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By Tony Mazzo

It has often been said by consulting engineers that foundation contractors are in the business of taking risks. One would agree that the mere fact a foundation project can be budgeted, planned, engineered and executed solely on the reliability of eight test borings made at a proposed site having an area of approximately 19,000 square feet, is a risky proposition, in and of itself. Now imagine that this site is actually one half of a city block located in an urban setting in an old, congested, historical neighborhood, surrounded by narrow city streets and historic landmark buildings. And suppose that the required depth of excavation for the construction of the new building on this site is approximately 35 feet and the natural groundwater table is at a depth below existing grade of only 25 feet. Given the difficult site conditions outlined above, one could certainly add the words "challenging" and "complicated" to the inherent word "risky" when describing the construction techniques involved to undertake a foundation project of this magnitude. This case study will discuss in detail how the excavation, sheeting, dewatering and underpinning work was accomplished as well as the problems overcome along the way.

Jan 1, 2003

By Harald Ludwig

In 2002, excavation support work commenced on the Capitol Visitor Center project located adjacent to the nation?s Capitol building in Washington, D.C. The outlying work (Slurry Wall Work at Main Site is not discussed) consisted of providing excavation support for a new truck tunnel approximately 1900 feet long up to 50 feet deep as well as support for the new underground auditorium and Library of Congress tunnel. The excavation support consisted of a combination of conventional drilled in soldier beams, lagging, tiebacks and braces; intricate underpinning inside the existing Capitol building; support of an existing Russell Tunnel; soil nailing and tiebacks underneath the existing Russell Tunnel; two temporary bridges; and a deep soil mixed wall with lateral support provided by braces. As part of an on-going research program, some of these braces were instrumented with strain gauges. The deep soil mixed wall was approximately 300 feet long and 65 feet deep on either side of the truck tunnel. Approximately 34,000 sf of deep soil mixed wall, 90,000 sf of conventional excavation support, 200 braces, and 320 tiebacks were installed. This paper describes the large scope and breadth of the project that required a variety of excavation support techniques. A few of the challenges in designing and installing the support of excavation are discussed. This paper also presents the results of the instrumentation program conducted on the deep soil mixed wall, which stood open for more than a year.

Jan 1, 2006

By D. Barber, A. D. Miller, P. A. Bray

The project was to develop an area within the existing West County Wastewater Treatment Plant which would enable the construction of a new Raw Wastewater Pump Station (RWPS) with a footprint of approximately 85 feet by 190 feet and a foundation depth of about 82 feet below grade and a new Short- Term Detention Basin (STDB) with a footprint of about 80 feet by 130 feet and a foundation depth that varied from approximately 3 to 24 feet below grade.. The excavation support system had to be designed to withstand both normal and the 100-year flood elevations. A Reinforced Soil-Cement Wall (RSW)was chosen to provide a hydraulic barrier which consisted of a single row of soil-cement elements installed along the perimeter of the area to be excavated. Steel wide flange beams were installed on 4 foot centers to support construction loads and be resistant to the lateral forces of the soil and hydrostatic pressures. The RSW was installed to a maximum depth of 104.5ft using a triple-auger drill rig with mixing paddles with a 2ft key into weathered shale providing a cutoff wall consisting of 53,150 square foot of treated soil. The project was to provide the initial design of the excavation support for the pumping station excavation support system and groundwater cutoff. There was 534 linear foot of soil-cement-bentonite wall installed and 106 - 80 foot long W21 x 121 wide flange beams installed on four foot centers into the alignment of the wall. Each element was drilled down into the weathered shale to obtain groundwater cutoff. Derek R. Guthrie Water Quality Treatment Center Pumping Package is the site for a new pumping station that will service Louisville, Kentucky residents. After unplanned long term exposure into the winter, the effects of freeze thaw cycles were evident.

