Abstract: For large deep open-pit mines entering the end of mining，they will face problems such as difficult capacity continuation and poor safety production conditions when transferred from open-pit mining to underground mining. The wedge transition cooperative mining mode is constructed by using the techno⁃ logical advantages of open-pit and underground mining，and the technical points of cooperative mining and induced caving first mining area are sorted out and verified in Dagushan Iron Mine. The results show that the wedge transition collaborative mining technology can maintain the stability of mine production capaci⁃ ty，and has a significant effect on the safe and stable development of open-pit to underground mining in su⁃ per-large iron mines.

Key words: open-pit to underground mining, collaborative mining, wedge transition, induction cav? ing