The shaft guide is our patent product protected by intellectual property law, and it has been adopted in over 300 mines since 1994.
自1994年开发推广以来，冷弯方管罐道已在300多个矿井井筒安装使用。
2
The non-linear stability problem occurred in the interior steel sheet of a steel-concrete composite bored shaft lining in coal mines is discussed.
本文研究用煤矿钻井法钻凿竖井时钢板-混凝土复合井壁内钢板的非线性失稳问题。
3
Cement injection of perforating holes in a frozen pipe is a wholly new technology for consolidating shaft wall rock and stopping water of frozen shafts in coal mines.