Search Documents

By B. Anameric

The pig iron nugget process is gaining in importance as an alternative to the traditional blast furnace. Throughout the process, self-reducing?fluxing dried greenballs composed of iron ore concentrate, reducing-carburizing agent (coal), flux (limestone) and binder (bentonite) are heat-treated. During the heat treatment, dried greenballs are first transformed into direct reduced iron (DRI), then to transition direct reduced iron (TDRI) and finally to pig iron nuggets. The furnace temperature and/or residence time and the corresponding levels of carburization, reduction and metallization dictate these transformations. This study involved the determination of threshold furnace temperatures and residence times for completion of all of the transformation reactions and pig iron nugget production. The experiments involved the heat treatment of self-reducing?fluxing dried greenballs at various furnace temperatures and residence times. The products of these heat treatments were identified by utilizing optical microscopy, apparent density and microhardness measurements.

Jan 1, 2007

The impact of a methane explosion on mining operations cannot be over-emphasized. The explosion is a result of rapid combustion when a methane/air mixture is ignited by an unexpected energy release, such as a mine fire, electrical arc or sparks caused by frictions or rock falls. In most cases, an ignition of methane/air mixture could result in a deflagration other than detonation. Resulting flames and overpressure induced by a methane deflagration will harm neighboring miners and local ventilation control devices.. ,It is essential that the mechanism of an explosion and associated destructiveness be fully understood. This research seeks to predict an influence region of an incident happened within a representative underground mine geometry. The most common geometric changes in an underground coal mine are bends, regulators/doors, obstacle in airways and changes in sectional area. These geometric changes could result in an attenuation of the flame and pressure wave as a result of a methane deflagration. A study of this phenomenon could enable mine planners to have better understanding of the over-pressure redistribution due to the explosion. Both numerical and experimental work has been done in this study to ascertain a better insight of this potentially devastating event. The experimental data are also used to validate the turbulence and combustion models used in this test.

Feb 23, 2014

By K. C. Armstrong, A. B. Cron, L. A. Melis

"The Johnny Mountain gold mine in northern British Columbia, owned by skyline Gold Corporation, has been in operation since August 1988. Mill operating difficulties at the start of the operation resulted in a depleted cash flow situation and quick improvements were required to generate a self-sustaining financial basis of operation. In October 1988, Melis Engineering Ltd. was contracted to identify metallurgical difficulties, implement necessary modifications, and undertake mill operations and personnel training in order to achieve production targets.This paper presents the operating difficulties which existed at start-up and describes the methodology used to overcome production problems. Metallurgical testing results are described along with the modifications made to the milling circuit to suit ore metallurgy. Plant changes led to the operation of a simple gravity/flotation circuit to recover gold as bullion and in a copper concentrate. Operation of the originally installed cyanidation circuit was discontinued. This contributed to substantial savings in operating costs and virtually eliminated environmental problems. PROPERRTY LOCATION ANR DESCRIPTIONThe Johnny Mountain mine site is located in northern British Columbia along the Iskuit River about 60 km east of Wrangell, Alaska and 275 km north of Terrace, B. C.. A location map is presented in Figure 1 and a site plan is shown in Figure 2. The complex is located on a mountain plateau about 3, 600 feet above sea level. The plateau is flanked to the north by Johnny Mountain and surrounded on the other sides by steep cliffs."

Jan 1, 1990

By Gary P. Sames

The Bureau of Mines recently initiated a study of geologic features that contribute to roof instability in western U.S. underground coal mines. The purpose of the study is to provide information for use in ground control planning and safety hazard reduction in that region, where mining activity has been increasing. Hazardous geologic conditions were surveyed in selected underground coal mines in Utah and Colorado, and both depositional and structural features were identified as potential ground hazards. Although the conditions found do not differ in kind from hazardous geologic conditions in the Eastern United States, they do differ in intensity of occurrence and relative importance. Three depositional features dominate where unstable roof occurs in western underground coal mines: paleochannel deposits, crevasse splay deposits, and flood basin deposits. Three structural features identified as hazardous, but not so widespread or common as the depositional hazards, are faulting, jointing, and igneous intrusions. This survey establishes a foundation for future studies aimed at reducing and preventing ground control accidents in western coal mines.

