• A lightweight in-situ pressure- and gas-preserved corer was developed to collect coal samples under in-situ pressure, preventing gas loss and improving measurement accuracy.
• A gas migration model for deep coal mines was established, revealing that minimizing coring hole diameter and reducing pressure difference between coring-point and original pore pressure enhance measurement precision.
• Experimental validation at a test base confirmed the corer's performance and effectiveness in sample collection.
• Field tests in an underground coal mine roadway showed that pressure-preserved coring measured gas content 34% higher than open sampling methods.