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By Patrick Bermingham

This report presents the results of six STATNAMIC loading tests that were carried out on four different pile types at the CALTRANS 280 Test Site (Bridge No. 34-46) in conjunction with the Tension Pile Test Program. The STATNAMIC testing was performed by Berminghammer Corporation at the request of the California Department of Transportation, Office of Geotechnical Engineering. Others performed the static tension (uplift) and compression loading tests which werecarried out on the piles tested using the STATNAMIC method. A summary of the STATNAMIC test results is presented and discussed, and the appropriate results are compared with the static test results

Jan 1, 1993

By Mi, Dong Liang, Jingyuan Bai, Victor Zhou, Xujun

Squirrel cage induction motors are the mostly used motors at present. Currently, the rotors of the squirrel cage induction motors are produced by aluminum die casting technique with the advantages of low cost of rotors. It is well known that the copper’s electrical conductivity is around 40% higher than that of aluminum. If copper is used to replace the current widely used aluminum in rotors, the total loss of motors will be reduced, hence increasing the overall motor efficiency. Copper rotors can be used to produce high efficiency and even super premium efficiency motors without enlarge the motor frame size. Considering the huge quantity of motors, the die casting process is the best solution to produce copper rotor with economic cost. Because of the characteristics of copper, it is difficult to produce copper rotors by casting similar to that done in aluminum rotors. In order to improve the die casting quality of copper rotor, a new tooling structure was developed and the casting process of copper rotor was simulated and analyzed by Any-casting software. The filling process, solidification process, inner gas distribution and residual melt modulus were analyzed. It was found that the design of symmetrical runner and inner runner on both sides was helpful to reduce the impact of molten copper to the cavity surface during the filling process. The use of Slag traps array can reduce die casting defects inside the end rings. That will be helpful to improve the rotor quality. INTRODUCTION Squirrel-cage AC induction motors are most widely used in the world. In 2017, the total installed capacity of AC motors in China has reached more than 1.2 billion kW, and the annual power consumption accounts for about 60% of the total national electricity consumption. To improve the efficiency of squirrel-cage motor will be helpful to energy conservation and environment protection. There are several ways to improve efficiency of induction motors, using copper rotor is one of the most effective solutions. It is well known that the copper’s electrical conductivity is around 40% higher than that of aluminum. If copper is used to replace the current widely used aluminum in rotors, the total loss of motors will be reduced, hence increasing the overall motor efficiency. Copper rotors can be used to produce high efficiency and even super premium efficiency motors without enlarge the motor frame size.

Jan 1, 2019

By T. O. Hagan

Analyses of accident records show that a better understanding of very basic strata control principles and practices, by production personnel, will improve worker safety. Workers, lack of knowledge, with respect to aspects of strata control, increases their exposure to such strata control risks. The primary objective of the Safety in Mines Research Advisory Committee (SIMRAC) project 02 02 07 was to develop tools for the transfer of strata control knowledge. Four such tools were developed, three of which focused on illiterate underground mine team members who are not yet able to take advantage of the Mining Qualifications Authority (MQA) learning process (see project outcomes 2, 3 and 4 below). The tools were designed to equip these workers with sufficient knowledge and ability to work safely underground until such time as they can take advantage of the MQA system. Project outcomes: 1 A four-minute video using animation to illustrate the causes and prevention of falls of roof in South African collieries. 2 Software to demonstrate the capability of reconstructing, interactively, accident scenes and actions that have taken place underground in stopes. 3 A strata control bridging course for illiterate mine team workers. 4 Small-scale wooden models that will be used to design life-size mock-up facilities to assist with the above mentioned bridging course. 5 Workshops and presentations to demonstrate the outcomes 1to 4 above.