Jan 1, 1988

By Antonio Mendoza

El presente trabajo señala una metodología en gestión de seguridad, la cual proporciona un enfoque estructurado de procesos que permite la solución de problemas y facilita la toma de decisiones basadas en datos. Esta acción es una herramienta de gestión de seguridad aplicable a todos los aspectos de productividad, calidad y seguridad. Por tanto, se convierte en un instrumento de uso general a nivel de supervisión que faciilita la toma de acción correctiva de forma oportuna en la mina Quiruvilca, reduciendo los accidentes capacitantes en la industria minera.

Sep 13, 2001

By J. B. Czirr

MESA Corporation has completed a four-year program for the Bureau of Mines to develop a technique for measuring roof competence in underground coal mines. The preferred technique employs a tracer gas that is injected into a roof borehole drilled near the working face. The tracer gas performs the dual purpose of determining the pressure loss rate from the borehole and of marking the diffusion pattern of the the escaping gas. The primary detection technique relies upon observation of the rate of pressure drop in a hole drilled in the roof strata under test. If this measurement indicates a significant probability of roof collapse, the gas diffusion pattern is outlined with the Leak-gun tracer-gas detector. These two techniques provide a comprehensive method for predicting the relative probability of roof collapse in operating coal mines.

Jan 1, 1985

Interest in industrial minerals in recent years has increased to such an extent that it has taken them into the mainstream of the Australian mineral industry. Notwithstanding that time series data on the values of production, exports, and imports show that industrial minerals are overshadowed by metals and energy minerals, their contribution to the national economy is important and more significant than would seem to be indicated by the statistics. Whereas the ex mine value of metals generally includes some processing (at least to a concentrate stage), most industrial minerals are valued at little more than their extraction cost, in addition to which such costs are generally low because most industrial minerals are exploited in low-cost surface operations. Consequently, values of mine production of metals and industrial minerals are not strictly comparable in that values of mine production of metals tend to be overstated Short term growth of the industrial minerals sector is assured because of several new projects already commissioned but not yet reflected in the statistics. Longer term growth is also assured, based on various other major projects that are likely to come on stream in the early to mid 1990s.

Jan 1, 1989

By Gordon A. Irons

"Powder injection for melt refining is widely practiced in the steel industry, and is gaining acceptance in the non-ferrous industries. In these commercially-important systems, the thermodynamics and kinetics may be very complicated. More than one element may be removed by refining, and often the refining agents are not just one compound. In this paper, the thermodynamic and kinetic aspects of these processes are reviewed. A number of examples are given, such as the desulphurization of iron with a variety of reagent mixtures, and selenium removal from copper with several different reagent combinations.IntroductionI am very pleased and honored to present a paper at this Symposium recognizing the many contributions of Professor Howard Womer. Even at the time I was an undergraduate student, the WORCRA process was part of the curriculum. I remember at the time that I was fascinated by the concept, and due to it and the many other rapid developments in Process Metallurgy, I chose it as my field of study. I think the Symposium is testimony that Professor Womer has touched the lives of many others as well.My original assignment was an overview of the basic aspects of gas and solids injection. However, I reviewed most of this material at the Savard/Lee Symposium [1]. In the present paper, I will present some of the basic issues related to refining with powder injection, using work that we have recently completed in both ferrous and non-ferrous systems."

Jan 1, 1996

By W. G. Pariseau

Introduction Caverns of 50 m in linear dimension at depths below 2300 m with a life of more than 25 years are proposed for the next generation of water-filled neutrino detectors. Little precedent exists for excavations in such an extreme environment, although some guidance is available from mining experience at great depths, for example, in South Africa, in Canada and at the former Homestake Mine in the U.S.A. Unlike mining for ore, there are choices available in the construction of such caverns that may mean the difference between success and failure. These choices should be informed by rock engineering principles. Recently proposed guidelines for orientation of brick-shaped caverns where the long dimension is a small multiple of the short dimension indicate that the most favorable orientation is with the long and short dimensions parallel to major and minor preexcavation principal stresses (Pariseau, 2005). Numerical analyses at reduced strength indicate some yielding at cavern walls should be expected but that an equilibrium state is quite possible and is aided by arching the back into a spherical dome when the cavern is an empty cylinder (Tesarik and others, 2002). The same indications of stability occur with brick-shaped caverns. However, the most dangerous situation occurs during the excavation sequence to final cavern dimensions. There are any number of excavation sequences that lead to the same final cavern shape, so there is an opportunity to partially optimize the sequence with construction guidelines that minimize peak stress concentrations during construction. This contribution discusses three practical excavation sequences that lead to the same brick-shaped cavern in the strong, massive Yates formation at the Homestake Mine where considerable rock mechanics data has accumulated through the years(e.g., Pariseau, 1985, Pariseau and others, 1995) and where actual mining on the 8000 Level indicates a strong possibility of successful investment in the next generation of large, deep neutrino detectors. The main results are: (1) a favorable brick-shape is one with dimensions in the same proportion as the preexcavation principal stresses (compressionpositive), and (2) favorable orientation of the most extreme but temporary shape of excavation is also best for the construction sequence. Analysis results from a mix of Homestake Mine data and possible excavation geometry illustrate the advantages of these guidelines.

