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By John D. Abbatt, H. B. Newcombe

The Eldorado Epidemiology Project formally began in late 1978. It consists of a retrospective cohort study, to be followed by and to leave in place the mechanism for a prospective cohort monitoring program. These present and future activities are intended to merge into one another. The current study includes all Eldorado employees past and present for whom records are available. The objectives of the undertaking are - 1) to obtain cause-and-effect, dose-response data with which to evaluate the risks to workers in radon and radon daughter containing atmospheres, and to provide additional quantitative information on which to base possible improvements in working conditions; 2) to identify any dead employees of E.N.L. whose cause of death suggests that a potential compensation claim right exists for their survivors, and to similarly identify living ex-employees of E.N.L. whose work histories and states of health suggest potential compensation claim rights. The nature of the study has been determined by the history of Eldorado, which will be described briefly. Eldorado began (as Eldorado Gold Mines) in the late 1920's, operating relatively unsuccessfully in Manitoba. In 1930-31 the emphasis shifted from gold to uranium, and what became the Port Radium mine was first staked. From the very early 1930's until 1942 the company's purpose was almost entirely devoted to the mining of pitchblende - uranium ore - from the Port Radium site, and the extraction of radium from this ore at the Port Hope refinery in Ontario, a process from which the uranium was a largely stockpiled byproduct. In 1942 the company was requested by the Canadian government to accelerate the production of ore, and of uranium. At the same time, all its stockpile of uranium (then being stored in silos as a "waste" product which might later "come in") was acquired for the Manhattan Project. In 1944 the company shares were bought by the Canadian government and the company itself became Eldorado Mining and Refining (1944) Limited; it has operated as a Crown corporation ever since. The name was changed to Eldorado Nuclear Limited in 1968. The Port Radium mine was closed in 1960, and since 1953 the Beaverlodge uranium mine complex has operated on the northern shores of Lake Athabasca. Radium production was discontinued in 1954 when the radium circuit was taken out of the refinery, and since that time the refinery's products have been various types of refined uranium (uranium dioxide, uranium trioxide and uranium hexafluoride) plus metallic uranium. The refinery, of course, processes the company's own yellowcake but as it is one of only five refineries in the western world, most of its work consists of custom refining for a large variety of customers. In addition to the mining and the refining operations, there have been three other divisions involved, and these are, respectively, Aviation, R. & D., and Exploration, in addition to the financial, corporate, administrative and support activities. MATERIAL AND METHODS The human study population (Abbatt, J.D. et al., 1980) consists of all Eldorado employees who have ever worked for E.N.L. and for whom records are available. The total nominal roll to December 31, 1980 is approximately 21,000 and consists of employees of the Mining, Refining, R. & D., Aviation and Exploration Divisions, as well as a relatively small number of other employees (Head Office, etc.). The basic epidemiologic design, as has been mentioned, is for a retrospective cohort study merging into a prospective cohort study, and depending very heavily upon automated record linkage and file matching. The original design called for an initial assembly of the bulk of the nominal roll, prior to the first of two matches with the National Mortality File. The first of these two matches is now complete and the second is to be separated from it in time by 18 months to two years. The second match will be the definitive match prior to the analysis, the interpretation of the data, and the publication of the results. The period between the two matches was designed to permit completion of the nominal roll, including: - addition of previously missing individuals and groups, elimination of duplicates, and amplification of identifying information, - assembly of work histories and exposure information for each individual, - digestion and application of lessons and modifications resulting from the first match with the National Mortality File at Statistics Canada, - preparation of files for the definitive second match. The analysis of data will be carried out by the National Cancer Institute of Canada Epidemiology Unit based at the University of Toronto. This group, with whom Eldorado Nuclear has a memorandum of understanding, have for a variety of reasons, including their familiarity with record linkage and their expertise, been members of the Project Team since

Jan 1, 1981

By Alfred G. Hoyl

The small miner and small mine have an important role to play in the finding, developing and production of our mineral resources. "Help, not hinder" must be our byword. We must push in every way we can devise to change the adversary position of government and environmental movements. We need the small mines and they must be encouraged, not hindered. Technically excellent and adequate equipment is available, and needed information is also available to the small operation. Environmental questions and problems must be fully considered regardless of the size of a mining operation.