Jan 1, 2005

By \/eena Sahajwalla, Jonathan Dicker, Paul O'Kane, Cath Skidmore, James Dankwah, Magdalena Zaharia, Rita Khanna, David Knights, N Saha-Chaudhury, Somyote Kongkarat

Due to the inherent limitations of current methods of disposal of end of life polymeric materials, avenues are researched towards developing alternative, environmentally friendly and economic recycling processes. Different polymeric materials (i.e. rubber, high density polyethylene (HDPE) and polyethylene therephtalate (PET)), quite distinct in terms of chemical structure and composition, were considered in the present study as carbon resources in EAF steelmaking. Investigations were conducted in both laboratory and industrial scale steelmaking to assess the effectiveness of using these materials as carbon sources for slag foaming in EAF steelmaking. Slag foaming is important because it enhances furnace efficiency.

Jan 1, 2011

By J. Drzymala

Particle beneficiation tests are often conducted to determine how the recovery of a key component of a particle mixture varies with overall product yield, i.e., the separation curve. The results can be misleading when an attempt is made to determine the effect of feed grade by comparing separation curves representing different feed grades or key component concentrations. This is a shortcoming of the conventional recovery versus yield diagram, which may not appear to be affected by feed concentration. To overcome this shortcoming, a method is presented for transforming and normalizing the recovery and yield coordinates so that the separation curves representing dif-ferent feed concentrations are directly comparable.

Jan 1, 2007

By T. Bhambhani, D. R. Nagaraj

"Ultramafic Ni ores present significant challenges in processing in that both recoveries and grades are not satisfactory, due to the presence of Mg silicates in large amounts. Significant quantities of xanthates and CMCs are generally used for their recovery by flotation. Additionally, given that some of these ores are processed under acidic conditions, CS2 generation due to xanthate decomposition presents some safety hazards. Technology to replace xanthate has been developed for which the safety and health issues are absent. Collector S-10294 shows significant improvements in Ni and overall S recovery at a dosing rate of one half that of xanthate. New polymeric modifiers have also been developed that help reduce the Mg content of the concentrates at very low dosages. The reagents are custom designed for use in normal or hypersaline water, and acid or alkaline conditions.INTRODUCTION The use of xanthates in sulfide mineral flotation is reported to have started as early as 1925 (Nagaraj 2005). The reagent is now ubiquitous in the mining industry, accounting for 40-50% of total collector consumption. In recent years, the development of more selective reagents has rendered xanthates largely obsolete in Cu flotation. However, xanthates continue to be sold in large amounts in the Au, PGM and Ni flotation industry, where bulk sulfide flotation is required. The low cost and easy availability is the largest driver for the use of xanthates in the minerals industry. Of particular interest to this study is the use of xanthates in the flotation of Ni sulfide ores. About 60% of the world’s annual nickel output is obtained from sulfide Ni ores (Hoatson, 2006). A strategically important category of these ores is the ultramafic hosted sulfides, such as those of Western Australia and Canada. These ores are characterized by low Ni grades (<1%), with the Ni minerals being pentlandite, violarite, millerite and mackinawite, and gangue minerals comprising an array of altered Mg silicates, mostly serpentines. The challenges associated with treating these ores are well documented (Eltham et al. 1973; Claridge et al. 1975). One challenge is that Ni recoveries from these ores are lower. This has been attributed to the increased pulp viscosity, as discussed in detail by Vasudevan et al., 2010. Additionally, Mg silicates tend to report to the concentrate in large quantities, which is problematic for two reasons: a) concentrate dilution, and b) the high melting point of Mg silicates tends accelerate wear on the refractory lining of smelters. This has been attributed to network transport to the froth phase via bubble flux and entrainment (Patra et al, 2010)."

