Search Documents

By Clyde Baker

Drilled shafts for many situations offer an economical alternative to driven piles. The Federal Highway Administration (FHWA) has spent considerable time and money in research and developing design and construction guidelines for drilled shafts. However, the full potential of the technology may not be realized because of the uncertainty of the effects of construction on the actual service behavior and the lack of either reliable quality control tests to check for or evaluate defects, or inexpensive load test procedures. Static load testing is very expensive and it is not feasible to load test each shaft on a project. Therefore, other means are necessary to confirm or evaluate the integrity of the completed drilled shaft or to determine the capacity of the completed shaft.

Jan 1, 1989

By Bill Kyslinger

In underground mining, machine design is predominantly dictated by mine conditions and individual customer desires. In partnership with Boart Longyear Poland and KGHM, J. H. Fletcher & Company was tasked to design and manufacture a single-boom, single operator drill module for installation of 1.2 meter expansion bolt in a 1.6 meter height mine. The objective was to produce a machine to provide ergonomic improvements for the operator while working in the mine environment. This dictated the requirement for a small easily controlled, maintenance friendly design with a remote operator?s control station. The selected design method was to use starter and finisher drill steels. This combination, requiring a number of mechanized machine motions, provides the ability to drill the required depth in the specified mine height. To accomplish the task from a remote location, a conscious decision was made to employ current technology in the form of small pressure compensated hydraulics and electronic controls. The result of the design method is a modular assembly with each sub-component designed to be replaceable and adjustable independently from other machine components. The low profile remote roof bolting module is made up of six major sub-components. Each major component is painted a different color to help the operator make the visual connection from the drill module to the operator?s control/display monitor. The Stabilizer (White) secures the module between the mine top and floor. The Drillhead (Orange) produces the drilling rotation and torque but also must slide out of position to allow the machine to manipulate the drill consumables. The Drill Steel Carousel (Blue) holds and indexes the starter and finisher steel from position to position. The Manipulator Arm (Green) moves and guides the drill steels and drill consumables from position to position during installation. The Roof Reference Guide (Yellow) locates the mine roof and guides the drill steels and drill consumables into position. The Linear Bolt Carousel (Purple) holds the drill consumables. The low profile remote roof bolting module allows the operator to drill and install a roof bolt manually or automatically with the push of a button. This design substantially reduces the operator?s exposure in the mine environment, as well as inherent pinch points and rotary hazards. Positioning the operator safely in the confines of the air conditioned cab.

Jan 1, 2006

By Michael S. Wieland

Toxic fumes cause fatal and nonfatal incidents in underground mining, where the working environment tends to trap the fumes, hindering the restoration of nonharmful conditions. Workers can underestimate the residual fume toxicity and return to the work site too quickly. The toxic fumes from charge explosions depend upon a number things: formulation ingredients, mixture uniformity, water resistance, hole contaminates, rock hardness, and dust interactions. Hole-to-hole shock waves and rift compressions can partially desensitize charges, ruin the reaction kinetics, and worsen the fume toxicity. Traditionally the fume hazards for candidate explosives are resolved for a restricted set or tally of theoretical or measured fume components, transformed to standard reference conditions. The relative fume toxicity RFT is the resultant influence reckoned from a formulated sum of concentrations within the tally that are unweighted or weighted with chosen multiplying constants. The RFT result is compared to a rule criterion that represents the worst case tolerable fume toxicity stipulated by regulations or otherwise. The ranking and comparison of different hazard potentials that would otherwise remain unwieldy is rendered tractable by the common format of the RFT notation.

