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By G. F. Vander Voort

The accident at Unit No. 2 of the Three Mile Island nuclear reactor (TMI-2) on 28 March 1979 was the worst nuclear accident in US history and crippled the nuclear industry. An international Vessel Investigation Project was formed to assess the integrity of the vessel. However, it was not possible to remove specimens from the lower head until January?March 1990. Fourteen of the fifteen specimens removed by electrical discharge machining were from under the debris pile that accumulated on the lower head due to melting of approximately 19 000 kg (45%) of the core. Specimens were previously cut from the lower head of a cancelled reactor of very similar size and design destined for Midland, Michigan. These specimens were subjected to controlled heating cycles with peak temperatures from 800°C to 1100°C for periods of 1 to 100 minutes. The initial study qualitatively compared the structures in the 15 specimens from TMI-2 to the control specimens from the Midland lower head. The writer used the same specimens and employed microindentation hardness traverses, electron microprobe analysis, and selective etching followed by quantitative metallography (by image analysis) to obtain a far more detailed description of the thermal exposure experienced.

Jan 1, 2013

By Carl-John Grävare

This paper deals with some of the systems and equipment that are being developed and/or are in use in Scandinavia. The main subject is the development of loading tests on the piles using monitoring equipment. This paper also describes ground improvement using lime-cement columns, expander body piles and steel core piles.

Jan 1, 2000

Effect of Hydrophobicity and Frother Concentration on Bubble-Particle Interactions in Turbulent Flow

Sep 13, 2010

By C. G. Dunn

James, Jones, and Leak (JJL) conclude that growth-rate and orientation-distribution data obtained in a steep thermal gradient should be used with caution to account for isothermally produced recrystallization textures. I agree. However, it is not clear whether they conclude a) that the orientation dependence of rate of growth of secondaries in (commercial) silicon iron depends on both temperature and a temperature gradient or b) that, in applying rate data obtained in a steep thermal gradient, the isothermal annealing temperature must be close to the temperature for which the rate data apply. Also, it is not clear what tem-

Jan 1, 1967

For small particles of niekel flotation eoncentrate (av. size 50 pm) the predominant heat transfer mechanism under suspension smelting conditions, prior to ignition, is conduction from the gas and not radiation from nearby hot bodies. Results of laboratory tests using gas temperatures 380-700°C and furnace wall temperatures 380-1100°C were in accord with heat transfer theory. In practieal flash smelters earlier ignition, and hence better utilization of the space in the shaft, would result from introduetion at the top of the shaft of gases hotter than the ignition temperature of 500-600°C.

Jan 1, 1979

By H. J. McQueen

ORDER OF PRESENTATION ?INTRODUCTION TO THE VICTORIA BRIDGE ?REASONS FOR A BRIDGE AT MONTREAL ?RAILROAD BRIDGE REQUIREMENTS ?IRON PRODUCTION CANADA / WORLD AL ?METALLURGICAL INDUSTRY CANADA ?FAIRBAIRN, STEPHENSON SHIP PLATE-RIB BOX GIRDER ?VICTORIA BRIDGE (PREFABRICATED BRITAIN) ?IRON ORE SITUATION THE VICTORIA BRIDGE 1859, TUBULAR -WROUGHT IRON* 1898, TRUSS ?STEEL* (*HOT RIVETED) 1957, SPUR, LIFT SPANS ??DUCTILE WROUGHT IRON WITHSTANDS FATIGUE ?TO KEEP THE TRAINS ON TIME & ON TRACK? ??IMMOVABLE SHARP PIERS SPLIT ?THE IRRESISTIBLE ICE, STOPPED CITY FLOODS? ? ?********* ??111 YEARS-YOUNG STEEL TRUSS, (1898): ?STILL VITAL SEA-T0-SEA RAIL LINK? ? ?********* ??51 YEARS HAVE PASSED SINCE SEAWAY (1958) ?SWITCHED BRIDGE INTO DOUBLE LIFT SPANS?