Jan 1, 2012

By R. C. Neavel

One of the most important requirements to be met by any coal producer is delivery of size consists tailored to specific applications. Generally these specifications include a minimum as well as a maximum size limit. The customers of a major Indiana coal producer noticed that some shipments of sized coal contained a large proportion of undersize pieces. Also, in these shipments, the pieces which remained within the specified limits were cracked and, when handled, crumbled readily. The producer, certain that these shipments had been properly sized at the tipple, suspected that degradation had occurred in transit. The Indiana Geological Survey was requested to examine the coal from one of these shipments to attempt to determine the cause of breakage. Two basic facts about coal and coal seams led to the employment of petrographic techniques in this investigation. First, all coal seams consist of accumulations of diverse organic and inorganic constituents; and second, most coal breakage, either desirable or undesirable, can be attributed to the inherent weakness of some of these constituents or to poor adhesion between certain constituents. Analyses of degraded coal Sampling: Samples were secured from 2 stock piles of 2-by 4-inch coal in a dealer&apos;s yard. The coal in both piles had received the same treatment from mining to storage, although it had been mined and shipped on two different days. The size consist of one pile, however, appeared smaller than that of the other. The sample from the degraded pile is referred to as the slack sample, and the other is called the unslack sample. Size analyses: In order to determine the actual size consist, the samples were screened, with a minimum of rough handling, on square 2-inch, 1-inch, 1/2-inch, and 12-mesh screens. It is assumed that 100 percent of the 2-by 4-inch coal is retained on a 2-inch round screen at the tipple. Analyses of several loads at the tipple indicate that approximately 26 percent of the 2- by 4-inch coal, 100 percent of which was assumed held on a 2-inch round screen, passed through a 2-inch square screen. Twenty-six percent may be taken as the normal difference between round and square screens. Results of the analyses of stockpile coal are shown in Table 1. Cumulative percent versus size are plotted on a Rosin-Rammler chart as Figure 1. Both samples approximately follow normal size distribution; this indicates that breakage is not size preferential and also that the samples are representative of the stockpiles. Although both samples exhibit the same general size distribution, the median size of the slack sample is considerably smaller than that of the unslack sample. Fifty-five percent of the unslack sample was undersize (29 percent greater than the normal 26 percent difference), and 83 percent of the slack sample was undersize (57 percent greater than the normal 26 percent difference). Both piles contained a greater percentage than normal of undersize coal; this indicates that they were both affected by degradation, but to a different degree. Bedding-plane analyses: Coal, because of its laminated nature, will break preferentially along bedding planes, especially where adjacent constituents are poorly cemented to each other. Subsequent breakage perpendicular to the

Jan 1, 1961

By Dale S. Preece

"Detonation delay timing has been an important aspect of quality rock blasting for decades. Detonators that enable delay timing have improved over the years especially with the recent advent of precision electronic detonators. The positive effects of precision delay timing have been observed repeatedly in the field with improved fragmentation, heave and overall blast control. Three-dimensional computational capabilities in terms of software, material models and computer speed have recently made possible the computer simulation of multiple blast holes in a bench configuration with precise delay timing between holes. Some of the key physical phenomena enabled by precise delay timing include: 1) collision and interaction of stress waves produced by adjacent blast holes, 2) reinforcement of stress waves from multiple holes as they reflect from the bench face and ground surface, 3) reflection of stress waves from “dynamic free surfaces” created by previously detonating holes, and 4) deformation induced fracturing, cracking and fragmentation. Simulating rock blasting in 3D has shed light on the physics involved and is resulting in an evolution of our understanding of fragmentation mechanisms. Routine use of these 3D computational tools will result in a much better understanding of the complex physics set in motion by the rock blasting process and allow predictionof improved blasting."

Jan 1, 2009

By A. N. Baldwin

This report documents the work performed under Bureau of Mines Contract J0265029 to study and develop two innovative mining systems: ? An underground auger capable of augering into the right and left ribs without repositioning the machine ? A conventional mining system employing recently developed innovative machinery. The report is separated into two volumes to document the two studies separately. Volume I describes work performed and the recommended concept for a bidirectional auger. Volume II describes the studies of mining equipment performance and mining plans developed to determine a conventional mining plan offering improved productivity.

