The multilayer goafs and a large number of accumulated tailing strata in Luanchuan molybdenum mine in Luoyang lead to hole wall failure during drilling， which is generally exhibited as collapse， block falling； meanwhile， the detection equipment can not be lowered to the bottom of the hole and the construction period is delayed. In view of this situation， this paper summarizes two new exploration techniques： （1） A new process of strengthening the hole wall with loess is adopted during drilling， by which loess forms a protective layer on the hole wall through compaction. （2） a new type of tapered bit is designed， which can be stricken down to the bottom of the goaf with a heavy hammer； thus， the borehole television and other detection equipment can be run down hole with protection of the central hollow drill string. Field use has proven that the techniques are feasible by repeated field practice， and the hole wall remained stable and no longer appeared unstable with progress of the construction period， providing guarantee for the subsequent geological exploration of goafs. They have ensured the smooth implementation of the operations economically and safely， and also provide reference for the exploration of complex strata in the future.