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Collaborating Authors
Results
Monitoring the Behavior of a Sill Pillar At Failure In a Narrow-vein Mine
Labrie, D. (CANMET Mining and Mineral Sciences Laboratories, Natural Resources Canada) | Boyle, R. (CANMET Mining and Mineral Sciences Laboratories, Natural Resources Canada) | Anderson, T. (CANMET Mining and Mineral Sciences Laboratories, Natural Resources Canada) | Conlon, B. (CANMET Mining and Mineral Sciences Laboratories, Natural Resources Canada) | Judge, K. (CANMET Mining and Mineral Sciences Laboratories, Natural Resources Canada)
ABSTRACT ABSTRACT: Trials were undertaken in a narrow-vein mine of Northern Quebec, Canada, to monitor stress changes in sill pillars due to mining. Trials were carried out in active mine areas using vibrating wire proving rings and short extensometers, installed in boreholes to monitor radial and axial displacements in three orthogonal directions. Trials took place at intermediate depths, 600 meters underground, in areas with extraction ratios exceeding 80%, and lasted several months. The present paper focuses on a successful trial, showing regular stress changes within the sill pillar all along its loading curve. Stress changes were relatively slow during the first half of the experiment. Changes increased significantly during the second half, resulting in the definition of a clear inflection point when the stope reached about 75% of its final height. Mining was stopped when a rock burst resulted in complete sill pillar failure, which prevented any return to the burst area. Monitoring and numerical modeling records were reviewed. These show reasonable agreement and validate the trial and the data gathered during the period of monitoring. This experiment provides insights into the unpredictability of rock burst events, and ways to prevent or alleviate their damage. 1 INTRODUCTION Mining and excavation of rock material inevitably produce a redistribution of stresses around mine openings, within pillars and abutments. Loading of pillars and abutments is limited by the strength of rock materials. Once this limit is reached, rock material will either deform plastically, in the case of soft rocks, or fail violently, in the case of hard brittle rocks. Intermediate rock materials show an intermediate behavior, with failure progressing through limited ductile deformation and relatively small bursts (Labrie et al. 2002). Trials were done in a narrow-vein mine of Northern Quebec, Canada, to monitor stress changes taking place within pillars during mining.
- North America > Canada > Quebec (1.00)
- North America > Canada > Ontario > National Capital Region > Ottawa (0.15)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Mineral (0.70)
ABSTRACT ABSTRACT: Linking resource modeling and geomechanical numerical modeling tools is arguably a step towards a more integrated mine design process. This paper presents a methodology that aims to integrate tridimensional data, modeled through resource modeling tools, into a tridimensional geomechanical modeling code. Numerical experiments are then conducted on the created model. The objective of the experiments is to establish the impact of internal fracturing and fracture degradation on slope stability. 1 INTRODUCTION Nowadays, numerical analyses are performed on a routine basis to study the stability of rock slopes. On the other hand, resource modeling and mine optimization software tools are used everyday to establish the geological resources, ultimate pit and mining sequence for an open pit mine. This paper presents, through a case study, the use of resource modeling tools to define the problem geometrical characteristics within a numerical modeling code. It also presents a series of numerical experiments aimed at establishing the impact of internal fracturing and fracture degradation on the stability of the slope. 2 RESOURCE MODELLING 2.1 Resource modeling tools Resource modeling is at the very core of today’s mining operations. In this case study, the rockmass was modeled using one of the most popular resource modeling and mine planning tools in the mining industry, Surpac Vision, Surpac Minex Group (2006). Ore reserve estimation relies on the analysis of rock samples obtained through diamond drilling. Block modeling is used to represent the spatial distribution of ore grades. Ore grades are interpolated at those blocks, based on geostatistical methods. The size of the selected block is usually dictated by the diamond drilling pattern and the mining bench height. Each block is assigned various properties such as ore grades, level of contaminants, geology and rock properties.
