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By Robert A. Pond

Heavy (exceeding 35 tons) roadheaders have not seen much use in the United States, but are used extensively in Europe to excavate many types of underground openings in civil and mining applications. Early models of roadheaders were light and suitable only for utility excavation such as drift enlargement or chamber excavation, unless the ground was very soft and easily cuttable. Frontier-Kemper Constructors, Inc. is now using a 45-ton roadheader to excavate two mine slopes in Kentucky and a 70-ton roadheader to excavate a long decline at a new mine in Utah. Results to date indicate that heavy roadhead machines are an effective alternative to both conventional excavation and full-face boring machines in many cases; and where circumstances are favorable are a superior choice. This paper concentrates on applications in the mine development construction industry, but the conclusions are no less valid for civil construction.

Jan 1, 1983

By W. G. Huang

To recover the coal resources of high-sulphur anthracite in Jincheng Mining Area, underground coal gasification (UCG) of No. 15 seam in Fenghuangshan Coal Mine was proposed. The feasibility of the project was confirmed by investigations of occurrence conditions, coal properties, and roof conditions, as well as experimental studies and theoretical analysis. It was found that UCG technology is appropriate to be adopted in the mining of the No. 15 seam, due to the stable rock conditions, simple geological structure and hydrogeology, the high carbon content of the coal, non-cohesiveness, medium-thermal stability, high ash fusion temperature, and weak reactivity with CO2. Further factors are the characteristics of the immediate roof, which consists of 9.11 m of limestone and mudstone with a compact structure and low permeability, and 4.27 m of dominantly mudstone with low permeability.

Jan 1, 2012

By S. D. Viljoen

The use of ceramics to protect equipment subjected to wear in abrasive and corrosive applications has been accepted by most plants as the industry norm. Little is, however, known about alternative special ceramic based products which are available for the protection of plant assets. With careful engineering, impact resistant ceramics can be used in high impact zones using modern ceramic technology. Properly selected and properly installed, ceramics will provide a tough wear resistant lining for protection against abrasion and impact. Basalt, on the other hand, is widely used in coal washing plant process pipes with varying degrees of success. Basalt is normally not used for the lining of bends, ?T? pieces or reducers due to the reduced wear resistance compared to alumina ceramic. The advantage is a much reduced initial capital cost. A patented ceramic composite non-return valve solved an old problem encountered in the operation of medium sumps. The design approach overcomes the lack of functionality of alternative designs and reduces valve wear while preventing medium settlement during plant shutdown periods. Direct bonded ceramic pulley lagging is becoming the industry norm, eliminating most of the problems encountered with conventional pulley lagging systems.

Jan 1, 2010

By Steve Kral

As the current boom in the global mining industry rumbles on, mining companies have had to step up their efforts to replace mined reserves. Many of the majors are replacing and adding to their reserves and resources through acquisitions. This situation has allowed junior mining and exploration companies to do what they do best. They have been re-examining once uneconomic gold, copper and other metals properties with an eye to partnering with a major to develop them. And mines that have been closed for years due to poor economics are being given another look.

Jan 1, 2006

By T. D. Parris

Within a 30-mile radius of Sudbury, Ontario, the Ontario division of the International Nickel Co. of Canada, Ltd., operates nine underground mines and two open pits. Prior to 1966, ore removal from the underground workings was mainly by scraping, using 125-hp electric slushers in blasthole and caving mining, and 30-hp or less air-operated slushers for fill- method mining. The development and evaluation of low-profile, diesel-powered front-end loaders, designed specifically for underground operations, was followed with keen interest during the period 1964-1965.

Jan 6, 1969

By JeffreyS. Vipperman, Daniel R. Babich, EricR. Bauer

In response to the continuing problem of noise induced hearing loss NIHL among mine workers, the National Institute for Occupational Safety and Health NIOSH has conducted numerous noise surveys in coal preparation plants. The research, consisting of worker dose monitoring, task observations, and equipment noise profiling, was completed in eight separate preparation plants. Worker dose monitoring was conducted for three shifts in most cases. Workers experiencing higher than allowable doses were task-observed for one full shift to correlate dose to noise source(s). Finally, noise levels on all floors, and in lunchrooms and control rooms, were characterized. Results indicate that only workers who routinely spend a significant portion of their shift in the plants (away from the control rooms) are susceptible to overexposure from noise. Certain pieces of equipment (screens, centrifuges, sieve bends) are the loudest primary noise sources responsible for the worker noise exposures.