Jan 1, 2006

By Fabrice Mathieu

The Cutter Soil Mixing (CSM) provides a cost effective solution for the rapid construction of retaining and cut-off walls using new equipment developed from diaphragm wall cutter technology. CSM consists of cutting and mixing drums mounted on compact hydraulic motors. Soletanche Bachy CSM has been designed to leave the space above the tool free, thereby mixing the soil efficiently during all the phases of the wall construction, with high penetration rates. The precise positioning and verticality of the wall is achieved using a kelly bar and full monitoring. Soletanche Bachy CSM is a versatile equipment which can be mounted on various carriers: pile rigs, hydraulic crane, carrier equipped with telescopic mast. The major phases of Soletanche Bachy CSM development are presented, including the results of an extensive trial carried out in Le Havre (France). The soil consists of hydraulic fill with soft soil lenses overlying sandy deposits. 20m deep panels were constructed to support a rectangular shaft. During the construction, and after its completion, the shaft was subjected to an extensive series of tests followed by a partial excavation. The paper discusses also the future development of the technique and its potential applications.

Jan 1, 2006

By Louis W. Cope

Since its discovery, Cuba has been called the “Pearl of the Antilles.” The country remains that, albeit a little tarnished these days. In Havana, many of the buildings are being refurbished, while some new ones are under construction. Since 1991, the laws have been relaxed so that Cuba is developing a mixed economy of central control with free market. Joint venture agreements have been signed with businesses from many countries. This does not include the United States due to its embargo. But even these regulations have been relaxed some.

Jan 1, 2003

By Galen G. Waddell

The Deep Creek zinc and lead mine afforded an excellent example of a relatively small underground mine operation that approached the low mining costs of large, highly mechanized mines, An open stope mining method incorporating sublevel benches and vertical long holes was used (fig. 1). Detailed descriptions are given on the exploration program, stope development, stoping procedures, and pillar removal. Pressure grouting was used to check the inflow of water and thus prolong the life of the mine. Statistics on mining costs and on electric power consumption, haulage from mine to mill, and milling costs are included.

Jan 1, 1963

"This paper reviews the chemistry involved in the recovery of gold from cyanide solution with anion-exchange resins, and also discusses the most critical aspects of the engineering of an effective resin-in-pulp (RIP) process. As far as the chemistry is concerned, the conclusions reached by a great many researchers, as well as the performance of the only operating RIP plant in the Western World, at the Golden Jubilee Mine in South Africa, support the view that the process is technically viable and, in many cases, could prove to be more attractive economically than alternative processes such as zinc cementation and carbon-in-pulp (CIP). On the engineering side, there is still a need for further development before larger scale ( > 50,000 tpm) RIP plants can be designed, built and operated with confidence. However, the experiences gained during nearly 3 years of operation of the Golden Jublee RIP plant indicate that the process can be engineered with confidence for smaller operations ( < 50,000 tpm), and this will probably be the scope of application of the first-generation RIP plants. INTRODUCTIONThe use of anion-exchange resins in gold processing has, for a number of years, been proposed as an alternative to more conventional processes such as zinc cementation and carbon adsorption, and detailed research programs that have been carried out at a number of laboratories have demonstrated the technical viability of the process. (Burstall et al, 1953, Davison et al., 1960, Tataru, 1973, Laskorin et al. 1978, Hosking, 1984, Riveros and Cooper, 1987 and Palmer et al., 1988)The main incentive for this work was the fact that resins have several characteristics that are quite different from carbon, which make them potentially more attractive substrates for the recovery of gold. The following are examples: -"

