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By M. Hopf, E. Rossouw

Keywords: Pyrometallurgy, furnace, copper coolers, freeze lining, monitoring, Saveway The use of water-cooled copper components as sidewall elements of submerged arc furnaces and other pyrometallurgical applications has become increasingly common. The high cooling efficiency of copper has made it possible to increase the service life of furnace refractories when compared to conventional refractory linings. However even the self-healing effect of ?freezing? worn areas of the lining does not necessarily protect the copper coolers against wear or corrosion completely. In order to avoid furnace explosions, various methods have been used to monitor the wear of coolers. Unfortunately, these have not been able to consistently identify localized wear. Thos Begbie (South African) and SAVEWAY (German) jointly developed technology to embed a line sensor into the copper cooler during the casting process. This system allows an exhaustive monitoring of the copper cooler. A SAVELINE sensor is placed inside the copper-cooling panel between the water-cooling passage and the hot face of the panel. The sensor follows the meandering shape of the cooling water channels. In the first instance, the sensor provides analogue information as the thickness of the copper reduces. Secondly, this wear signal will be confirmed by a signal of interruption if the sensor is washed away. Because of the structure of the sensor, a self-diagnosis is possible and indications can be confirmed (double proofed). Subsequent to the manufacture of some test pieces, coolers for a large submerged arc furnace were manufactured. The sensorized coolers have been installed at the intermittent surface (slag line) where the largest amount of corrosion has been encountered. The system has been operating since December 2005 in what is considered one of the largest submerged arc furnaces in South Africa.

Jan 1, 2006

By W. O. Philbrook, A. H. Jolly, T. R. Henry

In the course of a study of slag-control methods, the authors devised a laboratory technique by which the basicity of basic open-hearth furnace slags could be estimated with sufficient accuracy to make the method of possible interest for slag-control purposes. The process consisted of measuring the slight basicity of an extract of the powdered slag in water. The procedure was presented, for the benefit of those who might care to experiment with it, in a paper submitted in the 1944 McKune Award Contest and presented at the 1944 Open-hearth Conference in Pittsburgh.' Interest expressed at that meeting and favorable operating experience with the method at a neighboring plant, as described in a related paper by Michael Tenenbaum and C. C. Brown,; have encouraged us to present further details of the development, technique, and pitfalls of the method and some additional data not included in our first report. At the outset it must be admitted that this method of estimation of slag basicity is not perfect; neither is any other that we know of. It is subject to somewhat greater errors than would be desirable, but compares favorably with other techniques in this respect. It has the disadvantage that it places the final determination of slag basicity in the hands of a laboratory technician rather than the furnace oper- ator, although it can be operated in a control laboratory adjacent to the furnaces. It requires close attention to certain details, as do most laboratory procedures. On the favorable side, it eliminates the "human factor" of personal judgment inherent in estimation from pancakes or powdered samples. The procedure can be placed in practice much more rapidly and presents much less of a training problem than visual methods of estimation. The principle and operation of the method are so simple that it would not be surprising if others have experimented with the same or similar procedures, but we are not aware of any prior publication of details. Our own shop has been operating fairly successfully for several years with the aid of slag pancakes. Since the past year or two have not been favorable for the expenditure of time and energy where the need was not urgent, we have not introduced the new practice for actual slag control and hence do not have extensive operating data. In presenting this method, therefore, we make no claims as to theoretical justification nor guarantees as to practical applicability, but offer it as an empirical observation. We believe it has sufficient merit to warrant its investigation by those just instituting a slag-control program or in search of supplementary methods for judging slag basicity Principle of the Method It is well known that when burnt lime or slaked lime is shaken up with water it

