Excessive noise from transmission gear of electric drills means that the product still owns unclear problems in quality and security.

Conclutions Drilling and sunction noises during an otological surgery can cause temporary hearing threshold changes in the contralateral ear.

This article introduces the practice of releasing gas by using the wind coal drill in the big road of shaft,which shows that the technology is reasonably,the economic efficiency is remarkable,the security has guarantee,is a practical feasible effective way and has broad application prospect.

The method of drilling by the wind coal drill,the coal body produces the crack and releases gas under the conditions of the dynamic pressure function of mining field,then draining gas with drainage facility to govern the local high gas region at working surface are introduced.