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28 th International Conference on Ground Control in Mining

Morgantown, West Virginia 7/28/2009 – 7/30/2009. 28 th International Conference on Ground Control in Mining. Kazem Oraee, Navid Hosseini, Mehran Gholinejad. Coal Pillar Strength Based On The Ground Reaction Curve – A New Approach. Coal Pillars. Coal Pillars Strength Formula.

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28 th International Conference on Ground Control in Mining

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  1. Morgantown, West Virginia 7/28/2009 – 7/30/2009 28th International Conference on Ground Control in Mining

  2. Kazem Oraee, Navid Hosseini, Mehran Gholinejad Coal Pillar Strength Based On The Ground Reaction Curve– A New Approach

  3. Coal Pillars

  4. Coal Pillars Strength Formula • Holland-Gaddy (1964) • Bunschinger (1876) • Salamon-Munro (1967)

  5. Coal Pillars Strength Formula • Bieniawski (1967) • Bieniawski (1968) • Holland (1973)

  6. Coal Pillars Strength Formula • Oraee-Hosseini (2007)

  7. Coal Pillars Bearing Capacity • Width to Height Ratio (W/H) • Uniaxial Compressive Strength of Intact Coal

  8. Ground Reaction Curve (GRC)

  9. Coal Pillars • Solid (Stiff) Pillars • The solid pillars remain in elastic behavior phase and support the applied loads with their inner-core • Yield Pillars • The yield pillars reaching the plastic behavior phase, and by creating a pressure arch, transfer the applied loads to the abutments on both sides

  10. The Typical GRC for Coal Pillar

  11. Pillar Design for Tabas Coal Mine Linear Phase (Elastic) Non-Linear Phase (Plastic)

  12. Coal Pillar Design Based on GRC Linear Phase (Elastic) Non-Linear Phase (Plastic)

  13. Coal Pillar Design Oraee-Hosseini (2007); Tabas Coal Mine, Iran Linear Phase (Elastic) Non-Linear Phase (Plastic)

  14. Conclusions The presented new method, based on the GRC, can advantageously identify the elastic and plastic behavior phases and the critical point that is similar to yield point in the stress-strain curve, which denotes the transition of phase behavior. Therefore, this new approach can determine the elastic and plastic behavior phases of pillar based on the W/H ratio. Moreover, for each phase, a dedicated equation is presented. With measurement of coal pillar horizontal strain, that is done simply, and by using these new equations, the coal pillar strength is calculated accurately. Undoubtedly, the knowledge of coal pillar behavior phase with accurate estimation of coal pillar bearing capacity is the basis in coal pillar logical design. The new method for coal pillar design with applied approach is the general pattern in design of various pillars in underground mining methods elsewhere.

  15. Thank You For Your Kind Attention

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