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By Italo Onederra, Jason Furtney, Ewan Sellers

The detonation reactions occurring during rock blasting result in high pressure gas phase products from the condensed explosives typically used in mining applications. After detonation and the initial fracturing, the work done by the expansion of this gas contributes to burden movement and further rock fracturing. Before all of the energy in the reaction product can do useful work on the rock, some of this energy is lost to crushing and possibly to gas venting to the atmosphere. Borehole gas pressure decreases by three principle mechanisms: (i) expansion of the borehole cavity, (ii) flow into the fracture network, and (iii) flow through the stemming. To simplify the problem and to get a better understanding of the interaction of these mechanisms, a simple model for each of these mechanisms is developed. A comparison is made of the time-scales and the influence on burden movement for each. A comparison of gas flow behavior is made between typical ANFO and emulsion products.

Jan 1, 2012

By Richard F. Lynch, Frank E. Goodwin

"The development of Galfan, a new generation 95% zinc-5% aluminum-mischmetal alloy coating for steel, offers opportunities for greater fabrication flexibility and upgraded corrosion performance in automotive applications. The formability of Galfan is equivalent to that of electrogalvanized steel, based on laboratory tests and automotive component fabrication. Corrosion resistance of Galfan exceeds that of hot dip and electrogalvanized, including performance in automotive industry tests. Automotive production applications for deep drawn and stamped components in France and Germany are based on the ability to meet dual performance requirements for upgraded formability and corrosion resistance. The first U.S. Galfan application was on 1985 model Ford cars and light trucks for transmission oil cooler lines which has now expanded into a number of power steering tubing uses. IntroductionContinuing requirements for improved vehicle performance coupled with the ever present need for reduced cost have spawned the development of a number of new coated steel products. Among this new generation of coated steels is Gaifan™, a 95070 zinc-Solo aluminum-mischmetal hot dip alloy coating. Galfan exhibits particular promise for automotive use based on broad fabrication advantages and upgraded product performance(I ),The unique characteristic of Galfan is the key combination of greatly improved formability with much longer corrosion life. Galfan provides significantly better formability than any other hot dip coating. Testing shows that formability is limited primarily by the steel substrate to which the Galfan coating is applied. Galfan exhibits excellent resistance to flaking and microcracking during commercial forming operations. The result is the elimination of unnoticed damage to the coating which would show up later as premature rusting on the finished product."

Jan 1, 1987

"This paper describes some of the methods and equipment used for fine milling of minerals, and gives particular attention to the Vibro Energy system.In addition, the paper describes a specific application in the gold mining industry. This is the 200 tpd plant built by Anglo American Corporation at the President Brand Mine in South Africa in 1985, now a division of Freegold. This plant treats a gold bearing pyrite flotation concentrate which is finely ground to 15 microns prior to cyanidation and carbon-in-pulp (CIP). l .0 INTRODUCTIONFree milling gold ores are those that yield acceptable dissolution and recovery of the gold following grinding to what can be described as normal fineness, frequently between 50% and 90% passing 74 microns.Increasingly, gold metallurgists are faced with ores that are refractory. The traditiona1 treatment route for refractory gal d ores and concentrates has been by roasting, but for environmental reasons this is becoming less acceptable, or in some areas of the world, totally unacceptable. New methods of treating refractory gold ores are being developed and applied in practice. These new methods include pressure and biological oxidation. Higher gold liberation can also be attained by increasing the fineness of grind, although with conventional systems there are economic limits to this.In flowsheet development and test programs on new deposits, a standard procedure is to establish the relationship between the grind and subsequent go 1 d extraction. The normal situation is that gold extraction increases as the ore, or concentrate, is ground finer. Typically, this relationship is as shown in Fig. l, where the incremental additional extraction is very small once an optimum, or economic, grind has been achieved. This generally app1ies whether the material is free milling or refractory. The limits to grinding are set by the type of equipment which is commonly in use, usually ball mills. These mills have the obvious advantage of high capacity, however, they are increasingly inefficient as finer grinds are required. In general, ball mills are used to reduce ore to some agreed percentage passing 74, or possibly 53 microns."

