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By Jacques Mongrain, Serge Barbeau, Gary Brierley

The Communaute Urbaine de Montreal is currently involved in construction of the South Interceptor which consists of 53 kilometers (33 miles) of 1,800 mm (6.0 ft) to 5,400 mm (18.0 ft) diameter tunnels for the purpose of collecting, storing, and delivering sanitary and combined sewage to the treatment plant. Work is divided into ten separate contracts; nine of which have already been bid. The purpose of this paper is to describe construction activities that have been performed through the end of 1986 with emphasis on a general layout of facilities, a summary of subsurface conditions, and brief descriptions of actual construction activities for the six contracts where tunneling has been performed. All projects are being excavated with tunnel boring machines.

Jan 1, 1987

By G. Konstantopoulou

Environmental degradation due to abandoned quarries is an international problem, more intense when these sites are found in urban or suburban zones, in environmentally sensitive areas or are visible from sites of special interest. Rehabilitation solutions applied worldwide, range from simple relief restoration and planting to more sophisticated site exploitation in order to serve specific social needs. The elaboration of rational rehabilitation plans for every site presupposes deep knowledge and comparative evaluation of all the parameters of the problem. In this paper, a methodological approach of rehabilitation solutions for abandoned quarry sites is elaborated, based on domestic and international experience and practice. Solutions are grouped in eight main categories. In every category the framework of prerequisites and confinements (environmental, technical, social, economic, legal) for their application in Greek quarry site is investigated. A comparative assessment of alternative restoration solutions is introduced, using tools supplied by environmental economics, cost-benefit analysis, G.I.S. and multi-criteria analysis and follows in two stages: 1) Establishment of a set of criteria aiming at a priority list for a number of quarry sites located in a geographical or administrative district. 2) Assessment of alternative solutions for every single quarry from the previous priority list for the selection of the most adequate using technical, economical, social and environmental criteria.

Jan 1, 2008

By A. S. Ericson, J. H. Corrigan, E. J. Jahnsen

Calcine is transported from the Reduction Plant at 850°C in insulated hopper cars and charged into three rectangular electric melting furnaces each equipped with three - 18.5 MVA transformers. The electrical energy is applied through six in line prebaked carbon electrodes, and slag and metal are tapped at opposite ends of the furnaces on an intermittent basis. The slag, 5000 tonnes per day, is disposed of by a pot train directly to the dump. The ferronickel, 250 tonnes per day, is tapped into 40 tonne capacity ladles in which it is refined in two ASEA-SKF ladle furnace stations. Casting is done over lip at 1520°C in a pig casting machine with stepless speed control at up to 55 tonnes per hour. The ingots are stacked into self palletizing bundles weighing about 1500 kilograms and are strapped and tagged and transported to the seaport, from which the final shipment is made to the world market. The paper describes constructional details and gives information of both normal operation and start-up and shut-down procedures. Consumption figures for refractory, electrodes, electric energy and refining additions are given and metal chemistry is given before and after refining.

Jan 1, 1979

By K. F. Jakob

Sustainable development is a principle for the way we should act in the present. It ensures also options for the future to achieve a balance between social, economic and ecology development. The efficiency of raw material utilisation is being enhanced through technological developments, starting from extraction through all the following stages of the value creation chain. The use of domestically produced resources helps to assure the technological know-how. Additional indicators being collected and published by individual companies are questionable in countries with a tightly regulated legal framework such as in Germany, but make sense in developing and threshold countries. Sustainability in terms of efficient use of raw materials will manifest itself at the next stages of the value creation chain. Examples for efficiency improvement can be found in the steel, the power generation and agriculture industries. The approval procedures for German mining operations entail an internationally extremely strict assessment of the potential impact on the environment. All the mining activities include remediation and recultivation where the practise in Germany has become model character by international levels.

Jan 1, 2005

By Lawrence K. Nordell, Vinit Sethi

Published standards and specifications do not adequately cover engineered class pulleys for modern high strength steel cord belt conveyors. This paper discusses the Conveyor Dynamics, Inc. (CDI) design criteria and stress analysis techniques emphasizing the finite element method (FEM), fatigue failure criteria, design limits and manufacturing requirements to ensure successful and safe pulley installations.

