Abstract: With the caving method from open pit to underground mining，the overburden seepage discharge in the open pit relates to the safety of underground mining. Through the analysis of rainfall intensity，the catchment area of the open pit and the structural characteristics of overburden，the relationship between these factors and the seepage discharge of open pit overburden is studied，which is of great significance to reduce the underground water and ensure the mining safety.

Key words: Transferring from open pit into underground, Overburden, Seepage discharge