Jan 1, 2017

By Andhra Pradesh, Nagarajkumar B. V

As a part of Mumbai City Mega Drinking Water Project at Amar Mahal Tunnel-1 Ghatkopar East Mumbai, drinking water tunnels were proposed by MCGM from Amar Mahal to Trombay reservoirs, Amar Mahal to Wadala and further up to Parel. The pipeline has to be underground and laid at a depth of 5.5m. The initial proposal was to provide sheet piling to enable the safe excavation and installation of underground pipeline. However, installation of sheetpiles was practically not feasible due to the existing soil strata for driving the sheet piles. Hence, it was proposed to install micropiles instead of sheet piles. In this paper we discuss about the purpose, basic design, detailed design approaches and actual work implementation of micro pile with temporary struts for shoring protection works in this project.

Sep 1, 2022

By Hugo Meggitt, Damian R. Siebert, Wystan Carswell

Excavation-induced ground movements are a critical component in the design and construction of deep excavations in urban settings due to the potential adverse effects on adjacent structures and infrastructure. Ground movements are influenced by soil stratigraphy, soil properties, adjacent structures, and construction means and methods. The use of empirical relationships, computer models, and reliance on experience with similar excavations in similar soil conditions often provides a basis for predicting excavation-induced ground movements. In this paper, data from 21 deep excavations approximately 20 ft to 75 ft deep supported by concrete diaphragm “slurry” walls in the Greater Boston area are compared to published literature, considering how different foundation systems (e.g. shallow foundations, caissons, and piles) of abutting structures have been affected by adjacent excavations. The influence of construction method (conventional vs. top-down) on adjacent foundation movements indicate that top-down construction typically results in smaller foundation movements. INTRODUCTION Estimation of ground movements due to excavation is a challenging endeavor, even with complex three- dimensional finite element modeling and high-order constitutive models that are increasingly available in modern engineering practice. Aside from the expense of the soil exploration and testing used to inform these higher-order models, the challenges of modeling past stress history, adjacent structures, and the groundwater conditions during excavation require not only large investments of time during design but also validation from past experience (to avoid a “garbage in, garbage out” paradigm). While site conditions such as soil stratigraphy, soil properties, groundwater conditions, and as-built conditions of adjacent structures can be obtained, measured, and estimated, the effects that means and methods of construction have on ground movements are difficult to quantify. During early phase design, assessments of predicted ground movement are unable to account for all aspects of project construction, nor is it cost-efficient to fully design an excavation while project parameters such as site size and excavation depth are under consideration by the design team. While construction is in progress, benchmarking support of excavation performance and associated ground movements in the context of successfully completed projects allows for a more nuanced view of system performance and provides the opportunity for more informed decision-making (if required) as construction proceeds. For these reasons, the use of empirical relationships and the collection of historical support of excavation performance holds high value for the practicing geotechnical engineer at all phases of the project.

Jan 1, 2019

By L. C. Reese

? Good construction and inspection presumed. ? Capacity-computation factors are independent of construction method. ? To account for variable or uncertain site conditions, anticipated construction problems, and/or minimal inspection, increase factor of safety. ? Conduct load tests and/or develop easily implemented design alternates (e.g., straight shaft in case bell can't be formed) to reduce factor of safety.