Jan 1, 1998

By Donald E. Garrett

Sodium sulfate is one of the larger tonnage industrial minerals. A little more than half of this tonnage — 3 Mt/a (3.3 million stpy) of natural product— is recovered from ore deposits. Most of the rest is produced as a byproduct from other manufacturing operations. Sodium sulfate is mined in a variety of ways. These include conventional room-and-pillar mining, strip mining, in situ leaching of thick ore beds, solar evaporation and cooling-crystallization of lake brine, and the pumping of brine from complex salt deposits. There is also a variety of commercial sodium sulfate ore sources. They include thenardite (the mineral form of sodium sulfate, or Na2SO4), mirabilite (glauber salt,Na2SO4•10H2O), glauberite (Na2SO4•CaSO4), astra-kanite (bloedite; Na2SO4•MgSO4•4H2O), burkeite(2Na2SO4•Na2CO3), sodium sulfate-containing caliche and various brines.

Jan 1, 2002

By Tom Szynakiewicz

Micropiles are routinely used in the United States for foundation support and underpinning applications. The high capacities achievable with the use of micropiles, combined with specialty rigs for easy installation in low headroom and difficult access areas makes them a good choice for situations often encountered on existing commercial projects. The bond zone of the pile is typically drilled into a competent stratum such as sands, gravels or bedrock. In this paper, the authors will discuss a project where the lack of a shallow ?competent stratum? led the geotechnical contractor to create their own bond zone for the micropiles using jet grouting. Due to problematic clay (CH) soils, the original foundation of a six story office building in west Houston had experienced up to five inches of differential movement in-between the shallow under-reamed shafts. The owner desired a permanent solution to the problem without disturbing the majority of the tenants. The structure was underpinned with a hybrid system of jet grouted micropiles as well as jet grouting alone and the structure was re-leveled using hydraulic equipment to within a 0.25? tolerance. Design, construction and sequencing of the project are discussed in the paper. QA/QC methods are also discussed, including coring for verification of jet grout column diameter as well as a full-scale micropile compressive load test. The structure was successfully re-leveled and the entire project was completed without disturbing any tenants on the floors two through six.

Jan 1, 2008

By V. Arslan

The primary advantage of using oxalic acid is in the formation during leaching of soluble complexes that are both photo-chemically and microbiologically degradable. In this study, chemical leaching and bioleaching methods were used for quartz sand. Using the ANOVA-Yates test technique, the effects of solids rate, temperature and oxalic acid rate were investigated using chemical leaching experiments. Solids rate and temperature were effective parameters on the chemical leaching. After the tests, the removal of Fe2O3 increased to 97.02%. Finally, the iron content decreased from 0.315% Fe2O3 to 0.0094% Fe2O3 in the leached quartz sand. The effect of pulp density was investigated on the bioleaching experiments. The bioleaching of iron oxides by Aspergillus niger resulted in removal of 47.70% of the total iron in the quartz sand, and suggested that this strain has not a good ability to remove iron impurities from quartz sand in comparison with chemical leaching. The iron content decreased from 0.315% Fe2O3 to 0.164% Fe2O3 in the bioleached quartz sand.

Jan 1, 2009

By M. Hagfors

When establishing an underwater testing site for the energy measurements of the explosives, the dimensions of the measuring pool have to be measured to find out what is the maximum weight for the test charge. Secondly one has to decide the distance between the pressure gauge and the shooting point. Thirdly the pool has to be calibrated because of the reflections of the explosions by measuring the bubble periods of the calibration charges. The calibration shots can also be used to estimate the minimum weight of the explosive charge for the reliable energy measurements by calculating the shock, gas heave and total energy values and their standard deviations.