Jan 1, 1977

By T. B. Acton

There are two types of ore transportation systems in use at Newmont&apos;s Magma Copper Co. San Manuel mine in Arizona-rail-mounted, box-type rotary cars and the newer rail-mounted, bottom-dumping ASEA cars. Though the cost per car for the ASEA units greatly exceeds the cost per rotary car, the advantages of the ASEA units, including much faster dump times, have made the ASEA system a successful alternative at the San Manuel mine. The rotary system of ore transportation has been in use at San Manuel since production began in 1956. The system employs 7.9-m3 box-type cars to transport ore by rail to shaft pocket areas. A rotating dumping mechanism turns three cars at a time upside down to empty them, and returns them to an upright position. Trains of 15 cars each are dumped in about six minutes. Each 15-car train is pulled by an 18-t rated trolley locomotive. There are about 400 rotary cars in service at San Manuel and the system is used for the majority of ore haulage. This well-proven rotary method was instrumental in achieving the December 1977 world record of 272 Mt hoisted from an underground copper mine. Magma Copper Co. began using ASEA cars in late 1977. Designed by ASEA of Sweden, the cars are built for San Manuel by Kasper-Hall Manufacturing Co. in Tucson. The cars basic design feature is a hinged floor that opens at the side as the car is pulled through the dump. As it passes over the dump, a fifth wheel attached to the hinged floor (opposite the hinges) travels along a rail in the dump. This rail dips down into the pocket and then returns to track level. As the fifth wheel travels along the rail, the car floor opens, the car dumps, and the floor is then returned to track level. As the car is dumping, the body remains suspended over the pocket by wheel rollers attached to each side of the dump. Trains of 10 cars each are emptied in about 45-50 seconds. Each ASEA train is pulled by an 18-t rated trolley locomotive, adapted at San Manuel to allow it to pass through the ASEA dump. At minimal cost, "wings" are welded to each side of the locomotive. These wings suspend the locomotive over the pocket as the train passes through the dump. Advantages of the ASEA System Major design characteristics of the ASEA and rotary systems are shown in the accompanying table. The comparison points out some of the following advantages demonstrated by the ASEA system. • Faster dumping-An ASEA train dumps in 50 seconds, while a rotary train takes at least six minutes. There is no stopping or starting when dumping an ASEA train. The train enters the dump area, dumps, and leaves in one continuous motion-in contrast to rotary trains which must stop and start five times to dump. With the rotary system, three cars are spotted in the dump mechanism by remote control. When the cars are in place, the train operator activates the dump, the cars are turned over, and then returned to an upright position. This process is repeated until all 15 cars in the train are emptied.

Jan 4, 1980

By Jacques F. Abrahamse, Kevin A. Bahe, T. Arthur Palm, Gregory E. McCluskey, Stephen L. Bessinger

Introduction Basis For System San Juan Coal Company (SJCC) is a subsidiary of BHP Billiton. Until recently, BHP Billiton operated three surface mines in northwestern New Mexico: Navajo, San Juan, and La Plata. The San Juan and La Plata Mines supplied the San Juan Generating Station operated by Public Service of New Mexico. Stripping ratios at those operations were increasing, and by 2000 a feasibility study was underway to develop SJCC’s vast underground reserves as a replacement. Early in the evaluation and planning phase for the San Juan Underground Mine, it was determined that the target seams (Fruitland #8 and #9) had a high propensity for spontaneous combustion. Spontaneous combustion was identified as a risk, both to personnel and equipment, and to the ability of SJCC to reliably fulfill its obligation to the power plant. In the last 20 years, several western US coal mines suffered underground spontaneous combustion events and/or mine fires. Included in this group were Colorado Westmoreland’s Orchard Valley Mine (1987), RAG’s Willow Creek Mine (1998 and 2000), Oxbow’s Sanborn Creek Mine (1999), the West Elk Mine of Arch Coal (2000), Arch’s Skyline Mine (2002), Western Fuels’ Deserado Mine (1996), and the West Ridge Mine of Andalex Resources (2003). The cause for the majority of these fires was spontaneous combustion. Fighting the fires required injection of an inert gas or foam. Nitrogen and carbon dioxide were the predominant choices of inert gas. In all cases, the gasses had to be trucked in from considerable distances. Before the inert gas could be used, injection holes had to be drilled into or near the suspected fire locations. This drilling and trucking caused costly delays in the timing of the fire fighting effort, and was not as precise as desirable. Emergency purchasing of gas and pumping services was extremely expensive, running as high as $70,000 per day at one mine. As a result of the experience of other western US coal operators, and the risk inherent with spontaneous combustion at SJCC, it was decided to pursue installation of a nitrogen delivery facility on-site at SJCC. This decision was later expanded to include a continuous supply of nitrogen.

