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By John F. MacDonald

From 19BS thru the present, Guy F. Atkinson Construction Company has been involved in several transportation construction projects in the Seattle area. Two of these contracts, the Mt. Baker Ridge Tunnel, and The Seattle Bus Tunnel, had unique foundation features. MT. BAKER RIDGE TUNNEL ACCESS PITS The Mt. Baker Ridge Tunnel is part of the general upgrading of the I-90 freeway between I-405 and I-5 (see Fig. 1). It is located on the western shore of Lake Washington and consists of a 1300 foot long large diameter tunnel thru Mt. Baker Ridge. The ridge consists of over consolidated silts and clays overlain by a loose to medium dense silty fine sand. The water table is perched in this upper layer of material. The clays of Seattle have a history of being very sensitive to excavation. The hills are marginally stable and numerous landslides have occurred recently in the area of the tunnel. [ ]

Jan 1, 1990

By Erdal Ünal

The computer program introduced in this paper is based on design guidelines developed for selection of support systems used in mine roadways. The support types considered include rock bolts as well as rigid and yieldable steel arches. Using the computer program, the design engineer can select the type, pattern and specifications of the support systems suitable for various roof conditions. The concepts utilized, assumptions made, support selection criteria and description of the computer program, developed for the PC, are included.

Jan 1, 1989

Some 50 miles of tunnel have been driven in the Snowy Mountains Area since tunnelling commenced in 1951. Hates have improved progressively due to the know-how of American supervision and use of large matched equipment of modern design.The work has been carried out by contractors, working almost exclusively under schedule of rates contracts. The Authority has maintained active research into tunnelling problems, especially that of support, and this has resulted in considerable economies and improved rates of progress. The contractors also have sought economies both by management and equipment techniques. Ammonium nitrate came into favour as an explosive essentially because of its lower cost, and handling techniques have improved progressively. Rock conditions preclude use of the "Mole" type equipment in its present stage of development, but one contractor introduced the "sliding floor" and this could exert a great influence on future tunnelling methods.Examination of tunnels that have been in service for some time confirmed the quality of the work and endorsed the policy of continued research and development.GENEHALThe Snowy Mountains Scheme provides for the diversion of the Snowy and Eucumbene waters through two transmountain tunnels to the western river systems. These diversions, together with additional regulations provided for waters already flowing inland, will provide an average additional discharge of 1,818,000 ac it per year for irrigation.Furthermore, approximately 6,000 million kWh of electrical energy will be generated annually in power stations with a total installed capacity of some 3,000,000 kW (Fig. 1.).INVESTIGATIONThe aim of investigation work is firstly to collect sufficient information to allow the overall scheme to be planned and then to follow up with detailed information on eachproject. The correct balance for all aspects of this work is a matter for keen judgment, as the tunnels must be planned...

Jan 1, 1963

By S. Bargigli, S. Ulgiati, M. Raugei, F. Cherubini

Metallic magnesium is mostly used in lightweight alloys in order to decrease fuel consumption in automotive applications. Several different production processes are currently used worldwide, and the magnesium production scenario is changing rapidly, with Chinese production increasingly dominating the world market. For the purpose of this paper, a novel approach to Life Cycle Assessment was applied, in which Material Flow Accounting and energy-based methods (Embodied Energy, Exergy and Emergy Analyses) are integrated and complemented, with a detailed description of the environmental hazards associated with emissions from all the different processes.

Jan 1, 2005

By K. T. Damodaran

The Chavara and Manavalakurichi placer deposits have been known since a long time for their rich reserves of heavy minerals like ilmenite, rutile, monazite etc. While detailed work has been conducted on the mineralogy and texture of the bulk placer sediments, reports on the detailed investigations on individual minerals are relatively scanty. Though, limited work pertaining to the chemistry of ilmenite has been carried out by Nair et al (1995) and Ramakrishnan et al (1997), a comprehensive study of the weathering patterns of ilmenite along the longitudinal and vertical profiles has not been, so far, undertaken. Data on the microscopic analysis of ilmenite from the southwest placers, too, is sketchy. The present work deals with the variation of the weathering undergone by ilmenite in the southwest placer deposits based on chemical and mineralogical analyses.