Jan 1, 1993

By P. Soupios

Seismic geophysical methods have long been used by geologists and geophysicists to delineate subsurface features. These techniques work because different types and strengths of soil and rock transmit energy at different velocities. The Crosshole-Downhole tests (CH-DH) and seismic refraction survey (RS) are among the most used methods in engineering applications to obtain the elastic properties of subsurface layers. As a result, seismic methods have evolved into a cost-effective tool for rapidly determining depth to bedrock in engineering and construction projects. The seismic methods are best suited to sediment thickness analysis, bedrock quality determination and detection of the presence of weaknesses in the bedrock before the erection of any civil engineering structures such as bridges, tunnels, dams and portals. Seismic methods are also useful in estimating the rippability of bedrock ahead of construction. These methods are particularly useful for large-scale projects that require a significant number of drill holes, resulting in a substantial investment of time and costs for drilling. The CH-DH and RS methods are typically comparable in total cost to drilling, but provide significantly more information in 2-D and 3-D and therefore reduce the likelihood of conceptually oversimplifying the subsurface conditions. The above mentioned methodologies were considered to be the most appropriate geophysical methods for investigating the shallow structure and the dynamic soil properties of the area where the Ilarionas Dam is scheduled to be constructed. The main target of this work was to prove the potential of geophysical methods in providing accurate information to the civil engineer and to obtain information on the dynamic soil and rock properties for earthquake design analyses for the dam construction. Specifically, nine refraction seismic profiles and three cross-hole-downhole seismic tests were implemented to determine the subsurface conditions of the study area. The tests determined the shear and compression wave velocity profiles versus depth and other crucial parameters such as Young and Rigidity modules. Furthermore, they allowed the detailed 2-D mapping (along several profiles of the study area) of the subsurface variation of the soil and rock dynamic moduli.

Jan 1, 2006

By Gordon T. Clark, Stephen H. Gleaton

This paper discusses the conceptual design of cut-and-cover tunnels currently being considered as one of the replacement options for the earthquake damaged, elevated double-deck highway and seawall built in downtown Seattle 50 years ago. The 4.8 km (3 mile) long, 6-lane improvement consists of 1.6 km (1 mile) of at-grade roadway with aerial interchanges, 1.6 km (1 mile) of large two-level cut-and-cover tunnels along the Elliott Bay waterfront, and retrofit of the 50-year old, 1.6 km (1 mile)long Battery Street tunnel and north transition to grade. Construction of deep cut-and-cover tunnels, in complex glacial geology overlain by hydraulically placed fill immediately adjacent the existing sea wall, will require extensive use of concrete diaphragm walls, ground improvement and dewatering. The potential liquefaction and lateral spreading of the fill materials in this active seismic region pose significant design challenges and risk.

Jan 1, 2003

By Bruce B. Hanshaw

The Tertiary carbonate aquifer of central Florida is composed of about 2/3 calcite and 1/3 dolomite with minor amounts of quartz and apatite. The Mg content of the calcite is lower in the recharge areas than in the deeper confined parts of the aquifer system. Various geochemical lines of evidence indicate that much of the dolomite is of penecontemporaneous origin but that some may have been formed much later, possibly by ground water. Theoretical studies indicate that the Mg/Ca ratio in solutions is about unity for the three-phase equilibrium, calcite-dolomite-water. Solutions, such as ocean water and some subsurface brines, have Mg/Ca ratios higher than one and should represent dolomitizing solutions. In the areas of principal recharge to the Floridan aquifer, ground water is undersaturated with respect to both calcite and dolomite, and the Mg/Ca ratiois as low as 0.05. As the water moves downgradient, the Mg/Ca ratio systematically increases and approaches unity; saturation of the solution with respect to both calcite and dolomite also increases with length of travel in the system. Thus, in the zone of active potable-water circulation, the chemical process is one of dissolution of minerals until saturation is reached or exceeded. However, in the deeper brackish-water zones that underlie peninsular Florida, dolomite may be forming where the Mg/Ca ratio is greater than one. The necessary Mg may be derived from ocean water or brines recycled through the system as the hydrologic regimen is changed. The driving force may be simple mixing, relative fluctuations of sea level, or a combination of mechanisms.