Jan 1, 2005

By M. D. Budeba

Determining the efficiency of a surface coal mine operation is an essential activity, which can help in deciding on the optimal use of input resources, including effective capital allocation, in generating a desired quantity of coal of a specific quality. Mines operate today in challenging conditions, with diminishing reserves of high-quality coal, remote location of new coal deposits, infrastructure problems, environmental legislation, and the effects of climate. All these have an impact on the performance of a mine. Given such challenges, a company has to be technically efficient compared to other existing coal producers in order to generate profits. It can use the measurement of its efficiency to evaluate its productivity, benchmarking this against the best-performing mines and determining optimal variables in order to minimize slack and achieve the desired outputs. This paper discusses the use of Data Envelopment Analysis (DEA) in evaluating the efficiency of a surface coal mine supply chain for the coal export market. The supply chain is considered to be composed of subprocesses that are modelled as a multistage system. Numeric examples will be used to illustrate the application of DEA.

Jan 1, 2014

By VIVEK KASHYAP, Evody Tshijik Karumb, PATRICK TAYLOR

The partial reduction of zinc ferrite to zinc oxide and iron (II, III) oxide can enhance the leaching rate of zinc. Zinc ferrite has often been found as a major component of zinc residues and electric arc furnace dust. The Waelz process is an existing process for zinc ferrite processing, which requires a temperature of more than about 1200 °C to produce Waelz oxide containing ZnO. Since zinc residues have been deemed as a potential way for the extraction of zinc and other critical metals, it is important to analyze the reaction kinetics in the temperature range of interest. This manuscript discusses the chemical kinetics of zinc ferrite reduction by hydrogen gas. Several researchers studied the reduction of zinc ferrite with CO; however, unlike CO, the use of H2 gas as a reductant allows partial reduction of zinc ferrite even at low-temperature range (400–600 °C). Thermogravimetric analyses (TGA) experiments were performed in the temperature range of 300–700 °C with 10% and 30% H2, and the data obtained was analyzed using the isoconversional method of kinetic analyses. The standard models used for isoconversional kinetic analysis were chosen from literature and experimental data were fitted to determine the controlling mechanism and calculation of kinetic parameters of reduction of zinc ferrite. The rate of reaction was found to be increasing with an increase in temperature and partial pressure of H2 gas. The reaction could be divided into three stages, where reaction interface contraction was found to be the controlling mechanism at the initial stage of reaction. As the reaction proceeds, product layer thickness increases, and thus, diffusion was found to be the controlling mechanism. Roasting products obtained from TGA experiments were also characterized using a scanning electron microscope (SEM) to verify critical morphological details.

Jul 26, 2022

By S. J. Duda

Procedures for detecting and locating seismic sources are adapted to the case of entrapped miners. During an emergency the entrapped miner is likely to generate seismic signals, by knocking against the walls of the shaft. With a seismic array station deployed near the disaster area, the seismic signals can be recorded. Two algorithms are presented for the location of the source from the arrival times of a seismic phase: The first algorithm produces one, most probable location, under the assumption of constant velocity of propagation of seismic waves in the medium. The second algorithm is similarly applicable, however without any restriction on the seismic velocities in the medium between the source and the array. While the first algorithm uses an analytic approach, the second one is based on a trial and error procedure. The second algorithm gives locations with arbitrarily high accuracies, depending only on the accuracy of arrival time measurements and on the compatibility of the true velocity distribution and the assumed velocity model. The algorithm is shown not to require under certain conditions direct .arrival time measurements, thus eliminating a potential source of errors in the location of entrapped miner.