Jan 1, 1988

By M. Superfesky, P. Michael

Introduction The US Office of Surface Mining (OSM) is proposing changes to the Code of Federal Regulations in the interest of minimizing the adverse effects of excess-spoil-fill construction on the “prevailing hydrologic balance, fish, wildlife and other environmental values” (70 FR 35112). The proposed changes will require: (1) minimization the amount of excess spoil generated at a mine site; (2) minimization of the size of the fills constructed; (3) consideration of alternative configurations for disposal; and (4) development of a disposal plan that would minimize adverse impacts to the environment.1 To achieve those objectives, mining companies operating in steep-sloped Appalachia will likely build excess spoil fills (also called valley fills) that toe out at higher elevations in the hollows (i.e. to prevent or limit burial of streams). Consequently, the slopes of fill foundations will generally be steeper. Whereas the authors of this paper support these measures to protect the hydrologic balance and general environment, we wish to point out that placement of fills on steeper foundations can negatively impact the stability of the fills if proper care is not taken during their construction. It is important to note that in addition to impairing human safety, valley fill instability can negatively impact streams, the riparian habitat etc., and thus defeat the very purpose of the spoil minimization measures proposed. We do not, however, propose additional regulatory requirements pertaining to valley fill stability. Rather, we intend to emphasize the importance of engineering requirements already on the books, especially as they apply to the predominant type of valley fill constructed: the durable rock fill. We believe that the practice of restricting valley fills, to higher elevations in the watershed leaves less room for error in the design and construction of stable structures. This paper gives a quick review of the nature of excess spoil generation; methods and requirements of excess spoil fill construction, and the to-date stability record of the fills. The interest in excess spoil minimization and how it affects valley fill construction is also discussed. Most importantly, we will review long-standing issues pertaining to proper design and construction measures with respect to durable rock fills and discuss how they will become more critical as spoil minimization is practiced.

Jan 1, 2007

By Karl A. Higgins

In August 2004, the long-awaited National Harbor project in the DC metro area sprang to life with the design of Gaylord National Resort and Convention Center. When the project was in its final stages of construction in 2007, it was noted as largest building development of the east Coast and the 4th largest Building project in the U.S. The final construction costs were above $900M and it served as the catalyst for the overall National Harbor development which added another $1B in construction costs over the next few years. The Gaylord Hotel is supported by approximately 150,000 linear-feet of driven precast concrete piling, one of a handful of major DC area projects in the early 2000s that were supported by this pile type. The project overall was a success, but the fast-paced construction schedule created significant challenges to the designers and contractors. Piling installation was the first major building construction task, and it did not start out well. While the test piles were installed without damage, when production pile driving began in the summer of 2005, pile head and body breakage soon became evident. Typical of most highprofile projects, there are many stakeholders involved and an equal number of opinions on why the piles were breaking. The financial and contractual implications of starting the project off awkwardly were evident to all. The pile driving criteria was scrutinized by the contractor, and the engineer’s had reservations about the size and type of the hammers used for pile driving. Ultimately, it was proven the leading cause of pile breakage was neither the pile driving criteria nor equipment, rather the pile materials themselves. The author of this paper is also the Geotechnical Engineer of Record for Gaylord National and many of the adjacent National Harbor buildings including the recently completed MGM casino. About 100 piles were damaged during Gaylord’s construction some requiring multiple piles for replacements. Over the past decade or so, rumors on the causes of the pile breakage have spread in the market, with some alleging this pile type is not compatible with the geologic setting. I have purposely avoided writing this case-study due to the controversy surrounding the subject, but now some 15 years later it seems appropriate to do so considering DFI’s annual conference location. This will be a fact-based assessment of pile breakage at Gaylord and will also include a comparison to the neighboring buildings where far fewer driven piles were damaged, once a more appropriate concrete mix design was required. The pre-cast supplier is no longer in business.