Jan 1, 1945

By Bruce Watzman

Can the United States mining industry achieve its long-stated goal of zero fatalities ? and what will it take to do so? Does it require new laws and regulations, as some propose, and a continuation of the commandand- control model that has been born out of more than 40 years of regulation and enforcement under the Federal Mine Safety and Health Act of 1969? Or, is it time to consider a new model to manage safety and health and drive continuous, sustained improvement? These are questions that many are debating as mine safety performance, while improved, appears mired in a trough where improvement followed by declines seems to have become the rule rather than the exception. Without doubt, U.S. mines have made significant progress in safety performance during the last four decades, yet the stalled decline in fatality numbers, the industry?s report card of its success or failure, has led some to question whether the industry will achieve zero fatalities in U.S. mining by relying solely on the Mine Act?s framework and implementing its regulations. These are questions the CEO-led task force, set up by the National Mining Association (NMA), considered as it sought to identify impediments to zero fatalities posed by the current regulatory regime. Out of that effort came CORESafety, a common safety and health framework that relies on a management system approach to improve safety and health performance. The goal of CORESafety is to achieve zero fatalities and a 50-percent reduction in the rate of injuries in U.S. mining within five years ? 0:50:5. CORESafety is built on the plan-do-checkact model, which has been successfully deployed by industries, mining and nonmining alike, to drive continuous improvement in safety and health performance. The improvements in safety performance that can be achieved by shifting from a command-and-control regulatory approach to a risk-based systems approach built on the plando- check-act model have been documented in numerous industries. For example, the United Kingdom quarrying industry (Fig. 1), not satisfied with the number of reportable accidents being experienced 1995-2000, established a hard target of a 50-percent reduction in the number of reportable accidents during the period 2001- 2005. Having met this target, the industry then established a further target zero for the period 2006-2010. The mechanism to achieve these reductions? The plan-do-check-act model.

Jan 1, 2014

ASDIE from the John Fritz Medal, in which the Institute participates through its representation on the John Fritz Medal Board, the Institute itself has four awards it may make annually, as follows: the Robert W. Hunt Medal and Prize, the J. E. Johnson, Jr., Award, the James Douglas Medal, and the William Lawrence Saunders Medal. Robert W. Hunt Medal and Prize The partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules: 1. The award shall consist of two prizes: first of a gold medal, second of a sum of money; a certificate to accompany each prize. The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age. In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal. 2. The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel. The scope of the term "iron and steel" shall be determined by the subcommittee considering the awards. In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt's main contributions to the industry have been in the improvement of production and quality of material. 3. A subcommittee of three to five, including the Chairman of the Iron and Steel Committee, shall be appointed by the Iron and Steel Committee annually to adjudge the award subject to approval. 4. The awarding committee shall submit its report to the Iron and Steel Committee at its October meeting, and the award shall be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of the Institute. 5. The recipient of the award shall be designated "The Hunt Medallist." This prize is administered by the Iron and Steel Division. Awards of the medal have been made as follows: 1920—Robert Woolston Hunt. 1926—Charles Lewis Kinney, Jr. 1928—John A. Mathews. 1929—Edgar Collins Bain. J. E. Johnson, Jr., Award This award is made from the income of a fund of $3000 donated by Mrs. Margaret Hilles Johnson in memory of her husband, J. E. Johnson, Jr., who was a prominent engineer, author of two valuable volumes on iron blast-furnace construction and practice, vice-chairman

Jan 1, 1929

By N Cusworth

The development of a resource project inevitably requires the investigation of a vast range of issues across most engineering disciplines û mining, metallurgical, chemical, civil, electrical, mechanical and environmental û as well as the geosciences. It is also a characteristic feature of the resource industry that no two orebodies û and hence no two development projects û are the same. So these technical issues have to be addressed to a greater or lesser extent in evaluating any resource projectÆs development potential. Not surprisingly then, technical issues tend to predominate when assessing the development potential of a project in the process typically referred to as ædoing a feasibility studyÆ. But the principal purpose of a æfeasibility studyÆ is to determine whether a development opportunity makes good business sense, not just whether it is technically possible. Resolution of technical issues is often seen as the primary focus of a feasibility study, whereas in reality, these technical issues are the basis upon which an asset delivery and business plan is built. This is not to say that technical issues are unimportant û they are a prerequisite to the demonstration of a projectÆs viability. The feasibility study process must therefore demonstrate that not only have the technical issues been satisfactorily addressed, but also that the broader commercial, economic and social issues have been considered in the development of a comprehensive business plan, which includes an assessment of the risk-reward profile of the proposed development. This paper will present a framework for the conduct of æfeasibility studiesÆ and provide guidance to minimum standards and best practice.

Jan 1, 2007

By A B. Opperman

For many years explosives energy has been utilized in mining and construction as well as many other applications which are vital to our way of life. Many types of explosives have made their contribution as technology has moved forward. One of the best known was dynamite, which for many years was the mainstay of explosives users. Although dynamite had many advantages over its predecessors, it had the principal shortcomings of being somewhat hazardous to handle and was known as a headache producer.