Jan 1, 1973

By John M. Devine

Hydrogen sulphide associated with natural gas was noted as early as at Point Albino, Canada. The presence of this impurity was recognized also in other of the earlier oil and gas fields, although the occurrence was by no means common. However, in recent years, with the development of the producing zones of test Texas and the Texas Panhandle, the Production of "sour" crude has increased greatly and hydrogen sulphide has proved a generally troublesome factor--frequently a major problem--in the drilling and operation of many wells in those areas. The problems arising from the drilling and producing of oil or gas wells in hydrogen-sulphide areas, fall under two general divisions: safety problems and corrosion problems. Mention is made of a third division which is closely related to the other two, that of treating--or the development of processes for the removal of hydrogen iron the standpoint of safety and health hazards, hydrogen sulphide in the petroleum industry has been discussed in a number of publications. Likewise, the problem of hydrogen-sulphide corrosion of production equipment has been given considerable attention in the literature.

Jan 1, 1931

El presente trabajo explica el panorama historiográfico del proyectoToquepala, -en tanto proyecto industrial de la historia minera del cobre-, así como su influencia en el desarrollo económico y manufacturero del Perú. El depósito mineral de Toquepala está situado en el departamente de Tacna, zona sur del país. El reconocimiento como zona cuprífera es partir de Velarde en La Minería enel Perú (1908) y Basadre en Estado actual y porvenir de la industria minera en los departamentos del sur del Perú (1918). Posteriormente en 1937, Juan Oviedo de Villegas denunció los depósitos en Toquepala y fue el geólogo Schmedeman de la cerro de Pasco Corporation, quien reconoció la mina como un depósito de pórfido de cobre. Es a partir de 1938 que se inicia la explotación y en 1948, la Northern Peru Mining and Smelting Company se hace propietario de la zona minera. La exploración del depósito de Toquepala se realizó por medio de taladros verticales, perforados con máquinas de diamantina y de percusión. Durante el periodo de perforación, se realiza un sondaje de percusión previo que determina la extensión hacia otros hoyos para muestrear los valores y así medir la capa y espesor del mineral, mientras que el sondaje diamantino informa sobre la interpretación geológica del subsuelo de esa sección. Para la comprobación de los resultados de la perforacíón se buscó comparar los resultados de perforaciones de diámetro pequeños y grandes, con aquellos del minado del mineral en volúmenes de muestras relativamente grandes. Los métodos de muestreo empleados fueron acorde a las prácticas más estrictas actualmente recomendadas en este tipo de trabajos y supervisados bajo el control de un personal técnico. Luego del trabajo de comprobación del depósito de Toquepala, a mediados del año 1955, se unieron cuatro compañías para formar la Southern Peru Copper Corporation y en ese mismo año el gobierno peruano aprueba el desarrollo del programa y operación de este proyecto . Los planes de minado fueron terminados en 1955 minero. El avance de los trabajos de preparación de este proyecto se realiza a través de dos partes: la construcción de los servicios necesarios para la operación y los trabajos de preparación preliminares a la explotación minera. El ajuste de constucción y minado del programa se culminó en cuatro años (1952 - 1954), dando inicio a la operación en 1955. Finalmente, hablar la inflluencia del proyecto de Toquepala en el desarrollo económico industrial en el sur del Perú, es señalar su apoyo en el manejo de las vías de comunicación, favoreciendo el intercambio comercial entre las zonas ganaderas de la sierra de Tacna, Moquegua y el resto del país, así como del progreso de pequeñas industrias. El acceso a la educación y la erradicación de bajas condiciones sanitarias son elementos que también ayudan al avance social de la población, otorgándole a este proyecto sureño, un lugar importante en el panorama industrial y minero del país.

