Home / Standards / GB/T 42638-2023 GB/T 42638-2023 Active The direct measuring method of the coal seam gas drainage radius in coal mine—Method of drainage volume 煤矿井下煤层瓦斯抽采半径直接测定方法 抽采量法 Standard Type GBT ICS 13.100 CCS D09 Status 现行 Issue Date 2023-05-23 Implementation 2023-12-01 Responsible Dept 中国煤炭工业协会 Drafting Unit N/A