Through adding public side, setting appropriate cutting route and using proper adding joint to the workpiece,we can improve producing efficiency and workpiece quality, can also reduce the consumption of gas and improve material utilization ratio of steel plate at the same time, the costs of production will be saved for the enterprise.

The key parameters of grouting technique for water-shut-off was determined,water control plan of "besieging a stronghold in order to strike at the reinforcements" and a set harnessing technique were formed for most-water bursting under water-flowing conditions,which consists of checking,seeking,deciding,bl.

In view of the limitation of signal dotting and phonetic communication device used for coal mine,a kind of flameproof signal dotting and phonetic carrier-current communication device especially suited to satisfy the current needs of modernization mine production with high-capacity and high-efficiency is designed,its effects and performance has been validated.