Search Documents

By G. Thom, A. Kay, J. B. Hyde

"This paper will initially outline the specific types of copper castings used in blast furnace iron production. Tuyeres, tuyere coolers and stack cooling plates will be discussed in some depth, with particular reference to their dimensional configuration and purpose.Following this, the failure of such cooling members will be discussed, with special focus on tuyeres. Tuyeres are the most common casting which often requires replacement. Reasons for failure and its effect on operations will also be included.The latter sections of the paper will deal with the strict specifications demanded by ironmakers regarding copper castings. The justification for such rigid demands will be explained through the material presented earlier in the paper.IntroductionThe modern 5000-tpd blast furnace, worth millions, is a large capital investment to be sitting idle. Consequently, ironmakers strive to minimize the loss in iron production and revenue from furnace downtime. Two major causes of downtime are furnace relines and shutdowns to replace damaged tuyeresor tuyere coolers. Copper ancillaries are important items in the production of iron. They are consumable items, therefore they contribute to the campaign life or to the downtime in blast furnace production.Several combinations of lining and cooling systems have been used with varying degrees of success. Blast furnace refractories have evolved from ceramic to carbonaceous linings. The Russians and Japanese have successfully introduced stave-cooled furnaces that may have several forms, such as evaporative cooling. Stelco has two furnaces which use the Russian-designed cast iron system. However, this paper will be confined to the use of copper cast cooling members in a conventional internally cooled furnace.Figure 1 is a schematic cross section of the E blast furnace. The three major sections of a blast furnace-the stack, bosh and hearth-are identified. Further, the locations of the various copper members are indicated. This furnace produces an average of 5300 tons of hot metal per day."

Jan 1, 1982

By Dean Bray

During the past three years, a new rear-dumping dragline bucket technology has been patented, developed and tested at North Dakota coal mines. Field testing has shown that this new concept in dragline bucket technology can improve strip-mining efficiencies by reducing cycletimes and increasing dumping radius. This article details the process, participants and the results for the development of a rear-dumping dragline bucket. Participants in the process In November 1995, the board of directors of Dakota Coal authorized the execution of a field test and option agreement and a license agreement with the partnership of D.F. Schmidt, electrical/maintenance supervisor, and Bill Lengenfelder, president of Modern Industrial. The board also authorized entering into a dragline bucket field-testing agreement with the Falkirk Mining Co.

Jan 1, 1999

By J. Hop, A. Støre, T. Foosnæs

The carbon cathode for aluminium electrolysis is also part of the container of the process. In order to understand the behaviour and possible failure of the cathode, detailed material properties under operating conditions are needed. The paper reports experimental studies of bath and sodium in filtration, graphitization with time, loss of strength due to sodium, sodium expansion as function of pressure, as well as creep due to the developed stresses. As an example, sodium and thermal expansion data are used to calculate strain-stress models of realistic cell designs, and possible design weakness can be pointed out. Keywords: carbon, cathodes, sodium expansion, strength, graphitization, creep

Jan 1, 2004

By Edward A. Barrett, Roberta A. Calhoun

MORE THAN 30 MILLION EMPLOYEES each year are exposed to hazardous occupational noise, and approximately one-third of them develop permanent hearing loss (NSC, 2000). Possible explanations for the latter statistic include worker regard for noise as a mere nuisance rather than as an occupational safety and health hazard, and consequent neglect of established protective measures (e.g., hearing protection); lack of knowledge concerning noise; improper use of hearing protection; worker indifference; and inadequate training (Bauer & Babich, 2004). Many drill rigs generate high sound levels, which vary according to the type of machine, its location with respect to the physical surroundings, and the location of the sound measured around the rig. A NIOSH study measured noise output from several types of drill rigs during field investigations (Ingram & Matetic, 2003). Two types of data were recorded the actual noise generated by the drill rig at various positions around the rig and the noise to which the drill operator was exposed during the drilling cycle. For the latter, sound level measurements up to 120 dBA were recorded while hammering casing (metal on metal) in drilling a water well (Photo 1). Several types of administrative controls exist to address worker exposure to loud drill rig noise. Rotating duties to decrease exposure time and posting warning signs in high-noise work areas are two such controls. Another is the use of hearing protection. Worker use of hearing protection has been disappointing, however. One study by the University of Michigan found that construction workers used earplugs and earmuffs only between 36% and 61% of the time that they were necessary (Lusk & Kerr, 1998). In a 2001 study, OSHA reported a relatively low rate of 30.4% for use of earplugs among construction workers (Walker, 2001). Why are rates for hearing protection use so low? One explanation may be workers' lack of concern for noise in the workplace. They expect workplace noise to be a loud and in¬ evitable nuisance and, therefore, accept it as part of the job. As a result, they disregard proven measures that can protect their hearing. Other workers may use hearing protection, but do so improperly. They may misguidedly remain in high-noise areas for extended periods thinking they are protected when in fact they are not. Other reasons for low use and/or misuse of hearing protection include poor education, lack of awareness and inadequate training (Nash, 2003). To address the training issue, NIOSH developed two exercises from which drillers can learn about noise, hearing loss and hearing protection. The first is an invisible ink exercise, titled "Drill Rig Incident" (DRI) (Photo 2); the second is a 3-D slide reel training aid, "Wearing Hearing Protection Properly" (WHPP) (Photo 3). DRI is an instructor-

