Study on the Mine Pressure Law and the Pressure Frame Mechanism of an Overlying Goaf in a Shallow Coal Seam

<div>Principle of multipoint drag staging hydraulic fracturing. (a) Multipoint drag staging hydraulic fracturing of the first stage of the fracturing process. (b) The second stage of the multipoint drag hydraulic fracturing process.</div>

Shock and Vibration

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Figure 16

Figure 16: Study on the Mine Pressure Law and the Pressure Frame Mechanism of an Overlying Goaf in a Shallow Coal Seam 