Jan 1, 1988

By Varadarajan Seshadri

Geometallurgical characterization of iron ore which is a raw material for Iron making as in the case of charcoal blast furnaces operating in Brazil or for production of agglomerates such as iron ore sinter which serves as burden material for blast furnces of high productivity or pellets extensively used in the direct reduction processes all over the world in the iron and steel industry. Selection of proper raw material after due characterization should lead to an improvement of the productivity of the respective processes The usual classification of quality of iron ore is uniquely based on chemical analysis, granulometric and physical parameters. However not much emphasis has been given to the structural characteristics which also are important in the processes. Different typological categories of Brazilian iron ores have been used in the characterization . For instance, several kinds of hematite crystals like specularite, martite and microgranular hematite, etc with variable crystal sizes are found in the different ore types. They are also composed of different of fabrics and types of accessorial mineralogical constituents and have different porosities, pore diameters, etc which influence the cold and the hot agglomeration stages of the ore fines, and also chracteristics such as reducibility, decrepitation etc, important for assessment of quality of iron ores. . The first step for attaining a good characterization of ores is to know in detail about the structure of the deposit, shape of the body, types of iron ores and their distribution. This requires a geological-structural study and the mapping of the bodies using mineralogical criteria for typological classification of ores. followed by structural characterization of materials in stages of mining, comminution, screening and concentration processes. In this contribution a geometallurgical approach for quality control of Brazilian iron ores for sintering and pelletizing processes is highligted.

Jan 1, 2006

By Remo Grandori

The Umiray Angat 13,2 km long tunnel in Philippines have been bored through extremely variable and difficult ground conditions including a number of special events. In particular the following adverse conditions were found: faults in decomposed ground, high temperature rocks, extremely rapid and important convergence phenomena, water inflows up to 800 litres per second. The special El Nino climatic conditions caused a long dry season and lower the level of the lake that was granting the access by barge to the site under the minimum navigable level. Many equipment have had therefore to be transported to site by a 10 ton capacity helicopter, after having been partially dismounted. For the same reason most of the tunnel drive have been bored servicing the site by 1 ton capacity helicopters to transport materials, spares and personnel. In order to overcome the above geological and logistic problems several innovation were introduced and tested in this project. Despite all that difficulties the 13,2 km of tunnel were bored in about 24 months, with a global average of 500 m/month.

Jan 1, 2001

By Stuart McTavish

"Noranda's Goldstream mine is a 1,500 ton per day copper-zinc mine located 60 miles north of Revelstoke, B.C.The orebody which contains 3.69% Cu and 2.69% Zn was discovered in 1972. Construction of the mine and mill was completed in 1982 and start up was achieved in May 1983.This paper will describe the flowsheet and related equipment 1n the crusher and mill, in particular the dewatering section where two Larox pressure filters are used to dry the concentrates.INTRODUCTIONThe Goldstrean property is located 60 miles north of Revelstoke, B.C. in the Goldstream River Valley (Figure #1). It was discovered during the construction of a logging road in 1972. Exploratory drilling was initiated in 1975, and in 1976 a portal was collared to obtain underground data. Samples were taken from the underground workings for metallurgical bench tests and a pilot plant run.Due to economic conditions, the decision to go into production was delayed until 1980. Concentrator construction and underground development progressed simultaneously during 1981 and 1982, and were completed by the end of 1982. Start up of the concentrator was achieved on May 2, 1983.The ore typically contains about 40% sulphides, which are chalcopyrite 10%, sphaletite 6%, pyrrhotite 20%, and pyrite less than 5%. The sulphide minerals have a high degree of intergrowth. Most of the sphalerite occurs in micron sized grains which are embedded in the pyrrhotite and, to a lesser degree in the chalcopyrite. There is also some fine dissemination of the chalcopyrite in the pyrrhotite. The waste rock is made up of about 30% quartz, 20% guange silicates, and 10% carbonates. The ore has a specific gravity of 3.2 and a natural pH of 8.2."

