Research on the Technology of Small Coal Pillars of Gob-Side Entry Retained in Deep Mines Based on the Roof Cutting for Pressure Unloading in the Lower Key Stratum

Figure 7

Cloud map of vertical stress distribution of different coal pillar widths under the effect of one mining.

(a) 5 m coal pillar

(b) 6 m coal pillar

(c) 7 m coal pillar

(d) 8 m coal pillar

(e) 10 m coal pillar

(f) 12 m coal pillar