Jan 1, 2002

By D. C. Kaliampakos, A. G. Benardos

The existence of quarries near or even within the boundaries of urban centres is the cause of many environmental problems, despite their significant contribution to the cities’ development. Hence, the question arises as to how quarrying activities can be compromised within the spirit of sustainable development in big cities. In the case of Athens, two dominant, though opposite opinions have been formed. The first argues that all quarries must be forced to suspend their activities as soon as possible; the second presses for the continuation of quarrying. Consequently, the question is transposed on the dilemma between improved environmental conditions and economic development. This paper demonstrates that if a complete redesign is employed to specific, nonvisible quarrying sites, the continuation of quarrying activities is acceptable. It is a good compromise between the economical demand and environmental protection.

Jan 1, 2000

By Charlie Adcock, Rob Farnfield, Andy Wetherelt

The ISEE Blasters Handbook gives guidance on the level of air overpressure likely to cause occasional window breakage (151dB) and general window breakage (171dB). A long-term safe level of 140dB is also suggested. This guidance is widely used by demolition and other contractors to assess damage zones in the region of explosive applications employing unconfined charges. Other reference material gives more detailed guidance relating to window area, aspect ratio and glass thickness. Despite the guidance given in these references, complaints by members of the public regarding window breakage continue to be received by explosives engineers from air overpressure levels well below the longterm safe limit. Such complaints are not limited to the use of unconfined charges but can even be generated from the highly confined use of explosives in quarry blasting. This paper describes a series of experiments with explosive charges fired in unconfined conditions close to various window configurations. The aim of the work was to test the existing guidance levels and to extend the knowledge base in this area. Topics covered include the role of differential pressure across windows in the walls of an enclosed space such as a room.

Jan 1, 2006

By Brent Duncan, Doug Harding, Bob Stier

The 73rd Street Tunnel Project is part of “The Tunnel and Reservoir Plan” (TARP)also known as the Deep Tunnel Project, and is located in the Village of Bedford Park, County of McCook, State of Illinois. The project consists of a ø 4.42 meter × 2,060 meter long (14´-6? bore, 6,760 foot)tunnel. The completed tunnel is used as a bypass tunnel for the McCook Cup Reservoir Project. The project was awarded to Affholder Inc. of St. Louis, in 2000. The paper describes the project in which a new, high-powered open gripper type main beam machine was used in which high advance rates have been achieved using conventional muck haulage techniques. Features of the project include the installation of rock support consisting of counter-sunk rock bolts that are required to be pull-tested for strength per project specifications. Installation and testing of the bolts are done during the boring cycle. Muck haulage was done by conventional muck car train and hoisting at the construction shaft. As the site layout did not include a tail tunnel, the trains needed to be shuttled at the shaft bottom. Even with the bolting requirements and the muck haulage without a tail tunnel, the Affholder site personnel still achieved high advance rates on the 73rd Street Project.