By Jair Alarcón, Lucas Steffen, Leopoldo Muñoz

Flyrock is one of the most significant hazards associated with blasting in open pit mining, especially for blasting operations near communities. Flyrock can lead to severe injuries, fatalities, and property damage, compromising the license to operate. For this reason, defining exclusion zones is critical to ensure the safety of people and equipment. A very large radius will reduce the risk of flyrock; however, excessive exclusion zones can significantly impact the productivity of the operation and, in some cases, compromise the extraction of ore in critical sectors. Many mine sites use distances derived from pre-established standards, experiences from other mines, or still use simple methods for analysis, like recording blasts with a terrestrial camera and performing deterministic calculations to determine exclusion areas, applying an arbitrarily safety factor for people and equipment. In this paper we present a new approach that allows the calculation of the exclusion zone by measuring critical flyrock parameters with a high degree of accuracy through a new video analytics technology, this data then is used as input to calibrate probabilistic flyrock models to have more robust calculations, allowing optimized and safe exclusion zones. The proposed methodology leverages high-accuracy data and continuous monitoring to dynamically adjust D&B designs and exclusion zones, ensuring maximum safety without unnecessarily restricting operational efficiency. A case study is presented where the application of these new digital technologies allows precise prediction and control of flyrock trajectories, enhancing the accuracy of exclusion zone boundaries. In this case we successfully reduced the exclusion zone radius to 100m, allowing the ore extraction in a critical region close to the community safely. The study shows notable improvements in safety and productivity, including zero flyrock incidents and enhanced protection for nearby communities. The adaptive nature of these digital tools offers scalable solutions for various blasting environments. The paper concludes by recommending the integration of these tools into standard blasting protocols, highlighting the potential for widespread adoption in the industry to mitigate flyrock risks effectively.

Jan 21, 2025

By Franklin M. Grynkewicz

As part of the Boston Harbor clean up project, the new 1,000 mgd Deer Island Sewerage treatment plant includes ten 240 feet high egg-shaped "residuals" tanks. Contract documents called for these structures to be supported on 2,600 sixteen inch concrete filled pipe piles. The project site is underlain by highly variable glacial and marine deposits. Subsurface conditions vary from one extreme where firm glacial deposits exist at subgrade to the other extreme where 70 feet of medium stiff clays overlying weathered bedrock must be dealt with. The most common profile consisted of 15-20 feet of sands, 20-40 feet of marine clays, and 20-60 feet of stratified glacial deposits (commonly called tills) overlying Argillitic bedrock. Post bid redesign work, initiated as a cooperative effort between the owner and the general contractor, demonstrated that an $8 million savings could be realized if high capacity 48 inch diameter caissons replaced the specified pipe piles. A highly unusual arrangement of having the general contractor and specialty subcontractor providing input to the owner's engineering team allowed the redesign work to proceed on a "fast-track" schedule.

Jan 1, 1992

By Kiyotaka Ohno, Nobushige Yasuoka, Yosuke Hioki

"The diameter of improved columns adopted by the original DJM Method had been 1000 mm, however, in order to comply with the social need for construction cost reduction, the Expanded Dry Jet Mixing (EX-DJM) Method with maximum column diameter expanded to 1300 mm was developed between 1998 and 2001 and has been widely applied since then. From the first application of EX-DJM in January 2002 for a first construction project, the total volume of improved soil has reached 325,000 m3 in 17 projects up to September 2014. Because of the advantages of the EX-DJM such as reduction of construction costs and periods leading to reduction in the number of improved columns, adoption of this method is expected to increase in the future. This paper describes the advantages of the EX-DJM, its construction results and case examples including those applied to restoration projects after the Great East Japan Earthquake, 2011.1. BACKGROUND OF DEVELOPMENTThe Dry Jet Mixing (DJM) Method is a soil stabilization method in which a powdery or granular binder is pneumatically fed into and mixed with soft soil to induce chemical reactions that stabilize and strengthen the soil. It was developed by government - private collaboration in Japan between 1977 and 1979. Up to March 2014, the total volume of soil improved by DJM method reached 33,500,000 m3. The initial diameter of improved columns of the original DJM Method was 1000 mm. In order to comply with the social need for construction cost reduction, the Expanded Dry Jet Mixing (EX-DJM) Method with maximum column diameter 1300 mm was developed between 1998 and 2001.2. ADVANTAGES OF EX-DJMThe construction equipment for the EX-DJM consists of two major parts, which are DJM machine and binder plant are shown in Fig. 1.The construction machine is of double mixing-shaft type with its column diameter expanded to 1200mm or 1300mm. In association with the increase in the column diameter, the binder feeder has also increased its discharge rate by approximately 1.69 times. Same as the increase rate of the area of original diameter 1000mm to diameter 1300mm are shown in Fig. 4."

