bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Analysis of Slope Stability in Open Pit Mining Based on an Integrated Geology and Geomechanics Approach
Authors: Sun Z. , Balasubramanian G. R. , Fager A. , Crouse B. , Barlow G. , Abouaali M. 
Published: August 2024

ABSTRACT:
The slope stability analysis usually requires consideration of both geological and geomechanical factors. However, due to the limitation in geological model, current slope stability analysis is typically based upon simplified geological frameworks and does not integrate the key geological complexities required to accurately model the geomechanical response to slope excavation. This study presents an integrated geology and geomechanics approach that can readily assess the geomechanical risk of open pit mining while preserving the geology's integrity. The geological model adopts an implicit modeling of radial basis functions to represent the geology generated from mining survey and borehole drill samples. The 3D geomechanical model is based on a non-linear quasi-static finite element method and the mesh is generated directly from the underlying geological framework. The geomechanics simulation adopts the strength reduction method to evaluate the factor of safety (FOS). The baseline simulation results show a FOS of 1.94, which indicates no shear failure on the open pit mine slope. We also investigate the impact of rock mass geomechanical parameters. The proposed workflow permits us to combine a reliable geological representation with a state-of-the-art rock mechanics finite element solver, which can be used to yield a high fidelity slope stability analysis.

1. INTRODUCTION
Open pit mining refers to mining directly on the ground surface and is a critical mining type around the globe. Slope failures of an open pit mine may lead to catastrophic consequences such as economic losses and fatalities. As the mining depths of open pits continue to increase with the decrease in shallow mineral resources, slope stability analysis is becoming more and more important (Du et al., 2022; Zhang et al., 2022). Slope stability analysis is one of the most classical areas in geotechnical engineering (Christian et al., 1994; Duncan et al., 2014; Sjöberg, 1996). In spite of the slope analysis using conventional techniques, open-pit mines are still experiencing slope failures, which indicates the need to develop better models which improve the prediction and understanding of slope behavior (Kolapo et al., 2022).
Analysis of Rockfall Risk Using Image Analysis and Data-Driven Models
Authors: Ghahramanieisalou M. , Sattarvand J. , Abbasi B. , Peik B. , Battulwar R. 
Published: August 2024

ABSTRACT:
The challenge of rockfall and its associated risks has been haunting the mining industry for quite some time. It has been a significant cause of fatalities, serious injuries, and financial losses. Taking advantage of recent technological developments, novel methods of studying rockfalls are introduced. Such renovations are mainly focused on automating geological mapping of the rock surface and data-driven trajectory estimation. UAV photogrammetry and LiDAR were used to gather point cloud data to build a 3D model of the rock slope and extract its geological features. Furthermore, a trajectory estimation model of rockfalls, also developed at UNR's Mining Automation lab, uses the mass and origin of rockfalls to calculate the impact characteristics and simulate a rockfall's energy changes during its fall. Both these developments rely on a combination of physics-based and data-driven models, necessitating continuous data flow. A lab-scale study will further examine the impact of projectile shape and volume on the coefficients of restitution. Building upon the existing correlation's initial results, a data-driven model for trajectory estimation of rockfalls will be developed.

1. INTRODUCTION
Rockfall is the continuous movement of a rock down a steep slope instigated by adverse discontinuity orientation, freeze-thaw cycles, inefficient blasting, water presence, weathering, and vegetation on the slope. The rockfall movement is categorized into free-falling, bouncing, rolling, or sliding (Kliche, 2018).
The rockfall hazard rating system (RHRS), introduced by the US Department of Transportation, is a uniform method to acquire the geographic locations of rockfall sites and categorize them using a two-phase process including three preliminary groups and a detailed classification to identify the most hazardous sites (Kliche, 2018).
However, the general problem with these empirical procedures is their resource-exhaustive approach that requires a very experienced expert to yield the appropriate results. Hence, there is a need for a faster, state-of-the-art, and economical method to deliver reproducible results regardless of the raters' experience.
The geotechnical digital twin (DT) will be a hub for a high-fidelity 3D model, an automated geological mapping algorithm of the rock discontinuities based on point cloud data, and a realistic 3D trajectory simulator for rockfalls, all combined to present the most holistic overview of the rockfall study and analyses.
Comparison of European (EN) and American (ASTM) Abrasion Resistance Test Standards on Some Igneous and Carbonate Origin Natural Stones Subjected to Foot Traffic
Authors: Buyuksagis I. S. , Cakir A. , Gursoy M. , Rostami J. 
Published: August 2024