Jan 1, 2003

By R. S. Pratt

IT is proposed to discuss the materials and furnaces, as well as the melting procedures used in preparing metal for casting billets, bars or cakes for mill fabrication. As far as possible, consideration will be given to the alloys that are commonly made in most brass mills producing strip, tube, rod and wire. RAW MATERIAL The basic raw material for such mills, of course, is copper, which may be obtained in the form of ingots, ingot bars or cathodes. Refinery-cast ingots and ingot bars, which are simply double ingots, are supplied in accordance with A.S.T.M. Specifications as regular electrolytic or fire-refined tough-pitch copper. In the wrought-metal industry, the electrolytic brands have been preferred, although during the war large quantities of fire-refined coppers sufficiently pure to be suitable for all existing requirements were imported from South America. With the exception of Lake copper, most primary fire refined coppers produced in this country have not been considered satisfactory for wrought metal alloys. Cathode copper, which is now widely used instead of ingot copper for alloying, is the electrolytically deposited metal that is normally remelted in the production of electrolytic tough-pitch ingots. It is in the form of rough, flat plates not suitable for processing but quite satisfactory for melting when sheared into suitable sizes. Raw zinc is perhaps the next most important raw material and this is obtained in various grades, depending on the analytical requirements of the alloy to be made. The grades of zinc as outlined in the A.S.T.M. Specifications vary in cost with the amount of impurities-lead, iron, cadmium-and are purchased in such a way as to produce the most economical mixture consistent with the purity required in the alloy. Other virgin metals (lead, tin, aluminum and nickel) are used in varying quantities for making copper alloys. These elements can also be purchased in accordance with the appropriate A.S.T.M. Specifications where available. Also available are a number of special alloys, which are used as deoxidizers or as means of adding relatively small quantities of elements not suitable for adding directly as virgin metal. In this category are such materials as phosphor copper or phosphor tin, silicon copper, manganese copper, cadmium copper, and copper-iron or zinc-iron alloys. Some of these alloys may be purchased on a definite alloy basis or may be produced in the plant itself for its own use. For largely economic reasons, however, a great proportion of the charge to the melting furnaces consists of alloy scrap. In the production of many finished products, as much as 70 or 75 per cent of the metal originally cast may be discarded at various points along the production line. This material eventually finds its way back to the casting shop as mill scrap, overhaul or scalping chips, skeleton scrap, rod turnings, or miscellaneous fabricating scrap. One of the most serious problems in the

Jan 1, 1946

By O. Bazhko, F. D. L. Uahengo, Y. R. S. Hara

Although the conventional acid-reductive leaching method effectively extracts copper (Cu) and cobalt (Co) from Cu–Co oxide ores, efforts to enhance hydrometallurgical performance are ongoing. This study evaluates the influence of sulphuric acid (H2SO4) and sodium metabisulphite (Na2S2O5) on metal extraction from Zebesha Cu–Co oxide ore using ferrous sulphate heptahydrate (FeSO4·7H2O) and ferric sulphate (Fe2(SO4)3) as lixiviants. Ore samples (<150 μm) were leached at ambient temperature for two hours, and metal concentrations were determined via X-ray fluorescence analysis. In the FeSO4·7H2O system, Co, Mn, and Ni recoveries increased w=ith Na2S2O5 concentration, reaching a maximum of approximately 80% Co at 150 kg/t, while Cu recovery remained below 5%. Conversely, with Fe2(SO4)3, Cu recovery peaked at 88% at 50 kg/t Na2S2O5, then declined to 79% at 150 kg/t. The addition of H2SO4 improved metal recoveries in both systems. Notably, 60 kg/t H2SO4 yielded 92% Cu extraction in Fe2(SO4)3, while Co, Ni, and Mn remained below 40%. However, in FeSO4·7H2O, Co recovery improved from 40% to 84%. These findings suggest Na2S2O5 is more effective for cobalt extraction with FeSO4·7H2O, whereas H2SO4 enhances copper extraction in Fe2(SO4)3.

Oct 24, 2025

By G. S. Scott

In the course of the investigation into the causes, behavior, and control of mine fires, which the Bureau of Mines is now conducting, some attention was given to the subject of spontaneous heating. It is self-evident that the temperature of a pile of broken coal will rice if the rate of generation of heat exceeds the rate of brat dissipation and will fall if the opposite is the case. Factors that affect the rate of generation of heat are:

Jan 1, 1941

A stronger U.S. economy stimulated the domestic mineral sector in 1994. Metals demand was spurred by robust U.S. motor vehicle sales, while demand for major industrial minerals rose in response to highway and building construction. Domestic mineral and material demand is expected to increase in 1995, particularly if interest rates do not restrain the building industry and international monetary exchange rates remain advantageous to U.S. automobile manufacturers. Additional information on events, trends, and issues in the mineral and material sector is presented below and in the commodity sections that follow. Overall Performance Processed materials of mineral origin produced in the United States during 1994 increased to an estimated value of $360 billion. Domestic output of raw nonfuel minerals in 1994 was estimated at $34 billion, about 6% more than that of 1993. The value of U.S. minerals production has increased in 29 of the last 34 years.