Jan 1, 2007

By F. Seitz

STAFF: Editor, Gerhard Derge Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Managing Editor, James J. Burke THE METALLURGICAL SOCIETY: John Chipman, President; W. R. Hibbard, Jr., Post-President; C. C. Long, Vice-President; T. D. Jones, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: R. Maddin, Chairman; Dennis Carney, J. C. Fulton, J. H. Hollomon, T. B. King, C. C. Long, W. 0. Philbrook, J. D. Sullivan, David Swan, and F.L. Vogel. Review and selection of manuscripts is under the supervisian of the following Publications Committees: Extractive Metallurgy D ivis ion: T. 0. King, Chairman; S. J. Dick inson, R. P. Hermsdorf, R. Schuhmann, Jr., and H. H. Kel logg. Institute of Metals Division: F. L. Vogel, Choirmon; R. L. Smith, Vice Chairman; R.W. Balluffi, J. H. Bachtold, A Servi, C.D.Graham, Jr., C. G. Goetzel, F. E. Joumot, Jr., G. E. Pellissier, Paul Gordon, Jock Washburn, Harold Margol in, A. U. Seybolt, I. R. Kromer, R. A. Meussner, R. W. Guard, M. Harmon, J. N. Hobstetter, Dean Starr, P. Shewmon, R. Gordon, J. 0. Betterton, and E. Morgan. Iron and Steel Division: W. 0. Philbrook, Chairman; F. C. Langenberg, C. W. Sherman, J. Wagstaff, and E. J. Whittenberger. Published bimonthly by the American lnstitute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription $20 per year for non-AIME members in United States and North, South, and Central America; $25, foreign; $5 for AlME members. Single copies, $4.00, single copies foreign, $5.00. The AlME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1959 by the Americon Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AlME New York ... Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts . . .Second class postage paid at New York, N. Y. , ond Ann Arbor, Mich. Volume 215, Number 3

Jan 1, 1960

By Walter Ensinger

Special foundation works is one of the most innovative sectors in civil engineering and construction. Both engineering techniques and construction machinery are undergoing continu­ous further development. These developments are providing ways to meeting the world-wide requirement for special geotechnical works even faster, even better and more efficiently. Unfortunately, accident prevention organisations have had to realise that the figures on in­dustrial accidents in special foundation works are still above average in number. The Safety & Environmental Working Group of the EFFC thereupon started to carry out a survey on acci­dents occurring in this sector and used this information as a basis for the preparation of acci­dent statistics and an accident analysis. The objective of this undertaking is to determine key accident occurrences and their causes and to consequently determine measures for improved health and industrial safety.

Jan 1, 2002

By J. F. Havard

The enterprises based upon the industrial minerals are diversified in geologic habit, mining systems, processing techniques and marketing methods. Nevertheless, in 1972 these enterprises faced many of the same frustrations and hopes and knotty problems and crucial decisions. Volume and profits were generally improved but were uneven in extent and effect. The U.S. cement industry, for example, was unable to meet demand in major markets. It was constricted by a frozen low-level price structure, faced expensive pollution control measures and watched heavy imports penetrating its markets from several European nations, Mexico and Canada.

Jan 1, 1973

As the 2009 George Fox Conference neared its conclusion, Arthur Silber, project chief of the Mass Transit Tunnel (MTT) project was able to pull away from the constant buzzing of his Blackberry long enough to give a short presentation and a significant piece of news to the record 318 attendees at the Graduate Center, City University of New York regarding the MTT project. ?As the former administration (The Bush administration) was leaving office, we were told that Congress was notified of the FTA?a (Federal Transit Authority?s) intent to issue final design construction approval to us,? Silber said of recent advancements concerning the $7.2-billion dollar project. It will add passenger rail service from New Jersey to New York City as part of the Access to the Region?s Core project in the form of the Trans Hudson Express Tunnel (THE tunnel). ?That 10-day waiting period ended yesterday (Jan. 26).? In days leading up the Fox Conference, those involved in the tunneling industry, and the MTT in particular, had a lot to be optimistic about. The MTT received environ-mental approval on Jan. 14 (see page 9) and, with the acceptance of the final design, the multi-billion dollar project moved that much closer to a ground-breaking ceremony. So close, in fact, that before leaving his office for the conference, Silber posted the contract documents and plans for the Manhattan Tunnel project online at www.arctunnel.com (an indepth look at the project from Silber is on page 22). While many were interested in the progress of the project, Silber also spoke about the new plans for the cavern complex at the New York Penn Station expansion. The original plans called for two lines that would come into a large cavern complex with a north and south cavern to access the trains. After numerous core samples were taken from the streets of Manhattan, it was deter-mined that this design was not feasible and changes were made that will include a deeper cavern under Sixth Avenue, with 14-m (45-ft) of cover with a 30-m (96-ft) wide cavern that resides entirely under 34th Street. The cavern was also moved 20 m (60 ft) to the west to remain at least 61 m (200 ft) away from New York City Water Tunnel #1. The new design will include three-over-three track arrangement. The mezzanine will be 46 m (150 ft) below street level at 8th Ave, Silber said.

