Abstract: The Dagushan iron mine is a large deep concave open-pit iron mine. During the transitional period from open-pit to underground mining， a new underground transition mode of improved induced caving mining for hanging wall ore was adopted. The 3D modeling of the existing hanging wall ore was carried out in Dagushan mine. Based on the the safety requirements of open-pit and underground cooperative mining in transitional mode， the south-hanging wall ore was selected as the open-pit and underground cooperative mining area during the first phase of the transitional period. By adopting a reasonable sequence of extraction， the range and volume of collapse pit at the slope were controlled， so that the slip body slides into the collapse pit. In the second stage of the transition from open-pit to underground mining， the mining of the east hanging wall ore was used to rapidly improve the underground mining capacity and to control the sliding rock mass of the east side slope in a reasonable manner. Finally， it was used to design and verify the mining method of transition from open-pit to underground in Dagushan iron ore mine.

Key words: hanging wall ore, deep concave features, induced caving mining, Dagushan mine, from open-pit to underground mining