Jan 1, 1975

By A Hekmat, R Castro, A Casali, R Gómez

Block caving is the most economic underground methods for excavating massive orebodies, due to the high productivity and low production costs. The success of block caving operations depends on the fragmentation and draw control as large blocks decrease the equipment efficiency, inhibit the material flow and may lead to expensive secondary blasting. Even though ore handling system design, as well as overall economic results, both critically rely on secondary fragmentation, this parameter continues to be one of the least understood issues in the caving operations.This research focuses on the experimental study of secondary fragmentation, considering the impact of vertical pressures and material flow. Experiments using a load-haul-dump extraction system were conducted under laboratory conditions to quantify the influence of pressure and particle size on secondary fragmentation. Results demonstrate that increasing the vertical pressure (simulating deeper conditions) leads to higher fragmentation (smaller particle size) and greater fines generation during draw. The experimental results were applied to calibrate the developed mathematical model based on kinetic matrix. The acceptable accordance between the comminution model results and the reality showed that this method is convenient in predicting the secondary fragmentation in block caving.CITATION:Castro, R, Gómez, R, Casali, A and Hekmat, A, 2016. Experimental and comminution model framework for secondary fragmentation prediction in block caving, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 175–182 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By George B. Clark

Many basic engineering principles of all four phases of mining operations, namely, prospecting, exploration, development, and exploitation, can be analyzed better in terms of quantitative geology. Geological data from both field and laboratory will also complement scientific methods now being developed. THE geological data emphasized so successfully in prospecting for new deposits, that is, structural controls, strength of solutions, and type of mineralization, are basically those required for successful exploitation. In the mining of newly discovered deposits the most economical methods should be employed as early as possible to keep the overall cost per unit produced at a minimum and to permit maximum extraction of valuable minerals. A crucial question is: How can geological data be translated into useful quantitative results which will aid in achieving this end? H. E. McKinistry' has suggested that a solution may be reached in one of two ways: 1—the usual approach, use of judgment based on experience; or 2—mathematical calculations and tests on models, both subject to certain limitations. He also suggests that in addition to better use of geology more case data and theoretical data are needed on which to base sound judgment. Further research, therefore, is necessary. Perhaps in this field the emphasis should be on more specialization in mining methods and ground movement by men with thorough training in physics, engineering, geology, and underground mining. These specialists would be equipped to point out the most economical and scientific methods of exploitation. Selection of a stoping method is governed by the amount and type of support a deposit will require in the process of being mined, or by the possibility of employing the structure of the deposit to advantage in mining the ore by a caving method. In addition to these factors there are others which almost invariably influence the choice of an economical method of mining:' 1—strength of ore and wall rocks; 2—shape, horizontal area, volume, and regularity of the boundaries of the orebody, and thickness, dip and/or pitch of the deposit and individual ore shoots; 3—grade, distribution of minerals, and continuity of the ore within the boundaries of the deposit; 4—depth below surface and nature of the capping or overburden: and 5—position of the de- posit relative to surface improvements, drainage, and other mine openings. In the final analysis it is usually necessary to disregard the less important of these factors to satisfy the requirements of the more important. Because of the variation of geological conditions throughout and surrounding the deposit, no mining method will be everywhere ideally applicable to the conditions encountered in one ore deposit. The immediate problem is to interpret the above physical characteristics of deposits in terms of geological characteristics. Very few quantitative geological data are available on the factors related to a choice of mining methods. However, there are many descriptive data in mining and geological literature which collectively show how important an effect details of geology have upon all phases of mining operations. The following categories of basic mining methods were investigated to establish the geological factors that have affected their successful application: 1— open stopes with pillars; 2—sublevel stoping; 3— shrinkage stoping; 4—cut-and-fill stoping; 5— square-set mining; 6—top slicing and sublevel caving; and 7—block caving. It should be noted that the first five of these methods are listed in the order of increasing support requirements. Mines were selected as examples only where geological descriptions were complete enough to warrant their use. A study of the geological factors involved in mining operations led to a choice of the following classifications, employed in Table I: 1—structural type of orebody; 2—dimensions (geometry); 3— country rock (type); 4—faulting, folding, and fracturing; 5—alteration of ore and rock; 6—type of mineralization; and 7—geological factors determining mining method (summary). Of these factors only one yielded results that can be defined from available data in a quantitative manner, i.e., dimensions of the deposit. These are the most reliable guides that can be used in selection of suitable mining methods. They are, in general, the properties of geologic structure most difficult to evaluate by studies of models, pho-toelastic studies, and other laboratory methods, all of which are at present more limited in their applications than the geologic method. Application of geology has proved a reliable guide in other phases

Jan 1, 1955

In a field test at Mount Isa Mines Ltd., a system developed by ICI Australia Ltd. for bulk loading "MOLANITE", an ammonium nitrate slurry blasting agent into ring drilled holes of wblcvel open stopes, was shown to be satisfactory. The fragmentation produced by the slurry was a significant improvement over ANFO and the stope production rate was increased by approximately 50%. Indications are that the charging rate and labour costs will not be greatly changed if a slurry system is used.