ABSTRACT:
This study compared the results of European Union (EN) and American (ASTM) standards, which are used to determine the abrasion resistance of rocks subjected to foot traffic. The amount of abrasion that will occur due to the friction of pedestrians, especially in the floor covering areas of natural stones, is a crucial criterion in estimating the life of natural stones and deciding whether to use them. In this paper, the correlations between the results obtained by applying EN 14157 and ASTM C241 Abrasion Resistance Determination (ARD) standard test methods on some igneous and carbonate origin stones (limestone, marble, travertine) were determined. Moreover, statistical relationships between some rock properties and abrasion resistance values were investigated. In conclusion, highly reliable correlated inverse relationships were found between the two standard test methods. Statistically highly reliable equations have been proposed to convert a result from the ASTM or EN standard abrasion test method to the outcome of the reciprocal standard test method. The result of single-multiple linear regression analyses, statistically significant regression models with high prediction accuracies were derived (p-values &lt; 0.05; R2 ═ 0.79). In this way, unnecessary time and cost losses for unnecessary sample preparation and testing will be prevented for researchers, and it will help professionals and final users make quicker and more accurate decisions when choosing natural stone for flooring.

1. INTRODUCTION
The appearance of natural stones, currently used in areas inside and outside buildings where pedestrian traffic is heavy in the natural stone industry, deteriorates due to wear and tear caused by friction (Fig. 1), and their repair or replacement causes a significant loss of time and money. To prevent such situations, the European Union (EN) and the American (ASTM) standard test methods are available to predict the amount of wear of natural stones due to friction. These standard methods (EN14157-ASTM C241) are entirely different from each other, and it is impossible to compare or convert the results obtained with each other. According to the results obtained, instead of natural stones with low wear resistance, use those with high wear resistance in places where friction is higher due to pedestrian and goods traffic, such as floors, stairs, thresholds, pavements, etc.
DEM Modeling of 3D Kinematics in Rock Slope Failure
Authors: Keissar Y. , Brown I. R. , Gardner M. H. , Sitar N. 
Published: August 2024

ABSTRACT:
We compare solutions obtained using 3D Limit-Equilibrium (LE) and the 3D Discrete Element Method (DEM) analyses of rock slope stability and runout to illustrate the importance of kinematics in modeling of rock slides. While 3D LE methods provide a measure of the factor of safety against failure, the failure surface is assumed, and the rock mass is typically represented by vertical columns in the analysis. Thus, the kinematic response of the rock mass is artificially constrained, and the quality of the analysis heavily depends on an accurate capture of the potential failure surface and the failure mechanism. In contrast, a specific mode of failure is not assumed in DEM, since natural discontinuities, joints, shears, and fractures, as observed in the field can be used to create a more realistic representation of the rock mass such that failure can occur along any of the discontinuities. We use a case of rock slope failure in an existing mine to illustrate the difference between 3D LE and 3D DEM analysis results. We also show that with an increasing number of rock blocks in the model (tighter spacing of the joints), the rock mass is less stable. This has implications for rock slope stability evaluations, as rock that is more fractured will be less kinematically constrained and require more mechanical strength to remain stable. Additionally, during rock slide initiation, the rock within the sliding mass may fracture and disintegrate, such that it becomes less constrained as it deforms. The outcome is a progressive rock slope failure and accelerating displacements as the rock blocks within the sliding mass become more fractured.

1 INTRODUCTION
In fractured rock masses, slope failure occurs along pre-existing discontinuities, such as joints and fractures. The interaction between the discontinuities and the geometry of the slope plays an important role in the displacement of the blocky rock mass, both for failure initiation and runout. While 3D DEM methods have been available for some time, their utility for routine analyses has been limited due to their high computational demands and lengthy execution times in serial code implementations. However, the implementation of DEM in a modern HPC (High-Performance Computing) environment opens opportunities for efficient and affordable, full-scale analyses of failure initiation and runout.
Microscopic Defect Dynamics During a Brittle-To-Ductile Transition
Authors: Pec Matej , O’Ghaffari Hoagy , Mok Ulrich , Chang Hilary , Evans Brian , Bernabe Yves , Mittal Tushar , Cross Andrew 
Published: August 2024

