THE DEVELOPMENT AND PROBLEMS OF UNDERGROUND DRILLING TECHNIQUE IN DOMESTIC COAL MINES

Compared with the surface drillng,the underground drilling was developed slowly technically,however,the situation was changed largely since the late of 1970s,when the development of fully mechanized mining was decided as an important technical policy,and the underground drilling was developed with the unprecedented speed.In 1980s,a greater progress was obtained in the development of underground driller,and in 1990s,a new breakthrough also was attained in the drilling technology,the equipment and technology are fully development.In this paper,the main achievement in this field obtained in near 20 years is reviewed briefly and the existed problems are pointed out.