Strategies for Improving Operation Efficiency of Mining Bolt Rigs

This paper focuses on the 20103 fully-mechanized mining face of Qinyu Coal Mine, analyzing geological conditions, supporting systems, existing bolt rig problems, and putting forward optimized equipment selection, process parameters, and efficiency-improving strategies with complete field data.

1. Working Face & Geological Conditions

• Strike length: 1707 m, mining width: 160 m, mining height: 1.7 m
• Buried depth: 150–320 m, seam dip: 0–8°
• Immediate roof: sandy mudstone, thickness 2.5–4.2 m, UCS 36 MPa
• Main roof: medium-grained sandstone, thickness 6.5–7.8 m, UCS 35.2–36.8 MPa
• Floor: mudstone, UCS 8–10.5 MPa, water absorption 5.16%

2. Bolt Support System Parameters

• Support type: bolt + cable + beam + mesh
• Bolt: Φ20 mm, 2300 mm left-hand rebar
• Cable: Φ17.8 mm steel strand, 7300 mm / 9300 mm
• Row & spacing: 800 mm×800 mm, 600 mm×600 mm in broken zones
• Roof separation: controlled within 50 mm

3. Existing Rig Problems (ZDY-1250)

• Torque: 1250 N·m, insufficient for hard rock
• Drilling efficiency: only 1.0–1.2 m/min in hard rock
• Angle deviation: exceeds ±5°, low positioning accuracy
• No automatic grouting system, unstable anchoring quality
• Large size, poor mobility, high labor intensity

4. Rig Selection & Parameter Optimization

• Required minimum torque: 830 N·m
• Recommended upgrade: ZDY-1900 hydraulic bolt rig
• Hole diameter: 42 mm, hole depth: 2.3–4.5 m
• Drill bit: carbide spiral wing type
• Angle control: within ±3° with laser guidance

5. Efficiency Improvement Strategies

• Enhance geological adaptability: 3-speed hydraulic motor, stable propulsion
• Automatic collaborative control: auto-alignment, auto-drilling, auto-grouting
• Positioning error: within ±2°, hole repeatability: 95%
• Average drilling cycle: from 6.2 min reduced to 4.1 min
• Support time reduced by 28.7%, error reduced by 42%
• Fault early warning: oil temperature > 65°C triggers automatic protection

6. Conclusion

• Upgrading to ZDY-1900 significantly improves drilling efficiency and stability
• Optimized parameters and laser guidance greatly improve hole quality
• Automatic collaborative control greatly reduces working time and labor intensity
• The strategy can be widely applied in similar coal mine working faces