The object of this paper is to give a description of the new office and changehouse building and equipment at the Zinc Corporation Limited, the office section of which has now been in full use for approximately three years, and the changehouse section for approximately two years. As the expectations of the design have been fully realized, it is thought that this description will be of interest to members and possibly of some use to others faced with similar problems.GENERALIn the centralization of the surface plant around the new main shaft the combined office and changehouse building forms a prominent feature, being located between the shaft and the mill and facing the workshops on the northern side.The scheme for housing all employees in one building was proposed by the Manager, Mr. A. J. Keast, who was familiar with a similar successful structure built at the McIntyre Porcupine Mines Ltd. in Ontario, Canada.The principal features of this building were adopted as a basis for design, and the present layout evolved to suit the particular requirements of this mine.Some of the advantages of the design are:(a) Economy in first cost and space occupied when compared with plants having separate office and changehouse buildings.(b) Easier and more constant supervision of employees and of the plant by the senior staff members.(c) Close contact between officials of all departments.(d) Close covered connection between changehouse and shaft.(e) Avoidance of duplication of ,essential services such as electric power, water, heating plant, sewerage, etc.The Managing Director, Mr. W. S. Robinson, further instructed that the following requirements be adhered to in the new building:(a) Ample accommodation to be provided for office staff and other employees.(b) Special attention to be paid to lighting, both natural and artificial.(c) Working temperatures to be controlled to facilitate comfort and efficiency.(d) The buildings and equipment' to be of a permanent nature with furnishings and fittings of modern design.

Jan 1, 1941

By R. B. Rao, B. Das, J. K. Mohanty, D. S. Rao

Physical, mineralogical and geochemical characterization, along with some beneficiation approach to pre-concentrate the Ni content of the chromite overburden material of the Sukinda Valley, India, have been carried out in detail. Mineralogically, the overburden consists of geothite, quartz, hematite, magnetite and secondary silicates in varying proportions. A specific Ni mineral phase is absent in this material with the Ni and Fe being mostly enriched in finer fractions. Distribution of Ni and Fe in various size fractions and increase of Ni with increase in Fe (goethite content) indicate that goethite is the major Ni-bearing mineral phase. Quantitative estimation of goethite from chemical analysis and weight loss data indicates that the goethite quantity varies from 40% to 90%. Electron microprobe analysis (EPMA) indicates that Nirich and Ni-poor goethite are present in the overburden material. A sequential dissolution study indicates that more than 50% of the Ni are present within the goethite lattice as a lattice substitution. The results of pre-concentration studies (size classification, gravity, flotation and magnetic separation) indicate that Ni is richer in finer fractions. Further, the enrichment of Ni content is limited to 1.1% with 50% recovery by classification followed by hydrocyclone separation of the below 53 m m fraction.

Jan 1, 2000

By Neil White

South Africa (SA), a country in which all three commercially important asbestos minerals have been mined and milled, has retained proven cases of mesothelioma linked with environmental exposure to asbestos. This study illustrates the importance of fiber type in the occurrence of environmental mesothelioma. Four studies have reviewed the source of occupational or environmental asbestos exposure in 504 histologically proven cases of mesothelioma in South Africa. One hundred and eighteen cases (23%) were thought to be related to environmental exposure to asbestos. In the vast majority of these cases, exposure was linked to crocidolite mining activities in the Northern Cape Province. Two cases were thought to have occurred in relation to amosite and Transvaal crocidolite exposure in the Limpopo Province. In the balance of cases there was some uncertainty. No cases were reported with exposure to South African chrysotile. Consequently, in the vast majority of cases of mesothelioma, environmental exposure to asbestos occurred in the Northern Cape Province, in proximity to mines, mills and dumps where crocidolite was processed. Crocidolite appears to be far more mesotheliomagenic than amosite, and chrysotile has not been implicated in the disease. This is true for both occupationally and environmentally exposed individuals. ©2007 Elsevier Inc. All rights reserved. Keywords: Crocidolite; Mesothelioma; Chrysotile; Amosite; South Africa

