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By Descour Jozef, Suguru Shirasagi, Takuji Yamamoto, Koji Murakami

For TBM tunneling no visual inspection of excavated ground is possible. This may hinder the high-speed excavation, particularly in complex ground conditions. The TBM Excavation Control System was developed for better prediction of geological conditions ahead of the tunnel face during excavation. The seismic reflector tracing produces volumetric images of anomalies in the ground in “near-real time.” These images are verified using logging data from pilot boring and TBM driving data, to improve reliability and precision of ground mapping. Also good correlation was obtained between the rock strength index computed from TBM data, and one derived from volumetric seismic images.

Jan 1, 2007

By Martin D. Conyac

Results of the minerals survey indicate low potential for the discovery of placer gold along Deck Creek aid for copper, silver, and gold in PreTertiary rocks within the boundaries of the Lake Fork RARE II area. Potential for oil, natural gas, coal, and geothermal resources is negligible. No evidence of economic mineral resources was found during the examination of the study area, and no assays of rock or placer samples taken from the urea showed economic mineral values. There are no producing or developing mines within the boundaries o of the lake Fork study area. SETTING Mining Districts The Lake Fork RARE II area is on the eastern fringe of the Cornucopia Mining District, which is centered about 6 mi west. It is also on the western edge of the Homestead district, centered about mi east.

Jan 1, 1983

By John N. Cunningham

Despite the wide use of micropiles for rehabilitating and retrofitting existing structures, little is known regarding the load-transfer distribution of grouted micropiles in various soil deposits. The rehabilitation of a concrete-frame warehouse in Portland, Oregon, required provisions for the seismic restraint of a new shear wall; the installation of two micropiles was specified to meet project requirements. The micropiles were uncased, 19-m (63-ft) long, 200-mm (8-in) nominal diameter, and reinforced full-length with a 64-mm (No. 20) diameter hardened steel threadbar. Due to space limitations, a sacrificial, instrumented micropile was installed near the two production piles to verify design assumptions. This paper describes the geologic setting of the project within the unsaturated Missoula Flood deposits, instrumentation, load-displacement behavior, load transfer, and Beta-coefficients for the sacrificial micropile.

Jan 1, 2011

By W. Stumpf

Mean flow stress analyses from plant mill logs for the conventionally produced hot rolled low carbon steel from the Ispat Iscor Vanderbijlpark strip producing plant, indicated a higher temperature sensitivity than that found for the equivalent SAE 1006strip steel produced in the compact strip plant of Saldanha Steel. This was confirmed quantitatively through detailed hot deformation studies on an as-cast structure as well as on a finer grained condition on the same steel. In the conventionally produced steel, activation energies for hot deformation of 309 kJ.mol-1and 388kJ.mol-1for the two respective starting structures were found, both values extending over the entire normal hot deformation temperature range of 1140 to 900°C. These and other experimentally determined constitutive hot deformation constants were applied to the hot rolling austenite grain size development model used earlier. From this, it is predicted that dynamic recrystallization occurs only in the first two break-down passes at the Vanderbijlpark plant and thereafter static recrystallization occurs after exiting from all of the remaining ten or eleven roughing and finishing passes. This is significantly different from what was predicted earlier for the Saldanha Steel plant with its lesser number of passes where static recrystallization is predicted to occur only in the last three passes. The effects of this process difference and other observed product differences between the two types of product are discussed. Keywords: Low carbon steel, hot rolling of strip steel, rolling mill log analyses, austenite grain size, grain size modelling.

Jan 1, 2004

By José Díaz Barrios

El proceso de la explotación minera de la veta Oroya Techo, perteneciente a la mina Casapalca, ha generado un desequilibrio del macizo rocoso, donde la energía que la roca de la caja, piso y techo (volcánicos de la formación Carlos Francisco) no pueden soportar mas allá del límite de su resistencia y deformabilidad natural, es liberada o “compensada” con el estrujamiento plástico de la veta Oroya Techo (estructura carbonatada). En ese sentido, el presente texto describe una manera de cuantificar dicha deformación a través del monitoreo de convergencias, donde se emplea un simple extensómetro de cinta manual y asímediante una análisis estadístico, seleccionar estaciones de convergencia por rangos de mediciones.