Jan 1, 1985

By Fulton Flick

THE micrography and macrography of aluminum and its alloys present certain difficulties. Many of the difficulties attendant on the micrography have been removed by methods developed during the past few years, notably those of E. H. Dix, Jr.1 The development of grain size in aluminum and its alloys may be equally troublesome, yet comparatively little detailed attention appears to have been given to it. Satisfactory reagents. are available for the development of such structures in ferrous and most non-ferrous metals, but those applied to aluminum and its alloys, i. e., alcoholic or aqueous solutions of sodium hydroxide or hydrofluoric acid are not entirely satisfactory. Hanson and Archbutt,2 in speaking of these two reagents, state that "These two reagents give fairly satisfactory results, but they sometimes produce badly tarnished surfaces from which the surface deposit is difficult to remove." It has been our experience that neither of these reagents is to be entirely relied on for developing structures suitable for study or photography. This means that when the etch fails to produce satisfactory results the, specimen must be repolished, through the 000-paper at least, and then etched with another reagent. This procedure entails a con¬siderable loss of time, and the final results may not be all that might be desired. However, the reagent to be described, although not a panacea for all etching troubles, has improved results so markedly that it is felt that it is worth offering as a grain-size etch generally applicable to aluminum and aluminum alloys. Czochralski3 in 1915 mentioned the application of a solution of 10 to 20 c. c. concentrated hydrofluoric acid in 100 c.c. absolute alcohol, etching in this reagent being followed by dipping in concentrated hydrochloric-acid solution.

Jan 2, 1925

By T. C. Alex, S Srikanth, Premchand

It has been suggested that reduction of the iron and manganese phases as far as FeO and MnO is preferred for the complete liberation and selective reduction of the copper, nickel and cobalt oxides in manganese nodules. The oxygen partial pressure/temperature regime suitable for this purpose has been delineated. Free-energy minimisation and thermogravimetric results indicate that the requisite conditions can be achieved if more than 10% of neutral oil is used at temperatures greater than 923 degrees C. Neutral oil content, temperature and roasting time have been optimised to maximise leaching recoveries of Cu, Ni and Co: up to 96% of Cu and Ni and up to 85% of Co can be recovered if 15% of neutral oil is used as a reductant at 973 K for 90 min

Jun 21, 1905

By Mauro Vivaldino Fernandes

Os desafios para o aprimoramento do desempenho operacional dos altos-fornos constituem um campo aberto para o desenvolvimento e aplicação de métodos de controle que promovam a otimização da operação do reator, aliada ao prolongamento da sua vida útil. O Alto-Forno 3 da Usiminas - Ipatinga, nesta sua 4ª campanha, foi projetado para 15 anos de operação, com uma produção estimada de 41 milhões de toneladas de gusa. Os resultados da campanha atual, em termos de produção e de duração da campanha, superam os dados projetados. Neste contexto, são apresentadas as principais características do Alto-Forno 3 na sua atual campanha, a evolução do seu desempenho em termos de produtividade e tempo de operação, além das principais ações direcionadas para a preservação e estabilidade do sistema de refrigeração e do cadinho, contribuindo para o prolongamento da sua vida útil. Como resultado destes esforços, a vida útil estimada do Alto-Forno 3 é de 22 anos, superando em 7 anos a duração prevista.

Oct 30, 2017

By J. Hu, F. Lin, R. Chen, F Peng, S. Yang, W. Yu

"Microseismic monitoring technology has become one of the most effective method of mine ground pressure monitoring after decades of development. But safety assessment of mine ground pressure by using microseismic monitoring is still in the development stage, it needs to be perfected continuously in practice, and choose the optimal assessment indexes and methods. The definitions and physical meanings of wave velocity, b value, and EI-VA value are introduced in this paper. Statistical calculation of the microseismic events in Luomu Mine is finished by using these indexes, then the functions and calculation results of V, b value, and EI-VA value with the variable of time are also given in the paper. The preliminary safety assessment method is established in Luomu Mine, and it has achieved good results in practical application.1.1 Engineering background The Luomu Mine is a super large molybdenum and tungsten production base in China, ore reserves is up to 2 billion tons, first in Asia and third in the world. It begins mining since the 1960. and bases on underground mining until 2002. In order to recover resources more effectively, it began to use opencast mining method and formed a production of 30000t/d in the early 1990. After about 30 years of underground mining, a large mined out spaces was formed under open pit mine, up to area of 1.2 million m2 and volume of 18 million m3, as shown in figure 1. The large number of mined out spaces seriously affects the normal production, mining and handling of mined out spaces are in the high risk. In the past years, several rock mass collapsions happened, and it caused a serious security threat to persons and equipments. According to the distribution characteristics of mined out spaces, Luomu Mine is divided into A, B, C, D and E mining area. The stability of D mining area is studied in this article. D mining area mainly includes 1376,1350,1340,1317 mined out spaces and 1280 deep large mined out area, as shown in figure 2. The mined out spaces of D mining area is extremely complex and high-risk. Therefore, a microseismic monitoring system was built to monitor the stability of D mining area, a large number of valuable datum has been obtained, and it has a striking effect (Cheng & Peng, 2013; Peng et al., 2013)."