Jan 1, 1991

By Don Langlois, Udo Weber

"The effect of grinding media performance on milling and operational behaviour was demonstrated under different selected milling conditions of calcium carbonate. A variety of grinding media material and bead sizes, along with 2 different stirrer tip speeds, were used in the grinding process to generate a particle size reduction of the calcium carbonate (CaCO3). To determine the optimum milling parameters the collected test data was used to calculate and evaluate specific energy as well as stress intensity under different milling conditions.INTRODUCTIONAs a result of increasing energy costs and raw material prices it is important to look at the efficiency of the manufacturing process. Wet grinding and ultrafine wet grinding in stirred media mills are now a possible cost-effective production step for the processing of industrial minerals and precious metals. The generation of smaller particle sizes (down to micrometer scale) can be advantageous for further production steps – i.e. better liberation of precious metals or improved industrial mineral qualities.In the following, the wet grinding process is investigated under different milling conditions of calcium carbonate. Different grinding media materials varying in specific weight, bead size and stirrer tip speeds are used to determine optimal energy consumption for the milling process.DESCRIPTION OF TEST CONDITIONS AND PARAMETERSMill ParametersTests were performed in a Drais Laboratory Perl Mill PML H/V with an installed electrical motor power of 3 kW. The mill chamber is silicon carbide where as the stirrer and discs are made of yttria stabilised zirconia. The mill working volume is 0.9 l. A screen cartridge with a screen size of 0.2 mm is used to separate the beads and slurry at the outlet of the mill. All tests were performed with a grinding media filling grade of 80% (Mill working volume). The stirrer tip speed was set at 6 m/s and 10 m/s."

Jan 1, 2009

By Juan Garcia de Blas

O presente trabalho aborda o desenvolvimento de liga titânio-nióbio obtida por metalurgia do pó no qual foi introduzida uma operação de extrusão angular em canal (Equal Channel Angular Pressing - ECAP) com o propósito de promover uma consolidação que favorecesse a homogeneização na etapa posterior de sinterização. Após o processamento o material foi caracterizado por microscopia ótica e microscopia eletrônica de varredura (MEV/EDS). Os resultados preliminares indicaram a importância da redução do tamanho das partículas de nióbio.

Aug 17, 2017

By Y. P. Huang

Experiment results and operation practice on reutilizing old tailings dumped at SCIM (Shang-chang Iron Mine) of KISCO (Kunming Iron and Steel Corp.) are presented. In a production period over 30 years SCIM dumped about 8 million tons of iron ore tailings. For improving resources utilization instead of wasting, experiments on processing for reutilization of the old tailings are con-ducted. These tailings are fine size fractions of weathered iluvial ores rejected out by classification- des-liming in ore washing and dressing processes, containing TFe 21%~22% in hematite mainly and limonite occasionally. Their particle size distribution, in average, is of 72.26% minus 0.037mm and 30.88% minus 0.005mm. Existence of plenty of micro-fine particles makes the tailings refractory to process, resulting in poor metallurgy. The whole sample of the old tailings without size-classification is fed into experimental process. Slon-100 type high grads WHIMS (wet high intensity magnetic separator) with cyc-pulsing is adopted, which magnetism-focusing rod?s diameter is changed from 3mm into 2mm. Operational conditions of optimizing rougher separation tests are strengthened. An iron concentrate assaying 52.21% Fe at quantity rate of 18.39% and iron recovery of 44.40% is obtained. Operational practice shows that metallurgy and economy of the old tailings treatment are close to what achieved at experiments. It is estimated, therefore, that some 1.4 million tons of this iron concentrate may be recovered from the old tailings. This means that KISCO has moved its key one-step in re-mining and reutilizing the secondary resources, which would be a good demonstration in this industry. This is also of social and economic significance in response to China government?s request on reducing consumption of resources and establishing society with economy for achieving sustainable development.