Jan 1, 1973

By B. Soundara, A. Suganya, S. Selvakumar

"Expansive soils have a potential for shrinkage or swelling under changing moisture content. Attempts were made to reduce the swelling potential of expansive soils with conventional additives such as lime, cement, etc. and non-conventional additives such as industrial wastes. In this research an attempt is made to study the feasibility of using granulated waste expanded polystyrene (EPS) as an additive to expansive soil to control swelling. To investigate the effect of mixing waste EPS granules with expansive clays, three expansive soils with different plasticity index were manufactured in the laboratory by mixing sand with sodium bentonite of various proportions. A series of standard proctor test, California bearing ratio (CBR) test, one dimensional free swell and swell pressure tests were performed on these soils. Test results show that the inclusion of EPS granules significantly reduces the percent swell and swelling pressure when subjected to one-dimensional free swell conditions. The dry density and CBR values decrease with increase in EPS content and increased plasticity of the soil.INTRODUCTIONExpansive soils cover an area of about 257 Million hectares on the earth’s surface (Dudal et al. 1965). In India, the area covered by expansive soils is nearly 20 percent of the total area (Mohan et al. 1961). Movement is usually in an uneven pattern and of such a magnitude as to cause extensive damage to various structures, especially lightly loaded structures or pavements (Chen 1975). Stabilization is one of the methods of treating the expansive soils to make them fit for civil engineering purposes. The variety of stabilizers may be broadly divided into three groups (Petry et al. 2002): (a) traditional stabilizers (lime, cement etc.), (b) by-product stabilizers (fly ash, quarry dust, phosphor-gypsum, slag etc.) and (c) non-traditional stabilizers (sulfonated oils, potassium compounds, polymer, enzymes, ammonium chlorides etc.). Apart from these, a number of other ground improvement techniques such as sand cushion technique (Satyanarayana 1966); cohesive nonswelling (CNS) layer technique (Katti 1978) were adopted for the stabilization of expansive soils. Expanded polystyrene (EPS) is a polymeric foam normally available in white colour and is a wellknown packaging material. The geotechnical specialists recognize EPS as the most commonly used geofoam material, a type of cellular geosynthetic which has been in consistent use in geotechnical applications since the early 1960s (Horvath 1995). EPS has very low thermal conductivity and nearly 98% of the volume is air (Lye et al. 2002). EPS has many exceptional properties such as being lightweight, thermal insulating, shock-absorbing and having low-water pick-up, etc. EPS find its applications in geotechnical engineering as light weight fills in the form of blocks (Refsdal 1985, Karpurapu et al. 1992, Zou 2001, Ikizler et al. 2008). EPS can be used as compressible inclusion and as a vibration damper (Horvath, 1994&1995). EPS is also used in lightweight concrete owing to its lightweight, excellent heat preservation and sound insulation properties (Ravindrarajah et al. 1994; Miledet al. 2004 and Babu et al. 2005). Waste EPS granules have been used in with horticultural soils to improve a number of soil characteristics like improving drainage, lightening heavy soils and improving water uptake capacity of soils (Scheirs 1998). Furthermore, it was also used as sub-base materials for pavements and railway track beds (Hanna 1978; Duskov1996), construction materials for floating marine structures and fenders in offshore oil platforms (Bagon et al. 1976), sea beds and sea fences; as an energy absorbing material for buried military structures, (Perry et al. 1991)."

Jan 1, 2017

By R. Altındag, D. Akbay

The point load index is a simple, fast, and inexpensive method for determining rock strength and can be applied both in the field and in the laboratory. There are, however, some disadvantages and limitations to the method, and the test results can be affected by the person carrying out the test, the rock characteristics, or the test device. In this study we describe an investigation into how the point load index value is affected by the shape of the conical platens used in the test. Point load index tests were carried out using different devices fitted with conical platens of different spherical radii, and on a modified device which circumvented the limitations/disadvantages. It was seen that the point load index value increased as the platen radius increased, as expected. In the case of testing using non-standard conical platens, an equation is proposed to normalize the point load index value with respect to the standard spherical radius value.

