The main factors affected on the drillingspeedofdrilling method are rock-cutting and mud discharge.
影响钻井法钻进速度的因素主要有破岩和排渣。
2
This paper analyses the main factors that influence the speedofdrilling hole, puts forward the methods to settle the main working parameters of the rotary drill.
分析了影响牙轮钻机钻孔速度的主要因素，提出了钻机主要工作参数的确定方法。
3
The world's longest tunnel will take shape deep beneath the Swiss Alps on Friday when a giant drilling machine clears a path for a key high speed railway through the heart of Europe.