jumbolter

1.After several years to jumbolter research,the hard rocks always present in the soft ones in the wall rock procedure using jumbolter,which results in changing the boring tool during the procedure.

经几年对锚杆钻踪研究,发现锚杆钻在围岩作业中遇到软岩中有硬岩夹层现象,造成程经更换钻具问题。