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By B Manda, K L. Sandvik, K Musiwa

Mining and processing of pyrite ore at Iron Duke Mine, north east of Zimbabwe, generates large quantities of acidic mine water as a result of the oxidation of iron sulfides on exposure to air and water used in the drilling and blasting operations. The acid mine drainage (AMD) contains elevated levels of dissolved Fe, Al, Mn and sulfate and has characteristic pH values ranging from about 0.50 to 3.00. Handling and disposal of such a drainage places significant impacts on the economics of the mining operation due to the corrosive nature of the drainage on infrastructure, the limitations placed on water reuse and discharge to the environment under a new law governing effluent discharge. Treated sludge at Iron Duke is chemically unstable, changing pH from ~7 to ~3 within four days after deposition in the evaporation ponds. The effluent does not meet the permitted level of neutral pH, 500 mg/l sulfate and less than 2000 mg/l total dissolved solids. Excessive acid seepage from the evaporation ponds has resulted in contamination of the ground water below the ponds area, which shows high mean annual levels of iron (368.67 mg/l), sulfate (1702.89 mg/l) and low pH (2.86) in addition to other pollutants. This poor quality seepage infiltrates into the nearby Yellow Jacket River, contaminating the public water source. Furthermore, a deterioration of the land area and vegetation adjacent to the tailings dump is also observed. Understanding the controls on the neutralisation of acidic drainage and long-term sludge stability after placement in evaporation ponds is essential to minimise costs of closure requirements and for the protection of environment and human health. This study examined the effects of the master variables pH, redox potential, acidity and alkalinity on acid neutralisation. The results indicate that ferrous hydroxides are not as stable as ferric hydroxides and that proper oxidation of iron also leads to better sludge stability, higher treatment efficiency and a manageable sludge viscosity. Metal hydrolysis and secondary mineral formation at the evaporation ponds under a wide range of pH and redox conditions is responsible for equilibrium shifts in metal reactions, resulting in high potential for metal leaching and mobility. Mechanisms of metal attenuation are also discussed.

Jan 1, 2006

By R Wheeler, E Stalenberg, J Lemon, M S. Crowther, D Lunney, K Ross

Gunnedah, in north-western New South Wales (NSW), including the town, the surrounding Liverpool Plains and the Pilliga forests to the west, are currently the subject of intense mining interest for coal and coal seam gas. Achieving positive outcomes for koala conservation on mined landscapes will require a sound grasp of koala ecology; and local knowledge of koala movements, tree choice and associated threats to the continued survival of koalas, particularly roadkill from increased mining infrastructure. This requires a research-oriented approach to testing ideas applicable to the long-term survival of koala populations. Our recent koala research in NSW has shown that, in 2006, Gunnedah had the largest koala population west of the Great Dividing Range, and the only population in NSW that was expanding. That prompted us to instigate a detailed study in 2008 - 2011 to determine, inter alia, whether the koalas were using trees that were planted in the 1990s to cope with rising soil salinity. Our GPS-tracking has shown that regrowth trees as young as ten years old can attract koalas. In 2009, the demise of about a quarter of the local koala population from an intense heatwave gave us a foretaste of how habitat and climate change interrelate at the landscape scale. We are now examining the optimal combinations of tree choice, and patch size and shape, for habitat restoration. This will be relevant to local coal seam gas and coal mine proposals, and ongoing mitigation actions. The Senate enquiry of September 2011 on the koala and demonstrated the intense public interest in the survival of this iconic species. Its subsequent listing for Queensland and NSW under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 further raises its profile and obligations for management of koalas and their habitat. It will take considerable effort to manage the Liverpool Plains koala population for the next 50 years in the face of extensive land-use changes from mining, and the attendant threats from road kill, compounded by the new threat of climate change manifesting itself as an increased frequency of heatwaves and more severe droughts. This paper describes the research that underpins these conclusions, identifies some of the research approaches needed, argues for working strategically now, rather than try to patch up matters after the event, and presents a set of guides for environmental plantings. CITATION:Lunney, D, Lemon, J, Crowther, M S, Stalenberg, E, Ross, K and Wheeler, R, 2012. An ecological approach to koala conservation in a mined landscape, in Proceedings Life-of-Mine 2012 , pp 343-352 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By J. Nalaskowski

