Feasibility experimental study on plugging leakage in goaf based on two-phase foam

Area of Science:

• Mining Engineering
• Materials Science
• Environmental Science

Background:

• Air leakage in goaf exacerbates coal spontaneous combustion (CSC), posing significant safety and environmental threats to mining operations.
• Effective sealing of goaf airflow is critical for mitigating CSC risks and ensuring mine safety.

Purpose of the Study:

• To investigate the feasibility of using two-phase foam for sealing air leakage in goaf.
• To evaluate the effectiveness and practicality of two-phase foam sealing technology for preventing CSC.

Main Methods:

• Conducted feasibility experiments using two-phase foam for air leakage sealing in loose media under ventilation.
• Performed numerical simulations and field measurements of airflow leakage in mine working faces.
• Proposed and analyzed two injection methods: point drilling and incremental buried pipe.

Main Results:

• Continuous foam injection completely sealed air leakage, withstanding wind pressures up to 600 Pa.
• A 2m foam seal remained effective for 60 minutes, with effectiveness increasing with sealed distance.
• Sealing airflow passages in the goaf behind the return airway corner is crucial for CSC prevention.

Conclusions:

• Two-phase foam technology is a feasible, practical, and economical solution for sealing goaf airflow leakage.
• The findings offer new insights into goaf sealing, addressing safety and environmental concerns related to CSC.