Jan 1, 2007

Laboratory scale equipment was developed to recover zinc as oxide fume from granulated lead blast furnace slag. The cyclone furnace process is characterised by high treatment rates combined with continuous and independent operation.Results were sufficiently encouraging to warrant pilot plant scale trials being undertaken.INTRODUCTIONSince granulation of lead blast furnace slag started at Port Pirie in 1921 the stockpile of this material has increased to nearly 5 million tons which averages 17·5 per cent zinc by weight. Although a number of processes for recovering the zinc have been examined, economic considerations indicate that a slag fuming process is likely to be most suitable.In the conventional slag fuming process zinc is extracted by injecting pulverized coal and air into a molten slag bath. By maintaining a suitable air to coal ratio the oxidised zinc contained in the slag is reduced to metal. Volatilization of the zinc is followed by reoxidation in the gaseous phase with the addition of further air above the bath. The zinc oxide fume so produced is collected by normal gas cleaning methods.By examination of the thermodynamics of this process Bell, Turner, and Peters (1955) determined the zinc oxide activity of the slag over the duration of the fuming cycle.A combination of high temperature and high carbon monoxide/carbon dioxide ratio was found necessary for rapid zinc elimination.Since melting of the slag is an essential step in the slag fuming process, only two treatment methods appeared possible at Port Pirie until recently...

Jan 1, 1964

Accurately estimating load distributions and ground responses around underground openings play a significant role in the safety of the operations in underground mines. Adequately designing pillars and other support measures relies highly on the accurate assessment of the loads that will be carried by them, as well as the load-bearing capacities of the supports. There are various methods that can be used to approximate mining-induced loads in stratified rock masses to be used in pillar design. The empirical methods are based on equations derived from large databases of various case studies. They are implemented in government-approved design tools and are widely used. There are also analytical and numerical techniques used for more detailed analysis of the induced loads. In this study, two different longwall mines with different panel width-to-depth ratios are analyzed using different methods. The empirical method used in the analysis is the square decay stress function that uses the abutment angle concept, implemented in pillar design software developed by the National Institute for Occupational Safety and Health (NIOSH). The first numerical method used in the analysis is a displacement-discontinuity (DD) variation of the boundaryelement method, LaModel, which utilizes the laminated overburden model (Heasley, 1998).

Jan 7, 2020

By F. Enslin

Heavy metals and sulphates in acid mine drainage (AMD) can beadsorbed onto bentonite clay, leaving clean water and a heavy metal loaded clay precipitate as products. Due to the toxicity of heavy metals, the clay could not be disposed of safely in the past. A method was thus required to remove the heavy metal content from the clay. Acid leaching was proposed to liberate the heavy metals from the loaded clay. Sulphuric, nitric and hydrochloric acid were considered as lixiviants. Loaded clay samples were leached over a range of pH values from 1 to 3.5 to identify an optimum leaching condition. From the results it was found that metals can berecovered from loaded bentonite clay by means of acid leaching and the optimum pH for heavy metal liberation was found to be 2.5, with uranium as an exception, being optimally leached at a pH of 3. This allows for the possibility of selective leaching. Furthermore, X-ray diffraction analyses indicated that the clay structure did not deteriorate significantly during acid leaching, suggesting that the bentonite could be reused. The treatment of AMD with bentonite clay, and subsequent acid leaching of the clay, is a sustainable solution, and current outcomes could possibly lead to industrial implementation of the process during water purifying and metal recovery from waste streams. Keywords: Acid mine drainage, bentonite, heavy metals.

Jan 1, 2010

By K. Englehardt

J BERESFORD introduced the subject of the paper which is the use of polymeric slurries to support the sides of diaphragm wall and bored pile excavations during construction. In the opinion of the authors the use of a suitable polymeric fluid offers financial and technical advantages compared with traditional bentonite based slurries. Under quiescent conditions a support slurry must have the following properties. - sufficient viscosity to support the sides of the excavation, to prevent infiltration into soils and to hold loose soil particles in suspension. - when agitated it should thin quickly to assist pumping transfer and cleaning and allow free passage of the grab or drill. - viscosity should be low enough during concreting to facilitate placement but high enough to prevent contamination of the concrete.

