Abstract: In order to inspect and assess the blasting effect of goafs in mines，according to the principle of volume balance before and after blasting，the two indexes，the filling rate and the left volume of goaf，are proposed to assess the blasting and caving effect in goafs.The morphological parameters of the goaf was obtained by 3D laser scanning on goafs，and then the volume of broken rocks was measured and calculated，and the volume of the collapsed surface after blasting was measured.Lastly，the evaluation index was got by the formula derived.The filling rate of goaf k is used to judge whether the main risk for the original goafs are eliminated or not.k>85% means the good blasting effect.The left volume of goaf is the characterization of judging the residual risks.The two indexes above can be used to assess the blasting effect in goafs.Practice has proved that this method has the advantages of high efficiency and low cost，and can meet the requirements of daily production with synchronously cooperation of underground goafs governance and risk-hidden resources exploitation.It provides some reference for the governance and assessment of goafs in other open-pit mines transferred from underground mining.

Key words: Open-pit mines transferred from underground mining, Crisis mine, Resources with potential danger, Mined-out area, Caving blasting