Jan 1, 2015

By Patrick E. Durnal

A joint venture of Ben C. Gerwick Inc., Sverdrup (now Jacobs) and DMJM (now DMJM Harris) designed the $779 mill seismic upgrade of the Richmond - San Rafael Bridge over the San Pablo Bay in the San Francisco Bay Area and provided construction support to Caltrans. Construction of the marine foundation retrofit was completed by a joint venture of Tudor Saliba/Tidewater/Koch-Skanska and their subcontractors: Pomeroy Precast Construction, AGRA Foundations, Dutra Construction and Vortex Divers. Construction management and inspection was performed by Caltrans with support of various consultants.

Jan 1, 2013

By Mona M. Fawzy, Ahmed A. Eliwa, Ahmed H. Orabi, Amal E. Mubark, Ebrahim A. Gawad

During the last decades, the growing demand for rare earth elements (REEs) has led to numerous recent studies to recover these elements from various bearing ores and wastes. Therefore, the recovery of REEs from Ras Baroud polymetallic concentrate has been investigated in the current study. Physical beneficiation for the Ras Baroud pegmatite sample was carried out, yielding a concentrate for euxenite (Y), fergusonite (Y), xenotime (Y), monazite (Ce), allanite, thorite, uranothorite, and Hf-zircon, which resulted in raising the concentrations of rare earth elements, Th, Zr, U, and Ti in the sample. Fusion digestion processes with sodium hydroxide were studied using the Conceived Predictive Diagonal (CPD) technique. The three experimental digestion groups proved the dissolution of 99.9, 95.6, 99.9, 52.5, and 0.47% for REEs, Th, U, Ti, and Zr, respectively, under fusion conditions of 723 K, 120 min, 1/1.5 ore/alkali ratio, and − 100-μm particle sizes. Fusion kinetics, isotherms, and thermodynamics were investigated using several suggested models, namely, pseudo reversible first order, uptake general model, and shrinking core model which matched well with the experimental digestion results. Selective recovery of actinide content from REE content of the digested concentrate chloride solutions was accomplished using solvent extraction with di-2-ethyl hexyl phosphoric acid. About 99.9, 99.9, and 4.2% extraction efficiencies for Th, U, and REEs were performed, respectively, using 0.3 mol/L solvent concentration in kerosene as a diluent, 1/2 organic to aqueous ratio, an aqueous pH of 0.2, and 15-min contact time. Thorium and uranium ions were stripped with sulfuric acid solution 2.5 mol/L with 94 and 98% stripping efficiency, respectively. A highly purified REE precipitate was obtained from the raffinate solutions. Zircon mineralization tailings were obtained as a by-product through the alkaline digestion process.

May 4, 2024

By Kazue Moriya

At the 1980 TMS-AIME world symposium, Dr. Davey mentioned that the traditional lead blast furnace is now being challenged by direct smelting processes. In the copper smelting field both the blast furnace and reverberatory furnace are also disappearing in favour of direct smelting processes such as Outokumpu flash smelting, Mitsubishi continuous smelting, Noranda furnace, Inco furnace and so on. Those new processes all have the following in common: (1) High degree of mechanization (2) Metallurgical reactions carried out in closed vessels (3) Application of oxygen and/or oxygen enriched air (4) Minimization of handling materials and gaseous volume (5) Minimum energy requirements (6) Removal of workers from near the furnace (7) Reduction of emissions of harmful gas to meet environmental regulations. (8) Improvement to the work place environment to avoid occupational hygiene hazards. Direct and continuous smelting of powdered concentrate in one vessel was a romance of the metallurgist since early times. However as mentioned above, in the copper field this objective is being achieved in practice. The industry however can't deny that the serious and severe regulation of environmental pollution in every country was the prime motive for the modernization of smelters. In early days, to meet regulations, it was anticipated that many economic difficulties such as higher capital and energy costs and extravagant use of resources and waste disposal would be the result. "Turn a misfortune into a blessing" is an old saying which reveals the current thinking and reacent developments in the nonferrous industries. In the last ten years in the lead smelting field, about two decades later than copper, commercial scale smelting using new furnance technology has started. The KIVCET process and QSL process, which is flash smelting and bath smelting respectively, are becoming major competitors. They will be sure to upgrade their processes to remain economically and environmentally viable in the comming decade.