By Alejandro Ferrada Vergara

Most blasting techniques that are designed to improve fragmentation and subsequently improve ore work index to downstream comminution processes, apply powder or energy factor increases, either by stretching the drilling pattern (burden/spacing ratio) implementing faster initiation sequences or using more energetic explosives. The new application will move detonation parameters up, making the blasting process riskier for the surrounding boreholes, explosive column or initiation systems functioning.

Jan 1, 2016

Plant for the production of sulphuric acid from pyrites flotation concentrates was commissioned at Cockle Creek during 1956, to meet increasing demands for commercial acid and superphosphate. Pyrite was chosen as raw material because of the uncertain supplyposition of imported brimstone and the desirability of utilising domestic sulphur.Desulphurisation of the pyrite is performed by two 40-ton per day roasters of the Turbulent Layer type operated under licence from the Badische Analin and Soda Fabrik (B.A.S.F.) organisation. These units are the first of their kind commissioned in the southernhemisphere. Pyrite is fed to the roasters in the as-received un-dried condition. Waste heat steam production is coupled with electricity generation within the plant. Sulphur dioxide is produced at comparatively high strengths and cleaned by conventional cyclone and hot electro-filter equipment.The acid unit has a capacity of 100 mono tons of sulphuric acid per day and includes cooling and wash towers, mist precipitators, a single stage drying tower, 4-pass oxidation section and absorption system.INTRODUCTIONSulphuric acid has been manufactured at Cockle Creek Works since 1913, when the first chamber nitration plant was commissioned. The raw material was brimstone roasted in Herreschoff furnaces. Since that time three additional chamber units have been constructed and have produced acid from brimstone, zinc concentrates, pyrites and -spent oxide, according to changing economic and supply factors.Three chamber units are still in operation. Contact processes have become increasingly important since the first Schroder-Grillo unit was commissioned in 1923. Six of these 5-ton per day units were operating in the mid-thirties, but have since been demolished. Two 15 ton Chemico hot gas contact units commenced operation in 1937 and 1938, and although modified, are still in service.The increasing demand over recent years for sulphuric...

Jan 1, 1957

By AIME AIME

ALL technical men who are planning to visit the Century of Progress Exposition in Chicago this summer-and all reports indicate that it will be worth visiting-should try to be there during Engineers' Week, beginning June 26. At that time most of the national engineering societies of the country will hold important meetings in that city. Engineers will thus have an opportunity not only to see the Fair at a time when special programs have been arranged for their benefit, but will have the opportunity to meet their professional brothers and to attend technical sessions of direct interest to them. The A.I.M.E. headquarters will be at the Stevens Hotel, and it will be to the interest of every Institute member who expects to attend the Fair at that time to secure his accommodations as promptly as possible. A request to the Chairman of the Chicago Section, A.I.M.E., or to the Secretary's office in New York, will bring a copy of the program as soon as it is available, together with any in- formation desired about hotel accommodations or other matters. The Chairman of the Chicago Section is J. R. Van Pelt, and his address is Museum of Science and Industry, 1525 East 53rd St., Chicago.

Jan 1, 1933

By Segnit E. R

Results are reported of a study of the reactions occurringin the combustion of chaIcopyrite particles underconditions simulating those in the shaft of a flashsmelter.The reactions were studied using kinetic and mineralogicaltechniques. Reactions. rates above 500°C wererapid, most of the reaction taking place in less than 50ms. Final products were copper-iron ferrites with spineltype structures. Probable reaction mechanisms are discussed.

Jan 1, 1977

By P. A. Plunkert, D. E. Morse, Pui-Kwan Tse, W. D. Menzie, Lucy McCartan, J. F. Papp

China’s burgeoning economy is responsible for a major share of recent world mineral consumption increases. In addition to factors traditionally recognized in market economies1 and factors unique to specific commodities, Chinese consumption now plays a major and increasingly important role in energy and mineral markets for many commodities, such as aluminum, copper, iron and steel, and oil. China has the world’s second largest economy after the United States. And its long-term importance to the minerals markets is even greater than indicated by its gross domestic product (GDP), which is currently less than two-thirds of that of the United States (Table 1). This is because China’s rising standard of living is accompanied by rapid industrialization and urbanization. Its consumption of mineral materials for infrastructure development for its very large population is significantly greater per capita than that of such developed economies as the United States, the European Union and Japan. In other words, China’s per capita production is rising at a rapid rate and will probably continue to do so for many years.

