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By Brian Isherwood

TransCanada Pipelines, Calgary (TCPL) is one of North America's leading transporters of natural gas through its energy transmission business. TransCanada also operates significant complementary businesses in energy marketing and energy processing in North America and internationally. The main trunk pipeline crossing Canada comprises as many as six pipes, 30" to 48" diameter delivering up to 7.8 trillion cubic feet of natural gas per day. To maintain the maximum operating pressure of 1000 psi, it is necessary to provide compressor stations at 60 to 100 km spacing. One such station is located at Potter, in northern Ontario, some 80 km north of Timmins, referred to as Station 102. The station contains two compressor plants, 'A' and 'B' Each incorporates a gas turbine driven centrifugal compressor unit. 'A' Plant uses an aero-derived gas generator (jet engine) rated at 15 MW (19,000 HP).

Jan 1, 1997

By Jay L. Hodkinson

Replacement of an aging twin span river crossing in Vermont required a temporary bridge to accommodate traffic during construction. Soils beneath the temporary approach embankment consisted of very soft organic clayey silt underlain by interbedded, loose alluvial fine sand and silt/clayey silt. Reinforcement was required for the southern temporary approach embankment to limit settlement and to increase global stability factors of safety. A ground improvement design was developed using Rammed Aggregate Pier® reinforcement and was included in the contract documents as an FHWA Category II Experimental Feature. Instrumentation intended to document the performance of the supported embankment was installed. Piers were then constructed and monitoring commenced as embankment and bridge construction occurred. Weekly instrumentation data reports indicated continuing excess pore water pressure, settlement, and lateral deformation of the subgrade soils as the embankment and temporary bridge abutment was constructed. In response to the unanticipated monitoring results, further investigation indicated that significant deviations from the conditions and basis upon which the ground support design was developed were made during construction. This paper discusses these deviations and their specific impacts to embankment support performance, how these deviations occurred, the role that the ground support system played in maintaining global stability, measures taken to limit further detrimental impacts to the embankment, and provides recommendations for contract document preparation and construction oversight to prevent similar situations from occurring on future projects.

Jan 1, 2011

By N N/A

To the members of The South African Institute of Mining and Metallurgy We have audited the annual financial statements set out on pages 239 to 245. These financial statements are the responsibility of the Institute?s Council. Our responsibility is to express an opinion on these financial statements based on our audit. Scope We have conducted our audit in accordance with statements of South African Auditing Standards. These standards require that we plan and perform the audit to obtain reasonable assurance that the financial statements are free of material misstatement. An audit includes: ?examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements ?assessing the accounting principles used and significant estimates made by management ?evaluating the overall financial statement presentation. We believe that our audit provides a reasonable basis for our opinion. Audit opinion In our opinion, the financial statements fairly present, in all material respects, the financial position of the Institute at 30 June, 2000, and the results of its operations and cash flows for the year then ended in accordance with South African Statements of Generally Accepted Accounting Practice.

Jan 1, 2000

By T. I. Nelson

Natural aggregates, primarily stone, sand and gravel, are recovered from widespread, naturally occurring mineral deposits and processed for use primarily in the construction industry. They are mined, crushed, sorted by size, and sold either loose or in concrete products to build roads, houses, buildings, and other structures. Smaller quantities are used in agriculture, cement manufacture, and industries employing chemical and metallurgical processes. The growth of cities, their buildings and the highways that connect them have created demand for enormous quantities of aggregates. The aggregates industry is the largest mining industry in the United States in terms of production by weight, volume and by number of active operations.

Jan 1, 2005

By B. M. Nyombolo

The interest shown in our paper by Drs Schaekers and Dew, and their favourable comments, are appreciated. However, some of their remarks require a response. Stability testing procedures Regarding the issue of stability-testing procedures, we concur that no long-term procedure has been accepted by either environmentalists or the mining/processing industry as a valid method to test the long-term stability of solid wastes. We agree that the method we used is no exception, and we certainly did not claim that it should be recognized as such. What we did attempt to portray was that we had designed the test procedure in an attempt to simulate, at a very small scale, a tailings dam environment.

Jan 1, 2001

By David C. Yang

A packed column (or static tube) flotation system is an innovative technology which utilizes a controlled dispersion reagent scheme and a new machine. The unique aspect of the machine is its packed-bed design permitting an unlimited froth bed height with countercurrent water washing for effective processing of fine particles. In operation, the conditioned ore slurry is fed into the middle section of the column where separation processes begin. Air, introduced at the bottom of the packed column, contacts the hydrophobic particles and floats them off continuously as the feed is added, while the gangue sinks to the base of the column. The system functions efficiently because intimate particle-bubble contact is achieved by the packing design which has no moving parts and requires no ancillary air-bubble generator. Other attractive features of the packed column flotation include high throughput, low power requirements, and simple control. Results from laboratory and pilot plant tests of this system show remarkable improvements over current industrial practices on a wide variety of ores and coals.