Jan 1, 1987

By M. Karmis, C. Haycocks

Geographic Information Systems (GIS) are becoming a more commonly used tool for resource estimation as they provide not only a database management platform, but also the graphical capabilities to visualize resource characteristics. Interpolation methods used commonly in these resource studies do not typically provide a quantitative answer to the question: "How accurate is the estimate?" By comparing localized measurements at several locations to the interpolated thickness distribution used in a resource estimate, a quantitative analysis of accuracy can be obtained. The technique is demonstrated with a case study from Central Appalachia.

Jan 1, 1999

By Drupad B. Desai, James G. Gallanes

A key component of the Inland Feeder Project is the Riverside Badlands Tunnel, a7.9-mile stretch subjected to high internal and external hydraulic pressures passing beneath highly eroded hills in a semi rural environment. The tunnel presented significant design and management challenges to the project team. This paper describes the formula for project success used to manage the design of this complex pressure tunnel, from team member selection to the completion of all contract documents, on schedule and below budget. The project team dealt with sensitive regional and local community issues and won the trust of the community. The team included participation by senior management and recognized experts from inception to finish. The team worked diligently to build quality into design and adopted a claims avoidance approach to management and preparation of documents.

Jan 1, 1997

By Zhengbin Cheng, Wenguang Lu, Baoqi Sun, Jiaying Tang

This paper studied the flotation separation of feldspar, zircon and kyanite from quartz with a mixture of cationic and anionic collectors. Tests show that collector mixture has specially good effect, using it, the separation of these three silicate minerals from quartz can be successfully achieved at the natural pH value of tap water in the absence of any acid, fluoride and other inorganic reagents. The properties and characteristics of collector mixture were analysed. By means of IR-spectra, ESCA and AES, the action mechanism between collector mixture and minerals was throughoutly studied.

Jan 1, 1995

By P. R. Khangoankar, S. Devasahayam

An experimental study of the particle charac¬teristics of the magnesium carbonate crystals formed by the reaction between magnesium chloride and sodium bicarbon¬ate at different temperatures is described. The rate of growth of magnesium carbonate crystals for any constant tempera¬ture is established, and this rate of growth is related to the degree of supersaturation at the given temperature. The activation energy calculated using empirical constants de¬rived from the relationship between the crystal growth rate and supersaturation, is indicative of a surface-reaction mechanism.

Jan 1, 1996

By H. B. Oblad

The WEMCO® SmartCell™ flotation machine is a continuously-stirred tank reactor in which solids are suspended in water and are contacted with air. The reaction is particle flotation resulting in the separation of valuable material from gangue. The effects of several operating variables on the flows of water and air and on motor power were measured. A miniature magnetic flowmeter was installed in the draft tube that allowed measurement of the water flows into the rotor. This work has led to a better understanding of machine function which will lead to improved performance and better operation. General equations for optimization, design, and scale-up were inferred.

Jan 1, 2002

By David Corkum, David Hatem

Subsurface construction projects are risky ventures and the decision to deliver a project using the Design-Build model does not eliminate those risks. Differing site conditions, inadequate design, and delays will continue to plague some projects. The Design-Build procurement model, however, presents a broad opportunity to allocate those risks much differently than in the familiar Design-Bid-Build model. Starting with a philosophical approach to risk and reward, this paper discusses the continuum of possible risk allocation strategies. It concludes with a proposed optimum strategy in terms of the project’s overall economic efficiency, and points to the dispositive contractual provisions that serve to contour the risks.

Jan 1, 2003

By C. DeW. Van Siclen

A simple mathematical description of the settling behavior of monosized particle suspensions is derived by consideration of the physical processes involved, and applied to data recently published in this journal.