A study of the interfacial properties of the basal plane and the edge surfaces of talc is described in this paper. The isoelectric point measured at the two different crystallographic planes by the streaming potential method was found to be similar and exists at about pH 3.0. In the case of the edge surface the zeta potential increases at higher pH values which can be attributed to the hydration of magnesium ions at the edge surface. The atomic force microscopy (AFM) colloidal probe technique was used to measure interaction forces. For such experiments a 20 um talc particle was attached to the AFM cantilever and forces between the edge of the talc particle and two different crystallographic planes of talc were measured at various pH values. These measurements, while being qualitative due to the poorly characterized contact area, show differences between the properties of the base plane and edge of the talc and correspond to the results from streaming potential measurements. Finally, the differences in the hydration of the basal plane and the edge of talc are revealed from molecular dynamics (MD) simulations. The basal plane of the talc is much less hydrated than the edge, as can be seen from the water density distribution functions, which correlate quite well with the contact angle measurements at the basal plane surface and the edge surface of the talc sample.

Jan 1, 2006

By E. L. Evans

The historical development of South Yorkshire mining is traced and note made of the liability to generate spontaneous combustion of some of the seams which have been worked. The liability factor is analysed firstly as an inherent property in the material of a coal seam, and secondly as a circumstance of a situation in which access is provided for the air necessary to sustain oxidation. The geological settings in which incidents of heatings have been known to occur is discussed and conditions favouring a natural pre-disposition to spontaneous oxidation exposed, particularly the effect of argillaceous material overlying the seam. An extensive strata-dynamic study follows to demonstrate the situations in which stray air currents tend to impinge on readily oxidizable material. Prevention techniques are indicated as the identification of strata-dynamic situations in which air access to broken coal is induced and thereafter th operational action to seal off the voids which have been opened up so as to exclude air from the broken coal. Measures to reduce the tendency for ventilating air to short circuit across waste voids, and to obviate deflection of air into packs are outlined. The importance of face and roadway design features is demonstrated and the consequences of practices inimical to good control of spontaneous combustion are related. Discussions on means of detection and also on the sealant materials available are included.

May 23, 1905

By Michael J. Castner

"INTRODUCTIONMultiple-seam mining is an ever growing concern for engineers and mine management in every portion of the mining industry and is especially true for coal mining operations. The goal of this report is to identify the location and severity of multiple-seam interactions, provide AMSS calculations performed on the worst of these locations, and follow up with a visual examination of the underground physical effects on the roof and ribs in the locations identified for analysis. Multiple-seam mining is increasingly being studied because:1. Multiple-seam mining can create a multitude of problems such as roof falls, pillar crushing, pillar failing, rib spalling, floor heave, and inundation of water, gas, or oxygen-deficient air that can disrupt mining operations and threaten the safety of the miners.2. Multiple-seam mining is becoming more prevalent due to the depletion of virgin coal reserves.Currently, coal mining in the United States has progressed to the point that a growing number of mining companies are operating in coal seams located above, below, and/or adjacent to previously mined out coal seams. As a result, the state and federal governments are enacting higher safety standards on mining operations. For example, in years past, pillars may have been properly designed to handle single seam interactions for a particular mine or mines; however, today, where mining is now being considered above or below a previously mined area, these loading conditions may not be adequate to handle the removal of additional seams above or below the previously mined reserve. Studies from 1981 estimated that two-thirds of the mineable coal reserves in the United States would be impacted by multiple-seam implications. Today, over three decades later, it is obvious that most of the remaining mineable coal reserve will be influenced by previously extracted seams. Thus, thefocus on multiple-seam mining interactions on current and future mining operations. In 2012, underground mining in the United States produced 342,287 thousand short tons of coal. Northern Appalachia accounted for over 30% (103,301 thousand short tons) of this total (U.S. Energy Information Administration, 2013). Rosebud Mining Company and Western Allegheny Energy (RMC and WAE) have a combined total of 23 actively producing underground mining operations and at least four new mines under or ready for development. All of these mines are located in coal seams (Upper and Lower Freeport; Upper, Middle, and Lower Kittanning) of northern Appalachia (Pennsylvania and Ohio). Currently, more than half of the RMC and WAE mines are dealing with multiple-seam interactions. Seven mines are undermining previously mined out coal seams, and five mines are overmining previously mined out coal seams. Also, between these companies, five mines have inner-seam sloping possibilities (2 completed, 3 planned), most of which will result in mining over or under previously mined areas."