Jan 1, 2006

By E. Marcoux, F. Lotfi, A. Belkabir, L. Maacha, A. C. Brown, S. Brunet

"Koudiat Aïcha is a small Zn-Pb-Cu deposit, enclosed in the Visean Sarhlef volcano-sedimentary series of the Moroccan Hercynian Jebilet massif. Base metal mineralization is located between a basal unit consisting of black argillite with arenite intercalations, and an upper unit composed of black argillite with locally fossiliferous calcareous units towards the top. Paraconcordant gabbro sills are present in both the upper and basal units, and the enclosing strata. Three successive phases of deformation linked to regional deformation overprint the volcano-sedimentary rocks and gabbros, as well as the sulfide mineralization.The mineral deposit includes several lenses of massive to semimassive pyrrhotite, 1 to 20 m thick, with a large halo of disseminated sulfide veinlets and sulfide nodules within a zone of intense chlorite alteration in the footwall. The ore mineralogy consists of massive to semimassive pyrrhotite with lesser amounts of sphalerite, chalcopyrite, arsenopyrite, galena, pyrite, and stannite.Lead isotope results (206Pb/204Pb averaging 18.27) suggest that the metals of the Koudiat Aïcha deposit are derived from the volcano-sedimentary host rocks. Sulfur isotopes also indicate a volcano-sedimentary origin, with bacterial reduction of sulfate (d34SCDT = -7.5‰ to -10.5‰). The conditions for sulfide meta-morphic equilibration range from 250° to 330°C (sphalerite and chlorite geothermometers). The gabbroic sills could have been a local heat source for hydrothermal circulation. Based on these geological and mineralogical features, a Besshi-type model seems appropriate for the genesis of the Koudiat Aïcha mineralization.Koudiat Aïcha est un petit dépôt de Zn-Pb-Cu, encaissé dans la série volcano-sédimentaire Viséenne de Sarhlef dans le massif Hercynien de Jebilet au Maroc. La minéralisation en métaux usuels se situe entre une unité basale d’argilite noire interlitée d’arénite et une unité supérieure composée d’argilite noire comprenant localement des calcaires fossilifères près de son sommet. Des sills de gabbro paraconcordants sont présent à la fois dans les unités basale et supérieure, ainsi que dans les strates environnantes. Trois phases de déformation successives associées a la déformation régionale superposent leurs effets sur les roches volcano-sédimentaires, les gabbros, ainsi que la minéralisation sulfurée. Ce gîte comprend plusieurs lentilles de pyrrhotite massive a semimassive de 1 a 20 m d’épaisseur au sein d’un large halo de veinules de sulfures disséminés et en nodules au sein d’une zone intensément chloritisée dans le mur du gisement. Le minerai consiste en pyrrhotite massive à semimassive avec des quantités subordonnées de sphalérite, de chalcopyrite, d’arsénopyrite, de galène, de pyrite, et de stannite. Les résultats de l’analyse des isotopes du plomb (206Pb/204Pb moyen de 18.27) suggèrent que les métaux du gîte Koudiat Aïcha proviennent des roches volcano-sédimentaires encaissantes. Les isotopes du souf¬fre indiquent eux-aussi une origine volcano-sédimentaire, impliquant la réduction bactérienne des sulfates (d34SCDT = -7.5‰ et -10.5‰). L’équilibration métamorphique des sulfures s’est produite entre 250° et 330°C (géothermomètres à sphalérite et chlorite). Les sills de gabbro pourraient avoir été la source de chaleur locale responsable de la circulation hydrothermale. Sur la base de ces caractéristiques géologiques et minéralogiques, il semble approprié d’invoquer un modèle de type pour Besshi pour expliquer la genèse de la minéralisation de Koudiat Aïcha."

Jan 1, 2008

The commonly used Stopes-Heerlen coal petrographic classification and nomenclature has over the years been subject to variable interpretations. This paper discusses the problem with specific reference to the inertinite maceral group. The effect of various interpretations of the Stopes-Heerlen system on maceral analysis is discussed and illustrated by means of comparative analyses conducted by a number of laboratories in Australia.An attempt is made to define the reflectance thresholds used by the authors to subdivide the inertinite group; the genetic and technological significance of these thresholds are compared.The difficulties of distinguishing structured and nonstructured macerals of the inertinite group are discussed in terms of possible improvements to the present StopesHeerlen system by extending the classification to include transitional maceral types.

