Abstract: In view of secondary mining of pillar for an extremely irregular mine，the multi-layered prospecting crosscuts were arranged to obtain the bilateral actual caving boundaries besides ore chamber.Then the three dimensional body model of pillar was established by Dimine software.It not only accurately ascertained the actual  boundaries after stopping，but also directly generated the construction drawing of blasting by using the software's functions of edit and the interactive modification of hole arrangement parameters( length，angle and loaded length).As a result，the quality of hole arrangement and work efficiency were highly improved.The practice indicated that the method effectively resolved the difficulties in determining the blasting boundary of pillar mining，and owns an important application value.

Key words: Dimine, Model, Pillar recovery, Blasting design