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By William M. Baldwin

Jan 1, 1946

By E. V. Konopleva, H. J. McQueen

"The isothermal bainite transformation kinetics of low- and medium-carbon alloy steels after hot deformation and the rmocycling treatment (TC) has been studied by the magneto - metric method. Deformation was produced by rolling at 800°C-1000°C. TC included three cycles of rapid (30°C/s) electro-heating up to 900°C-1000°C followed by quenching.Hot deformation retards bainite transformation in the lower part of bainite range (<400°C) and accelerates it in the upper part (>400°C). The effect is greater for higher strain and lower deformation temperature. Deformation also diminishes the overall bainite fraction below 400°C and increases the completeness of reaction above 400°C.Thermocycling provides more uniform ultrafine austenite grains with average size of 3 µm -4 µm compared to 12 µm -14 µm after conventional heating. The transformation rate after TC was almost the same as after conventional heating in low-carbon steel but was faster in medium-carbon with no change in the completeness of reaction. The degree of acceleration increased with rise of transformation temperature.There are a number of factors which are responsible for a change in bainite transformation kinetics in austenite deformed at high temperatures or subjected to TC. One of the most important factors is the refinement of structure, another one is structural and chemical inhomogenity of austenite due to deformation or to rapid heating. To estimate the contribution of these factors, ?-transformation was studied after different austenitizing conditions (low-temperature heating at 850°C- 950°C; high-temperature heating at 1100°C; step treatment – austenitizing at 1100°C, then cooling to 950°C-850°C). The results obtained make it possible to conclude that the structural and chemical inhomogeneity of austenite activate the bainite reaction while the grain refinement retards it. Intensity of the effect produced by each factor depends strongly on the steel composition."

Jan 1, 1997

By A. W. JR. Whitaker

Introduction Within the last quarter of a century the Lake St. John-Saguenay valley has been converted from a quiet agricultural district to one of the important industrial centres in the Dominion. First there was the expansion -of the pulp and paper industry, and then, starting a little over ten years, ago, the development, in large .blocks, of the enormous hydro-electric power resources of the Saguenay river. Coincident with this power development, the world aluminum industry was rapidly expanding and looking for a new source of cheap power. This was found in the Saguenay valley-and so, in 1925, Arvida was established by the Aluminum Company of Canada as a location for one of the largest aluminum plants in the world. Arvida, an incorporated city comprising an area of some ten square miles, is ideally located on a more or less level plateau about 350 feet above the Saguenay river. Seldom has industry stepped boldly forth and carved out of Nature a community with full city status. The process usually goes through the steps of camp, village, town, and city, involving improper planning or lack of planning; all of which has been avoided at Arvida by starting out in the right way. While this community has only a population of approximately 2,000 at the present time, it is carefully planned for a population many times this figure. Streets, city parks, business and residential sections, have been definitely planned, and, with a City government, proper ordinances were passed at the beginning to ensure the building and maintenance of a model industrial community. As the crow flies, Arvida is about 35 miles due east of lake St. John, and 0 miles west of the St. Lawrence river at Tadoussac. From a shipping standpoint, it is well served by the Canadian National railways, with direct lines to Quebec and Montreal, and by ocean shipping facilities at Port Alfred, which is about 15 miles to the east on the Saguenay river and is served by the Roberval & Saguenay railway. The latter has interchange connections with the Canadian National at Arivda, and also operates a branch line into the city of Chicoutimi.

Jan 1, 1933

By J. B. Platt

Many utility fuel choices 1990-95 defied expectations, with utility decisions and coal market developments ever more closely linked. The Central Appalachian coal boom never occurred; clean-enough coal was developed in the hard-hit Midwest; Colorado-Utah coal surged; Pittsburgh seam production strengthened; utilities embraced Powder River Basin coal; and emission allowance prices collapsed. Competition drove productivity gains, but the future is not a simple repeat. Phase 2 brings fewer viable compliance options. Mega-railroad pricing has become a key risk factor --will this be countermanded by merging utilities and power market competition? Revenue losses from vintage contracts are problematic. Uncertainty also plagues natural gas, in spite of unanimity across major forecasts, since recent experience has been so heavily influenced by the gas bubble.