Jan 1, 1972

By Jamal Rostami, Alireza Salimi, Christian Moormann

"Rock mass classification systems are often applied in many empirical design practices in rock engineering, some contrasting with the original intent and applications of these classification systems, for example, estimation of TBM performance in various ground conditions. While accurate estimation of machine performance is significantly impacted by rock mass properties, parameters used in many of the existing classifications are more related to ground support design and not rock mass boreablity. The results of many investigations on this issue have shown a weak correlation between TBM rate of penetration and rock mass classification. This limitation can be overcome by fine tuning the rock mass classification input parameters to represent influence of rock mass properties on TBM performance as has been the objective of RME or QTBM. This paper will offer an overview of the impact of rock mass on TBM performance and introduces an empirical equation for predicting performance of rock TBMs based on rock mass classification. The results of the preliminary analysis of a new model has revealed that the use of the proposed system can offer a reasonable accuracy for estimation of TBM performance in various rock masses. 1. INTRODUCTION Hard rock tunnel boring has become more or less the standard method of tunneling for tunnels of various sizes with lengths over 1.5–2 km. Estimating the performance of TBM is a vital phase in tunnel design, and for the choice of the most appropriate excavation machine. During the past three decades, numerous TBM performance prediction models for evaluation of TBM rate of penetration and advance been proposed. In brief, all the TBM performance prediction models can be divided into two distinguished approaches, namely theoretical and empirical ones (Rostami et al., 1996). The most common and recent works on this topic are summarized in Table 1. Currently, two models including Colorado School of Mines or CSM (Rostami and Ozdemir, 1993; Rostami, 1997) and Norwegian University of Science and Technology or NTNU (Blindheim, 1979; Bruland, 1998) models are the most recognized TBM performance prediction and prognosis models in use around the world."

Jan 1, 2016

By John K. Adams

Phosphorus may be incorporated into sedimentary rocks in at least four different ways: (1) by the accumulation of detrital mineral fragments, (2) by the accumulation of phosphatic organic debris, (3) by diagenesis and (4) perhaps by the primary precipitation of calcium phosphate. Based-on the petrographic examination of Cretaceous and Tertiary sediments from the northern and central parts of the Atlantic Coastal Plain, Diagenesis is the most important of these mechanisms. Both syndiagenesis and epidiagenesis are required to explain the origin of all the diagenetic phosphate mineral species which occur in the northern and central parts of the coastal plain. Syndiagenesis produced much of the coastal plain's apatite. It was operative below the sediment-water interface while the substrate was being compacted. Compaction forced pore waters, which were enriched in phosphate by the decomposition of organic matter, upward through calcareous sediments. The PO43- radicle replaced the CO23- and calcareous nodules, pellets and shell fragments were converted to apatite. Epidiagenetic reactions occurred in the subaerial environment where downward percolating meteoric waters carried phosphate in solution to cites where cation activity was sufficiently high to form new minerals. Vivianite may form where ferrous iron is available and wavellite and variscite may form in the presence of aluminum rich minerals. Textural evidence suggests that many of the reactions were repeated. The present day appearance of apatite, vivianite, wavellite and variscite in the coastal plain may represent several generations of diagenesis.

Jan 1, 1972

By Jesus M. Rohena

Concrete pipes and small boxes have been installed by the jacking method. This paper will describe a recent project were large concrete boxes were installed by the jacking method. This project is in the city of Boston, MA. By now everyone in the USA knows something about this project. The project official name is The Central Artery/Tunnel Project (CA/T). This is the biggest public work project in the USA right now, with an estimated construction cost of 14 billions. The main objective of the CA/T project is to replace an existing artery built in the 1950s to increase capacity and safety. One section of the new artery will cross under several railroad tracks near the South Station. To construct the section of the new artery under these tracks, big concrete boxes were installed by the jacking method. The jacking method can be used to install pipes, small concrete boxes, and the CA/T project has demonstrated that big concrete road tunnel boxes can be installed by jacking.

Jan 1, 2003

By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

"There are three distinct producing iron ranges in Minnesota, the Vermilion, Mesabi and Cuyuna. In trend the Vermilion and Mesabi are approximately parallel (E.N.E. and W.S.W.) and about fifteen to twenty miles apart. The Vermilion lies farthest north, near the. Canadian boundary. It is from seventy-five to eighty miles due north of Duluth. The length of its productive part is about twenty miles.The Mesabi Range is from fifty to seventy-five miles north and northwest of Duluth. Its length along the strike is about 110 miles, and the length of its present productive area about eighty miles. The Cuyuna range lies southwest of Duluth nearly ninety miles, and is the last of the Lake Superior iron ranges to be developed. The relative positions of the ranges are shown on an accompanying map. The Mesabi Range is by far the largest producer and contains the largest ore reserves of the three. The Cuyuna is next in quantity of proven ore, and in production since 1916, while the Vermilion is first in average quality of ore.On the west, both Vermilion and Mesabi ranges disappear beneath heavy glacial drift; and on the east, extend into Canada, the so-called Gunflint range near the international boundary being an eastward continuation of the Mesabi formation. This latter range is of no economic importance, however, at present. The exploration and development of the Cuyuna range has proved up a considerable tonnage of manganiferous iron ore, besides ordinary merchantable iron ore."