Jan 1, 2014

By J. S. Roberts

"Campbell mines has been in operation since 1948. Part of the process consists of roasting of a flotation concentrate which contains arsenopyrite.At present operation level the milling rate averages about 850 t.p.d. and about 48 t.p.d. of concentrate is roasted. The gas emissions at present contain between 3 and 3.5 t.p.d. of arsenic trioxide, about2 - 2.5 t.p.d. of particulate matter and between 19 - 25 t.p.d. of sulphur dioxide. The particulate is extremely fine calcine dust and it assays about 4 oz. Of gold per ton.Until 1974 the gas was discharged untreated through a 125' stack.UntreatedThe decision was made in 1972 to erect a gas treatment plant, construction ran through 1973 and operation began in 1974. The cost of the installation was about 1.3 million dollars.On investigation the process technology, it was apparent that the plant operated by giant Yellowknife for the same purpose was the model we should study. I would like to acknowledge the fine cooperation we had from giant, the plant that emerged is very similar to theirs and incorporates some improvements suggested by them and based on their operating experience.The plant is designed to remove arsenic and solid dust and it has no provisions to remove sulphur dioxide.We depend upon the 125' stack to assure adequate dilution. Because of the nearby airport the stack cannot exceed 125'. A stack burner is provided that can ""y used to heat the stack gas and carry it higher into the atmosphere when there is an inversion condition.The removal of arsenic from hot gas is fairly simple. The sublimation point is about 425°f, a few degrees above this point the arsenic is a gas and a few degrees below it condenses into a solid form. The arsenic could have been removed by simply dropping the temperature below the condensation point and collecting all the solids in a baghouse. This would have removed the possibility of recovering the gold in the calcine dust and would have produced an impure and more bulky arsenic material to be placed in safe storage. The decision was made to collect the solid dust in a hot electrostatic precipitator operating above the sublimation point and subsequently lower the temperature below the condensation point and collect the arsenic in a baghouse."

Jan 1, 1976

By B M. Wilson, B J. Turner, S Sinclair, R J. Buerger

The Trident Gold Deposit is centred on the historical Higginsville Mining Centre, between the world class gold centres of St Ives (+15 Moz) and Norseman (+6.5 Moz) in Western AustraliaÆs productive eastern goldfields. It lies towards the southern end of the Norseman-Wiluna Greenstone belt in the Archaean Yilgarn Craton. The current in situ resource for Trident is estimated at 840 000 ounces, with production to date in excess of 500 000 ounces.Trident is hosted primarily within a thick, weakly differentiated gabbro with subordinate mafic and ultramafic lithologies and comprises a series of north-northeast trending, shallowly north plunging ore zones. The deposit comprises two main mineralisation styles; thin, lode-style, nuggety laminated quartz veins (Athena and Artemis) that formed along major shear zones primarily at the contacts between the various mafic and ultramafic lithologies; and large wallrock-hosted ore-zones comprising sigmoidal quartz tensional vein arrays and associated metasomatic wall rock alteration (eastern zone, western zone and Apollo) hosted exclusively within the gabbro.The thin laminated quartz vein lodes are important to the Trident Gold Deposits production profile as they constitute 33 per cent of the metal from only 14 per cent of the tonnes. The delineation, grade estimation and extraction of these lodes require a disproportionate amount of geological and engineering input due to the small scale variability in width, grade and direction. Over time, a robust and thorough process has been developed at the Trident Gold Deposit to understand and then successfully mine these complex mineralised systems.CITATION:Sinclair, S, Wilson, B M, Buerger, R J and Turner, B J, 2012. The mining industry needs to be shaken and stirred, in Proceedings Narrow Vein Mining 2012 , pp 155-166 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

The Purification of Low-Grade Quartz Ore by Flotation and its Mechanism

Sep 13, 2010

By D. Randolph Berry

Volume II contains appendices which explain and document the recommendations of Volume I. The following topics are covered: Appendix A Discussion of Recommended Guidelines Appendix B Worldwide Use of Oxygen Self-Rescuers Appendix C Hypothetical Use of Oxygen Self-Rescuers in Post-1972 Coal Mine Explosions and Fires Appendix D Vibration Testing of SCSRs Appendix E Testing of In-Service Chemical Oxygen SCSRs Appendix F Discussions with Representatives of Underground Coal Mining Appendix G Recommendations for SCSR Storage Containers Appendix H Example SCSR Storage Plans Appendix I Testing of In-Service Compressed Oxygen SCSRs Appendix J 30 CFR 75.1714, 30 Regulations Pertaining to Self-Rescuers

Jan 1, 1981