② gas demarcation point: T 1 is1.5% CH4;
(3) Power outage range: T 1 refers to all non-intrinsically safe electrical equipment in the heading face; ?
④ Re-energizing point: T 1 less than 1% CH4.
High gas, coal and gas outburst mines;
(1) Monitoring content: Add 1 high-and low-concentration combined gas sensors in the return air flow of heading face.
(2) Layout of measuring points: layout as required in Figure 3-5.
Extended data:
The alarm concentration of methane sensor in front of local ventilator in series heading face is ≥0.5%CH4, the power-off concentration is ≥0.5%CH4, and the complex power-off concentration is < 0.5%CH4. The power-off range covers all non-intrinsically safe electrical equipment in series heading roadway. If the local ventilator is included, the power-off concentration shall be ≥ 1.5%CH4.
Methane sensors should be set at the following locations of coal roadway, semi-coal roadway and rock roadway driving face with gas emission, and gas wind power locking should be realized:
(1) at the mixed airflow of the heading face, that is, at a distance of ≤5m from the head-on.
(2) In the return air flow of the heading face, that is, at a distance of 15m from the return air of the mining area.
(3) The heading face with series ventilation is 3 ~ 5m in front of the local ventilator in series working face.
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