In allusion to the complicated phenomena of "hard rock,current loss,wall sloughing,water inrush and borehole deviation" during drilling in the Kengbing mine area,Longyong coalfield,based on practices in many years,tracked out a set of borehole structure designs and drilling methods.

It is difficult to control the hole and the slope during frozen drill in profundity surface soil, this text bring forward some experience of manage ment and construction.

The freezing trench of Gubei Colliery was constructed parallelly and crossly with the freezing hole boring, which combining with mechanization reduced the transition time from freezing hole boring to freezing process.

Construction process of bored concrete pile in pore-forming by drill and dig and analysis for execution effect;