Jan 1, 1920

By Duk-Wom Park

INTRODUCTION he most important information required for the engineering design of structures in rock is its inherent rock properties. Without providing adequate parameters on the rock property, high quality of the engineering design cannot be expected. Many laboratory rock testing methods have been developed, but they are mostly for testing intact homogeneous rock without appreciable discontinuities. In reality, the intact rock properties do not represent the behavior of rock masses because rock masses include irregularities such as joints, cracks, interlayers, variations in mineral compositjon, etc. In general the type and intensity of the rock defects may be much more important than the type of rock which will be encountered (Terzaghi, 1977; Bieniawski, 1984). In-situ rock testing can provide better information on rock parameters, but it takes a tremendous amount of effort, time and cost. In recent years, numerical modeling techniques are gaining popularity as a design tool for structures in rock bodies due to the enormous progress in computer technology (Wang, 1985; Kripakov and Melvin, 1983; Park and Ash, 1985), but it is quite dangerous to use numerical techniques without having proper input data. Bieniawski (1984) states as follows: Some design methods such as numerical techniques have outpaced our ability to provide the input data necessary for the application of these methods. In order to provide an adequate amount of input data, an extensive testing program may be required, thus major efforts in time and expenses are commonly spent, In this paper, a new rock testing method, which utilizes the principles of laser holographic interferometry, is introduced. This method requires only a few minutes to measure the modulus of elasticity and quality of a rock core sample, which does not have to be cut or ground. The Poisson's ratio can also be measured in a few minutes from a sliced rock specimen. HOLOGRAPHIC INTERFEROMETRY Principles of Holographic Interferometry In 1948, Gabor invented holography, which is the technique of reviving three dimensional images using a monochromatic light source. A full demonstration was not made then because a clean monochromatic light source was not available. Later, in the early 19601s, the laser was adopted as a monochromatic and coherent light source (Leith and Upatnieks, 1963). Since then, applications have been made in many different fields ranging from crime prevention to three dimensional television. In this technique, an image is usually recorded by means of constructing a hologram which is a record of the interference pattern formed on a high resolution photographic system as shown in Figure I. A beam splitter divides the laser beam into two beams: (1) an object beam which is expanded while passing through a beam expander and illuminates the object, and (2) a reference beam which is expanded and illuminates the holographic plate. Subsequent to an exposure, the holographic plate is developed and illuminated by the expanded reference beam. The original scene of the object is revived in a three-dimensional image. The entire instrument should be placed on a vibration free environment. The wave fields reflected by the object in two slightly different configurations can be superimposed to form an interference fringe pattern. Thus, it is possible to measure the displacement that took place between the two configurations. This method is called holographic interferometrv. There are two methods of achieving this phenomena. The first is the double exposure method, wherein two exposures of the object are made prior to developing the film. The first exposure represents the original condition and the second, the disturbed condition. The second method is the real time holographic method. In

Jan 1, 1986

By Richard C. Fox

"Why geophysics? We will have to drill anyway." Reliance on geophysical methods for detailed target appraisals will increase as direct surface evidence becomes more subtle. This will create a need for more effective and efficient geo- physical programs. Numerous computer-based techniques that deal with a broad range of geophysical problems are described in the literature. The purpose of this chapter is to provide a framework for the systematic application of these techniques to effect an overall optimization of the geophysical appraisal. The concepts described are not technique specific, but should serve as a guide for increasing the effectiveness and efficiency of any geophysical program. Fig. 1 shows a generalized flow chart of the major aspects of the program described. The three main subdivisions of a 'geophysical program are discussed: (1) survey design, (2) data processing, and (3) data interpretation. Detailed flow charts, outlining the goals, the requirements for meeting the goals, and the steps followed within each subdivision are presented at the beginning of each section. The objectives and type problems of each subdivision are defined, followed by a description of applicable computer methods. . References are cited that give a general cross section of computer techniques available in the literature, and examples are given in each subdivision to demonstrate basic concepts and the use. of computers in solving the type problems.

Jan 1, 1979

By Theodore Triplett

To assess the value of various subsidence mitigation techniques, twelve linear foundations were constructed above a longwall mine. The structures were monitored during and after undermining, and footing curvatures at the time of cracking were compared with predicted values. An unreinforced concrete footing sustained substantial damage. Other footings received varying degrees of damage, with inclusion of a sand layer significantly affecting performance. A post-tensioned concrete foundation suffered minimal cracking. Also, a technique developed by the Bureau of Mines is presented for determining the subsidence, slope, curvature and strain of the ground surface.