May 1, 2011

By D. J. Steynfaard

Sishen Iron Ore Mine is situated 280 km north-west of Kimberley in the Northern Cape Province of South Africa. The mine produces and sells high quality iron ore of various specifications to various national and international clients. The saleable product is derived from the blending and beneficiation of different types and qualities of hematite iron ore. This paper documents the new developments which were implemented (or are in the process of being implemented) on the mine in the long-term planning, medium-term planning, grade control and material tracking in the beneficiation plant with special attention being paid to the quality of the final, saleable product. The process starts with the long-term planning where the pit shell and pit optimization is determined by Whittle 4X. New developments include the introduction of a linear programming based scheduling system to enhance the long-term schedule generated by Whittle 4X. The LP route was decided on in order to take into account all the constraining factors of the final product that could not be configured in Whittle. To complement this the XPAC Auto Scheduler scheduling package was introduced to do the medium-term mine scheduling. This 18-month rolling plan includes cost parameters to enable the planner to extract a detailed operational budget from the scheduling while ensuring that production standards are maintained and grade constraints are met. The existing grade control system was enhanced with GPS capabilities and a computer system to do material tracking. The high precision GPS system introduced on the shovels allows for the accurate control of the loading procedures at the mining face. Because of the complicated geology and grade composition of blasting blocks it is imperative to accurately differentiate between different materials in the same blasting block and being able to excavate that with the loading equipment. The GPS system on the trucks allows for accurate location monitoring of dumping in order to keep track of specific material types. The state-of-the-art material tracking system developed for Sishen will enable the grade control officer to keep track and record various parameters of the material from its in situ position in the blasting blocks, through the crusher and onto different stockpiles, in various stages of the beneficiation process and onto the blending beds, into the dispatching trains and eventually into the ships for international distribution. These developments elevate the Sishen planning and grade control systems to a new level of service excellence from which management can obtain accurate and timely information on product status. It also enables Sishen to maximize resource utilization while still complying with the tough market constraints.

Jan 1, 2003

By Don Welch

Pressures for change ?Land use constraints ?Project financing ?Local communities ?Environmental issues ?Sustainability requirements ?Stricter regulatory procedures ?Technical excellence ?Reduce risk ?Impacts of failure & non-compliance

May 1, 2010

By Sam S. Taylor

"INTRODUCTION This report deals with a comparatively simple application of some of the engineering principles involved in the evaluation, installation, and operation of air- or gas-injection projects and well-clean-out and repair methods to increase the producing rates of oil wells in partly depleted pools during the war. The methods suggested for developing gas-injection projects take into consideration that in general no new wells will be drilled because of wartime restrictions of equipment and manpower and that only existing wells and second-hand machinery will be used. Because air will be employed as the injection medium in secondary-recovery operations where natural gas is scarce and expensive, the disadvantages and hazards accompanying, its use are discussed. Engineering techniques recognized as best modern practice are discussed in relation to the effect of simple air-injection development of properties on postwar operations and Probable ultimate recovery of oil. The report is an introduction to where, when, why, and how an air-injection project should be installed and operated; it is not intended to be an engineering manual for technical guidance in the selection, development, and operation of simulative methods of oil recovery.The report is intended mainly for these thousands of operators in the Appalachian region owning a few wells prodding small quantities or oil daily. Many such operators are anxious to increase their production rates by simulative means and to rehabilitate their wells so that they will produce more oil to help win the war but, in general, are unfamiliar with secondary-recovery operations and cannot afford to hire technical assistance."

Sep 1, 1944

A study of the swelling behaviour of a single batch of high-grade iron ore pellets during hydrogen reduction in a fixed bed showed that the extent of swelling is governed by the nucleation and growth of crystalline iron protuberances from the wüstite grains. Over the reduction temperature range 650 to 1000°C, it was found that substantial degrees of swelling can occur at temperatures in excess of 850°C, and significant variations in the swelling behaviour of individual pellets from different bed levels are observed under these conditions.The results are discussed in terms of a recent swelling theory and shown to be in general agreement.