Sep 12, 2005

By C Bailey, T Kojovic, M M. Hilden, M S. Powell

The Julius Kruttschnitt semi-autogenous grinding (SAG) mill model was developed by Leung in the 1980s and extensively updated to the variable rates model by Morrell and Morrison in 1996. Since then only minor upgrades have been incorporated in the version distributed in the JKSimMet simulator. A number of improvements, developed over the course of the AMIRA P9 project and in recent independent work, have now been incorporated. These improvements are based on a power-based model that directly relates the degree of breakage with energy consumption. The new size-dependent breakage function has been incorporated. The upgrades include more accurate predictions for a wide range of mill fillings (ten - 40 per cent), slurry hold-up in the mill, pebble discharge rate and the influence of changes in feed size and ball load.The paper presents the status of progress in the model development. The upgraded model will greatly enhance its application to challenging design and optimisation studies required to optimise the performance of SAG milling circuits.CITATION:Kojovic, T, Hilden, M M, Powell, M S and Bailey, C, 2012. Updated Julius Kruttschnitt semi-autogenous grinding mill model, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 71-80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By J. E. Bernick, J. Davies

This paper describes the design and construction of a 22.86 m (75 ft) long jacked tunnel, which was successfully installed, despite difficult mixed face conditions at Metro-North’s Westport Station, in Connecticut in the fall of 2003. The tunnel utilized what is believed to be, the first application of a steel grillage system within the United States. This grillage was installed before the jacking started and allowed the tunnel to be jacked under four live railway tracks, which included the Acela high speed line, without affecting train operations. The clearance between the top of the tunnel and the rails was only 0.9 m (3 ft).

Jan 1, 2005

By R. G. Fleck, W. R. Webb

Iron ore mining in the Adirondack region of northern New York dates back to the Revolutionary War. It is recorded that Benedict Arnold in his campaigns in the Lake Champlain area during the American Revolution utilized the local ores to produce armament and cannon balls. Through the efforts of early pioneers, the iron mining industry in northern New York gained impetus so that in the 1880's mines in the area accounted for nearly one fourth of the iron ore produced in the United States. Both magnetite and red hematite ores were mined during this period. With the discovery of the Lake Superior ores, the iron ore industry in New York started to decline and remained relatively unimportant until 1938. Modern day methods of mining and beneficiating sufficiently high tonnages of low-grade ores to justify the large expenditures for plant and equipment prompted a resurgence in northern New York mining. During the past several years, the production of iron ore from the Adirondack magnetites has greatly increased, and production which amounted to .6%, of the United States total during the 1918-1928 period (Mining and Metallurgy, November 1943) has been increased to 2.85% of the total in 1948. Today, Republic Steel is mining in the Port Henry-Mineville and Lyon Mountain areas; the

Jan 4, 1950

Study on Basic Theory of the Grain Settlement in Fluidised Bed This paper takes thick goal grains (less than 1.5 cm) as research object. According to different densities and particle sizes, thick goal grains are divided into 20 kinds of narrow density and narrow size level average grains. Free settling and hindered settling tests are respectively carried out in ?100 fluidised bed thick goal separators. Hindered settlement includes hindered settling velocity test and measurements of suspension density. Results show follows. (1) Fluid state in separator belongs to transition region. Alien's law is the appropriate formula of thick coal particles free settlement terminal velocity. (2) The main factors affecting hindered settling velocity are the number of solid particles in medium and the structure feature of the particle group. The bigger volume fractions of solids ? is, the smaller decreasing velocity coefficient of particle hindered settlement ¯ becomes. In the organism from bottom to top, density of suspended particles in fluidised bed gradually decreases, but near the top of the suspended particles, the density increased slightly. With increase of density and size, suspension density reducing extent increases from bottom to top of separators.

Sep 13, 2010

By W. Greuer

The objective of this paper is to demonstrate how site-specific slope stability analysis can be performed entirely from the desktop with satellite images, Geographic Information Systems (GIS), and slope stability software packages. This type of analysis would effectively eliminate or restrict the need for expensive field testing of geotechnical properties of a hillside, pit wall, berm, or embankment, and would be particularly useful for slope failure mitigation at remote or otherwise inaccessible locations.