Jan 1, 2009

By Marco D. Boscardin

Control and mitigation of building response to construction activities are assuming a greater role in design decisions for underground construction. Alternatives for controlling building response have multiplied with the continued development of ground modification methods, better control of construction activities that cause ground movements, and increased understanding of building behavior and response. This paper describes approaches to estimating building response to construction-related ground displacements caused by adjacent excavation and highlights the discussion with several case history examples. Examples discussed includes experiences with two, seven-story historic structures, supported by timber piles with granite block pile caps, which were underpinned in preparation for ground-freezing ground stabilization and tunnel construction beneath the buildings. The elevation of each building column was monitored and elevation adjustments were actively performed during construction. The second example examines the performance of a slurry wall braced cut, 45 to 50 feet deep penetrating through a stiff crust into a soft clay layer and associated building response. This cut was immediately adjacent to two, approximately 15-story office buildings, which were supported by deep foundations founded in the stiff crust.

Jan 1, 2003

The new legislative regime applying to the mining industry has been in force for nearly two years. However the parameters for the permits required under the Crown. Minerals Act 1991 and the resource consents required under the Resource Management Act 1991 are still being established. Mining operators will benefit from participating in the development of policies and plans currently being formulated by local authorities. The Energy Legislation Amendment Bill currently before the House contains amendments to the Crown Minerals Act to clarify points of uncertainty and to reduce transaction costs where possible.

Jan 1, 1993

By Adrian J. Moore, Alan B. Richards

Airblast overpressure levels can commonly be increased by up to 20 decibels (dBL) by the effects of meteorology, due to inversions and wind shear. Existing atmospheric refraction models can provide a good evaluation of the effects of meteorology, but have been limited in the accuracy of their outputs by the accuracy of the meteorological data that is available for input. This paper uses case histories from open-pit coal mine blasting in the Hunter Valley area of Australia to provide examples of increases in airblast due to inversions, wind shear, and a combination of both. It gives details of our experience of the accuracy with which predictions and assessments can be made using meteorological data of various levels of accuracy, and on the design buffer that is required to prevent the exceedence of airblast limits. The accuracy of meteorological prediction and assessment will shortly be improved by the use of sounding equipment that gives continuous measurements of temperature and wind velocity at significant levels above the ground. The paper also gives details of an industry funded research project that aims to permit the effective use of this data at distances many kilometres (km) (miles) from the location of the sounding equipment, and to develop a short term predictive model that will permit the amount of meteorological reinforcement that will occur at firing time to be determined before a decision is made to tie up a shot.

Jan 1, 2005

This paper forms the second of a series, in which it is proposed to communicate the results of an extensive research into the influence of alloying elements on the physical properties of lead, now being carried out in the Metallurgy School of the University of Melbourne.Some general comments on this research were made by the present writer as an introduction to the first contribution by R. S. Russell*: It was there pointed out that it was the intention to prepare lead as pure as possible, to determine its properties and then to make alloys with the various elements added singly, and in various combinations, in order to determine the effect of each. This line of action is still being pursued.It occurred to the writer, however, that this fundamental attack might, with advantage, be accompanied by a parallel investigation in which lead of commercial purity would form the basis material. In this way, using a standard *Professor of Metallurgy, University of Melbourne.