Nov 1, 2021

By F. T. Cawood

This article is a continuation of a series of publications by the authors on the international debate on resource nationalism, with specific reference to South Africa. Previous outcomes have shown that mine nationalization is not a solution for South Africa, and that maintaining stability of the current mineral and tax regimes is fundamental. It will not be wise to replace existing law and policy instruments until there is a better understanding of the distinction between fact and public perception about the impact of the current system. The new scheme of state custodianship linked to a mining royalty that effectively targets economic rents provides for effective resource use. The methodology in this article is to consider how South Africa's mineral tax regime can be tweaked to achieve optimal management and benefit from mineral extraction and associated rents by avoiding changes feared by investors. The major finding is that the current suite of instruments can be considered a suitable platform for optimal management of resource rents. However, it will be necessary to first investigate ways of improving the mineral beneficiation intent of the royalty structure, and secondly investigate whether the mineral rent portion of the royalty formula can be ring-fenced for the purpose of establishing a sovereign wealth fund.

Jan 1, 2013

By Masayuki Ishikawa

In a radio frequency and optoelectoronic device packaging, Gold-Tin (Au-20 wt% Sn eutectic) solder is used widely due to the excellent electrical and thermal conductivity, high strength, and negligible creep characteristic under repetitive thermal cycling. With the recent lead-free movement, Gold-Tin solder is recognized as an alternative material for high temperature Lead-Tin solder. Generally, Gold-Tin solder is supplied in the forms such as ribbons, pellets, and ring frames. However, these forms must be set-up accurately on the joint area to press chips in bonding, therefore, it is difficult for these forms to satisfy the recent requirements for the down sizing in the connection areas. On the other hand, Au-20 wt% Sn solder paste can be applied flexibly to various supplying methods, such as printing, dispensing system and pin transcript. These methods also make it possible to reduce the production cost. However, in the case of using the solder paste, the void issue is one of the most undesirable problems. The void causes the degradation of the characteristics such as the bond strength, electrical characteristic and thermal conductivity. We have been intensifying the development of the void free paste, and have achieved void reduction by optimizing the powder size, the flux composition and the reflow condition.

Oct 1, 2003

By James Paone

Subsidence movements have damaged houses, schools, streets, and public utility lines in some undermined sections of Belleville and Maryville, Ill. In cooperation with local officials and the State of Illinois, the Interior Department's Bureau of Mines is sharing experience in backfilling abandoned coal mines to demonstrate that bituminous coal mine workings in south-western Illinois can be successfully backfilled and subsidence-prone areas stabilized. Subsurface investigations revealed that mine workings are dry and underlain by underclay deposits susceptible to instability upon wetting. Backfilling will therefore be accomplished by pneumatic injection instead of the hydraulic methods used in previous subsidence-control projects.

Jan 1, 1977

Beaches contain the residue of eroded rocks which have resisted weathering, and it is common to find in all beaches some of the harder, heavy minerals. The natural sorting action of waves and winds tends to concentrate the heavy minerals into banded deposits.The value of such deposits is extremely variable. Even amongst the more concentrated deposits, the principal minerals, in the vast majority of cases, are magnetic, titaniferous magnetite and other forms of iron oxide, which, in the present state of mineral economics and technology, are of little or no value.Valuable minerals of fairly common occurrence in beach sand deposits are rutile, zircon, ilmenite, monazite and chromite, and each of these minerals, as well as others of less common occurrence, is obtained from beach deposits in various parts of the world.Along a stretch of 300 miles of coast from Coff's Harbour in New South Wales to North Stradbroke Island in Queensland, occur unique concentrations of heavy minerals. The principal minerals which occur are rutile, zircon and ilmenite, and for some years these deposits have contributed half to three-quarters of the world's consumption of rutile and zircon 1, ,2. The only other notable beach sand concentrations in Australia are at a number of places in the southwest of Western Australia, where deposits containing highgrade ilmenite are being developed.

Jan 1, 1950

By M. Moats

Copper electrowinning operations have dramatically improved their ability to produce high quality copper at low costs over the past several decades. Even so, some fundamental understandings are still lacking, which could allow operates to run more efficiently. For example, a rule of thumb exists that estimates a current efficiency loss of 2-3% per gram per liter of iron in the electrolyte. While several laboratory studies have been performed that demonstrate this rule of thumb is likely true, no definitive relationship exists. In this paper, the first steps in developing a definitive relationship are presented. The effective diffusivity of ferric ions in synthetic copper electrowinning solutions was measured using chronoamperometry and the Cottrell equation. The effective diffusivity of ferric ion was determined as a function of electrolyte concentration and temperature. Synthetic electrolytes were then used in laboratory scaled copper electrowinning experiments where relationships were found under stagnant conditions between current efficiency and solution composition.