- Materials > Metals & Mining (1.00)
- Energy > Oil & Gas > Upstream (0.95)
ABSTRACT ABSTRACT: The Swedish Nuclear Fuel and Waste Management Co. has carried out the Äspö Pillar Stability Experiment at the 450-m-level of the Äspö Hard Rock Laboratory. The stresses in the pillar were controlled by the geometry of the experiment drift, the spacing between the boreholes and heating of the surrounding rock. A large scale rock mass strength test was done at the end of the experiment. It was found that the observed fracturing was extensional in nature, that small confining pressure has a large impact on the fracture initiation and that the Mohr-Coulomb failure criteria gave the best estimate of the rock mass strength. 1 INTRODUCTION The Swedish Nuclear Fuel and Waste Management Company (SKB) is responsible for the disposal of spent nuclear fuel in Sweden. The fuel is to be placed in copper canisters that will be deposited in vertical 8-m-deep 1.8-m-diameter boreholes at 400- 700 m depth in crystalline rock. This will result in the formation of approximately 4500 rock mass pillars surrounding the emplacement boreholes. The stability of pillars in the mining industry is traditionally carried out using empirical methods. It is unknown if these methods are suitable for the design of a borehole emplacement pillar. Hence, SKB is conducting the Äspö Pillar Stability Experiment (APSE) to: 1) demonstrate our current capability to predict brittle failure (spalling) in a fractured rock mass, 2) demonstrate the effect of backfill (confining pressure) on the brittle failure response, and 3) compare the 2D and 3D mechanical and thermal predicting capabilities of existing numerical models. The rock mass that will be studied in the experiment is a 1-m-thick pillar between two vertical boreholes with practically the same geometry as the deposition holes described above but spaced only 1 m apart (Fig. 1).
- Water & Waste Management > Solid Waste Management (0.75)
- Energy > Oil & Gas > Upstream (0.52)
- Reservoir Description and Dynamics > Reservoir Characterization (0.95)
- Well Drilling (0.94)
- Well Completion > Hydraulic Fracturing (0.68)
ABSTRACT ABSTRACT: The re-opening of the Home stake Mine in Lead, South Dakota as a physics and earth science research laboratory known as the Deep Underground Science and Engineering Laboratory (DUSEL) provides important new opportunities for conducting deep, long-term, rock mechanics experiments in situ. This paper outlines a hypothesis-driven research plan to examine the coupling between the stress field and fluid conducting fractures, which would be integrated into a broad program of geosciences, geo engineering, and biology. The research program takes advantage both of the historical data base collected during the active mining operation as well as of the synergy of the future multidisciplinary collaboration. 1 WHAT IS DUSEL? DUSEL is the acronym for Deep Underground Science and Engineering Laboratory. It is a multidisciplinary effort among physicists, geoscientists, and biologists to establish a common facility for science and engineering programs that includes excavation of large halls and three-dimensional access to depths of several kilometers. For physicists, the rock overburden provides shielding from cosmic radiation as they conduct investigations into dark matter and other astrophysical phenomena The scientific motivation in all three disciplines has been a community effort summarized by Sadoulet et al. (2006) in a publication titled “Deep Science.” Within the geosciences a workshop-based document “EarthLab” (McPherson et al. 2003) was prepared for the National Science Foundation’s Division of Earth Sciences. A comprehensive search for siting an underground laboratory in the United States for earth science research dates back to the early 1980’s (Wollenberg et al. 1981) shortly after the Lawrence Berkeley Laboratory conducted its path-breaking experiments at the Stripa mine in Sweden (Witherspoon 2000). 1.1 Rock mechanics and DUSEL An aura of mystery surrounds the underground environment, even for scientists, because of its relative inaccessibility.