Jul 17, 2000

By S. Lubbe

South Africa and Australia are the biggest suppliers of zircon sand to the international zirconium industry. However neither South Africa nor Australia is well known for zircon beneficiation. Geratech Zirconium Beneficiation Ltd (GZB) continued with additional research on sodium hydroxide (NaOH) cracking of zircon sand during 2002-2003. In 2003 GZB started extracting zirconium from zircon sand by means of NaOH cracking on a commercial scale. Experience has shown that temperature profile and atmospheric control inside the furnace is crucial for the beneficiation of zircon sand. Silica carryover to zirconium chemicals could result if a high temperature is used. Once the sodium silicate is extracted from the sodium zirconate and dissolved in hydrochloric acid, two distinct routes can be followed to precipitate various zirconium chemicals. The most common route is to precipitate zirconium oxychloride crystals (ZOC), with subsequent purification from all contaminants (crystal route). Less known is the process (liquid route) that involves the direct precipitation of zirconium basic sulphate (ZBS). This route will yield a less pure product, with contaminants such as silica and titanium. An important factor in this route is the prevention of silica gel formation, which could hamper final product filtration. For applications like paint drying (zirconium octoate) or antiperspirants (zirconium hydroxychloride) low levels of contaminants have no effect on the final product. The advantage of the liquid route is fewer production stages compared to the crystal route. The disadvantage of the liquid route is that the market for the products will be significantly smaller. The optimum solution could be a plant design that could cater for both routes. Another example of an application of zirconium chemicals is the use of ammonium zirconium carbonate (AZC) in the paper industry. Zirconium basic carbonate (ZBC) is dissolved in ammonium carbonate to produce AZC solution. AZC is used mainly in European countries in the paper industry. For example, carton boxes were initially produced with formaldehyde as the binder, however, it has now been replaced with AZC since formaldehyde is considered toxic. AZC reacts with the cellulose fibres in the paper to act as the binder. The resulting product is not toxic, and printing ink dries very quickly due to the porous paper structure. Other applications of zirconium chemicals involve the use of acid zirconium sulphate tetrahydrate (AZST), zirconium orthosulphate (ZOS), potassium zirconium carbonate (KZC), and zirconium hydrous oxide (ZHO). Fluoride-based zirconium chemicals like zirconium tetra-fluoride (ZrF4) and hexafluoro-zirconic acid (H2ZrF6) are used in the aluminium industry. Zirconium oxide (Zr02) can be produced from any of the abovementioned precipitated chemicals via a high-temperature decomposition process. The physical properties of such oxides can differ tremendously, depending on the final application. The fired density of sanitaryware is typically 5.8 g/cm3, compared to milling media at >6.1 g/cm3. The required fired density is achieved by controlling the precipitation and decomposition conditions for these two oxides. The same applies to stabilized and mixed oxides, for example where zirconium oxide acts as an oxygen carrier in fuel cells.

Jan 1, 2012

The Takasima Coal Mines comprise four islands near the entrance to Nagasaki Harbour, and are owned and worked by the Mitsu Bishi Company.There are several unusual features in the occurrence and working of these coal seams, the steep angle of "dip," the numerous seams of good coal separated by hundreds of feet of sedimentary rocks, the extensive faulting of the strata, and the way in which the coal is won, when so little surface is available for works, and where there is the ever present danger of subsidence of the roof and consequent flooding of the workings by the ocean. The author trusts that short notes on these few points will be of interest to members.The Islands are named respectively Hasima (Extreme Island), Nakanosima (Middle Island), Takasima (High Island), and Yokosima, and are situated about one mile from the main land.

Jan 1, 1901

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 M. Hesham El Naggar, Yasser Abdelghany

"ABSTRACT: The axial and lateral monotonic and cyclic behavior of helical pile foundations was investigated and new innovative helical screw systems suitable for seismic loadings were developed and patented. More than one hundred full scale field load tests were conducted on instrumented helical screw piles installed in cohesive soil. The piles included: plain helical screw piles (P-HSP); grouted (G-HSPs); fiber reinforced polymer FRP-G-HSPs; and reinforced grouted RG-HSPs. The RG-HSP piles axial capacity was more than twice that for P-HSP, with minimal reduction after cyclic loading, and their lateral capacity was more than 3 times the P-HSPs capacity. A 3-D finite element model was established. The results of 3-D finite element modeling were used to establish the load transfer mechanism and a design methodology for the considered piles.INTRODUCTION AND LITERATURE REVIEWHelical (screw) anchors have been utilized in tension loading and have gained popularity for bearing load applications. Helical piles represent an overall cost effective alternative to conventional piles for new construction and repair applications. The helical piles speed and ease of installation, less noise during installation added advantage with regards to their efficiency and reliability for underpinning including re-support and reconstruction of distressed and damaged foundations for either stabilization or rehabilitation. The “square shaft” SS175 pile is a segmented deep foundation system with helical steel bearing plates (helices) welded to a central steel shaft. Load is transferred from the shaft to the surrounding soil through these bearing plates. Segments or sections are joined with bolted couplings. Practically installed depth is limited only by soil resistance and economics. A helical bearing plate or helix is one pitch of a screw thread. All helices regardless of their diameter have a standard 75 mm pitch (Figure.1). The performance of single helical anchors and group action were studied experimentally and theoretically by several researchers, the researches focuses on the installation torque and uplift resistance. Some researches focus on the load carrying capacity with little pile response to cyclic loading effects or to instrumented full scale field testing. Helical piles axial compressive or lateral loading still is not well characterized and needs more analyses and their seismic performance was not investigated. For such this research was initiated to investigate the helical piles monotonic and cyclic performances under axial and lateral loadings to consider their usage in different applications in seismic zones. Among the several researchers, Clemence (1983); Mooney et al. (1985) conducted field and laboratory testing; Hoyt (1989), Hoyt et al. (1995), and Ghaly and Clemence (1998) conducted theoretical and experimental testing, Puri and Vijay (1984), Huang et al. (1995), Perko (2000), and Pack (2000) conducted theoretical analyses. Rao and Prasad (1993), Prasad and Rao (1994), conducted experimental testing; Vickars and Clemence (2000) studied the performance of helical piles with grouted shafts."