Jan 1, 1970

By F. R. Camisani-Calzolari

Surface defects on continuously cast slabs require treatment by grinding. This extra phase in the process causes lower throughput of final product and extra energy costs. The elimination of slab treatment after casting implies that slabs can be direct rolled or hot charged, resulting in higher throughput and lower energy costs. To increase the number of slabs that can be direct rolled or hot charged, defects have to be predicted before a slab has completed the casting process. Transversal and longitudinal cracking, casting powder entrapment and other inclusions, bleeders, deep and uneven oscillation marks, stop marks and depressions are the defects thatare considered for prediction. A structure with two models is proposed. The first model describes the effect of mould level, water inlet temperature and casting speed (MV?manipulated variables) on 38 thermocouple temperatures (IV?intermediate variable). Casting speed is a manipulated variable while mould level and water inlet temperature are treated as measured disturbances. This model is known as the MV to IV model, and is used to control the occurrence of defects. The second model describes the effect of the thermocouple temperatures on the defects at different positions and locations on the slabs (OV?output variables). This model is known as the IV to OV model and is the predictor of defects. The models are determined using time-series methods in the form of auto regression with exogenous input using data of approximately 500 slabs cast over a period of 6 months. The models are validated using plant data from 44 slabs gathered three years later, with good results. As an example, published results give a sensitivity and specificity of 61.5 per cent and 75 per cent respectively for longitudinal cracks on validation data, while the presented method gives 63.6 per cent and 93.5 percent, respectively. The IV to OV model is used in an inversion to determine the optimal thermocouple temperatures for each slab width. Keywords: Continuous casting, model, defect, prediction, direct rolling, hot charging, goodness-of-fit, correlation, time-series, soft sensor, ARX.

Jan 1, 2003

Historically, the selection of mining sequence for multiple seam conditions has been based on many factors other than ground control considerations and minimization of interaction effects. Today, numerous operations are finding themselves mining above existing or abandoned operations, some of which exhibit large scale caving, pressure arches and subsidence troughs. Development of design criteria for the upper seam that would alleviate damage due to lower seam interaction effects can contribute substantially to the safety and productivity of many mining operations. The primary objective of this re search has been to identify methods of improving ground control conditions in the upper seam when mining through either passive or active subsidence waves. These methods concentrate on improved ground control practices for the upper seam, rather than reducing the amount of subsidence in the upper seams by improved practices in the lower seam. Design factors such as pillar size, pillar and opening orientation relative to the subsidence trough, offsetting intersections, and different support methods have been studied for the upper seam in a variety of typical geologic environments. Analysis has demonstrated criteria for ameliorating negative interaction effects and facillitating design in the superincumbent seam.

Jan 1, 1986

The Geological Resource Map of New Zealand (GERM) is a computerised inventory of aggregate, mineral, coal, petroleum and thermal water occurrences, containing summary information on location, production, geology, and geochemistry. The types of occurrences include quarries, mines, gold dredges, wells, outcrops, seeps, springs, and fields. The file contains entries for about 10,300 sites and is used to produce tables of data and maps at any scale, for single or multiple commodities. The published format is the New Zealand 'Geological Survey map series Geological Resource Map of New Zealand 1:250 000'. Seventeen of the 27 map sheets covering New Zealand were published by August 1991, with three more close to publication.

Jan 1, 1991

By L O. Filippov, C H. Veloso de Melo, A Correa De Araujo

Froth flotation of iron ores is one of the most widely used methods to upgrade iron ore into high-grade concentrates. In recent years, reverse cationic flotation of iron ores has been specifically the subject of several studies. Since quartz is the most common gangue mineral in iron ores, understanding the behaviour of this mineral was the main target of the majority of such studies. However, with the depletion of mineral deposits considered rich and easy to process, it has become more common to find iron ores with complex gangue minerals, which are composed not only of quartz but by a variety of silicates. The mineralogical composition of the ore is an important factor for determining reagents and mineral processing parameters. The mineralogical suite of an ore also presents a paramount role for operational optimisation of any given flotation process. Some studies were performed with different types of amphiboles and other Fe-bearing silicates, for example, but the influence of the mineralogical nature of these silicates in reverse cationic flotation has not been fully explored and will be discussed here. Changes in the traditionally used reagent scheme for reverse cationic flotation, generally including alkaline pH values, polysaccharides as depressant (mainly starches) and primary ether amines and diamines, are expected when dealing with iron ores with complex silicate gangue composition.CITATION:Veloso de Melo, C H, Correa de Araujo, A and Filippov, L O, 2017. Reverse cationic flotation of iron ores with complex silicate gangue minerals, in Proceedings Iron Ore 2017, pp 241–244 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By G. G. Goble