Jan 1, 1995

By C. Otto Walls

Six years after the start of gold heap leaching at Smoky Valley Mining, Round Mountain, Nevada, three areas of process improvements are examined to show how productivity was increased. Original design concepts and practices are reviewed in order to compare to current methods. The evolution of change in heap mainterance is also reviewed.

Jan 1, 1984

By Henry Brehaut

The International Network for Acid Prevention (INAP) was formed in 1998 by 17 international mining companies to promote significant improvements in the management of sulphidic mine materials and the reduction of liability associated with acid drainage through knowledge sharing and research and development of technology. Since its inception two panels have been formed to identify and move forward with research projects and eight networks have been constituted to initiate interaction and knowledge sharing within the membership in specific areas of technical interest. An INAP web site has been developed to facilitate the sharing of information and to encourage the exchange and development of new ideas.

Jan 1, 2000

By Michael Vitale, Lee W. Abramson, Daniel McMaster, Andrew J. Thompson

"Performing risk analyses on tunnel projects has become common place and on many projects it is required from an owner or regulatory perspective. After the project is planned, designed and constructed, the data concerning identified risks, assumptions, costs, probabilities and mitigations is generally long forgotten and buried in some file somewhere. A study was performed comparing predicted risks versus actual events on four recently constructed rock tunnel projects in New York, Ohio, Georgia and California. Probabilities and costs for selectively common risks on tunnel projects have been studied and re-evaluated. Conclusions are presented that can guide future projects and the veracity of the tunnel risk analyses performed. INTRODUCTION Tunneling is a risky business. More than ever, attention is being paid to the risks associated with tunneled facilities and implications on project or program cost and schedule. Questions about why tunneling projects notoriously exceed budget numbers abound. Evaluations in retrospect and going forward have focused on the wide breadth of inherent risks associated with tunneling. More and more, these risks are being identified, studied and managed to a higher degree. As more and more scrutiny pervades the industry, little value is being obtained and leveraged on future projects. The industry seems to be headed in a direction of making the same mistakes over and over. The notion of risk evaluation has been around for decades and received wide notoriety with the U.S. Space Program and ambitious projects in the energy industry such as hydropower and nuclear power in the 1960s and 1970s (Stewart and Melcher, 1997). This led to the evolution of tunnel risk analyses with more rigorous identification of the unique risks in tunneling projects impacting cost and schedule. As tunneling risks became more readily identified, more attention has been paid to the frequency and impact of the occurrences unique to tunneling (ITIG, 2012). Currently, few tunnel projects are being planned, designed or constructed without a formal risk register that identifies the risks, mitigates the risks and quantifies the probable impacts of risks that cannot be mitigated. In hind sight on many recent projects, events that brought projects to “its knees” were not addressed in risk assessments or were not dealt with to adequately mitigate the risk of these events."

Jan 1, 2016

By V. Saltas

The present work investigates whether dielectric spectroscopy can be used to detect contamination, which may appear in a natural porous material, due to the spreading of pollution. For this purpose, dielectric and conductivity measurements, in the frequency range of 10mHz to 1MHz, were carried out in sandstone samples, partially filled or saturated with solutions of leachates, at different concentrations. The experimental results suggest that although the role of water is dominant to the measured electrical conductivity, variations of two orders of magnitude are observed due to the different concentrations of leachates, in partially filled sandstone samples. Experimental data are well fitted with a Havriliak?Negami dielectric relaxation function, superimposed with a conductivity term. The parameters of the fitting function have been correlated to the concentration of leachate in the sandstone samples and considerable changes have been observed at low leachate?s concentration.

Jan 1, 2005

By R. Sharma, S. Svoronos, S. Gupta, N. A. Abdel-Khalek

This paper presents the results of a column flotation study on a fine feed sample of Florida phosphate. A central composite design was used to study the main and interaction effects of parameters affecting column efficiency. The statistical design is also used to determine the optimum conditions. The results indicate that, depending on the experimental conditions, it is possible to produce a high-grade concentrate with a high recovery. A 15ppm concentration of nonionic frother was found sufficient to maximize the recovery at pH of 9.5.