Jan 1, 1995

By Jeffrey A. Schaefer

The Olmsted Locks and Dam project is located on the Ohio River approximately 16.5 miles upstream of its confluence with the Mississippi River. It consists of twin 1200 ft. locks with floating and fixed approach walls, five 110 ft. wide tainter gate bays, a 1400 ft. wide navigable pass boat operated wicket gate section, and a 400-ft. section of fixed weir (Fig. 1). The project will have a total cost over 1.0 billion dollars, and as such is one of the largest civil works project underway in the Corps of Engineers.

Jan 1, 2001

By Don Steffa

Drift mining, according to California mining terminology - and it is distinctly a California development - is the blocking out and extraction (breasting) of the auriferous gravels of an ancient buried stream either through tunnels, inclines, or shafts; it is one of the minor divisions of the larger classification known as placer mining. The contribution of each of these divisions and of lode mining to the gross production of gold in California totals as follows:3 [ ] The total amount of gold recovered from the placers of California from 1848, when Marshall discovered the precious metal in the mill race at Coloma, to 1928, was $1,226,515,404. The same period saw a total gold production from all operations of $1,823,562,360.

Jan 1, 1932

By A. E. Anderson, H. J. Hilll

Laboratory data for 155 field muds and 77 .shales have been used to develop correlations to estimate the net streaming potential component of the SP. Analysis of these data and comparison with field tests show that streaming potential corrections must be made to obtain an accurate estimate of the electrochemical potential for use in the determinntion of formation water resi-iiviy. The self-potential curve is related to formation water resistivity, and considerable effort within the oil industry has been directed toward clarifying this relationship. The Schlumbergers and Leonardon1,2 recognized that two types of potentials, electrochemical and electro-kinetic, resulted in the net potential variation in the borehole. Most of the later papers have dealt with the electrochemical component and its controlling parameters. The investigations of Wyllie,2" Salisch&apos; and Moore5 provide the most extensive sources of data on streaming potentials across mud cakes. These authors observed streaming potentials of sufficient magnitude to be of critical importance in SP interpretation, if it is assumed that streaming potentials develop only opposite permeable beds. Streaming potentials across shales have been reported by Schenck and by Gondouin, et al.7 Since SP magnitude is the difference in potential opposite shale and sand beds, these authors suggested that the net streaming potential component may be negligible. The present investigation was initiated to evaluate empirically some of the parameters controlling the magnitude of the net borehole streaming potential and to determine whether useful relations between mud properties and net streaming potential could be established. Field muds were used in this investigation. These muds were characterized by the amount and type of chemical treatment utilized for five days before Sampling. Filter loss, mud resistivity, mud density and filtrate resistivity were determined for each mud with conventional methods and apparatus. Mud filtrate pH was estimated with Hydrion pH paper for the appropriate range. Streaming PotentIals Across MuD Cakes Commercial calomel-saturated KC1 electrodes are subject to potential changes attributed to contamination of the very small fiber-tip bridge by particles of clay from the drilling mud.3 To minimize this difficulty, a large diameter bridge (Fig. 1) was constructed with saturated KC1-agar gel and a filter disc of microporous porcelain. Experiments showed that streaming potentials across this bridge are less than 0.2 mv at pressure dif-

In 2007, a total of 4,639 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Stone mines comprised 31.2% of all mining operations. ? Mines producing the primary commodity of limestone (crushed and broken) comprised the largest number of operations (n=2,051; 44.2%). ? Stone mining operations were located in all states and territories except Delaware and North Dakota. ? Pennsylvania had the most stone mines (n=373; 8.0%), followed by Texas (n=352; 7.6%).