Jan 1, 2015

By Kiyotaka Ohno, Nobushige Yasuoka, Yosuke Hioki

"The diameter of improved columns adopted by the original DJM Method had been 1000 mm, however, in order to comply with the social need for construction cost reduction, the Expanded Dry Jet Mixing (EX-DJM) Method with maximum column diameter expanded to 1300 mm was developed between 1998 and 2001 and has been widely applied since then. From the first application of EX-DJM in January 2002 for a first construction project, the total volume of improved soil has reached 325,000 m3 in 17 projects up to September 2014. Because of the advantages of the EX-DJM such as reduction of construction costs and periods leading to reduction in the number of improved columns, adoption of this method is expected to increase in the future. This paper describes the advantages of the EX-DJM, its construction results and case examples including those applied to restoration projects after the Great East Japan Earthquake, 2011.1. BACKGROUND OF DEVELOPMENTThe Dry Jet Mixing (DJM) Method is a soil stabilization method in which a powdery or granular binder is pneumatically fed into and mixed with soft soil to induce chemical reactions that stabilize and strengthen the soil. It was developed by government - private collaboration in Japan between 1977 and 1979. Up to March 2014, the total volume of soil improved by DJM method reached 33,500,000 m3. The initial diameter of improved columns of the original DJM Method was 1000 mm. In order to comply with the social need for construction cost reduction, the Expanded Dry Jet Mixing (EX-DJM) Method with maximum column diameter 1300 mm was developed between 1998 and 2001.2. ADVANTAGES OF EX-DJMThe construction equipment for the EX-DJM consists of two major parts, which are DJM machine and binder plant are shown in Fig. 1.The construction machine is of double mixing-shaft type with its column diameter expanded to 1200mm or 1300mm. In association with the increase in the column diameter, the binder feeder has also increased its discharge rate by approximately 1.69 times. Same as the increase rate of the area of original diameter 1000mm to diameter 1300mm are shown in Fig. 4."

Jan 1, 2015

By Albert Neumann, Franz-Werner Gerressen, Giancarlo Santarelli

"Diaphragm walls are known as underground structural elements commonly used for retention systems and permanent foundation walls or elements. In addition they are also quite often used as deep groundwater barriers, named Cut-Off-Walls (COW). Due to the requirements of each particular job site, e.g. the need for carrying high loads or as seepage barriers, there is an increasing industry demand for efficiently cutting into rock. Besides the removal of boulders, cutting through rock, is always the most difficult part of the excavation process of a diaphragm wall or COW.There are a number of influencing factors which have an impact on the rock cutting performance. Besides the influence of the rock characteristics itself, which is not always the same, there are other factors related to equipment, tooling as well as the operating staff. In addition to RQD, the most commonly available rock property found in geotechnical reports is the Unconfined Compressive Strength (UCS) value. There are however some other related properties, such as weathering, bedding, inclination, abrasiveness, etc.,which can have a major impact on the achievable cutting performance. This paper will discuss the various parameters, and how they can be considered for performance estimation. Based on experiences gained on over 100 projects, a performance estimation chart was developed to allow for a better approach to these kinds of projects. This paper also explains the general installation process in as well as some specific features related to specific site conditions. In addition, some job site references will give more detailed information about such type of site conditions and how to deal with them.Keywords: Diaphragm wall, Cut-Off-Wall, Trench Cutter, RockINTRODUCTIONDiaphragm walls are known as underground structural elements commonly used as retention systems for excavation pits, shafts, permanent foundation walls and load bearing elements.It can be anticipated that, with the increasing trend of utilizing more and more underground space to accommodate environmental considerations and urban/suburban development, there will be an increasing requirement for diaphragm wall usage in even more difficult conditions.In addition diaphragm walls can also be used as deep groundwater barriers (Cut-Off-Walls). This market has demonstrated that the demand for these types of walls is reaching ever more difficult soil conditions and greater depths which are surpassing the current industry standards. The trench cutter is the most important tool for performing this type of work."