Jan 1, 2015

By Marco D. Boscardin, Paul A. Roy, Kevin J. DiRocco, Andy J. Miller

The North Shore Connector Project for the Port Authority of Allegheny County involves TBM mining a pair of subway tunnels through soil and rock under the Allegheny River and a narrow city street. Along the tunnel alignment are a historic building on shallow foundations and modern buildings on deep foundations, one constructed directly over the alignment during the latter phases of design. This paper provides an overview of the general site conditions, and technical basis for excavation support and tunneling decisions. Deformation limits, ground improvement, monitoring and mitigation plans, geotechnical baseline report development, and risk management will also be discussed.

Jan 1, 2007

By K. Iturralde

The article discusses the possibility of automation in refurbishment processes of social dwelling built from 1950 to 1970. These massively produced buildings were mostly designed prior to the law enforcement regarding thermal insulation or accessibility. Nowadays, many of these buildings are being retrofitted. The article focuses on the works in the external envelope. The task of renewing the whole social building stock is big and it requires a systematic process that facilitates a rapid upgrading, without neglecting the specific situation of each case. How could an automatic refurbishment process of these buildings be defined? The process should start with the data collection of the building and the creation of a 3D model using software such as BIM. The project, drafted in 3D, should facilitate the manufacture of building elements by robotics. In turn, it should be noted that during the assembly at the site, the pieces must be fixed quickly and efficiently. Is it possible to implement an automated process for the refurbishment of apartments built in the second half of the twentieth century? To approach the answer, a virtual refurbishment project is performed. The article focuses on the rehabilitation of the building envelope. Furthermore, it gives special attention to the double skin facade. It is well known that a second skin in this type of building can be an element that integrates several functions. Finally, needless to say that refurbishment of residential buildings is a need in our society. By extending its life cycle, robotic refurbishment provides more favorable socioeconomic and environmental capabilities than the sole construction of new buildings.

Aug 1, 2013

By Jonathan K. Hrica, CASSANDRA L. HOEBBEL, Jennica L. Bellanca

Accidents involving powered haulage and mobile equipment such as haul trucks often account for the greatest number of fatalities in the mining industry each year. Despite previous analyses that have identified root causes and other contributing factors, there is still a need to better understand the events leading up to these types of accidents, what lessons may be learned, and what strategies can be employed to prevent fatal accidents from occurring. This study examines Naturalistic Decision Making (NDM) using the critical decision method (CDM). The CDM is a retrospective interview approach used to explore timelimited, high-stakes, decision-making. In this study the CDM is used to obtain more information about what happens prior to, during, and after a potentially fatal situation such as a near-miss event, loss of control, or minor accident involving equipment damage. Researchers captured firsthand accounts from 21 haul truck operators involved in near-miss events from mine sites of various sizes and commodities throughout the United States. These accounts provide rich and detailed narratives from the perspective of haul truck operators themselves and reveal insights into what decisions haul truck operators make, what sensory cues they perceive, and what strategies they employ during challenging and non-routine situations. Decision-related themes that emerged from the data are presented and discussed. These results, along with potential solutions offered by study participants, can help to inform future research, raise awareness about hidden hazards, and build more creative interventions and realistic training scenarios for use by the industry to address haul truck safety issues.

Feb 1, 2024

By Armin W. Stuedlein, Jim Zammataro, Bernie Hertlein, Daniel Belardo, Qiang Li, Antonio Marinucci