Aug 1, 2009

By GILBERT C. DAVIS

ANY thought of Morenci naturally includes its sister town of Clifton, its gateway to the outside world. Clifton, the country seat of Greenlee County, is the terminus of a branch line of the Southern Pacific railroad from Lordsburg, N.M. Carload freight incident to the Morenci operation moves from Clifton over Phelps Dodge?s standard-gauge industrial railroad. Private freight must be hauled by truck. These two communities fell far short of supplying adequate housing for the personnel concerned with the new operations so a new townsite, Stargo, was developed adjacent to Morenci. Here 234 housing units with garages have been built and twenty similar units have been erected near the reduction works.

Jan 1, 1942

By R. L. Virta

Editor?s note: Each year, the June issue of Mining Engineering features an industrial minerals review. Several people put in a fair amount of time in developing the material for this issue. Thank you to the industrial minerals annual review editor, to the technical committees chair and vice-chair, and to the authors of the individual commodity profiles. Jim Norman, member SME, of GeoTrans Inc., is the industrial minerals annual review editor. Abani Samal, member SME, of Pincock Allen & Holt, is chair of the industrial minerals technical committees. Technical committee vice chairs include: ? Abani Samal, member SME, of Pincock Allen & Holt, agricultural minerals. ? Aaron McMahon member SME, of Pincock Allen & Holt, ceramics and refractories ? Bradley S. Van Gosen, member SME, of the U.S. Geological Survey, chemical raw materials. ? Mark Zdunczyk, member SME, of Continental Placer Inc., construction materials. ? Jerry Gauntt, member SME, of Marston, fillers and pigments. ? Michael Cheshire, member SME, of Indiana University, sorbents, filters and process aids. ? Candace Trimble, Oil-Dri Corp. of America, specialty minerals. Their help makes possible this June industrial miner-als issue. On behalf of ME readers, the editors thank them. Ball Clay Four companies ? H.C. Spinks Clay (owned by Lhoist Group), Kentucky-Tennessee Clay (owned by Imerys Group), Old Hickory Clay, and Unimin Corp. ? mined ball clay in four states in 2008. Production, on the basis of preliminary data, was 964 kt (1.1 millon st) with an estimated value of $45.3 million. That was a 10- percent decrease in tonnage from 1.07 Mt (1.2 mil-lion st) with a value of $49.2 million that was produced in 2007. Tennessee was the leading producer state with 63 percent of domestic production, followed by Texas, Mississippi and Kentucky. About 73 percent of production was airfloat, 16 percent was crude and 11 percent was water-slurried.

Jan 1, 2009

Review of the mining legislation in New Zealand has coincided with a number of radical changes. These include a redirection of economic management towards a more open and competitive economy; major reform of the state sector aimed at greater efficiency, transparency and accountability; a new environmental administration; and a fundamental review of policy for management of natural and physical resources. These changes provide an opportunity to develop a consistent and coherent approach in the minerals and related statutes that will achieve objectives of economic efficiency, equity, practicability and good environmental management.

Jan 1, 1987

Notwithstanding full concurrence with the dictum of a famous scientist that &quot;definitions are the most accursed of all things on the face of the earth,&quot; in view of the considerable confusion which exists in jigging nomenclature, it is considered advisable to commence this paper with the following explanations of the terms which will be used throughout the text.Jig Bed. The whole layer of material lying on top of the jig screen.Ragging. The layer of denser material lying immediately above the jig screen, which is too coarse to pass through this screen and is confined horizontally by the cells of the top grid.Ore Column. The layer of ore pulp between the ragging and the top-water.Top Water. The water, carrying fine material in suspension, which flOiWS over the surface of the jig bed.Hutch Water. The water added to the jig below the screen. (Except for the water discharged with the hutch concentrate, the &quot;hutch-water&quot; eventually becomes &quot;top-water.&quot;)Feed Water. The water in the ore pulp fed to the jig.(This water becomes part of the &quot;top-water.&quot;)Pulsion. The period of the jigging cycle during which the water is moving upwards relative to the particles in the jig bed.

Jan 1, 1937