Home / Standards / MT 71-1991 MT 71-1991 Active 矿用圆环链用开口式连接环 Standard Type MT71 ICS N/A CCS N/A Status Active Issue Date 1991-01-15 Implementation 1991-03-01 Centralized Committee 国家矿山安全监察局 Issuing Authority 国家矿山安全监察局