Jan 1, 2002

By John D. Nelson, Clint L. Strachan

Drainage of tailings impoundments is a key issue for impoundment stability, water control, seepage control, and reclamation. Drainage control is an established operating practice where climate and site conditions permit, such as in South Africa and various mines in North America. In these areas, drainage control is primarily used to maximize tailings densities and to provide adequate impoundment stability. Drainage practices during operation also become an important issue when tailings impoundments are reclaimed. Time required for cover placement and post- reclamation seepage control depends greatly on the ability for tailings to drain and consolidate. This paper discusses drainage issues associated with gold tailings impoundments in terms of mechanics of saturated and unsaturated flow and experience with design and reclamation of tailings impoundments.

Jan 1, 1988

By Yuusaku Tominaga, Sukumar Bandopadhyay

A power-series trend curve of elapsed time was estimated by using time series data of measured concentrations of carbon monoxide in the Taiheiyo coal mine, Hokkaido, Japan. The difference between the moving average concentration data and the estimated data from the trend curve showed linear correlation when plotted on a normal probability paper and a correlation coefficient value of 0.99. It is concluded that the estimate of carbon monoxide concentration using moving average values of concentrations compares very well with the results obtained from the trend curve within the three-sigma (standard deviation) range of the distribution. Thus, it is believed the results can be used to monitor and detect abnormal ventilation conditions in a ventilation network such as the occurrence of spontaneous combustion at an early stage.

Jan 1, 2002

By Burt Ensley, Viatcheslav Dushenkov, Ilya Raskin, David E. Salt

Roots of many hydroponically grown terrestrial plants, including sunflower (Helianthus annuus L.) effectively remove toxic metals such as Cu+2, Cd+2, Cr+6, Ni+2, Pb+2 and Zn+2 2 from aqueous solutions. It should be possible to scale up this process such that plant roots can be used to treat large volume aqueous waste streams. It can be extrapolated from laboratory results that to reduce the Cd concentration in a waste stream, from 1 ppm to below 4 ppb, with a flow rate of 4000 L/min, would require 3500 sq. m of plant roots with a density 5 kg fresh weight per sq. m. These results suggest that the roots of hydroponically grown terrestrial plants may provide an attractive alternative to the accepted water treatment technologies.

Jan 1, 1995

By C. A. Wiggins, J. M. Kennedy

The Benbrook Connection tunnel forms approximately 6,666 m (19,560 ft) of17,678 m (58,000 ft) of raw water pipeline connecting Lake Benbrook with the Rolling Hills Water Treatment Plant. This connection is designed to minimize costs to the owners, the Tarrant Regional Water District, for providing raw water to its’ various clients. The geological formations through which the tunnel passes and the design requirements resulted in some-what unique applications of initial ground support systems which were modified by the con-tractor to optimize the mining operations. The pipe sections, fabricated in 12 m (40 ft) sections, are concrete lined and coated steel pipe. Construction of the work shaft and tail tunnel was also modified to suit the contractors methods. A Lovat universal TBM was chosen to excavate through the various rock types. The pipe sections will be transported using beam carriers.

Jan 1, 1997

? The U.S. depends on minerals for economic growth and development, and for national security and defense. ? Public lands are an important, long-term source of essential minerals. ? Access to public lands for mineral exploration and development has become more difficult as large tracts of land have been designated for other uses. ? Mineral-bearing areas on public lands are routinely withdrawn or restricted from development before comprehensive resource inventories and economic assessments have been made.

Jan 1, 2011

By Jack K. Lemley

This paper will provide an update of the Channel Tunnel Project including a discussion of the overall legal structure and management organisation. It is important to understand the mission that TML, as a design/build contractor, has undertaken and how the various interfaces have evolved between the other entities involved in the project. The paper will describe the evolution of the management organisation and the approach to completion of our contract, recapping the historic events and moving into a projection of how we will manage the completion of this very large transportation system.

Jan 1, 1991