- North America > United States > Wisconsin (0.28)
- North America > United States > South Dakota (0.26)
- Geology > Structural Geology > Tectonics > Plate Tectonics (1.00)
- Geology > Rock Type (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (0.46)
- Materials > Metals & Mining (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.66)
- Well Drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
ABSTRACT ABSTRACT: Work on the Deep Underground Science and Engineering Laboratory (DUSEL) has made great progress in 2006, with the release of a Deep Science report by a site-independent study (Solicitation-1, or S- 1) and the submittals of two S-2 conceptual design reports¡ªone from the active Henderson mine in Colorado and the other from the abandoned (now State-owned) Homestake mine in South Dakota¡ªtowards the final DUSEL site selection scheduled for 2007. The earth-science collaborations in hydrology, geochemistry, geophysics, rock mechanics, ecology/geomicrobiology, and coupled processes have evolved since 2000 to include recent community-wide deliberations in six S-1 working groups, and extensive interest expressed through over 60 Letters of Interest to the Homestake Authority and Collaboration. The proposed initial suite of experiments at Homestake can start with establishing a seismic network by using boreholes and along multiple levels, sampling fluid for in situ hydrogeochemical/biological states, and improving site models using information about localized distributions of low-rate and slightly basic inflows into underground workings. The siting of niches and blocks for long-term coupled process testing and the design of large caverns can proceed with DUSEL entries. There is also interest in designing energy-related studies, for example, using a ventilation shaft or dead-end drift for carbon dioxide injection experiments. As another example, earth-science investigators are collaborating with physicists on geoneutrino and other radiation studies to quantify the distributions of geothermal sources in the earth¡¯s crust and at its core. Given the expected high stress at great depths, large excavations for physics detectors, and elevated temperatures anticipated in deep boreholes, the Homestake offers ample opportunities for DUSEL collaborations to design field-testing programs for solving critical earth-science problems. 1 INTRODUCTION New fields of science could emerge as earth scientists, engineers, and physicists collaborate on the Deep Underground Science and Engineering Laboratory (DUSEL).
- Geology > Rock Type (0.93)
- Geology > Structural Geology > Tectonics > Plate Tectonics (0.67)
- Geology > Geological Subdiscipline > Geochemistry (0.49)
- Geology > Geological Subdiscipline > Geomechanics (0.49)
- Materials > Metals & Mining (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.68)
- Health, Safety, Environment & Sustainability > Environment > Naturally occurring radioactive materials (0.68)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (0.66)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (0.49)
- Reservoir Description and Dynamics > Storage Reservoir Engineering > CO2 capture and sequestration (0.48)
ABSTRACT ABSTRACT: The international physics community is developing plans for a major particle physics experiment, The Long Baseline Experiment. The experiment will probe the fundamental behaviours and properties of sub-nucleic particles, neutrinos. The Long Baseline experiment will be long-term and data will be collected over a multi-year period. The particle detector associated with this experiment will need to be built at depth underground within a very large cavern. Experimental options currently under consideration call for the excavation of rock spans in excess of 50 m, mined at depths of up to 1500m with excavation of bank rock volumes in excess of a half a million cubic metres. Such dimensions are at or beyond the limit of conventional rock engineering practice and construction will be a major undertaking. In the US, the Long Baseline cavern would be one of a number of large underground sites housed within the boundaries of the US Deep Underground Science and Engineering Laboratory (DUSEL). The final DUSEL site is yet to be determined. In July 2005, the US National Science Foundation (NSF), the principal funding agency spearheading this new initiative, short-listed two candidate sites for funded conceptual design work. The two sites are the Henderson Mine, Empire, Colorado and the Homestake Mine, Lead, South Dakota. Both sites take advantage of existing mine excavations (shafts, winzes and decline tunnels) and installed infrastructure to support access to depth and provide the requisite operational services. The NSF will select the DUSEL site in 2007, based on the findings and recommendations of a design review panel. The designs for the Henderson and Homestake Mines and other prospective sites will be submitted early 2007. It is anticipated that construction at the selected site will start by the end of the decade.
- North America > United States > South Dakota (0.25)
- North America > United States > Colorado (0.25)
- Geology > Geological Subdiscipline > Geomechanics (0.69)
- Geology > Rock Type (0.68)
- Geology > Structural Geology > Tectonics (0.46)
- Materials > Metals & Mining (0.49)
- Energy > Oil & Gas > Upstream (0.46)
- Oceania > Papua New Guinea > Papuan Peninsula > Central Province > National Capital District > Petroleum Retention License 15 > P’nyang Field (0.98)
- Oceania > Papua New Guinea > Papuan Peninsula > Central Province > National Capital District > Petroleum Retention License 15 > Elk-Antelope Field (0.98)
- Oceania > Papua New Guinea > Papuan Peninsula > Central Province > National Capital District > Petroleum Retention License 15 > Angore Field (0.98)
- (9 more...)