Jan 1, 1991

By Michael D. Balen

The U.S. Bureau of Mines (Bureau) is currently conducting a four-year study to assess the mineral resources and the mineral development potential of the 5.7 million acre Valdez Creek Mining District (VCMD) located in southcentral Alaska. The VCMD study is part of the Bureau's ongoing statewide mining district evaluation program. This report is a summary of the 1988 field work. The field work involved collection of reconnaissance placer and rock samples, and also involved sampling and examination of the mines, prospects, and mineral occurrences which were identified by literature research of the geology, exploration history, and mining history of the district. During the 1988 field season, Bureau personnel spent a total of 11 weeks in the field, collected 1,006 rock and placer samples, and located, mapped, and sampled 106 of the known mineral occurrences. The Bureau has visited 243 of the 250 known mineral occurrences during the course of the VCMD project. Reconnaissance sampling for placer occurrences resulted in the identification of 4 previously unreported gold placer occurrences, and identification of 5 occurrences that contain detectable levels of platinum or palladium. Reconnaissance sampling for lode sources of base and precious metals resulted in the identification of 5 new Lode gold-silver occurrences, identification of 2 occurrences that contain elevated quantities of chromium, cobalt, nickel, palladium, and platinum, and identification of one occurrence that contains elevated quantities of copper, molybdenum, anti zinc.

Jan 1, 2011

By Wendy M. Brunner

A 70% excess of mesothelioma, an asbestos-related cancer, has been reported among men in northeastern Minnesota, where iron mining has been the major industry. The Minnesota Department of Health has studied iron miners who developed mesothelioma to identify possible sources of asbestos exposure. A database of all Minnesota residents diagnosed with mesothelioma between 1988 and 1996 was linked to a database of approximately 72,000 current and former Minnesota iron-mining employees to identify cases who had ever worked in the mining industry. The job histories of the cases were examined to determine if any of their jobs could have involved exposure to commercial asbestos. Seventeen individuals diagnosed with mesothelioma in Minnesota between 1988 and 1996 were found to have worked in the iron mining industry. Of the 15 for whom adequate work histories were available, 14 had identifiable sources of exposure to commercial asbestos in jobs held both inside and outside of the mining industry. The time between employment in these asbestosexposed occupations and the diagnosis of mesothelioma is consistent with the 20 or more year latency period that has been observed in other studies of this cancer. © 2007 Elsevier Inc. All rights reserved. Keywords: Mesothelioma; Asbestos; Iron miners; Taconite; Epidemiology; Case series

Jan 1, 2007

By Richard Rice

TURBO blowers for blast-furnace blowing have now been in use for some years, and a review of the experience gained and the present state of progress may be interesting. FIG. 1.-STEAM TURBINE DIRECT CONNECTED TO AIR COMPRESSOR. The first blast-furnace blowing engine of this type to be installed in America was built by the General Electric Co. and is installed at the oxford Furnace of the Empire Iron & Steel Co. This machine was put into operation March 8, 191.0. A duplicate unit is situated at the furnace of the Northern Iron Co. at Port Henry, N. Y., which unit was put into opera ion June 30, 1910 (Fig. 1).

Jan 5, 1914

By Qingxiang Huang

Shallow seam coal field has the largest coal reserve in China. Mining in shallow depth causes serious problems. One of them is subsurface dewatering. In this paper, the physical simulating model was performed to study overburden movement and aquiclude stability in the shallow seam mining of Yushuwan coal field, China. According to the characteristic of clay aquiclude in the overburden, the proper simulation materials and proportions of mixture for simulating the plastic clay aquiclude layers and brittle bedrock layers were determined by the stress-strain tests. The physical simulating model was carried out to simulate the failure and caving process of the roof and overburden. Based on the simulating tests, it was found that the movement of clay aquiclude follows the movement of the underlying bedrock layers. The basic caving mechanism of the overburden roof strata was also presented. The tests also showed that the best way to control the stability of aquiclude is to reduce the subsiding gradient Ts. This research provides a foundation for further study on mining dewatering and water conservation.

Jan 1, 2006

By D Crequer

Land rehabilitation at Golden Cross is reviewed, 8 years after mine closure in 1997/98, from the perspectives of a Peer Reviewer (land rehabilitation) and a Regional Council Officer (Resource Consents compliance). Land rehabilitation items we discuss include: management of restored pastures, native plantings (on-site riparian and block plantings and off-site environmental riparian enhancement plantings), wetlands (on-site tailings lake and sediment ponds littoral zone plantings, and basement of the open pit; and off-site wetlands enhancement plantings), pine plantations on-site and on surrounding land, stabilization of the Tailings Lake Embankment (landslide) and Open Pit capping, capping of acid-mine-rock, stability of discharge channels, buildings and amenities, public access for recreation, educational uses, and future management of the site. Pest control has helped to conserve the rare and endangered HochstetterÆs (Leiopelma hochstetteri) and ArcheyÆs (L. archeyi) frogs, and a regionally significant stand of rare swamp maire (Syzygium maire) has been conserved and fenced.