Jan 1, 1934

By F. Bruey, T. Bruce, D. R. Nagaraj, W. Thomas, P. Riccio, E. Guitard

"AEROPHINE® 3418A Promoter is a flotation collector that has been an industry standard in the Canadian mineral processing industry since its first commercial use at the Kidd Creek concentrator in 1980. Its wide range of applications in sulphide mineral flotation has made it successful, specifically in the processing of complex sulphide ores which contain copper, lead, zinc, and silver or any combination of these elements for selective separation.AEROPHINE® 3418A Promoter is a unique, phosphine-based collector originally developed for the flotation of copper sulphide minerals and activated zinc minerals. It is now recognized for its selectivity for complex, polymetallic sulphide ores and porphyry copper ores. In addition, AEROPHINE® 3418A Promoter is highly selective for copper, lead, activated zinc, nickel and precious metals. AEROPHINE® 3418A Promoter exhibits strength yet, selectivity against iron sulphides (pyrite, pyrrhotite, marcasite, and arsenopyrite), non-activated sphalerite, and many minerals which contain penalty elements.This paper outlines a brief history of the product’s development, its historical use in Canada and several potential innovative mineral processing applications with the use of the chemistry. Three Canadian case studies will be presented on various ore types including: a Cu-Au ore, a Cu-Zn ore, and Cu-Pb-Zn ore. A plant production update will also be given on the future supply of AEROPHINE® 3418A Promoter.INTRODUCTIONCytec Industries Inc. operates a phosphine derivatives plant in Niagara Falls, Ontario, that manufactures various products for their speciality chemicals division. The products from this site are based on phosphine (PH3) chemistry and are used in a variety of markets including electronics, agriculture, LED lighting, water treatment, metal extraction, and mineral processing. One of the major products is the phosphine-based sulphide mineral collector, AEROPHINE® 3418A Promoter.AEROPHINE® 3418A Promoter (Figure 1) was originally developed for the flotation of copper and activated zinc minerals (Thomas, 2010).."

Jan 1, 2015

By M. K. Sichone

Anglo Platinum?s Waterval smelting complex based in South Africa operates the Anglo Converting Process (ACP) that produces SO2 offgas. This SO2 offgas is treated in a double-contact, double-absorption acid plant allowing for conversion efficiencies higher than 99.90 %. The catalytic converter used in the acid plant to convert the SO2 to SO3 is a 4-bed reactor loaded with a combination of cesium-promoted and conventional vanadium pentoxide catalysts. In June 2008 there was a shutdown, in which one of the main activities was to screen the catalyst. Before this shutdown, the operator would control the converter pass temperatures manually, via the SCADA, especially during plant start-ups after which some of the automatic temperature controllers were used. After the shutdown, the control philosophy was revisited and all temperature controllers were put on auto mode during plant start up. Furthermore the set points of the pass inlet temperatures were reduced to maximize conversion in the first two passes. The result has been a reduction of SO2 emissions, from a daily average of 50 ? 70 ppm to as low as 20 ppm for similar sulphur dioxide and oxygen concentrations. Further work has been done to maintain high bed temperatures in the third and fourth passes at low SO2 strengths by splitting the gas stream between pass 1 and 2 thus increasing the SO2 content in the gas to pass 2. This increases the temperature of the gas exiting the second pass, which results in higher temperatures in passes 3 and 4. Comparison of the converter performance prior to and after the changes is made. The benefits of partially bypassing the first pass to increase the SO2 content in the gas to the second pass are shown. Conclusions and scope for further work have been drawn from the comparisons.