ABSTRACT:
The strength of the lithosphere is limited by pressure-dependent, "brittle" deformation of the upper crust and temperature- and strain-rate-dependent "ductile" deformation in the lower crust and upper mantle. From a simplified mechanistic point of view, intersection of these two strength envelopes can be used to estimate the depth of a region known as the brittle-to-ductile transition (BDT) where rocks deform by semi-brittle flow. This BDT is key for estimating the integrated strength of tectonic plates, constraining the earthquake cycle, and utilizing deep geothermal resources. The BDT region is associated with changes in 1) dominant deformation mechanisms, 2) strain localization, and 3) fault stability; however, the transitions in all three attributes are influenced by many parameters, including lithology, grain size, porosity, the presence and migration of pore fluids, the loading conditions, metamorphic reactions, and the geometric complexities of geologic formations and faults. Thus, the transitions in deformation mechanisms, failure mode, and stability do not typically occur simultaneously, resulting in complex behavior that is poorly understood.
In this talk, we show that the crossing of a BDT in marble during deformation experiments in the laboratory is accompanied by systematic increase in the frequency of acoustic emissions suggesting a profound change in the mean size and propagation velocity of the active defects. We further identify dominant classes of emitted waveforms using unsupervised learning methods and show that their relative activity systematically changes as the rocks cross the brittle–ductile transition. As pressure increases, long-period signals are suppressed, and short-period signals become dominant. At higher pressures, signals frequently come in avalanche-like patterns. We propose that these classes of waveforms correlate with individual dominant defect types, that is cracks, twins and dislocation avalanches. Complex mixed-mode events indicate that interactions between the defects are common over the whole explored pressure range (0.1 - 250 MPa), in agreement with postmortem microstructural observations. To corroborate these interpretations, we performed deformation experiments on large calcite single crystals recording acoustic emissions and imaging the propagating sources with a high-speed camera. We discuss our results in the framework of a new micro-mechanical model and link the onset of the BDT to stress states at which tensile cracking around spherical cavities ceases to be possible. Our measurements provide unique, real-time data of microscale dynamics over a broad range of pressures and aid in the development of micromechanical models for semi-brittle deformation.
Numerical Simulation of Long-Term Stability of Irregular Underground Salt Caverns Under Alternating Loads
Authors: Chang Zhi , Xia Yan , Dai Kun, , Liu Tianen , Zhang Qi , Ban Fansheng 
Published: August 2024

ABSTRACT:
The proportion of green energy, such as photovoltaic and wind power, in power generation is increasing year by year. However, green energy often exhibits significant periodic fluctuations. Therefore, it is imperative to construct a large number of compressed air energy storage facilities to meet the daily demand for peak power regulation. Utilizing the dissolved cavity of salt rock layers to build underground salt cavern energy storage presents an economical and reliable solution due to the low permeability and self-repairing properties of salt rock. Nevertheless, most salt rock layers in China contain mudstone interlayers, which pose challenges in accurately controlling the shape of salt caverns during the water injection process within the dissolved cavity. This often results in irregularities, unevenness, and large curvatures near the mudstone interlayer within the cavity shape. Such irregularities on the inner wall of cavities pose a significant threat to long-term stability as they are prone to stress concentration and collapse. The present study establishes a sophisticated three-dimensional geometric model based on the geometry and geological conditions of underground salt caverns in the Hengyang area. Utilizing COMSOL, a numerical simulation is conducted to investigate the long-term creep stability of irregularly shaped salt caverns over a period of 30 years. The impact of salt cavern geometry on long-term stability is quantitatively assessed through key parameters such as volume shrinkage rate, plastic deformation, and stress concentration areas.

1. INTRODUCTION
With the approaching of the carbon emissions peak date, the proportion of green energy such as photovoltaic and wind power in power generation is increasing year by year (Pan et al., 2023; Van-Tien et al., 2022). However, green energy usually has a large cyclical fluctuation (Mahdieh et al., 2023; Jean-Paul et al., 2013), and at the same time, the electricity consumption in the population gathering area itself has a daily cyclical fluctuation, so it is urgent to build a large number of compressed air energy storage to meet the daily demand for power peak regulation (Liu, X. et al., 2023). Therefore, the establishment of underground salt cavern energy storage is an economical and reliable scheme for power peak regulation (Chen et al., 2024).
Evolution of Seismicity at Malmberget Mine
Authors: Jonsson K. , Dineva S. 
Published: August 2024

ABSTRACT:
The Malmberget iron ore mine owned by LKAB (Sweden) is one of the largest iron underground mines in the world. At present 10 orebodies are being mined, with seismicity being a known issue for several of them. The seismic system consists of 143 geophones, of which 36% are triaxial. They are a mix of 4.5 and 14 Hz geophones installed underground and in crown pillars. On the ground surface five 1 Hz geophones have been installed to estimate seismic source parameters. The mine seismic system records on average 440 events monthly with ML &gt; 0. The largest seismic event recorded until the end of 2023 is with ML 2.9. The study was carried out in order to identify some trends in seismicity as the mining goes deeper and to find a correlation with some main controlling parameters – volume and depth of the production in order to obtain information for future seismic hazard and risk analysis. Another purpose of the study was to identify trends and behaviors for different orebodies (mining areas). The seismicity correlates strongly with the production depth, but there are differences between the orebodies.

