Home / Standards / GB/T 31089-2014 GB/T 31089-2014 Active Computation and requirement of recovery ratio of coal mine 煤矿回采率计算方法及要求 Standard Type GBT ICS 73.040 CCS D20 Status 现行 Issue Date 2014-12-22 Implementation 2015-06-01 Responsible Dept 中国煤炭工业协会 Drafting Unit N/A