... approaches, while numerical methods provide the required accuracy in the determination of stress variations across the pillars as well as the assessment of the pillar strength. In this paper, we adopt numerical modelling to better constrain the implication of employing simplified approaches for a proper...

... ABSTRACT: Pillar strength determination is a fundamental aspect of room-and-pillar mine design. Pillars are left between excavated rooms to maintain stability by restraining the hanging wall. In a typical mining environment, pillars of different rock mass conditions and geological...

... width-to-height ratios of 5 to 10. In the course of stope extraction, the dimensions of the pillars are altered, namely the height of pillars is increased and the width of pillars may be decreased. Consequently, the pillar strength is reduced and pillar crushing is triggered. A stable crushing process...

... on the pillar's stability factor and the width to height ratio, where the width is the smallest dimension of the rectangular base. The estimation of pillar strength in room-and-pillar stone mines has been studied by researchers and empirical relationships between traditional geometry (square and rectangular...

... ABSTRACT Over the past decades, many pillar strength relationships have been formulated from empirical observation of stable and failed case histories. These empirically derived equations are still widely adopted as a general technique for estimating pillar strength and simplified methods...

... also disrupt production and burden the pre-planned mine operations. The study for estimating pillar strength using numerical modeling could provide a pragmatic approach to designing future pillars affected by karsts. The shape and volume of the karst cavities inside the concerned pillar were...

... ABSTRACT: Underground stone mines in the United States generally use room-and-pillar mining method, and designing stable pillars, and knowing their behavior through the mine's life is of vital importance to avoid hazardous conditions. In the USA, empirical pillar strength equation and S-Pillar...

... pillar strength proceedings excavation grc reaction curve criteria strength convergence src stiffness ground reaction curve pillar deformation pillar deformation ARMA 21 1238 Support Design Using the Ground Reaction Curve and Support Reaction Curves at Underground Limestone Mines...

... the location of damage events track the intensity/density of rock damage as the simulation progresses and relate these changes to the modelled pillar strength. The results of this synthetic rock mass pillar study provide useful insights on damage evolution and rock bridge strength characterisation in pillars...

... for hard-rock pillar design. This paper presents the relevant geotechnical data related to the collapsed area and numerical model results that were used to estimate the pillar loading underneath the variable topography and compares the pillar loads to some established hard-rock pillar strength equations...

... dipping faults and sympathetic joints reduce pillar strength. The failed pillars are no longer contributing to the overall mine stability but provide local support due to the residual strength. New pillar design (7m by 4m) which takes into consideration the current structural data need to be implemented...

... ABSTRACT: The limitations of the current pillar strength formulas, empirical design charts, and continuum numerical modelling is that these methods do not consider discontinuity driven failure mechanisms (i.e. jointing at critical angles). Strength formulas have been very effective within...

... strength. The numerical model was calibrated with Obert and Duvall empirical pillar strength equation. A multi-variant regression has been used to established relationship between the modulus of deformation of the rock mass and the pillar strength for various pillar shapes and sizes. It can be concluded...

... university floor sf thickness safety factor us government pillar strength reservoir characterization stability illinois underclay thickness vg approach reservoir geomechanics pillar ARMA 15-224 Underground Disposal of Fine Coal Waste Siavash Zamiran Southern Illinois University Carbondale...

... to water flows. excavation classification mining cut geotechnical data formula stability pillar design span hangingwall strength reservoir characterization metals & mining calculation reservoir geomechanics redesign unsupported span pillar strength upstream oil & gas pillar...

... to estimate the stability of hard rock pillars was carried out. Considering different pillar geometries, and specially an abutment stress model, the induced vertical stress in a rib pillar type were evaluated by Stacey and Paige [1], and Lunder and Pakalnis [2] methodologies. pillar strength strength...

... Abstract Estimation of pillar strength is a vital part of assessing the stability of pillars used in mines. In this paper, numerical modelling using strain softening constitutive law have been employed to estimate the strength of 32 stable St. Peter Sandstone pillar cases. The model results...

... Abstract: Secondary pillar mining at the Doe Run series of underground lead mines near Viburnum Missouri often requires predictive modeling of pillar conditions to determine factors of safety. Pillar strengths used in modeling are based on empirical case studies as well as confinement theory...

... of 6.2 MPa (900 psi). Models of various pillar shapes replicated Bieniawski pillar strength equation estimates for pillar width-to-height ratios up to 8. Mohr-Coulomb properties in the floor were then varied to define a boundary between heave and no-heave floor response to loading for each pillar size...

... between Simon Fraser University, Golder Associates and the Doe Run Company. Within this approach, a technique was developed to relate the rating system to an estimation of pillar strength, via a method that considers the differing amounts of confinement within a pillar. Subsequently, the pillar strength...