ABSTRACT ABSTRACT: The potential development of a deep underground science laboratory offers unusual opportunities for inquiry and experimentation in the geosciences and in geoengineering. The completed facility will extend to ~2000m deep, and be available for multi-decade occupancy. Experiments will investigate methods of in situ characterization using geophysical methods, extend our understanding of complex interactions of coupled processes which control the evolution of the dynamic Earth, and which extend methods of excavation and construction, especially at extreme depths. These general categories of enquiry accommodate suites of experiments related to: rock mass characterization, examining the role of scale effects on mechanical and transport properties, evaluating the evolution of mechanical and transport properties prompted by physical and chemical perturbations, and in examining methods of excavating deep boreholes and constructing habitable cavities at depth. 1 INTRODUCTION Cosmology, the study of the origins of the universe, is undergoing a golden age of discovery. The basic features of the universe are now apparent (Turner 2007): the universe is 13.7 billion years old, spatially flat, and expanding at an accelerating rate, while it is comprised of atoms (4%), exotic dark matter (20%) and dark energy (76%). Despite this broad understanding of age, form, and composition, much less is understood about the elementary particles which comprise these broad groups, and the laws which in turn govern their interaction. These environments may be deep within the oceans, deep within ice (Halzen 2007), or deep within the terrestrial underground (Sadoulet 2007). This latter option is central to the potential for the development for a deep underground science and engineering laboratory (DUSEL), where advances in particle physics (Waxman 2007) may develop in concert with the search for deep life, and concomitantly spur advances in geo-engineering and in geo-science.
- Geology > Geological Subdiscipline > Geomechanics (0.68)
- Geology > Structural Geology > Tectonics > Plate Tectonics > Earthquake (0.51)
ABSTRACT ABSTRACT: We plan to install and operate a permanent seismic observatory illuminating the volume of the Homestake Mine from all six possible directions. We have chosen the Homestake DUSEL site because it offers a unique opportunity - the large volume of mine working of the deepest mine in North America is surrounded and underlain by literally hundreds of open bore holes, which can affordably be instrumented with accelerometers. We envision a seismic array that allows the community to image rapid dynamic changes in the rock mass. For instance, we will be able to estimate seismic parameters of events associated with dewatering, excavation, and various rock mechanics experiments, and estimate source kinematics caused by activity within or near the mine. Given the damage location of the event determined by the array, the rock mass can be back-excavated to find the source damage in the rocks. When found, a direct connection can be made between the damage process and seismic waves generated. This fundamental knowledge would be applicable to all sites, and help answer important questions concerning the energy budget of fracture growth and dynamics, local frictional behavior within a rock mass, seismic scaling laws, and interpretation of seismic moment tensors. 1 OUR IDEA 1.1 Transparent Earth at Homestake DUSEL We are developing a deep in situ seismic observatory that will move us closer to the realization of rapid imaging of dynamical geo-processes at depth. The project is comprised of the installation of a unique three-dimensional seismic array, further research and development of unique MEMS-based downhole seismic instrumentation, and implementation of software to locate and characterize underground seismic events associated with various rock damage mechanisms within the Homestake Mine. Extensive mining provides access to large volumes of rock, and large blocks of virtually pristine rock are readily accessible for experiments requiring these conditions.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics > Earthquake (0.30)
- Materials > Metals & Mining (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > Canada > Newfoundland and Labrador > Newfoundland > Nova Scotia > North Atlantic Ocean > Sydney Basin (0.99)
- North America > Canada > Newfoundland and Labrador > Newfoundland > North Atlantic Ocean > North Atlantic Ocean > Sydney Basin (0.99)
- North America > United States > Texas > Permian Basin > Delaware Basin > Yates Field > Whitehorse Group > Word Group > San Andreas Formation (0.97)
- North America > United States > Texas > Permian Basin > Delaware Basin > Yates Field > Whitehorse Group > Grayburg Formation > San Andreas Formation (0.97)
- Information Technology > Architecture (0.46)
