Feasibility test of roof resistivity monitoring for super-high mining face

The failure of roof overburden is one of the main reasons for water inrush in mining working face. Roof resistivity monitoring by mine electrical method can be used to detect overburden failure dynamically. However, roof resistivity monitoring for super-high mining face has many problems, such as audio electromagnetic signal by conventional methods is difficult to penetrate through wide working face, burying of roof monitoring electrodes is difficult, monitoring electrode in the roof of air return lane is hard to protect, and so on. In order to solving these problems, feasibility study of roof resistivity monitoring for super-high mining face is carried out by audio electromagnetic perspective instrument and working face resistivity monitoring system. Experiment result shows:perspective distance of audio electromagnetic signal by pole-dipole arrays can be 340 m; anchor bolt can be used as monitoring electrode for current transmission and signal acquisition; monitoring electrodes of the return air way can be arranged on the way floor for protection. On the basis of above research, a resistivity monitoring system for mining working face is arranged for a super high mining face. The signal test results are consistent with the feasibility test results.