In order to enhance the efficiency of excavating coal, Beishan coalmine attempts to adopt millisecond delay directinitiation at working face.
百善煤矿为提高采煤效率，尝试在采煤工作面实行毫秒延期反向起爆。
2
Primary disease always be clinical common disease and frequently encountered disease , not only direct influence people's health, but also initiation other complication.