Study on Permeability Improvement Technology by Injecting Air into the Gas Drainage Borehole in Low-Permeability Coal Seam

<div>Plots of content variation of gas at 0.4 m in vertical direction of gas injection. (a) Influence of different negative pressure on eliminating outburst risk. (b) Influence of different gas injection pressure on eliminating outburst risk.</div>

Advances in Civil Engineering

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Figure 3

Figure 3: Study on Permeability Improvement Technology by Injecting Air into the Gas Drainage Borehole in Low-Permeability Coal Seam 