ainsi que des guides d’exploration pour ce secteur, lesquels pourraient aussi être appliqués ailleurs dans le sud de la province et, possiblement, dans l’ensemble des Appalaches du nord. Les gîtes aux environs de Clarence Stream dans le sud-ouest du Nouveau Brunswick sont un exemple de ce type de gisement, mettant en valeur ce qui pourrait devenir un district aurifère majeur dans la région."

Jan 1, 2008

Plurigaussian simulation allows constructing lithofacies or rock type models that reproduce the contacts between facies in accordance with the geologist?s interpretation. Its implementation requires inferring the local facies proportions, but the uncertainty in the true proportions is not accounted for. The simpler model with constant facies proportions may not yield realistic results, due to the possibility of obtaining facies at locations where it is geologically unlikely to find them. This article presents a variation of the plurigaussian model, in which the facies proportions are represented by random fields. The realizations can be made conditional to soft geological informati onto account for local changes in the facies proportions. The model is illustrated via a case study of a porphyry copper deposit where four Gaussian random fields are simulated conditionally to drill hole data and to constraints on the probability of finding a given facies at specific locations (control points) in the deposit. Then the first two fields are truncated using the random thresholds defined by the last two, generating a three-facies model. The proposed random proportion model proves to be simple to use and to account for spatial variations of the geological characteristics and for the uncertainty in the facies proportions. Keywords: categorical variable; lithofacies; truncated plurigaussian simulation; regionalized proportions

Jan 1, 2008

By Martti Hagfors

UNDERWATER EXPLOSIONS - Part 6 - EFFCTS OF CYLINDERICAL SHAPE OF CHARGE TO THE RESULTS OF ENERGY MEASUREMENTS OF EXPLOSIVES

Jan 1, 2008

By W. R. Reed

NIOSH continues to conduct respirable dust control research for surface mine blasthole drilling operations. Research areas have included testing variables (shroud leakage area, drill deck cross-sectional area, shroud height, collector-to-bailing airflow ratio, etc.) that have the most impact on respirable dust control, development of a dust collector inlet hood, development of a dust collector dump point shroud, and testing of a small diameter water separating sub. This paper summarizes the results of the aforementioned research that has been completed. Additionally, past dust control research for drilling operations of both underground and surface mines completed by the U.S. Bureau of Mines, created in 1910 and incorporated into NIOSH in 1997, is reviewed.

Jan 1, 2008

By Len Harris

Webster?s Dictionary describes culture as: ? The totality of socially transmitted behavior patterns, arts, beliefs, institutions and all other products of human work and thought typical of a population or community at a given time. ? A style of social and artistic expression peculiar to a class or society. ? Intellectual and artistic activity. ? The art of developing the social, moral and intellectual facilities through education. The authors have nearly 100 years of combined experience in the mining industry working with and consulting to mining companies and companies engaged in the supply of goods and services to the mining industry worldwide. In this report, they present their experiences and ideas on the importance of cultural aspects in the successful development and implementation of mining ventures. Their suggestions on how to handle culture shock will be of interest to expatriate managers, operators, social workers, and engineering and construction personnel posted to overseas operations, as well as to nationals posted to other parts of their own country.

Jan 1, 2008