Jan 1, 1997

By David G. Chedgy

The Meadow River No. 1 Preparation Plant, owned by Sewell Coal Company, a subsidiary of the Pittston Company, was commissioned in the spring of 1974. The plant is designed to process 400 TPH of 5" x 0 raw coal. The 5" x 114&apos;l fraction is processed in a Heavy Medium Vessel with the 114 x 28M reporting to Deister Tables for cleaning. The 28M x 0 fraction is cleaned in flotation cells, with the froth going to clean coal vacuum filters and the tailings to a static thickener where the underflow is reclaimed on Refuse Filters prior to disposal. The noise dosage a worker receives is determined by the ratio of the length of time the worker spends in a particular noise environment divided by the noise exposure in that particular environment. If the worker is exposed to several different sound levels, his total dosage would be the sum of each of the individual dosages. The equation for determining the dosage is: [ ]

Jan 1, 1976

By Susanne Pignolet-Brandom

Flash smelting products of a copper sulfide concentrate collected at successive levels in an experimental reactor have been studied by reflected light microscopy, scanning electron microscope - energy dispersive analysis and electron nicroprobe analysis. Chalcopyrite, intermediate solid solution, bornite, chalcocite, metallic copper, magnetite, iron-copper spinel, pyrrhotite, hematite, delafossite and cuprite have been identified in the product samples. The detailed reflected light microscopy study of these phases and their abundance in the samples has resulted in the identification of the series of reactions during flash smelting.

Jan 1, 1985

By Andrea Gambi, Giancarlo Olivucci, Maurizio Lenzi

"In the paper a criterion for the evaluation of the sharing of the lateral loads in a piled foundation is presented. It relies on the the compatibility condition between the rotation of the rigid pile cap and the rotations of the pile heads, following in that the criterion suggested by the Eurocode 8 - Part 5. This assumption leads to an analytical solutions which allows to deal with the sharing of the lateral loads and moments by means of two main interaction parameters only. A sharing domain is also derived and it shows the role played by the eccentricity of the lateral load on the values of the axial forces and of the bending moments at the head of the piles.INTRODUCTIONIt is well known that the interaction among soil, piles and foundation is one of the most complex subject to deal with in Geotechnical Engineering. Its rigorous study needs to employ suitable finite element software nowadays available and able to take into account the non linear behavior of the soil as a continuum and the inelastic response of the structure. A deep insight to the topic of the sharing of the loads cannot obviously renounce to this approach.On the other hand it is a daily need of the designers to have at their disposal simple tools that allow to make preliminary evaluations of the basic equilibrium conditions. To this purpose many methods of analysis have been developed in the past to face the sharing of the loads in a simplified version. The present contribution follows this way trying however to introduce some improvements that leads to find a solution that satisfies both the equilibrium of the forces and the compatibility of the movements (Lenzi, Gambi, Olivucci, 2002). The proposed model allows to identify the basic parameters which govern the sharing of the lateral load and it allows to perform also parametric analysis and quick checks that may be useful in the design of the piles."

Jan 1, 2005

By Carlos Del Río S

Se presume que el valor de los concentrados en tungsteno es afectado por un alto contenido de impurezas, generando considerables multas en el mercado minero. Por ello, el presente estudio señala la eliminación de estos sedimentos, a través de tres sistemas como el "leaching", la flotación y la separación magnética, donde además de obtenerse limpio el producto a costo de operación pequeña, se valoralizan los concentrados, evitando el pago de multas. Al tiempo que muestra la flotación de los sulfuros metálicos como el sistema más adecuado para separarlos de la hubnerita de los preconcentrados de la mina Pasto Bueno.

Jun 20, 1954

By W. Edwin Dill

For the mining industry, the Internal Revenue Code and regulations offer a range of choices in arriving at the allowable depletion. Each case is essentially unique. Two prerequisites can optimize these opportunities: communications between the mining company&apos;s tax specialists and its technical staff; and an understanding of IRS definitions. For the latter, a logical starting point is consideration of exploration and development, since they precede production and depletion is unallowable prior to production. Criteria for selecting engineering and accounting options for exploration and development indicate the necessity of interaction between these company functions to achieve the most favorable tax position.

