The mining pressure of the pillars is complicated and difficult to manage compared to the pressure of the mine. Because the pillar is subjected to concentrated stress and blasting of the mine, and the mining tunnel that has been excavated in the pillar. Its overall performance is weakened to varying degrees, reducing the stability of the pillar.
For example, when the two sides of the column are untreated mined areas, the column is often the part where the stress is concentrated. If the bottom is further pulled at the bottom of the column, the column is too suspended, which may be due to stress. Concentration and destruction or degeneration.
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