Jan 1, 2016

By Dena Morgan, Emre Biringen

"Abstract This paper discusses the execution of pile installation and design issues at two environmentally challenging industrial sites in North America. Environmental regulations set constraints on the design and require versatility in choice of technology.For a proposed bridge, due to protected fish habitat, performing soil borings within 30 m of the creek embankment was prohibited. The limited subsurface profile indicated a thick upper layer of granular material, thus driving H-piles was considered. However, to limit generation of vibration and noise in the protected area, drilled piles had to be used. During execution, the subsurface profile differed from that in the borings 30 m away. Very soft, saturated silt was encountered at the bottom of the caisson and the length had to be redesigned very quickly while the contractor waited for instruction. For a new structure in uncontrolled fill area, performing soil borings was not allowed. It was known that a layer of peat was present in the area, but no information regarding the thickness and extent. The subsurface profile generally consisted of granular material overlying a thick compressible silt layer. Somewhere within the granular layer peat would likely be encountered. Franki piles were chosen to penetrate the peat and bear in the underlying granular material. During environmental sampling in the area, methane gas was encountered and Franki piles were no longer a viable option due to safety concerns. The foundation system was changed to steel H-piles driven to bedrock, which was more than 50 m below the ground surface and sloping. Rock shoes that would work to significant slopes had to be used in order to increase the likelihood of good embedment within the bedrock. Also, due to obstruction of an approximately 3 m thick debris field that was encountered in the upper granular soils, some of the piles had to be relocated and extra piling needed to compensate for such differences. The results of PDA testing to estimate compressive capacity and a series of lateral load tests are presented.INTRODUCTIONThe design issues that are encountered during construction can be quite problematic and have a significant impact on schedule. In order to avoid such impact on the project, a thorough subsurface investigation should be considered prior to design and construction. Better understanding of environmental regulations also prevents costly changes to the foundation design. This paper discusses the execution of pile installation and the design issues at two environmentally challenging sites in North America.BRIDGEDuring the subsurface investigation for a proposed industrial building complex, several boreholes were drilled within the footprint or in close proximity of various structures, with Standard Penetration (SPT) sampling of the upper coarse-grained soils (sand/gravel) and undisturbed sampling of the lower fine-grained soils (silt/clay). The SPT blow counts (N60) were corrected by a factor of 1.35 in order to incorporate the SPT automatic energy transfer ratio. When Modified California Sampler was used, a correction factor of 0.44 to 0.64 was also applied. N60 values were further corrected for gravel to avoid artificially high blow counts during the analyses due to spoon samples contact with gravel and cobbles, and the corrected values of (NG)60 (limited to a maximum value of 50 blows/300 mm) were used for design. The information from the SPT boreholes was then used to assess the subsurface conditions beneath the structures, as well as for a nearby bridge that was designed to cross over a creek. Since performing soil borings within 30 m of the creek embankment was prohibited due to the protected fish habitat, the investigation with regard to the bridge abutments was limited to two deep boreholes (B10-33 and B10-34) at the bridge location and two additional boreholes (B10-35 and B10- 36) located approximately 200 m upstream. The bridge location and two sets of boreholes are"