Jan 1, 1978

By John R. Goode

"The year 2011 witnessed a major surge in rare earth prices as China, supplier of +95% of the world’s rare earths, reduced export quotas and increased export taxes and duties. In response, companies around the world are scrambling for alternative sources. In Canada too, there is a race to be the “first” rare earth producer. Something that is not generally realized is that Canada has a long history of rare earth production and was a major supplier from the early 1960’s to 1990. At one stage, Canada was said to be supplying more than one third of the world’s yttrium and probably supplied even more than that. Five decades ago, thorium was a key element in many non-nuclear applications and Canada became a major supplier of thorium from the late 1950’s to 1968, first as a by-product of uranium and then as a co-product of rare earths. This paper reviews the development of Canada’s original rare earth and thorium production facilities, which were located in the Elliot Lake uranium camp in Northern Ontario. The uses of these elements, geology, mineralogy, markets of the time, and processing are all discussed. Some of the lessons learned from these pioneering operations might be useful in today’s race to develop the next generation of rare earth production plants.INTRODUCTION The rare earths and thorium were first identified in the early 19th century but were little more than curiosities for the next century. However, in the mid-1960’s the invention of rare earth-based phosphors for the cathode ray tube in colour television sets launched a major demand for certain rare earths. The use of thorium as an alloying agent in aircraft and missiles grew rapidly in the late 1950’s. In the same period, demand for uranium for both weapons and power production soared. Also in the late 1950’s, the Elliot Lake uranium-thorium-rare earth deposits (also known as the Blind River deposits) were discovered. This conjugation of events led to uranium production in the Elliot Lake camp, quickly followed by the co-production of thorium and, later, the rare earths. Uranium production in the Elliot Lake camp continued from 1955 to 1996. Thorium was produced continuously from 1959 to 1969. Rare earths were produced, intermittently, from 1965 to 1990. Complete production records are not readily available for thorium and the rare earths but unquestionably Elliot Lake production made a significant contribution to world production. This paper is intended to present as much of the information that is available."

Jan 1, 2012

By D Craw, D Wilson, D Chappell

Gold is extracted by cyanidation of a sulphide-rich concentrate at Macraes mine, and after cyanidation, the concentrate is discharged to tailings impoundments. The concentrate tailings were discharged to a dedicated concentrate impoundment from 1989 to 1993, afterwhich they were blended with the flotation tailings. Since mid-1998, concentrate tailings have been redirected to the dedicated concentrate impoundment. The concentrate tailings contain up to 1 ppm gold, and will be reprocessed in the future. However, it is a regulatory requirement that a contingency plan be in place to rehabilitate the concentrate tailings should the mine operation cease for any reason. Initial predictions suggested that the sulphide-rich tailings would oxidise and acidify, creating a potential long term environmental problem. Investigations of the state of the tailings after 4 years show that these predictions were overly conservative. Only minor oxidation has occurred in the upper 2 metres of the tailings where the pH has locally dropped from 10 (discharge condition) to between 7 and 8. Below 2 metres, the tailings are essentially unchanged from their deposition state. The low rate of change in the tailings is due to their very low permeability which in turn is a consequence of the fine grain size (ca. 15 ¦m). Dewatering is extremely slow, and incursion of oxygenated water is negligible. Calculations suggest that water movement over 30 m will take at least 100 years and possibly 1000 years. The contingency plan is to capitalise on the very low permeability and keep the tailings from drying with a semipermeable cap. A layer of limestone will be added to the top of the tailings, beneath the cap, to enhance alkalinity of any percolating water. If acidification does occur, contrary to expectations, any acid produced will be neutralised by underlying calcite-bearing schist, schist in the concentrate impoundment wall, and the flotation tailings immediately downstream. In addition, dilution by alkaline ground and surface waters would further ameliorate any acidic discharge.

Jan 1, 1998

By D Nobes, D Trumm, D Manhire, A OÆSullivan, M W. Milke

Coal seam gas (CSG) exploration and development requires the abstraction of significant amounts of water. This is so because gas desorbtion in coal seams takes place only after aquifer pressure has been reduced by prolonged pumping of aquifer water. CSG waters have a specific geochemical signature which is a product of their formation process. These waters have high bicarbonate, high sodium, low calcium, low magnesium, and very low sulphate concentrations. Additionally, chloride concentrations may be high depending on the coal depositional environment. This particular signature is not only useful for exploration purposes, but it also highlights potential environmental issues that can arise as a consequence of CSG water disposal. Since 2002 L&M Coal Seam Gas Ltd and CRL Energy Ltd, have been involved in exploration and development of CSG in New Zealand. Anticipating disposal of CSG waters as a key issue in CSG development, they have been assessing CSG water quality along with exploration work. Coal seam gas water samples from an exploration well in Maramarua closely follow the geochemical signature associated with CSG waters. This has helped to identify CSG potential, while at the same time assessing the chemical characteristics and water generation processes in the aquifer. Neutral pH and high alkalinity suggest that these waters could be easily managed once the sodium and chloride concentrations are reduced to acceptable levels.