Significant progress has been made in the past decade in determining the load bearing capacity of pile foundations. Developments in the means of prediction of pile capacity as limited by soil strength have been substantial, particularly in the use of dynamic methods. The use of currently available equipment, analytical procedures, and practices in the field, will often produce material economies on a job by allowing increased loads with proven factors of safety. This approach justifies the minimum number of piles required for a safe foundation in a wide range of job sizes and soil conditions. To avoid exposing the reader to excessive detail in the body of this paper, technical topics have been covered more thoroughly in several appendices. I. Wave Equation Analysis of Piles Appendix A II. Dynamic Monitoring and the Pile Driving Analyzer Appendix B III. Case Method Capacity Calculation Appendix C IV. Case Pile Wave Analysis Program Appendix D 1 Preliminary Analysis In designing driven pile foundations, there must be a close relationship between design, construction control procedures, driving practices, and the size of the job. Small commercial buildings or residences involving loads that are only a fraction of the pile capacities do not justify the expense of detailed design processes or elaborate construction controls. Nevertheless, some preliminary analysis of the job requirements and a limited subsurface investigation must be made to understand existing conditions and the possible foundation solutions. In other words, it is necessary to determine that driven piling is the best overall choice of foundation.

Jan 1, 1988

By Lawrence M. Zanko

Eighteen coarse taconite tailings samples were collected in 2000-2001 from five western Mesabi Range taconite (iron ore) operations located in northern Minnesota, i.e., EVTAC, Hibbing Taconite (Hibtac), USX Minntac, Ispat Inland (Minorca), and National Steel Pellet Company (NSPC), to test their physical, geological, chemical, and mineralogical properties [Zanko, L.M., Niles, H.B., Oreskovich, J.A., 2003. Properties and aggregate potential of coarse taconite tailings from five Minnesota taconite operations, Minnesota Department of Transportation, Local Road Research Board, St. Paul, MN, Report No. 2004-06 (also as Natural Resources Research Institute technical report, NRRI/TR-2003/44)]. The goal was to assemble a body of technical data that could be used to better assess the potential of using a crushed taconite mining byproduct like coarse tailings for more widespread construction aggregate purposes, primarily in roads and high¬ways. An important part of the mineralogical assessment included X-ray diffraction (XRD) analyses and microscopic (polarized light microscopy, scanning electron microscopy, and transmission electron microscopy, i.e., PLM, SEM, and TEM, respectively) evaluation of the size and shape (morphological) characteristics of potentially respirable microscopic mineral particles and fragments. Quantitative mineralogy, based on XRD analyses, showed that the dominant mineral in all samples was quartz (55-60%), followed by much smaller amounts of iron oxides, carbonates, and silicates. Specialized microscopic analyses and testing performed by the RJ Lee Group, Monroeville, PA, on both pulverized (-200 mesh, or 0.075 mm) and as-is sample composites showed that no regulated asbestos minerals or amphibole minerals were detected in the western Mesabi Range samples. A small number (26) of non-asbestos and non¬amphibole mineral cleavage fragments/mineral fibers were detected by SEM out of 1000 fields analyzed, but most were identified as min¬nesotaite and talc, silicate minerals common to the Biwabik Iron Formation. Amphibole minerals, absent in coarse tailings samples from the five western Mesabi Range taconite operations, were present in a single eastern Biwabik Iron Formation sample collected in 2003 for Lake County from the Cliffs Northshore operation in Silver Bay, MN. Importantly, the Superfund Method for the Determination of Releasable Asbestos in Soils and Bulk Materials [United States Environ¬mental Protection Agency (USEPA), 1997. Superfund method for the determination of releasable asbestos in soils and bulk materials, EPA 540-R-97-028, U.S. Environmental Protection Agency, Washington], as modified by Berman and Kolk [Berman, D.W., Kolk, A.J., 2000. Modified elutriator method for the determination of asbestos in soils and bulk materials, Revision 1: Submitted to the U.S. Envi¬ronmental Protection Agency, Region 8, May 23, 2000] failed to generate any protocol fibers, i.e., fibers longer than 5 µm and thinner than 0.5 µm, from either the western coarse tailings samples or the single eastern Biwabik Iron Formation sample. The combined findings suggest coarse tailings and other taconite mining byproducts should be treated with the same common sense safety and industrial hygiene approach practiced for all mineral-based materials that have the potential to generate respirable dust. © 2007 Elsevier Inc. All rights reserved.

Jan 1, 2007

By Paul S. Goodman

Volume II The purpose of this study is to explain reasons for the productivity differences in mining crews. The literature on group productivity is examined. Then a new approach to estimating productivity differences is proposed and estimated across seven different mines. The results indicate a fairly robust model in terms of explanatory power. Recommendations on how the model can be used as a managerial tool are presented.

Jan 1, 1985