Jan 1, 2014

"INTRODUCTIONThe information compiled in this volume initially formed the response by the Generic Mineral Technology Center for -Respirable Dust (GTCRD) to a review of its research and technology transfer programs performed in 1990 by the Advisory Committee on Mining and Mineral Resources Research. This review for each mineral technology research center is accomplished, as required of the Bureau of Mines by the House/Senate Joint Conference Committee, through site visitation to the research institutions of the GTCRD and an in-depth questionnaire. The information provided by that questionnaire becomes an important factor in their recommendations concerning future directions of the program.The site visitations took place during January and February 1991 at the Milton S. Hershey Medical Center~ The Pennsylvania State University, West Virginia University, University of Minnesota, and Michigan Technological University, in addition to an in-mine visit conducted at the Loveridge Mine in West Virginia. The questionnaire was prepared and made available to the Advisory Committee and the Research Council for their review at the GTCRD annual project review meeting in Hershey, Pennsylvania, in April 1991.The comprehensive nature of the questionnaire and the scope of the information contained therein make it an excellent retrospective of the Center. Having a clear vision of where the Center has been and knowing where it is now helps to guide it into the future. It is believed that such a detailed view of the Center's facilities and research program will be of value to Center personnel and Advisory Committee members. Each aspect of the questionnaire was examined, answered in detail and documented thoroughly. With the completed questionnaire as a guide, this review of the Center's activities provides an update to Respirable Dust Center Research Program Review 1988, published in 1989 as the seventh of the Generic Mineral Technology Center for Respirable Dust volumes. As does that volume, this review presents the complete General Mineral Technology Center questionnaire, with the GTCRD's expanded responses and supporting documentation appended. An examination of the research program, Center personnel currently active on GMTC projects, the number of graduate degrees granted with GMTC supports GMTC publications, the degree of individual interaction, technology transfer activities, the reference center, GMTC equipment and facilities, and envisioned plans for future research directions provides updated information in these areas. In addition, this year, information has been included to demonstrate the interaction between the Center's goals and its research projects, with thorough consideration of actual research needs as specified by the National Academy of Sciences. This volume serves as a review of the years 1989 through 1990, the sixth and seventh years of the Center's operation."

Jan 1, 1990

By Michael D. Balen

During the years 1987 through 1989, the Bureau of Mines Alaska Field Operations Center (Bureau) in cooperation with the Western Field Operations Center and the Alaska Division of Geological and Geophysical Surveys (ADGGS), conducted mining, geological, and geochemical investigations in the 5.7 million-acre Valdez Creek Mining District (VCMD). This investigation was conducted as part of the Bureau's continuing Mineral Land Assessment (MLA) mining district studies program. The Bureau's MLA program is designed to provide reliable and comprehensive mineral resource information that supports mineral resource policy and land use decisions made by Congress and Federal land management agencies. The information also provides the basis for decisions that would expand the domestic supply of important mineral resources, primarily strategic and critical minerals. Much of the MLA work is done jointly with cooperating State or U.S. geological surveys.

Jan 1, 1992

By A Valero, G M. Mudd

There is active debate and research around the most suitable indicators to assess the sustainability of mining. The most common approach is to report a range of data for a given mine site (or less preferably, a company total), such as inputs, outputs, benefits and potential costs. The most popular protocol in use (and growing rapidly) is the Global Reporting Initiative (GRI). However, these measures are numerous and still do not allow a single over-arching indicator to be developed. Other measures, such as known mineral resources over time, do not account for critical challenges such as declining ore grades, increasing wastes and poorer quality ores or more difficult mineralogy. By adopting a thermodynamic approach to sustainability, through the concept of æexergyÆ, it is possible to incorporate into a single measure the effective quality of mineral resources. Exergy involves the assessment of the minimum energy costs involved in producing a mineral resource with a specific chemical composition and concentration from common materials in the environment. The exergy of a mineral resource is evaluated from mineralogic composition, concentration (or ore grade) and, of course, quantity, by multiplying the unit exergies with the tonnes of the resource produced (or consumed). Since exergy is a thermodynamic quantity (ie energy or joules), it is additive across different minerals, such as iron ore to gold to copper or even oil and gas or coal û making it an ideal indicator to assess mineral resource sustainability at the industry scale rather than the individual mine scale. This paper briefly outlines the theoretical basis for exergy, and then presents a range of commodity case studies showing the application of exergy to the Australian mining industry. Overall, the usefulness of exergy is clearly demonstrated for use as a broad indicator of the sustainability of mineral resources at the national or even global scale.

