Investigation of Pillar Width Effect on Pillar Stability in Inclined Layers by Numerical Model, Hamkar Mine Field Study

One of the most important sections of mining operations is pillar designing. One of the best methods for optimum pillar designing is the numerical method, which is done at this paper by FLAC2D software. There are a lot of differences between designing of the pillar in inclined layers and in normal horizontal layers. In inclined layers, the pillar is affected by vertical and shear stresses significantly. For analyzing of pillar width effect on stability in inclined layers, two pillars width (10-15m), at constant 30 degrees layer inclination are modeled. This study is in the coal layers of Hamkar coal mine in Iran. One of the results of this numerical model is that with increasing the pillar width, the vertical stresses, which are applied to the coal pillar, are decreased. Similarity applied shear stresses decreasing by increasing the pillar width. It can be recognized that with increasing the pillar dimensions, the instability of pillar is reduced at constant layer inclination degree. Finally, it can be concluded that at the specified constant layer inclination, the pillar width must have an optimum magnitude to not be damaged. Therefore, just the pillar with 15m width is safe in 30 degrees Hamkar mine layer inclination.