Jan 1, 2009

By Ray Brainard

The Jollyville Transmission Main will be a 10.5-km- (6.5-mile)-long, 213-cm (84-in.) diameter rock tunnel. The tunnel will pass beneath the Balcones Canyonlands Preserve, which was established to protect two endangered bird species, six endangered cave invertebrates and a threatened salamander. To address the sensitive habitat that the transmission main is to pass through, the city of Austin developed an environmental commissioning (EC) process that brought together environmental engineers and scientists, the city?s project management team and the designer team to work collaboratively to meet the city?s goals of producing a cost-effective design while also protecting the environment. This paper describes the environmental commissioning process and the benefits it brought to the project and environment through some unique environmental mitigation measures to protect this sensitive area.

Jan 1, 2012

By P. Wells, P. Quinn

"A moveable flotation miniplant was designed and constructed at the research laboratory of Inco Technical Services Ltd. to address the need for flowsheet development with a limited amount of ore (such as drill cores). It consists of one rod mill, two regrind ball mills, one vibratory screen, 24 flotation cells of various sizes and two Venturi aerated flotation columns. The setup has continuous monitoring capability for pH, dissolved oxygen, oxidation-reduction potential, conductivity and temperature in conditioning tanks and flotation cells. Various options regarding flotation reagents, circuit configurations, and fineness of primary grind and regrind can be readily evaluated. The throughput of the miniplant is 20 – 30 kg/hour ore.Unit operations such as flash flotation, magnetic separation and gravity concentration can also be evaluated as an integral part of an entire flowsheet development.This communication describes the basic design features of the miniplant and some examples of applications are given.INTRODUCTIONInco operates numerous mines in Sudbury and Thompson and will shortly bring the Voisey’s Bay mine into production. It has long been recognized that the ores from different mines or from different depths of the same mine can give different responses in flotation. There is a growing need to properly evaluate the ores before feeding the mill to maximize the return of the mine/mill operation. Inco Technical Services Limited at Sheridan Park, Mississauga, Ontario has developed a batch laboratory procedure to address this issue. The results are considered in the overall economical assessment of new mine operations.For ores that cannot be processed by the existing mill operations or that will be processed by a new mill, it is necessary to develop a flowsheet that can maximize the economical return of the mine/mill operation. While recognizing the importance and contribution of the laboratory batch flotation procedure, it does not generate reliable data for flowsheet simulation and design. A full-scale pilot plant campaign is normally required to obtain the design data but often this is not possible due to a limited amount of ore obtainable from the drill core. A small-scale pilot plant (mini pilot plant or miniplant) capable of processing 20-30 kg/h ore can provide this data prior to a full-scale pilot plant campaign. A miniplant can also be used to optimize the circuit configurations, reagent additions and recycle options of process water before pilot plant work and can be used to test a different flowsheet configuration for an existing mill before re-piping a plant circuit."

Jan 1, 2003

At Copper Refineries Pty. Ltd., Townsville, two reverberatory furnaces of 420 tonnes capacity are used to melt 210000 tonnes/year of copper for subsequent anode casting. When the refinery commenced production in1959, these furnaces were of 300 tonnes capacity. The original furnaces featured a silica brick hearth, magnesite and chrome magnesite side 'walls, and a sprung silica brick roof, but were unsatisfactory because of thelow refractory life and high costs. With continuous expansion in production and the incentive to increase furnace life and capacity the design of these furnaces has changed greatly since that time.The present furnaces feature all basic brick, a flat suspended basic brick roof, very extensive use of watercooled copper sections, and are of substantially increased (420 tonnes) capacity. Particular attention has been concentrated on high wear areas such as the taphole, side walls, and charging door jambs. Each furnace in its 24 h cycle, is charged, the copper melted, impurities skimmed off, metal "poled" prior to casting, and cast.The service condition during each of these operations is important in considering furnace refractory life.The improvements in operating practices and furnace 'construction which enabled the capacity of the furnaces to be increased are discussed. The life between major repairs to side walls has increased from 90 charges to300 charges.The scope for future improvement is considered and areas for development are suggested.

Jan 1, 1977