A Study on the Mechanism of Dynamic Pressure during the Combinatorial Key Strata Rock Column Instability in Shallow Multi-coal Seams

<div>Collapse characteristics of overlying strata of concentrated coal pillar in working face. (a) Approaching the concentrated coal pillar. (b) 25 m under the concentrated coal pillar. (c) 7 m beyond the concentrated coal pillar.</div>

Advances in Civil Engineering

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Figure 4

Figure 4: A Study on the Mechanism of Dynamic Pressure during the Combinatorial Key Strata Rock Column Instability in Shallow Multi-coal Seams 