Jan 1, 2006

By A. K. Snelgrove

Introduction ?Concerning the inland commodities, as wel to be drawen from this land (Newfoundland) there is nothing which our East and Northe.rly countries of Europe doe yeelde, but the like also may be made in (ît) as plentifully by time and industry : Namely, rosen, pitch . . . metalls, and many moe. All which the countries will aford, and the soyle is apt to yeelde ... For besides these alreadie recounted and infinite moe, the mountains generally make shew of minerall substance : Iron very common, lead, and somewhere copper. I will not auerre of richer metalls: albeit ... more then hope may be concieued thereof. " - Narrative of Captain Hayes, second-in-command to Sir Humphrey Gilbert's Expedition, IJ83 (From Hakluyt). The investigations set forth in the following pages were made in the field in Newfoundland during the summer of 1927, and later in the laboratories and library of McGill University, and in the library of the Canadian Geological Survey at Ottawa, with the purpose of collating and adding to our knowledge of the geology of an area roughly wedge-shaped in outline, and nearly nine thousand square miles in extent, stretching across the centre of the island of Newfoundland, from the southwest to the northeast coasts. To the description of this district, which contains most of the known mineral occurrences of Newfoundland, the term mineral belt is here introduced.

Jan 1, 1928

To the industrial geologist, as wen as to the general or historic geologist, the possession of a reliable key to the true order or sequence of the stratigraphy or position of the various upper rocky envelopes of the earth's crust, is, equally, a desideratum of the utmost importance. Of similar value to the two groups of students is the possession of facts which throw light upon the relationships which subsist between the puccessive rock formation of different countries, especially between countries lying close to each other, or within the same great geographical division.But there is necessarily a fundamental distinction which marks the respective limits of the field of observations of the industrial geologist, and the purely historic interest of the general geologist. The former has a more definite though less extensive scope. The scope of the latter is wide and indeterminate. In short, the observations of the industrial geologist are, 'from a commercial or economic point of view, of a more practical character, and are, therefore, intentionally restricted to the study of all geological questions which throw light upon the rocks which yield products of economic value and only include the study of the character and history of other rocks, in so far, as they afford aid to the more perfect comprehension of the best manner in which materials of economic value are likely to be sought, and the best means whereby these products may be secured for the material advantage of the community. The motive of the general geologist-in most cases-is a love of the study of some particular branch or province of the geological field, and the fascination of opening a new volume in nature's library, and the hope of extending the realm of knowledge, however slight, are often sufficient, as a motive, to enlist the energy and life's devotion of the true brethren of the hammer, irrespective of considerations regarding the commercial utility of the pursuit.

By Christof Metzger

This paper discusses the process utilized by the Kiewit?Bilfiger Berger Joint Venture (Contractor) to select, design, and procure the largest mixshield tunnel boring machine (TBM) ever implemented in North America. The mixshield will excavate the 8,534 linear m × 6.7 m ID (28,000 linear ft × 22 ft ID) tunnel for the City of Portland Oregon?s, Bureau of Environmental Services (Owner) East Side CSO Tunnel Project. TBM selection was conducted under a preconstruction contract in which the Contractor, Owner, Construction Management Consultant and Designer collaborated on TBM selection prior to commencement of construction. This paper focuses on TBM design considerations, including the use of one versus two machines, machine configuration,extended-wear protection, hyperbaric interventions, boulder digestion, and erection of a steel-fiber-reinforced segmental lining

Mine drainage and mine reclamation are topics of major interest to the mining industry, federal and local governments, and the general public. This publication and its companion three volumes are the proceedings of a conference held in Pittsburgh, Pennsylvania, April 24-29, 1994. There were twelve sessions (69 papers) that dealt with mine drainage, including modeling, geochemistry, prediction, treatment, control strategies, characterization, hydrology, and case studies. These sessions comprise volumes 1 and 2. The six sessions (34 papers) that dealt with reclamation and revegetation of disturbed lands are included in volume 3. Volume 4 includes the six sessions (34 papers) that dealt with such topical issues as fires at abandoned mine sites, subsidence, hydrology, mine wastes, and policy. Poster session presentations are represented by 49 papers and 92 abstracts that have been placed in the back of volumes 2, 3, and 4, consistent with the subject of that volume.

Jan 1, 1994