Jan 1, 1982

By Liang Dong, Jinxuan Liu, Biao Qiu, Jing Chai

"The Cenozoic unconsolidated strata in the east area of China are composed of clay, sandy clay, fine sand, hardpan, etc. Numerous shafts of the coal mines in these areas have been damaged in various degrees since 1987. The main reason for this disaster is the vertical additional stress on shaft caused by the subsidence of the thick unconsolidated strata. In order to monitor the subsidence deformation of the unconsolidated strata, a sensing network system with multiplexed Fiber Bragg Grating (FBG) for monitoring settlement deformation of the unconsolidated strata in deep borehole is proposed. The field monitoring results show that, soil layers settle or expand with decrease or increase in ground water levels. The thick hardpan generates the main compressive deformation. This FBG strain monitoring method can take place of traditional ground water measuring method. This system is stable and reliable, and the monitoring results can show the subsidence deformation of different layers, which has significance for the predictive maintenance of the shafts.INTRODUCTIONSince 1980s, a specific geologic hazard has occurred frequently on the coal mine shafts in eastern China: non-mining-induced shaft deformation, involving up to 100 shafts located in Jiangsu, Shandong, Anhui and Herran province, distributed in Xuzhou, Datun, Huainan, Huaibei, Yanzhou and Yongxia coal fields. This kind of geologic hazard can lead to shaft wall deformation, water infiltration, cage stuck, water-sand burst or shutting down of coal mines, which seriously risks the coal mines. Zhangshuanglou coal mine, Haizi coal mine and Linhuan coal mine shut down for 2-8 months due to this hazard (Chen, 1997; Cui, 1998). The main reason for this geologic hazard is the subsidence of the super thick unconsolidated strata (Liu et al., 2007; Xu et al., 2006).An innovative structure health ·monitoring and damage estimation method has been developed in recent years, i.e., optical fiber smart material and structure (Nobuo, 2002; Wang et al., 2000). A Fiber Bragg grating (FBG) sensor is a device that can transfer the change of the measured strain or temperature to the change of Bragg wavelength. One of the most important applications of FBG sensors is to monitor the internal stress and strain distribution of material and structure (Philipp et al., 2000; Ansari et al., 1998). Compared to traditional electrical sensors, FBG sensors have many advantages; they are adaptable to harsh environments, abrasion resistant, immune to electrical magnetism (EM) interference, safe and reliable. They also offer integrated sensing and transmission on a single fiber, have simple structure and are convenient to use, which satisfies the requirements of long distance, distributional and long term use in monitoring mining and geotechnical engineering structure. Due to such advantages, the FBG sensor has already been applied in petroleum engineering (Kersey, 2000), rock mechanics testing (Cornelia et al., 2003; Yang et al., 2007; Wei et al., 2008), physical simulation experiments (Chai et al., 2007; Chai et al., 2006; Zhu et al., 2008; Li et al., 2008; Chang et al., 2008), strain sensor (Li et al., 2007; Chai et al., 2008) and construction structure damage diagnosis (Dong et al., 2004; Kerrouche et al., 2008; Whitten et al., 2001)."

Jan 1, 2010

By G B. Douglas

Lime-based neutralisation has long been the remediation treatment of choice for acidic mine pit waters. While suited to the attenuation of acidity, lime-based neutralisation may be difficult to implement efficiently due to variation in quality and the partial loss of neutralisation efficiency due to armouring. Large volumes of gypsum-bearing sludge may also require mechanical dewatering and transfer to final voids prior to resumption of in-pit mining or closure. Thus, operational costs may be substantially higher than primary neutralisation alone. Lime production also results in large greenhouse gas (CO2) emissions.Hydrotalcites (HT) are a class of Mg-Al layered double hydroxide minerals with the composition Mg6Al2(CO3 )(OH)16.4H2O. A range of other divalent and trivalent cations may also readily substitute for Mg (eg Cu, Ni, Pb, Zn), Al (eg Fe, La, Ce) and metalloids/oxyanions (SeO42-, AsO43 -/CrO42 -, MnO4-) for CO3 into the hydrotalcite structure. A common feature of acid mine pit waters, often overlooked in assessment of potential remediation options, is the frequent predominance of divalent and trivalent cations as a consequence of partial decomposition of both ore and gangue minerals during in-pit wall rock leaching. Thus, given the presence of substantial divalent and trivalent cations in acidic mine pit waters, an opportunity exists to exploit and in effect work harmoniously with the prevailing pit water composition to form a polymetallic hydrotalcite.The utility of hydrotalcites in the remediation of acidic mine pit waters lies in their ability to incorporate a wide range of contaminants; instantaneous formation, often in a single step; simple post-treatment solute composition; rapid settling; low sludge volume; and the potential to form ore-grade precipitates potentially amendable to reprocessing to (partially) recover remediation costs. Examples of hydrotalcite formation as a method to remediate contaminated acidic mine pit waters at laboratory-scale to full-scale will be presented.CITATION:Douglas, G B, 2015. Whither lime? In situ hydrotalcite precipitation as a method of remediation for acidic mine lakes, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 97–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By L. R. Gremillion