Jan 1, 1988

By Fumihiko Sumiya, Hideki Hamashima, Shigeru Itoh, Shinya Tanaka

The detonation characteristics of non-ideal explosives, especially the emulsion explosives, are critically affected by the confinement of case. In this study, we focused the shock wave propagating in case as confinement factor. Therefore, the objective of this study was to obtain a better understanding of the influence of shock wave propagating in case on the detonation characteristics of explosives in laboratory scale.

Jan 1, 2007

By Chris Bennett, Glen Kosick

"Process modeling and equipment sizing procedures for SAG circuits has advanced significantly over the past two decades. However, no matter how exact the hardness tests, models and scale-up calculations, if the ore samples being used for design do not accurately represent the orebody then major design errors can be encountered. This paper will describe a hardness testing method for identiQing the power requirement profile of an orebody, to an extent that design errors due to poor sampling can be greatly reduced or avoided altogether. It will provide some insight into the magnitude of hardness variability that can be encountered in an orebody. Finally, the paper will preview how detailed hardness distribution data can be incorporated into mine block models, to optimize SAG circuit design for an orebody, both fi-om a capital investment and throughput point of view.INTRODUCTIONIt has long been known that many SAG/AG' circuits experience wide swings in throughput. These throughput variations are almost always of a magnitude not anticipated in the plant design; consequently, they are detrimental to the expected return on investment for the mining companies. It is clear that the throughput swings are mainly caused by changes in ore hardness. In 1993, in an attempt to address this problem, MinnovEX began investigating the possibility of using a small scale SAG test (2 kg charge) to predict SAG power requirements from drill core samples. The objectives of the small scale test were to enable mining companies to do many more SAG hardness tests than currently undertaken for a particular orebody. To make this possible, the SAG tests had to use a minimal amount of sample, be cost effective, and give acceptable accuracy in the prediction of SAG power. If this small scale SAG test proved accurate, then the high sampling frequency would yield results that approach the true hardness distribution of an orebody. This hardness distribution could then be used to derive the distribution and variability of specific energy required throughout the complete orebody. This specific energy (kWh/t) can be thought of as the power required to grind one tonne of ore per hour (kW/tph) to a specified size. Once the true distribution of power requirement throughout the whole orebody is understood, the grinding circuit design team can make an informed decision regarding the hardness value that is most appropriate for sizing the SAG equipment. Throughput losses due to hardness variation could be deliberately planned for or avoided altogether (a capital cost decision)."

Jan 1, 1999

The 103rd Annual General Meeting of The South African Institute of Mining and Metallurgy was held in the Gold Room, Transvaal Automobile Club, 60 5th Street, Lower Houghton, Johannesburg on Wednesday, 16th August, 2000. Welcome The President extended a special welcome to the guests and representatives of our sister institutes and other associations. Also to recipients of awards, senior members of industry, Honorary Life Fellows, Past Presidents, our Members and other guests, among them the following: Reinie Meyer, President, The Geological Society of South Africa Dr Nielen van der Merwe, Chairman, The South African Institute of Rock Engineering Chris Fourie, President, Institute of Mine Surveyors of South Africa

Jan 1, 2001

By Mark S. Sanders

This report presents a summary of the work reported by Sanders and Kelley (1981). A task analytic approach was used to define information requirements and visual features which served as sources of information. Information requirements were prioritized and the location of visual features determined. From this analysis, visual attention locations, containing one or more important visual features, were indentified. The visual attention locations are contained in this report. A procedure was developed for assessing whether operators in existing machines could be expected to see the visual attention locations. The procedure makes use of a Human Eye Reference Measurement Instrument (HERMI) designed for this project and an outside-in photographic procedure for documenting compliance with the recommendations. A sample of continuous miners, shuttle cars & scoops were used to test the procedure. Illustrative results are presented in the report.

Jan 1, 1981

By G. W. Jones

In cooperation with the Edison Electric Illuminating Co. of Boston, Mass., and the-Boston Consolidated Gas Co., the Bureau of Mines, United States Department of the Interior, has conducted a survey continuously since 1929 to determine the general hazards of combustible gases and vapors in manholes of the Edison Electric Illuminating Co.

Jan 1, 1942

By G. W. Jones

In cooperation with the Edison Electric Illuminating Co. of Boston, Mass., and the-Boston Consolidated Gas Co., the Bureau of Mines, United States Department of the Interior, has conducted a survey continuously since 1929 to determine the general hazards of combustible gases and vapors in manholes of the Edison Electric Illuminating Co.

Jan 1, 1942

By Robert Stefanko

A series of workshops were conducted -with invited participants from the coal mining industry to identify the most pressing research and development needs of the industry. Six workshops were held on the following subjects; Research Priorities for Mining-Oriented Universities, R&D Needs-for Surface Coal Mining, R&D Needs for Deep Coal Mining, R&D Needs for Anthracite Coal Mining, R&D Needs for Coal Mine Health and Safety, and R&D Needs far Environmental Control in Coal Mining.