"An experimental program focusing on four drilled shafts was conducted to determine the effect of high strength steel reinforcement bars on lateral resistance, steel casing on axial and lateral resistance, and steel casing without internal reinforcement on lateral resistance. Thermal Integrity Profiling (TIP) Thermal Wires and crosshole sonic logging (CSL) access tubes were installed in each shaft, and thereafter the corresponding non-destructive testing (NDT) was performed on each shaft to assess the integrity of the shafts and to compare the results from the different NDT methods. The results of the CSL tests using scored PVC tubes are compared against those conducted in 73/56 fully-threaded steel hollow bars, whereby the results indicated that the threaded bars served as a good host for performing the CSL tests. The data from the TIP Thermal Wires is compared against the results from the CSL tests for each of the four shafts, and the similarities and discrepancies between the two methods are discussed. This paper will serve as a reference to those interpreting the measurements and data obtained by performing nondestructive integrity tests on drilled foundations.INTRODUCTIONNon-destructive tests (NDTs) embody a set of critical tools for the evaluation of the integrity of constructed deep foundations, particularly for cast-in-place foundation elements. Construction defects may require the rejection of the foundation element by the owner’s representative, resulting in costly repairs or replacements and delays to the project schedule. The use and appropriate interpretation of the results from the NDTs provide the information required when evaluating the integrity of these constructed elements. A cooperative research program was conducted to assess the effects of various construction variables on the axial and lateral performance of drilled shaft foundations, which provided an opportunity to compare the established Crosshole Sonic Logging (CSL) test method to the newer Thermal Integrity Profiling (TIP) Thermal Wire method. This paper presents an overview of the experimental program performed at the geotechnical test site at Oregon State University (OSU), details of the CSL and TIP installation and testing methods, and the results of the NDTs on the constructed drilled shafts. Because one of the shafts was constructed with fully-threaded longitudinal steel hollow bars, this experimental program also allowed the assessment of the use of the hollow bars as access tubes for the CSL tests. Both the CSL and TIP test methods indicated that the shafts were of good quality and free from defects or anomalies; the data obtained using the TIP method also provided an estimate of the as-constructed shaft diameter and the reinforcement cage alignment, which will prove helpful when back-calculating axial and lateral load transfer during future loading tests."

Jan 1, 2016

By Franz-Werner Gerressen

New developments are required each day as our industry becomes more competitive. To improve performance, continue and to ensure future demands can be met. This requires the development of technical support systems that enable a more constant delivery and quality of installation of pile foundations and other applications. For example: assistance systems capable of relieving the machine operator of automating monotonous or repetitive operations. Real time installation control of the production process to manage quality control, or data transfer and reporting systems capable of keeping pace with the digital future. This paper will describe these new approaches and considerations required for these new developments. The paper also describes the equipment which is needed to execute the work under the various conditions and provides references herein. INTRODUCTION The success of a construction site is influenced by a number of factors. Selecting the most efficient and economic methods during the planning phase to defining the right direction. This means having multifunctional equipment available. To ease the usage of this equipment by the operator, uniform operation and control systems are essential. Systems like this can provide uniform handling procedure for more than 20 different installation techniques. Experienced operators are not always available. Therefore, to ease the start for beginners and to support training, numerous assistance systems were developed. This ranges from simple information for controls shown on the monitor avoiding misuse to systems which can partly automate the construction process. Regardless, the best equipment is not enough when the construction is not running smooth. The control system not only helps to organize and coordinate service of the equipment; moreover, it allows the operator to control the quality during the installation process reacting if needed. It allows process optimization as well as documentation which might be required for later negotiations.

Jan 1, 2019

By G. T. Lineberry

Horsepower requirement is recognized as a most important equipment characteristic. Other critical equipment characteristics will be isolated and analyzed by traditional operations research techniques, using off-highway trucks as an archetype. A computer search technique has been developed, employing various production and cost analyses. With this model, the optimum combination of horsepower, capacity, and velocity can be found, minimizing handling cost per ton. An example of the program's use and interpretation of its results will conclude the paper.

Jan 1, 1984

By J. S. Walker

The Bureau of Mines monitored surface subsidence and water level fluctuations in 10 shallow observation wells above a series of four adjacent longwall panels in southwestern Pennsylvania, for about 4 yr. This study attempted to correlate the changes in the water levels within the observation wells to the measured vertical and horizontal ground movements associated with subsidence. Results of this study indicate that the fluctuation of the water levels appears to be a function of the well location relative to the mine layout and the proximity of mining. Wells are generally unaffected by mining of a preceding panel unless they are located within the angle of draw for that panel. Wells located at the centerline of a longwall panel exhibit the greatest fluctuation and head loss. This relationship may be related to the strain developed by the advancing longwall face. The water levels in the wells monitored fell at the greatest rate when the ground surrounding the well was in tension. The rate of the decline decreased as the dynamic development of the strains was changing from tension to compression. The water levels were found to be near the premining level before the ground was subject to maximum compressive strain. Nine of the ten wells investigated recovered to their premining water level after mining was completed.