1. INTRODUCTION
The Malmberget iron ore mine owned by LKAB (Sweden) is one of the largest iron underground mines in the world. Mining in the area started by the official records in the mid-18th century, but in a small scale. The railroad was finished in the 1890s, which meant an upswing in the mining activities. Already in 1914 underground mining dominated the production. The Malmberget underground mine consists of about 20 orebodies, of which 11 are mined at present (December 2023), covering a surface area of about 4 × 8 km. The orebodies vary in size, shape and dip in addition to having different rock mechanics issues related to geology and extraction sequence. Some orebodies have been mined by surface mining, while mining in others started some distance below the ground surface, leaving a crown pillar. At present the mine uses the sublevel caving mining method.
Influence of Monitoring Time on Rockfall Magnitude-Frequency Uncertainty
Authors: Phillips C. , Walton G. 
Published: August 2024

ABSTRACT:
Rockfall along mountainous roadways poses a hazard to transportation infrastructure, commercial traffic, and the public. Lidar scanning and photogrammetry are powerful tools to create high-resolution point cloud models of rock slopes and quantify change, facilitating rockfall volume estimation. The empirical magnitude-cumulative frequency (MCF) distribution of rockfall defines the number of rockfalls of various sizes that occur for a certain study area over a given period of time. The time required for the MCF curve fit parameters to stabilize varies for different slopes depending on source area size and rockfall frequency. Four Colorado rock slopes with remote-sensing-based rockfall inventories were studied to determine the typical length of monitoring necessary to produce an MCF power law that accurately reflects long-term slope rockfall activity. Bootstrapped confidence intervals on the MCF fit parameters were used to quantify the power law variability for each slope over time (as additional monitoring periods are added) and with the sequential addition of rockfalls to the database. The results of this research include guidelines for minimum rock slope monitoring time and database size to accurately constrain the rockfall magnitude-frequency relationship.

1. INTRODUCTION
Empirical distribution fitting is commonly used to model natural, difficult to predict phenomena in the geosciences. Many natural processes follow an empirical power-law to describe the relative frequency of their size or energy over a certain range, including earthquakes, forest fires, landslides, rockfall, and volcanic eruptions (Corral & González, 2019). In rockfall hazard analysis, an inverse relationship of decreasing rockfall frequency with increasing size has been consistently observed from rockfall records (Benjamin et al., 2020; Guerin et al., 2020). A power law model fit to this magnitude-frequency distribution is commonly used to predict the exceedance probability of a given rockfall volume (Dussauge-Pessier et al., 2002; Graber & Santi, 2022; Hungr et al., 1999; Janeras et al., 2023). Use of this model as a predictive tool is dependent on the accuracy and completeness of the rockfall inventory used to define the power law.
Approximation of Stress near Tunnel Intersections in Deep Burst-Prone Mines for Support Selection and Rockburst Hazard Assessment
Authors: Rigby A. , Malovichko D. A. , Kaiser P. K. 
Published: August 2024

ABSTRACT:
Assessing the depth of rock fracturing around tunnels is of critical importance for the design of ground support systems in strainbursting ground. Considering the heterogeneity of the rock, explicit modelling of stress-fracturing around tunnels at such a massive scale is a numerically demanding task. Previously, a semi-empirical approach to evaluate the extreme depth of failure based on elastic modelling has been suggested. It can be adopted at a mine scale by performing explicit modelling of large excavations (stopes, caves, chambers, etc) and then approximating anticipated conditions at tunnel locations using elastic approximations to obtain the local stress level. This implicit approach to incorporating tunnels into the stress model ignores interactions between tunnels, which can result in the underestimation of stress when tunnels are in close proximity, such as near intersections. To investigate this, we have explicitly modelled the stress distribution around tunnels near intersections with various configurations and loading conditions. Using these results, we present an approach to estimating stress magnifications near intersections that does not require explicit numerical modelling. A mine-scale example of an extraction level at a schematic block-caving mined is used to demonstrate the implications in the context of deformation-based support design and rockburst hazard assesment.

1 INTRODUCTION
The design and selection of support in stress-fractured and strainbursting ground is informed by the displacement demand anticipated prior to a strainburst and both the displacement and energy demand during a strainburst (Kaiser and Moss, 2022). The pre-burst displacement demand depends on the depth of damage dpre that has accumulated since support installation and the rockmass bulking factor (BF). Similarly, the displacement and energy demands imposed during a strainburst can be related to the depth of strainbursting dSB. For rockburst hazard assessment (RBHA; Kaiser and Moss, 2022; Malovichko, 2023) in strainbursting ground, it is essential to obtain these demands and to asses their variability, which allows for estimation of the probability of exceedance of design thresholds.