Jan 1, 1986

By P. D. Pattillo, J. B. Cheatham, Y. -H. Lin

The stability of a hemispherical cavity, intended to model a perforation opening in the vicinity of a borehole, is analyzed for the case of poroelastic-plastic material behavior. Two plasticity models of differing complexity are considered, with the emphasis in either model being the use of strain softening to calculate inelastic stiffness. Sample results illustrate the effect of steady fluid flow on the response, and possible collapse, of the near perforation region.

Jan 1, 1986

By D. M. Larsen

Since start-up in 1985, the Cannon Mine has produced and shipped a 170-g/ton (5 oz/ton) gold flotation concentrate to various smelters for gold and silver recovery. Several processes have been investigated to economically produce done' at the mine site from the refractory concentrate. This paper describes laboratory and pilot scale test work used in the process design and engineering. feasibility study of a 73-t/d (80 stpd) pressure oxidation and carbon-in-leach (CIL) facility. The designed pressure oxidation circuit utilizes a series of verti¬cal autoclave units operating at 170°C (338F) and 1.4 MPa (200 psig). Projected operating costs are discussed.

Jan 1, 1993

By Peter W. Harben, Edward M. Dickson

The distribution of metallurgical grade bauxite deposits will be discussed with the aid of a comprehensive table and a reference map. Information will include operating companies, mine locations, ore grade, and chemical analysis, geological environment, and production capacities. General comments will be made on the distribution of production and its relationship with major consuming regions. The pattern for the future will be assessed, including potential new producers, changing specifications and industry structure.

Jan 1, 1984

By Robert C. Dunne, Jeffery P. Vaughan

The Archean ores of Western Australia are in total the largest producers of gold in Australia. In addition to numerous small and medium sized deposits, the province also contains the giant Kalgoorlie Golden Mile deposits. A variety of different gold ore mineralogical associations has lead to the development of a number of different processing routes for both refractory and non-refractory ore types. Intense weathering and lateritization of Archean greenstones in the semi-arid Yilgarn region have resulted in the development of a deeply oxidized profile (60-100m) above most sulphide orebodies. Residual and re-deposited supergene gold within iron oxide/silica gangue of this zone responds well to CIP, CIL, heap and vat leaching techniques. Although gold is easily liberated in principal from oxidized gangue, in practice recoveries are sometimes affected by iron oxide coatings on gold grains, and by clay minerals which can interfere with plant performance. Refractory ore types in the Eastern Goldfields fall into three main categories - pyritic, arsenopyritic and telluride-bearing. Pyritic ores may be either free milling or require roasting. The difference appears to depend largely on whether gold occurs along grain boundaries or fractures, which can be liberated by grinding, or whether gold occurs as inclusions within pyrite grains and therefore cannot be satisfactorily liberated by grinding. Arsenopyrite bearing ores are not well understood and are complicated by what appears to be a variable degree of gold solid solution, in addition to included gold. Gold occurring in complex gold-silver telluride assemblages has traditionally been recovered by roasting in the Eastern Goldfields.

Jan 1, 1987

By Michael Schmalzel

Freeport-McMoRan Copper & Gold, Inc. (FMI) will soon begin copper production from the Dos Pobres and San Juan deposits near Safford, Arizona. Ore reserves total 615 M tons grading 0.36% copper, predominantly as chrysocolla. Copper extraction will be by leaching with sulfuric acid. Fluor Canada Ltd. provided EPCM services to design an ore handling and conventional SWEW facility capable of producing a nominal 240 million pounds per year of cathode copper. The ore handling facility will process 114,000 tons per day of ore through three-stage, open-circuit crushing followed by agglomeration and product placement on the permanent leach pad. Stacking of ore on the leach pad will utilize Terra Nova Technologies' "Super Portable" mobile stacking system. The stacking system fleet consists of 13 self- propelled, crawler-mounted mobile conveyor units, each with 72-inch-wide belting and a capacity of 6,800 tons per hour, including ten 250-foot-long portable conveyors, a horizontal feed conveyor, a 285-foot-long horizontal conveyor and a 220-foot-long radial stacker. PROJECT BACKGROUND Project History The Safford Leach Project is located in the Safford mining district in Graham County, Arizona, approximately eight miles northeast of the town of Safford and 170 miles east of Phoenix. The 3,360-acre property is located in the Gila River Valley, immediately south of the Gila Mountains, at elevations between approximately 3,000 and 5,400 feet above sea level. The Safford Leach Project is comprised of the Dos Pobres and San Juan deposits, two of five known copper ore deposits in the Safford mining district.

Jan 1, 2008