Jan 1, 1975

By Roger E. Burleigh

In June, 1989, the U.S. Bureau of Mines, undertook a 9-day evaluation of the tin resource potential of the Sleitat Mountain tin deposit. Significant tin-tungsten mineralization is associated with quartz-topaz-white mica-tourmaline greisen alteration of a multi-unit, 57 Ma, peraluminous, granite stock which intrudes Cretaceous Kuskokwim Group flysch deposits. The granite comprises marginal biotite-, intermediate biotite-muscovite-, and central zinnwaldite-granite units, interpreted as a zoned alteration system. Major vein mineralization is confined to two east-west-trending zones of steeply oriented tabular lenses of greisen interleaved with mildly altered granite. Cassiterite is the dominant ore mineral while arsenopyrite, loellingite, wolframite, pyrite, sphalerite, chalcopyrite, and bismuth-oxides are present in minor to trace amounts. The north and south greisen zones are estimated to contain an inferred resource of 128 to 212 million lbs Sn in 28.6 million st of mineralized rock. An 1,800-lb representative bulk sample contained 0.37% Sn, 0.04% W and 17 ppm Ag and is considered an average grade estimate for the deposit. Drill testing by Cominco Alaska Exploration indicates that substantial widths of high-grade tin mineralization are included within the lower grade disseminated mineralization. Depth of deposit erosion is substantial and there exists a high probability for placer tin deposits.

Jan 1, 1991

By T. Ruben

Micropiles have been used for the last forty years to strengthen building foundations. This article gives information about the technology and capacity of micropiles.

Jan 1, 2000

By R. Fragoudakis

AISI 4130 steel is a medium carbon Cr-Mo steel used in automotive, aeronautic and other general-purpose industries. In this study, 4130 steel fatigue specimens were carburized at 927oC to enhance the carbon content in the steel, raising it from approximately 0.30% (non-carburized) to 0.90% (carburized, oil quenched and tempered). Rotating bending fatigue tests were performed on the R. R. Moore Rotating Beam Fatigue Testing System, in order to determine the high cycle fatigue (HCF) life of 4130 steel and plot the corresponding S-N diagrams. A comparison of the results of carburized and non-carburized specimens shows that carburizing of steel: a) increases the surface hardness and b) improves the fatigue strength of the steel by at least two orders of magnitude.

Jan 1, 2010

By Jeffrey S. Walker

The purpose of this U.S. Bureau of Mines effort was to determine if ground movement caused by mining-induced subsidence is directly transferred to a structure and, if so, how that transfer takes place. Four concrete block walls with foundations were constructed and monitored over an active longwall panel. Three of the walls were located perpendicular to the direction of mining in zones where maximum inclination, maximum tension, and maximum curvature were predicted to occur. The fourth wall was constructed along the centerline of the panel, parallel to the direction of mining. All of the walls and the surrounding ground surface were instrumented with conventional survey monitoring points and extensometer stations to observe the vertical and horizontal movements. The fourth wall instrumentation also included continuously recording tiltmeters. The results of this investigation indicate that these simple structures respond to subsidence in a similar manner as the ground surface. This suggests that once the transfer mechanism is more fully defined, prediction models can be developed to accurately estimate the effect of mining on surface structures.

Jan 1, 1989

By D. François-Bongarçon

When it comes to sampling theory, a bad sampler is a bad sampler, no matter what, and a sampler is either bad or good. It also is of critical economic importance to tell and understand the difference, especially in a metallurgical plant. In this paper, the grand principles of Sampling Theory are first recalled, then the most popular types of sample cutters for plants are critically reviewed. It is concluded that the industry has a lot of progresses to make in that direction, although improvements usually pay for themselves very quickly.

Jan 1, 2002

The National Institute for Occupational Safety and Health (NIOSH) conducted a monitoring field study to optimize the rib control plan in a room-and-pillar coal mine. The study mine is located in the Central Appalachia coal basin. Two monitoring sites were selected at different sections in the study mine. The selected sites have different overburden depths and geologies. The instrumentation plans at study sites include borehole pressure cells installed at various depths in studied pillars, rib and roof extensometers and load cells mounted on number of the rib bolts. The instrumentation results and observed geology for one of the study sites showed great potential for optimizing the rib bolt plan at that section of the mine. Therefore, a rib support optimization study was followed using numerical modeling technique. A calibrated threedimensional model was developed using the instrumentation results of the optimization section. The calibrated model was used to determine the optimum rib support for expected overburden depths and rib heights. Baseline rib bolt patterns were assumed for the optimization study. Additional rib bolts, above and beyond the baseline bolting parameters, were outlined and identified as solutions to contain the rib fracturing identified by the modeling results.

Jul 28, 2020

Discrete Element Method - Computational Fluid Dynamics Modelling of Flow Behaviour in a Stirred Mill - Effect of Operation Conditions

Sep 13, 2010