Jan 1, 2009

By J. N. Kondo, M. Hara, T. Smida, N. Ooto, K. Domen

"A porous material composed of two-dimensional anionic sheets of a layered perovskite, KSrNb30 10, was studied as photocatalyst for the production of Hz in the presence of alcohol sacrificial donors. Colloidal single and multi-layered HSr2Nb30 10 sheets were formed by intercalating ietra(n-buthylammonium) cations into the interlayeres of H+-exchanged KSr2Nb30 10 (HSr2Nb30 10), and addition of HN03 solution to the colloidal suspension precipitated the porous materials in which HSrNb30 10 sh~ets rand~mly stuck together. Original HSr2Nb30 10 before exfoliation had a BET surface area of 1 m2 g-1, whereas the surface area of a porous material prepared under optimal conditions exceeded 100 m2 g-1. The porous HSr2Nb30 10 had considerably higher photocatalytic'activitie8 for oxidation of 1-propanol and 1-buthanol than HSr2Nb39io, indicating that in the porous materials many niobate sheets are available for decomposition of these large alcohols.IntroductionQuite a research effort has gone into the design and study of porous materials. Such materials with large surface areas would have applications in highly efficient adsorbents or catalytic reactions.We have been studying photocatalytic reaction by cation-exchangeable layered metal oxides, where alkali metal cations are intercalated into the interlayers of inorganic sheets.[1,2] There are several advantages to using layered compounds rather than bulk powders for photocatalysis. Layered compound is rich in variety, in addition, modifications of them are easily performed by exchanging alkali metal cations in the inter layers for H + or other metal cations. The most important advantage is that some layered compounds have considerably high photocatalytic activities than bulk catalysts because the electrons and holes generated in each thin inorganic sheet readily reach interlayer spaces as reaction sites at the illterlayer spaces. It should be very important for further improvements· of layered photocatalysts to utilize two-dimensional inorganic sheets effectively."

Jan 1, 2000

By Georgene Renner, William R. Yernberg, Steve Kral

Advanced Terra Testing (ATT)is a full-service geotechnical testing laboratory. It specializes in rock and soil mechanics and geosynthetic materials testing. ATT provides services to the global mining industry. The company has performed more than 1,000 projects for more than 300 commercial and government clients. Services include coal pillar design testing, leach pad material and performance testing, tailings pile consolidation testing and closure and remediation services. Rock and soil mechanics tests include unconfined and triaxial strength, shear and tensile strength, permeability, index testing, consolidation, liquifaction potential, elastic moduli determinations, heap height versus percolation rate, long-term batch testing and dynamic loading tests.

Jan 1, 2003

By Kenneth Williams

Cargas a granel, incluindo finos de minério de ferro, devem ser embarcadas de acordo com as diretrizes acordadas entre os membros da Organização Marítima Internacional (IMO). Uma medida de segurança crítica é o Limite de Umidade Transportável (TML), exigido para cargas do Grupo A (cargas que têm tendência à liquefação). Diversos acidentes com navios envolvendo finos de minério de ferro da India, cuja causa suspeita-se ser a liquefação da carga, trouxeram à atenção o tema do TML de finos de minério de ferro. Um trabalho extenso de pesquisa foi desenvolvido pelos principais produtores de minério de ferro da Austrália e do Brasil para dar suporte à IMO no desenvolvimento de normas para o embarque desse tipo de material. Com essa finalidade, mineradoras patrocinaram o projeto AMIRA P1097, que foi conduzido pela TUNRA Bulk Solids (TBS) e o Centre for Bulk Solids and Particulate Technology (CBSPT), CSIRO e a Universidade de Auckland, com a gestão do projeto sendo feita pela Creative Process Innovation, a fim de estabelecer uma abordagem modificada de testes de TML específica para finos de minério de ferro. Esse estudo deu suporte aos resultados dos testes e conclusões do Technical Working Group do IMO, que publicou suas conclusões e descobertas em Setembro de 2013.

Aug 16, 2017