Jul 20, 1957

According to the Darcy?s law, filtration rate should increase with increasing pressure drop (?P) across a filter cake. In centrifugal filtration, ?P is created by the free water present on the surface of a filter cake. Thus, ?P can become negative when the free water disappears from the cake surface, which makes it difficult to achieve low cake moistures. In the present work, we have developed methods of overcoming this problem by either increasing the air pressure inside or applying vacuum outside a centrifuge. Laboratory dewatering tests conducted using these provisions showed that the moistures of various minerals and coal fines can be reduced to the level that can obviate the need for thermal drying. The new concept has been successfully tested both at pilot- and full-scale, which lead to commercial deployment through Decanter Machine, Inc., under the trade name Centribaric® centrifuge. Keywords: dewatering, hyperbaric centrifuge, pressure drop, Darcy?s law, Centribaric® centrifuge

Sep 1, 2012

By M. E. Rossi

All large-scale applications of conditional simulations intend to benefit from the ‘correct’ (or’ accurate’) characterization of uncertainty, adequately describing the variability observed from the data and its impact on the final objective. This paper discusses a number of relevant issues that highlight the extent to which, in reality, a model of uncertainty is dependent on the random function model chosen. Often in the presence of large number of conditioning data most available random function models will provide similar models of uncertainty. When conditioning is scarce, the resulting models of uncertainty will vary more widely, since the final output will depend mostly on the underlying assumptions of the model chosen. The application described in this paper is taken from a large porphyry Cu operation in northern Chile, and it demonstrates the impact of several variables on the resulting models of uncertainty. In particular, some of the decisions involved include the number of conditioning data and the underlying Random Function model used (Gaussian or indicator-based). Also, implementation-specific parameters must be decided upon, such as grid size used, random number generator, simple or ordinary kriging, multiple-grid simulation, and simulation of irregular three-dimensional bodies (as opposed to regular grids). Some practical guidelines are proposed to deal with these decisions.

Jan 1, 2003

By Nicholas T. Zilka

Mineral resource studies by the Bureau of Mines indicate three areas within the Selway Bitterroot Wilderness have mineral resource potential. Regional studies suggest that a granitic stock on the south side of the Wilderness has high potential for a Climax-type stockwork molybdenum deposit (pl. 1, no. 8); but detailed surface investigations failed to recognize a deposit. The Elk Summit area on the north side of the Wilderness contains subeconomic resources of columbium (niobium)-bearing ilmenite in placers (p1. 1, no. 19). Subeconomic silver-copper-lead resources occur in a vein on the northeast side of the Wilderness at the Clift Mine (pl. 1, no. 2-5). The study area has no known deposits of oil and Haas, coal, geothermal resources, or other energy-related commodities.

Jan 1, 1982

By T. Takayama Filho

Votorantim Metais Zinco is a smelting facility which produces SHG zinc, zinc alloys, sulfuric acid, liquid SO2, copper sulfate, cadmium metal and silver concentrate. It is located at Juiz de Fora, Minas Gerais State, Brazil. This facility has been operating since 1980 and its current capacity is 95,000 tonnes of zinc per year, using mostly imported sulfide concentrates.The plant uses the conventional roast-leach electrowinning (RLE) process, in which iron is removed from the circuit as jarosite. The residues generated by the RLE process, which amount to about 200 t/day (dry weight), were until 10 years ago, deposited in tailing ponds having no impervious lining. More recently, jarosite and other wastes have been deposited in a properly built reservoir, but this is reaching its maximum capacity. In order to decommission these disposal operations and to reclaim the sites in an environmentally acceptable manner, Votorantim Metais concluded in 2004 a rehabilitation project for the old tailings pond and prepared detailed plans for managing the current and future disposal of jarosite-bearing residues. This paper describes the procedure for removing iron from the hydrometallurgical circuit and discusses the past and current status of the residue disposal sites, as well as the future challenges related to the environmentally acceptable handling of iron residues.

Jan 1, 2006