- Information Technology > Information Management (0.46)
Stability Analysis of the Slope of a Debris-flow Fan Under Artificial Rainfall
Zhu, Y.-Y. (Key Laboratory of Mountain Hazards and Surface Process, Chinese Academy of Sciences) | Cui, P. (Key Laboratory of Mountain Hazards and Surface Process, Chinese Academy of Sciences) | Zou, D.H.S. (Key Laboratory of Mountain Hazards and Surface Process, Chinese Academy of Sciences & Dalhousie University)
ABSTRACT ABSTRACT: The slope failure of debris flow fans is distinct from common rock and soil slope failures due to the unique geotechnical features of debris flow sediment. This type of failure was not comprehensively and systematically studied in the past. In our recent research, based on the unique characteristics of debris flow fans, the Spencer slicing method with varying side force inclination is used to search for the possible critical slip surface, and the seepage force acting on the slip surface is considered in the calculation. This is done using spreadsheet-automated constraint optimization. A practical subroutine is developed to interpret the stability of a slope with varying physical parameters along the slope depth by using Visual Basic Application embedded in Microsoft Excel. To simulate the observed behavior of the slope failure, a series of triaxial tests was conducted to seek the varying physical parameters of in-situ debris flow sediment. The results of calculation are then compared with the actual slip surface observed in the field experiment. Significant findings result, regarding the mechanism of slope failure in debris flow fans. 1 INTRODUCTION Numerous active debris flows on different scales exist across the mountainous areas of southwestern China, forming debris flow fans, as a result of local intense tectonic movement, changing climate and topography. When these debris flow fans are chosen as construction sites for buildings and roads, they pose a danger if failure occurs owing to different triggering factors. Such slope failures are distinct from those common with rock and soil slopes in terms of their features of composition, physical properties and deposition constitution. This type of failure was originally defined as “gravel slope landslide” (Hu et al. 2002). However, it was not comprehensively and systematically studied in the past.
Compaction Behavior of Unbonded Granular Media: Discrete Particle Vs. Experimental Vs. Analytical Modeling
Holt, R.M. (NTNU Norwegian Univ. of Science & Technology and SINTEF Petroleum Research (currently at New Mexico Tech.)) | Li, L. (SINTEF Petroleum Research) | Stenebraten, J.F. (SINTEF Petroleum Research)
ABSTRACT ABSTRACT: Static stress vs. strain response and stress dependent P- and S-wave velocities have been measured in isotropic and uniaxial compaction experiments with uncemented glass beads. Discrete particle modeling reproduces within experimental uncertainty the experimental behavior during hydrostatic loading and the axial stress vs. strain as well as axial P-wave velocity in uniaxial compaction. The numerical model underestimates the lateral stress response in uniaxial compaction, and as a consequence thereof, underestimates Swave velocities and P-wave velocity in the symmetry plane. Analytical modeling gives a good representation of the static stress vs. strain data in isotropic stress conditions, anticipating a coordination number . 6, but also underestimates lateral stress response. Wave velocities increase more with stress than expected from pure Hertz-Mindlin contact theory, as a result of increasing number of load bearing contacts and / or a gradual transition from slip to non-slip at grain contacts with increasing stress. 1 INTRODUCTION The use of discrete particle modeling as a practical tool in rock mechanics analysis is becoming more and more realistic due to improvements in computer technology and availability of 3D pore structure characterization. The work presented here is part of the development of a “numerical laboratory” for computation of constitutive rock mechanical behavior and stress dependent petrophysical properties. An important part of this development is a comparison between results of numerical simulations and controlled laboratory experiments. The model forming the basis of our numerical laboratory is PFC (Itasca 2005), in which the building blocks are spherical particles (disks in 2D) (Cundall & Strack 1979, Potyondy & Cundall 2004). Quantitative comparison between modeling and experiments can hence be obtained by performing experiments with unbonded spherical particles. Since spheres interact through the Hertzian contact law (Johnson 1987), contact stiffnesses are controlled by the elastic parameters of the particle forming material.
- Research Report > Strength High (0.54)
- Research Report > Experimental Study (0.54)