Jan 1, 2005

By J. R. Long

The investigations described herein are concerned with a portion of a systematic research, by the Federal Bureau of Mines on ductile titanium. The Bureau's work on the metal has resulted in development of a semi commercial process for the preparation of titanium and has also made available significant information on the fabrication and physical properties of this new strong, light, corrosion-resistant metal. Considerable interest has been aroused by this work, and a number of other laboratories have begun similar investigations. However, the necessity for Consolidating titanium by normal powder metallurgy methods presents difficulties in producing commercial forms and shapes on a large scale. This investigation was therefore undertaken for the purpose of improving the technique for consolidation of titanium powder into solid nonporous metal.

Jan 1, 1949

By Frederick Bird

This paper is based upon a review of studies of mostly Canadian mining companies in Chile, northern Canada, Tanzania, Guatemala, Ghana, Sierra Leone, and the Democratic Republic of Congo. In spite of often well-meaning efforts most mining firms produce wealth in developing areas that largely benefit those immediately involved, sometimes neighboring communities, and often those in the governing strata. Typically mining takes place in enclaves and fosters enclave development, rather than the kind of inclusive wealth development favored by the recently UN published Inclusive Wealth Report. One way by which mining operations can foster more inclusive wealth development is to adopt much broader approaches towards the construction of the various physical and social infrastructures ? roads, water, electricity, health services, schools, security ? required for their own operations by collaborating with diverse regional, provincial, and/or national agencies and businesses to develop these infrastructures for larger populations and areas beyond the immediate sites where they are operating. Established mining firms can also foster more inclusive wealth development by establishing more formal, collaborative relationships with artisanal miners.

Aug 1, 2013

By Lane White

The 1989 Annual Meeting and Exhibit of SME in Las Vegas, NV, February 27 - March 2, 1989, was the largest ever, drawing more than 4000 regis¬trants and 240 exhibit booths. Technical sessions included presentation of nearly 500 papers, including symposia on Biotechnology in Minerals and Metals Processing, Surplus Capacity in the International Metals Industry, and APCOM `89 - the 21st International Symposium on Application of Computers and Operations Research in the Mineral Industry. Technical sessions covered the gamut of minerals industry interests; however, the proximity of the meeting to recently surging gold development in Nevada drew special attention to gold operating practices. Several of the papers on gold processing are reviewed below. To keep pace with the strong world- wide interest in gold development, SME has scheduled three additional upcoming programs that will focus specifically on gold: World Gold '89 - Gold Forum on Technology and Practices will be held November 5 - 8, 1989 in Reno, NV, as a joint meeting and exhibit between SME and the Australasian Institute of Mining and Metallurgy. Technical sessions will encompass a full program of papers covering geology and exploration, mining, and mineral and metallurgical processing. Cooperating sponsors for this meeting include the Canadian Mineral Processors Division of CIM, The Institute of Metals, The Institution of Mining and Metallurgy, The Mining, Geological & Metallurgical Institute of India, and The South African Institute of Mining and Metallurgy. Gold '90 - Salt Lake City, UT, February 26 - March 1, 1990, will be a symposium held in conjunction with the 1990 SME Annual Meeting. Current research on the processing of refractory gold ores will generate innovative papers on process mineralogy at this symposium, with special emphasis on gold with pyrite and gold with carbon. Other sessions are planned for gold exploration and mining, gold metallurgy, gold plant design and practice, and gold in scams. Advances in Gold and Silver Processing Conference, October 1 - 3, 1990 will be held in Reno, NV. Preliminary planning calls for technical sessions on heap leaching practice, refractory ore processing, non-traditional lixiviants, bioleaching, metal recovery from solution, and the environmental aspects of processing operations. PLANT DESIGN, OPERATION Technical sessions organized by the Minerals and Metallurgical Processing Division of SME at this year's meeting in Las Vegas covered a wide range of gold operating practices. Eight papers relating to gold plant design, operation, and equipment are summarized here. Preprints of these papers are available by writing to Publications Sales, PO Box 625002, Littleton, CO 80162-5002 ($2.50 per paper for AIME members, $4 for nonmembers). Continuous elution process A. M. Stone, of Bechtel Australia Pty. Ltd., described the "Development of the Continuous Elution Process for Extraction of Gold from Carbon" (pre-print 89-75). Developed by Bechtel Pacific Corp. for Ok Tedi Mining Ltd., the Continuous Elution Process uses the same reagents as batch processes for elution of gold from carbon, while yielding significant savings in stripping vessel size and energy consumed in comparison with equivalent batch processes. The process is also simpler to operate than batch processes. Other advantages include reduced maintenance costs, higher average eluate grade, and near steady final eluate grade. Pilot testing for the Continuous Elution Process was conducted at Western Mining's Kambalda gold plant beginning in December 1982. The Continuous Elution Process is a continuous countercurrent system operating in a pressure vessel at elevated