Jan 1, 2014

By C. Slotta, F. Charlier, P. Blomen

"Within the energy concept of the German government, the operating time of nuclear power plants was initially extended from about 8 to 14 years. It is planned, however, that every power plant will gradually be decommissioned until 2025 and that simultaneously the amount of renewable energies will successively be expanded. According to the political state, nuclear energy is a discontinued model. Looking at the global energy market, though, an obviously opposed development can be observed. At the moment, 443 nuclear power plants are running worldwide and further 62 facilities are being built. These about 500 nuclear power stations have to be supplied with nuclear fuel right now and in the future. The present paper will describe the worldwide use of nuclear energy, the extraction of the nuclear fuel uranium and in detail the available and predicted resources of uranium. The conclusion of the paper is the statement that uranium as nuclear fuel is no scarce resource but sufficiently available."

Jan 1, 2011

By M. Pernot

A 12 m-deep excavation has to be perfomed in the Shanghai soft clay to install an underground electric substation. This article was originally intended to study the behaviour of the wall, the excavation bottom and the surrounding ground during the excavation. Since the works are behind schedule, and the data referring to the excavations are not, therefore, available, the article is limited to a presentation of the analysis methods that we envisaged for the study of the behaviour of the excavation.

Jan 1, 2010

By Gordon Revey

The challenge of managing blasting risk, types of risk, public perception, and a system for managing risk were covered in the first part of this article in the May/June 2000 issue of the Journal of Explosives Engineering. This final part of this two-part series provides a method for identifying specific blasting risks and reviews the importance of community relations.

Jan 1, 2001

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

By David A. Lipton

In 1983, U.S. Bureau of Mines personnel examined mines, prospects, and mineralized areas to determine the mineral resources in the Carrizo Gorge Wilderness Study Area (WSA). The 14,571-acre WSA, located 42 miles east of El Centro, CA, is underlain primarily by Mesozoic granitic rocks and pre-Cretaceous metasedimentary rocks. Six prospects were found within the WSA and two mines are adjacent to it. Mineral deposits within the WSA have had insufficient development and rock exposures for calculating resources. The WSA contains no identified mineral resources; however, further exploration may disclose gem quality minerals. Two mines adjacent to the WSA, the Pack Rat and Beebe Hole, have produced gem quality kunzite and aquamarine from pegmatite dikes. According to the owners, a significant amount of gem minerals have been mined here in the last decade. Based on past production and the characteristic minerals indicating gem-bearing pockets, additional pockets are likely. Similar pegmatite dikes occur from Mt. Tule to Carrizo Gorge and may contain gem-bearing pockets. Pegmatite dikes also occur in the WSA near Rockhouse Canyon, but contained few of the mineral associations indicative of gem-bearing pockets. Manganese occurrences north of the Beebe Hole and Packrat Mines and within the WSA contain low concentrations of manganese. Significant sand and gravel were not identified. There is no evidence of deposits of oil and gas, or geothermal energy.

Jan 1, 1985

The copper-clay deposits consist largely of goethite and clayey mudstones carrying native copper, cuprite, and chalcocite. The mudstones are of Ordovician age, are interbedded with Fe-Mn carbonates, and probably contained syngenetic iron and copper sulphides. The secondary copper minerals have been derived from post-Devonian weathering in situ and also by deposition from surfaee and underground waters draining the adjacent mineralized volcanic rocks.

Jan 1, 1969