Jan 1, 1990

By F. G. Miller, H. C. Miller

Petroleum technologists and progressive operators constantly are striving to increase the percentage of oil that may to recovered from reservoir rocks through wells. The exhaustive studies that have been made of the function of natural as in the production of oil, for example, have aided operators greatly in increasing the quantity of oil recovered from reservoirs. Natural gas dissolved in and otherwise associated under pressure with oil in reservoir rocks, however, is not the only source of energy available for moving oil through sands to wells. In becoming "reservoir—energy conscious" engineers have learned that in many petroleum reservoirs the edgewater flanking the oil accumulation constitutes a potential source of energy capable, through proper control, of increasing oil—recovery efficiencies materially. No longer is the encroachment of water into the oil— and gas—filled tart of the reservoir considered as an evil to be combatted by devious methods but rather a natural consequence, incident to the withdrawal of nil and as from the wells, that may be used advantageously in lengthening the flowing life of wells and increasing the economic recovery of oil and gas.

Mar 1, 1938

By Kelly E. G

NZ Steel's flushing slag typically contains 1.2 per cent V203. Extraction of vanadium from powdered slag using a salt (NaCI or Na2CO3) roast/leach process was investigated. With NaCl, optimum extraction conditions were a charge containing 10 per cent NaCI, roasting in air at 875°C for 4 hours, followed by leaching in dilute H2SO4. Extractions were typically 30-50 per cent. NaCI roasting did not chemically attack the slag; the phase transformations that occurred were due to high temperature oxidation. Slag particle size had a significant effect on extraction.Optimum conditions for extracting vanadium by Na2C03 roasting were 20 per cent Na2CO3 in the charge and roasting in air for 3-4 hours at 850-875°C followed by water leaching.Na2CO3 roasting involved chemical attack that resulted in the formation of perovskite (CaTiO3) and carnegieite (NaAISiO4).The extent of vanadium extraction depended on the amount of Na2CO3 added and the original slag SiO2 content.Compared to the separate roasting treatments, simultaneous treatment with NaCI and Na2CO3 gave lower vanadium extraction, while requiring considerably higher roasting times and temperatures.

Jan 1, 1982

By Ana C. C. Pacheco, Maurício L. Torem

"The aim of this work was the study of the effect of the type (Fe3+, Al3+ and Fe3+ and Al3+ mixture) and of the coprecipitant concentration on As5+ removal by ACF. Removal of As5+ using sodium dodecyl sulfate (SDS) as a collector was studied by Adsorbing Colloid Flotation (ACF) at laboratory scale. The morphology of the precipitate retained in the foam was analyzed by Scanning Electron Microscopy (SEM/EDS).In order to investigate the effect of the initial concentration of Fe3+ on As removal, sets of experiments were performed with a concentration of Fe3+ in the proper range of pH (5,0 – 6,0) previously observed in the coprecipitation tests. As removal improves significantly as the concentration of the coprecipitant agent increases from 60 mg.L-1 (77,4%) to 80 mg.L-1 (99,7%). This is probably due to the higher concentration of ferric hydroxide (Fe(OH)3) which provides a larger surface area available for adsorption of As. From the initial coprecipitant concentration of 80 mg.L-1, As removal has shown to be rather high (? 99,7%), with the maximum being (99,9%) by using a Fe3+ concentration of 160 mg.L-1. Therefore, for a maximum As removal, under these test conditions, the optimum concentration of Fe3+ is 160mg.L-1.This paper also shows the effect of the initial concentration of Al3+ on As removal at a suitable range of pH (7,0 – 8,0). A very significant increase on As removal was found to occur as the initial concentration of coprecipitant was increased from 60 mg.L-1 (35,7%) to 80 mg.L-1 (97,7%) and a decrease in As floatability (43,7% - 54,5%) was found to occur from that Al3+ concentration amount. Based upon those results, the optimum Al3+ concentration so as to remove As under these test conditions is 80 mg.L-1."