Jan 1, 1988

By C Killip

Working in Australia’s harsh climate can have a significant impact on the health, safety and productivity of our teams, but is our working environment expected to be more prone to heat stress in the future? Climate modelling suggests that we are likely to encounter more frequent heatwaves and higher apparent temperature. Does this mean that our teams will be at greater risk of heat stress, and are we prepared to deal with the changes in our future climate and the potential impacts on our working population? This paper will review the recent research on climate and projected changes to all meteorological parameters that are important in understanding the likelihood of heat stress. The paper will also describe the challenges encountered in the management of heat stress in a workforce, and then outline a systematic approach to heat stress management that will allow you to assess your own risk and manage your day-to-day operations into the future.CITATION:Killip, C, 2015. Future climate – is heat stress a real risk for the future and how can we better manage it?, in Proceedings Third International Future Mining Conference, pp 181–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By Paul C. Merritt

The story now unfolding on the Mesabi Range is more than just another chapter in the continuing history of iron mining. It is an epic of foresight, research and pioneering instinct just now culminating in the rapid growth of a new industry hardly more than ten years old. And that growth has been impressive. In the decade that has passed since Reserve Mining Co. blazed a trail as the first successful large- scale commercial taconite operation, the number of plants now existing or soon to be operating has grown to six. From Reserve's initial capacity of 3 million tons of pellets per year, total production capacity on the Range has surged to 31.5 million tons while capital investment has leaped from $300 million in 1955 to almost $1 billion today. During the past year alone, more than $500 million has been committed to these projects, an amount probably greater than that going into any other single mining area in the world. There is more yet to come.

Jan 10, 1965

By R. Dehghan, M. Zarei, A. Tohry, S. C. Chelgani

Typical depressants for selective reverse flotation of iron oxides from complex silicates do not generally show high levels of efficiency. Therefore, as a hot topic, there are several ongoing investigations in this area. The main aim of this paper is exploring the potential of using humic acid (HA) as a depressant in reverse cationic flotation of hematite from complex silicates. For such a process, the wettability and flotation behaviour of pure minerals (hematite and silicates) was investigated at pH 10 in the presence of HA and cationic collector. Adsorption mechanism of HA on these minerals was measured by zeta-potential and FTIR. Results of flotation tests showed that at the lower concentrations of HA, selective separation of silicates from hematite is beneficial, where the floatability of amphibole was higher than pyroxene. A higher separation efficiency of hematite through reverse flotation was observed in the presence of amphibole, in comparison with the presence of pyroxene. Wettability studies showed that HA has a significant effect on reducing the hydrophobicity of treated minerals with the collector. The adsorption, ZPC and FTIR test results indicated that HA was adsorbed on both silicates and hematite. However, the absorption intensity onto hematite was much higher than silicates. It was found that the adsorption mechanism of HA on hematite takes place through both strong H-bonding and ligand exchange. Keywords: Reverse cationic flotation, humic acid, iron oxide, complex silicates, surface adsorption

Jan 1, 2020

By David Mast, Irwan Halim, Brian Hagan, Kaveh Talebi, Jason Edberg, Amanda Foote

On June 14, 2023 Jay Dee Contractors’ Tunnel Boring Machine (TBM) “Phoenix” holed through and completed mining the second drive of the I-75 Segment 3 Storage and Drainage Tunnel. Completion of the tunnel came only after overcoming several challenges, including a groundwater intrusion event which deposited thousands of cubic yards of wet ground material into the tunnel. This paper will discuss the events which delayed completion of the tunnel by over nine months, the risk management and construction approaches assumed by the Design-Build team during bid, several challenges faced by Design-Build teams when building stormwater resilience tunnels using traditional Department of Transportation standards, and recommendations for improving risk allocation and proposal documents for future similar Design-Build tunnel projects.

Jun 23, 2024

By S. J. Schatzel, V. Gangrade

A ventilation research study was conducted by the National Institute for Occupational Safety and Health and a cooperating trona mine in the Green River basin of Wyoming, USA. The mine operation uses the longwall mining method in trona bed 17, a commonly mined unit in the region. The longwall face length is 228 m (750 ft), and caving on the face occurred up to the back of the longwall shields. The mine is ventilated using a main blowing fan and a bleeder shaft. For this study, sulfur hexafluoride (SF6) tracer gas was released in two separate monitoring experiments. For the first experiment, tracer gas was released on the face, this test focused on airflow along the longwall face of the active panel. Face test showed the airflow patterns to be more complex than just head-to-tail flow in the main ventilation air stream on the active panel. For the second experiment, tracer gas was released 2 crosscuts inby the face on the headgate side, this test focused on gas transport in the mined-out portion of the same active panel. Gob test showed a pathway of movement through the front of the active panel gob that moved outby from the tailgate corner. The primary pathway of tracer gas movement in the active panel gob was towards the headgate and tailgate bleeders and out of a bleeder shaft. The rate of movement towards the back of the gob was measured to be 0.19 m/s (37 fpm).