Chemical and mineralogical data on 25 apatitic phosphate ores of diverse origins from commercial deposits around the world were widely variable. From 14 to 18 chemical constituents of each sample were determined, and each sample contained 4 to 10 mineral phases. Altogether there were 34 different mineral phases, many of which occurred in only one sample. The samples contained varieties of francolites, fluorapatites, and mixed hydroxyl-fluorapatites. The apatite compositions calculated from the chemical data showed that certain types of substitutions were characteristic of different apatite varieties, but every variety had some degree of substitution of (CO3)2 for (PO4)3 and the P2O5 contents of the apatites ranged from 35.1% for a North Carolina apatite to 41.9% for a Missouri apatite. In a concentrate with a grade of 32% P2O5, the North Carolina sample should contain about 8.7% gangue and the Missouri sample about 23.7% gangue. To optimize the digestion process of a phosphate are, it is necessary to consider the dissolution behavior of the different mineral phases during acidulation and the effects they may have on the chemical properties of a fertilizer intermediate. In the production of wet-process acids or superphosphates, the acidulation of certain minerals may cause foaming and formation of sludge, filtration, corrosion, and handling problems.

Jan 1, 1978

By William M. Baldwin

Jan 1, 1946

By Roderick I. L. Guthrie, Donghui Li, Mihaiela Isac, Luis Calzado

The HSBC is an ideal process for the production of BMG strips. The purpose of the present work was to investigate the casting of Ca-based, bulk amorphous strips. The possibility of casting three Ca-based alloys (60Ca-20Mg-20Al, 60Ca-15Mg-10Al-15Zn and 55Ca-15Mg-10Al-15Zn- 5Cu (at.%).) was investigated, using the HSBC simulator. Numerical simulation and mathematical modeling were used to predict temperature variations and cooling rates, under different interfacial gaseous atmospheres (helium and air) near the meniscus region. Given the critical cooling rates and glass temperatures needed to be reached for the vitrification of the respective alloys, this leads to predictions of the critical thicknesses possible with this novel casting process. To validate our predictions, these alloys were then prepared and cast onto the sand-blasted, solid copper substrate mould of the HSBC simulator. The possibility of producing Ca-based metallic glassy strips via the HSBC processes was confirmed, using optical microscopy, X-ray diffraction and Scanning Electron Microscopy, to characterize the glassy properties of the cast strips. It was found that the HSBC process would be able to provide sufficient cooling to form amorphous strips for the 60CA-15Mg-10Al-15Zn and 55Ca-15Mg- 10Al-15Zn-5Cu alloys, but not the 60Ca-20Mg-20Al alloy.

Jan 1, 2014

By Sam H. Patterson

Fuller&apos;s earth and bentonite are two clay commodities that are interrelated either by mineral composition or use. Because of this interrelation and the sale of both for many different uses, some ambiguity in their classification has resulted. The term "fuller&apos;s earth" has no compositional or mineralogical meaning, and it is used more or less as a catchall for any clay or earthy material suitable for certain uses. Most, but not all, of these uses require absorbent properties. Bentonite by geologic definition must have formed from volcanic ash or tuff or the glassy material in volcanic rock; most bentonites consist chiefly of montmorillonite but other clay minerals may be present. In industrial usage the term "bentonite" is applied to any clay consisting chiefly of montmorillonite, irrespective of origin. Georgia and Florida have historically been the leading States in the production of fuller&apos;s earth; bentonite has been produced in Alabama on a small scale. The first major use of fuller&apos;s earth was in refining of oils. Other materials have replaced fuller&apos;s earth for this purpose to a major extent, but many new uses for fuller&apos;s earth have been found, and production has increased in recent years. The new uses include absorbent products, insecticide and pesticide carriers, drilling mud, and many others. The bentonite now produced in Alabama is of the "southern," "low selling," or "calcium" type and is used mainly as foundry-sand bond. Most of the fuller&apos;s earth mined now is in the Hawthorn Formation of Miocene age; a lesser amount is produced from the Twiggs Clay Member and other beds in the Barnwell Formation of Eocene age. Inactive pits from which fuller&apos;s-earth was produced from other formations occur at several localities. The bentonite now mined in Alabama is in beds of Cretaceous age; several years ago bentonite was produced from Eocene beds in this State.

Jan 1, 1972

By Steven J. Schatzel, Mark M. Mazzella, Robert A. Kimutis, VASU GANGRADE, James D. Addis, Marcia L. Harris, Mayley Guitard

Researchers from the National Institute for Occupational Safety and Health (NIOSH) evaluated the impact of potential shale gas well breaches and subsequent gas inflow on selected mine ventilation systems of operating longwall panels using a 1:30 scaled Longwall Instrumented Aerodynamic Model (LIAM) and Sulfur hexafluoride (SF6) as a tracer gas. A series of tests were performed at 340, 400, and 500 cfm inflow levels utilizing different mine ventilation scenarios. Results suggest that the breached gas can be diluted to meet statutory levels when the longwall panel is adequately ventilated. The results enhance the understanding of the gas inflow and mine ventilation system interaction and provide critical information to the industry and regulatory agencies for improving miners’ safety.