Jan 1, 1989

By Alvin Kaufman

Following the gold discoveries of the late 1800's much was written regarding the vast mineral resources of Alaska, and much interest was aroused, and yet over the years little has been done to exploit those resources. Between 1906 and 1935 the Kennecott copper mines of the Copper River region were the keystone of the mineral economy (fig, 1). After the depletion of the Kennecott ore reserves and aided by the statutory rise in the price of gold, the yellow metal became the major mineral commodity. In recent years it has shared the honors with coal and sand and gravel. Although this trend should indicate the development of a stable, diversified mineral industry, yet the trend of production is downward. This report results from a study by the Federal Bureau of Mines to delineate the problems and to forecast the growth of the mineral industries in Alaska. The need for such a blueprint for the future was enhanced by the population explosion in the United States and the consequent eventual need for additional living space, as well as the current interest in new areas, and the necessity to develop reserves of strategic minerals.

Jan 1, 1961

By Mark Rybak

On Aug. 31, 2006, Tropical Storm Ernesto hit the city of Richmond, VA. The Battery Park area was hit particularly hard, as flooding forced an evacuation of the area. A large sinkhole collapsed a sewer line in the Battery Park area, blocking the pipe and causing more serious flooding. This article describes the fast track design, bidding and construction of an emergency tunnel to bypass the collapsed sewer. Innovative value engineering, tunneling and shaft-sinking methods and final lining design all contributed to the success of this project. The storm inundated Richmond, VA with up to 305 mm (12 in.) of rain that, in some areas, caused widespread flooding and damage. One of the hardest hit areas of Richmond was Battery Park. A major trunk sewer in the Battery Park area collapsed and caused local combined sewer and stormwater flooding. The collapsed sewer was a 2.4-m x 76-mm (8-ft- x 3-in.-) wide by 2.7-m- x 152-mm- (9-ft- x 6 in.-) high arch sewer that was constructed in the 1920s and later filled over with municipal solid waste and a soil fill cap to cur-rent elevations. A sinkhole was created in the area of collapse approximately 18 m (60 ft ) deep and 31 m (100 ft) in diameter. This caused the existing arch sewer to become blocked. As a result of this blockage, contaminated floodwaters reached depths in low-lying areas in excess of 8 m (25 ft).

Jan 1, 2008

By H. Gumede

The occurrence of fracturing due to high stress levels is a major factor in hangingwall stability in deep level gold mine stopes. However, rock falls cannot be the result of these fractures alone. Rock falls can result only from the occurrence of unstable rock blocks defined by the interaction of the stress induced fractures and naturally occurring geological planes of weakness. These planes include bedding planes and joint set planes. However, there is a general lack of information on the characteristics of these planes (orientations, spacings and lengths)?it does not appear that any such systematic and quantified information, if collected, has been published. To remedy this situation to some extent, joint mapping exercises have been carried out in several geological environments in two gold mines. The data collected on joint geometry included orientation, spacing and length, and this information is included in the paper. In addition, the paper describes the use of the data collected to evaluate the potential for rock falls and the probability of failure of stope support

Jan 1, 2007

By Ingrid Hann

The Triple Bottom Line ? Economic Sustainability ? Creation of Joint Venture companies ? Planned evaluation of other kimberlites ? Social Sustainability ? Impact Benefit Agreement and Participation Agreements ? Education and training initiatives ? Environmental Sustainability ? Environmental management ? Mine closure planning

May 1, 2008