Jan 1, 2003

By T. J. Serenko

The epithermal deposit is hosted by Tertiary volcanic rocks that lie between mid-Miocene normal faults of the Northern Nevada Rift. Petrographic, laser-ablation and metallurgical observations suggested that the gold occurs in two principal forms: native (and electrum) and disseminated in arsenopyrite. It was proposed that gold is distributed between two parageneses with distinct mineralogical associations. Detailed downhole geochemical study supported the observations. Concentrations of Au, Ag, As, Sb and Se were determined from drill core and reverse-circulation cutting composites and contoured on cross-sections. Gold was indeed shown to have a bimodal distribution with the two parts separated spatially and perhaps temporally, implying that two separate genetic processes acted to concentrate gold at Mule Canyon

Aug 1, 1995

By John L. Edwards, Anthony T. Iannacchione

There has been a persistent need to forecast roof falls so that miner’s exposure to hazardous underground environments can be minimized. Several monitoring techniques have been developed and are used today with varying levels of acceptance in the mining industry. This paper examines the potential for monitoring microseismic emissions activity as a means of forecasting roof falls. The use of this activity to forecast roof falls has drawn only limited attention, resulting in a lack of published field performance data. This deficiency is being partially addressed by analyzing data obtained during longwall mining at Moonee Colliery in 1998. The Moonee data base contains a wealth of information concerning roof fall forecast parameters and the seismic alarm criteria used to develop these forecasts. Four seismic alarm criteria were developed and used by Moonee with varying degrees of success. Roof falls were forecasted 73% of the time with average forecast times of 54 minutes. Ninety percent of the predicted roof falls had a warning time, i.e., the time between warning and roof fall event, of greater than 1 minute. The fraction of forecasted roof falls decayed logarithmically as a function of warning time, until only 20% of events were predicted more than 100 minutes prior to roof falls. False alarms occurred in 50% of the warnings. Many of the false alarms were quickly followed by a cessation in mining which could have temporarily halted the on-going failure process. If mining had continued immediately after the false alarms, a roof fall may have occurred soon after. The microseismic activity collected from Moonee Colliery demonstrates that techniques to forecast roof rock instabilities in underground mines are possible.

The London Metal Exchange began its first official session of aluminum trading on Monday, October 2, LME prices based on 3-month forward contracts opened Monday at 52.4 cents per pound, fell midway through the week to 52.3 cents and ended Friday at a high of 52.7 cents. For the week, LME metal averaged 52.5 cents. Although Reynolds Metals Co. and Aluminum Co. of American continued in September to value unalloyed 99.5 percent aluminum ingot at 53 cents per pound, other producers were at higher positions of 55-57 cents. Alcan Aluminum Corp. of Alcan Aluminum, Ltd., a Canadian producer, increased prices for its U.S.-marketed ingot by 2 cents to 55 cents per pound, effective September 21. New York merchants increased ingot quotes by approximately 0.5 cents to 52.8-53.5 cents per pound.

Jan 1, 1978

By Richard Givens, Thomas Baginski

Technological advancements in warhead designs and implementations have driven the development of arrayed initiation networks of highly accurate, highly reliable, and extremely safe detonators. Recent development efforts have produced advanced Exploding Foil Initiator (EFI) based systems that have been adapted for civilian use in commercial blasting applications.1,2,3,4,5 This novel, high technology system promises multiple improvements and advantages over the manufacturing, transportation, tracking, storage, inventory and field operation of current detonator systems. Ultimately the insertion of this technology would result in fielding a Non-Energetics Based Detonator (NEBD). Insertion of complementary technologies into the detonator’s supporting systems would greatly advance current detonator hardware/software.

Jan 1, 2011