Feb 1, 2024

By CorrOa de Araujo A, Salum MJG

The treatment of mining and metallurgical liquid effluents is becoming, everyday, a necessity felt by these industries. Physical-chemical and chemical methods for treating such effluents are generally necessary whenever heavy-metals and other toxic compounds such as cyanide are present. The present paper discusses the use of precipitate flotation as an alternative physical- chemical method that can be applied for the treatment of effluents containing heavy-metals (mainly zinc and cadmium) and cyanide. Examples of laboratorial scale applications on real effluents are given. In both cases precipitate flotation was able to reduce the concentration of toxic components of the effluents at a very high removal rate, generating a solid waste that can either be disposed, re-used or recycled. A cationic collector - dodecylamine hydrochloride - demonstrated to be the best choice of surfactant for the two systems investigated. Sodium sulphide and dithizone were selected for the precipitation of the zinc bearing effluent whereas a copper salt was preferentially used for precipitating cyanide in a form adequate for its recycling envisaging the use of an AVR (acidification - volatilisation - regeneration) technique.

Jan 1, 1993

By Mike Dry, Rod Dry

If humanity is truly serious about reducing emissions of carbon dioxide into the atmosphere, today’s power plants burning fossil fuels will have to be replaced by power plants that do not emit CO₂. Unless carbon capture/sequestration becomes practical, the new power plants will be hydroelectric, wind, solar or nuclear installations. Hydroelectricity requires the appropriate geography. Solar installations can only deliver power as and when sunshine is available, and wind installations when the wind blows. Therefore, power from these sources will be intermittent, but the demand for electricity does not follow the patterns of sun and wind. That will require large-scale electricity storage and/or load following by the remaining power suppliers, increasingly so as the use of fossil fuelled power generation declines. Modern nuclear power plants are designed for demand following. However, operating at lower than design output has a negative impact on the economics of nuclear power plants because the overall cost of the electricity they generate is dominated by capital cost. Primary (blast furnace) iron smelting is responsible for a significant part of global CO₂ emissions because the reagent used is carbon. Were it available in sufficient quantity (and at a low enough cost), hydrogen could replace carbon in the manufacture of raw direct reduced iron (DRI), using technology such as modified HYL (Tenova Hyl, 2018) or Midrex (Ravenscroft, 2017). This paper examines a scenario in which, instead of demand following, nuclear power stations are operated at their design capacities and surplus power is used to generate hydrogen in off-peak periods. This hydrogen is then used to replace carbon in the manufacture of raw steel.

Jan 1, 2020

By Yuanbo Zhang, Yikang Tu, Zijian Su

Stainless steel swarf is a typical by-product produced from stainless steel processing, which contains a significant level of valuable metals, such as iron, chrome, and nickel. About 1 million tons of stainless steel swarf are generated in China annually, but as mixed with impurities such as Al and Si, stainless steel swarf is not suitable to be directly smelted into stainless steel through refining process. In this study, stainless steel swarf was applied as a strengthening agent during limonitic laterite sintering process. The effects of adding stainless steel swarf on green bed permeability, the yield and quality indexes of the sinters, and the microstructure of the sinters were evaluated systematically. The results showed that the concentrated distribution degree of granules and green bed permeability were improved after adding stainless steel swarf. As the additional amount of stainless steel swarf increased from 0 to 3%, the tumble index and yield of the sinters rose from 50.07 to 54.69% and from 62.04 to 67.35%, respectively. The addition of stainless steel swarf would not change the phase compositions, and had little adverse impact on the metallurgical properties of the limonitic laterite sinters.

Aug 23, 2023

By I. J. Wu

China’s land area, comparable in size to United States or Canada, contains diverse geological environments and mineral resource potential. The diversity in geological environments is such that the potential for developing many world-class mineral deposits in China is good. However, China’s mining sector was not open to foreign investment until the1990s. The long-term prospect for Chinese resource development is attractive because of China’s enormous population and cumulative demand for minerals. Approximately 33 foreign mineral companies, including 11 major internationals, are to various degrees active in China. Chinese mining laws and regulations pertaining to joint ventures with foreign companies are, from the international investment prospective, evolving slowly, but positively. This positive trend is continuing under the current government reform process, which is moving China towards a freer market economy. Although improving the enforcement of relevant laws and regulations is an ongoing process, the environment for mineral investment and joint ventures is increasingly more accommodating to foreign companies.

Jan 1, 2000