By S. J. Schatzel, V. Gangrade

A ventilation research study was conducted by the National Institute for Occupational Safety and Health and a cooperating trona mine in the Green River basin of Wyoming, USA. The mine operation uses the longwall mining method in trona bed 17, a commonly mined unit in the region. The longwall face length is 228 m (750 ft), and caving on the face occurred up to the back of the longwall shields. The mine is ventilated using a main blowing fan and a bleeder shaft. For this study, sulfur hexafluoride (SF6) tracer gas was released in two separate monitoring experiments. For the first experiment, tracer gas was released on the face, this test focused on airflow along the longwall face of the active panel. Face test showed the airflow patterns to be more complex than just head-to-tail flow in the main ventilation air stream on the active panel. For the second experiment, tracer gas was released 2 crosscuts inby the face on the headgate side, this test focused on gas transport in the mined-out portion of the same active panel. Gob test showed a pathway of movement through the front of the active panel gob that moved outby from the tailgate corner. The primary pathway of tracer gas movement in the active panel gob was towards the headgate and tailgate bleeders and out of a bleeder shaft. The rate of movement towards the back of the gob was measured to be 0.19 m/s (37 fpm).

By Alper Turan, Hesham El Naggar

"The use of aggregate pier foundation systems has become widespread as the engineering practice moves towards cost-effective ground improvement solutions that provide accelerated construction schedules. Increased bearing capacity, effective settlement control and potential for liquefaction mitigation are commonly acknowledged benefits of aggregate piers. This paper studies the mechanisms by which aggregate piers interact with each other and with the surrounding ground when excited by seismic loads. A particular emphasis was placed on the response of a raft foundation supported on a site improved using aggregate piers. Three-dimensional nonlinear finite element analyses were conducted using commercial software package, ABAQUS. Non-linear soil behaviour is modelled using a three-dimensional total stress-based bounding surface plasticity model, which is able to simulate stiffness degradation and damping increase in the soil. The soil stratigraphy considered in this study was a 30 m deep soil deposit that comprised a very stiff base layer and a shallow soft surficial clay layer. Ricker Wavelet time histories with different frequency contents are used as the excitation force in the analyses. Various area replacement ratios (ARR) for aggregate piers are studied for a square plan layout. The results presented in this study are considered to be of interest to researchers and designers in evaluating the seismic ground response of the sites improved using aggregate piers. INTRODUCTIONThe schedule and cost limitations imposed by the traditional over-excavation and replacement method for the stabilization and settlement control for poor soils resulted are underlying factors for the significant increase in the use of aggregate pier foundation system, particularly in the last two decades. Various well known advantages of aggregate pier systems including increased bearing resistance, settlement reduction, and increased uplift capacity have been studied by various authors. The use of aggregate pier systems for settlement control in soft soil deposits was studied by various researchers including Lawton and Fox (1994), Lawton et al. (1994) and Wissmann et al. (2001). Lien and Fox (2001) studied the behaviour of aggregate pier systems supporting embankments and retaining walls. The stabilization of slopes by means of aggregate piers was studied by Lien and Fox (2001), Wissmann et al. (2002). Thompson et al. (2009) reported on a performance monitoring study of aggregate pier systems supporting MSE walls. The interaction mechanism between the aggregate pier system and the surrounding soil attracted attention of various researchers. Handy and White (2006a) and (2006b) studied the changes that occur less than 2 m from centers of the piers, and further away, respectively. The support mechanism of aggregate pier systems subjected to compressive loading were studied experimentally and numerically by White et al. (2007) and Pham and White (2007), respectively."

Jan 1, 2017

By N. S. Tanious

Retrievability of emplaced nuclear waste from the geologic repository is a performance objective imposed by Federal Regulations. This requirement is designed to provide confidence in the Department of Energy's repository design by keeping the option of retrieval open if the engineered or natural systems prove inadequate for containment and long-term isolation of high-level nuclear waste. This paper presents a summary of current Nuclear Regulatory Commission Staff thinking on the design of the repository for retrieval, and level of retrievability demonstration that may be required during site characterization. However, this paper does not represent official U.S. Nuclear Regulatory Commission position on this topic.

Jan 1, 1989