Jan 1, 2009

By Stefan K. Schwank

The paper describes the two foundation techniques - mini piles and postgrouted bored piles. The mini pile system is presented with its design and installation parameters, especially the drilling technique. Two case histories demonstrate the application under extremely limited space and traffic conditions and the required modifications of the equipment. After the description of the postgrouted bored piles and its grouting technique, the paper gives a comparison of postgrouted piles and standard piles on a large basic test in Germany. The Brooklyn Queen's Expressway, N.Y., case history shows the application of this technique after redesign of the original proposal. 1. General Increasing requirements to improve existing foundations to carry additional loads and to increase the bearing capacity of bored piles leads to two new piling techniques: the mini-pile and the post grouted bored pile.

Jan 1, 1991

By D. K. Sarkar, Ying Huang

"Superhydrophobic thin films were fabricated on aluminum alloy substrates by chemical etching followed by passivation with organic acid molecules; (ii) electrophoretic deposition (EPD) of functionalized ZnO nanoparticles and (iii) electrodeposition of organic-inorganic composite materials. The physical and compositional analyses of the deposited thin films were characterized by SEM, FTIR, XRD as well as contact angle goniometer. The contact angle and surface roughness of the superhydrophobic surfaces prepared by the chemical etching process were found to be 156° and 2.29 µm, (ii) by the EPD process were found to be 155° and 4.54 µm and (iii) by the electrodeposition process were found to be 159° and 7.11 µm, respectively.The corrosion properties were analyzed with both polarization and electrochemical impedance spectroscopy (EIS) in NaCl aqueous solutions. The results demonstrate that the superhydrophobic thin films on aluminum alloy substrates display better anti-corrosion behavior than the as-received aluminum substrate. The comparison of results pertaining to the compositional and corrosion properties of these thin films on aluminum will be discussed in this work.INTRODUCTIONSuperhydrophobicity is defined as a surface property which provides non-wetting characteristics with a water contact angle larger than 150°. It is observed that the creation of certain micro-nanoroughness structures promotes the entrapment of air in the spaces of the rough surface morphology. In addition, lowering the surface energy helps to reduce the affinity of water drops to the surface, thereby weakening the water-surface interaction. Recently, various fabrication methods for superhydrophobic surfaces have been explored (Sarkar, 2010, Huang, 2010, 2011, 2013, 2015a, 2015b), such as the sol-gel process (Brassard, 2011), plasma treatment (Marchand, 2013), chemical vapor deposition (Zheng, 2009), chemical etching (Saleema, 2011), electrodeposition (Ying, 2011) and electrophoretic deposition (EPD; Huang et al., 2015b)."

Jan 1, 2016

By J. Wong

We report a successful use of x-ray absorption spectroscopy to probe the chemical and structural environment of trace elements in coal. When applied to vanadium in coal, it was found that vanadium exists in at least two environments: a trivalent site 6-fold coordinated by oxygens at ca. 2.0~ and a tetravalent site 5-or 6-fold coordinated also by oxygens, one of which forms a short V=O bond at ca. 1.6a. No evidence of nitrogen (porphyrin)1'or sulfide environment was found. It was also found that the vanadium environ-ments in the raw coal did not survive unchanged in a liquefaction process. These findings have implications for coal cleaning processes and for trace element release into liquefaction process streams.

Jan 1, 1982

By Walter D. Holland

This study was undertaken to determine miners' breathing zone concentrations of diesel exhaust components, to investigate any relationships between these concentrations and vehicle type, the presence of emission controls, vehicle usage, and ventilation conditions, and to make recommendations for monitoring and ventilation requirements. Twenty-four mines including two con l mines were surveyed. Sampling was done for CON, NON, SOx, PNA, aldehydes, and particulates. hi most mines, concentrations of at least one contaminant exceeded one half the standard or TLV. The concentrations of gases arc probably sufficiently reduced by a minimum air velocity of 50 fpm. A sufficient reduction of particulate concentrations may require as high as 400 fpm air velocity. Vehicle age, type, or usage appear to have little or no effect on contaminant concentrations. PNA levels were below detection limits in all but a very few samples. Minimum requirements for routine monitoring should include formaldehyde, COx, NO2. It is further recommended that better definition of the minimum ventilation requirement be obtained.

Jan 1, 1978