Abstract: Aiming at the unidentified goaf area of a small fluorite mine，endangering the safety of the main shaft and the surface，three-dimensional laser scanning technology was used to scan the empty area， and the accurate shape of the empty area was obtained.It is found that the empty area continued to fall up⁃ wards.The nearest point of the main shaft is less than 20 m.Aiming at the problem of the lack of tailings and other filling materials in the mine's non-concentration plant，the ultra-high water filling technology was studied.The filling system has the characteristics of low construction cost，flexible layout，less occupation， high automation and good filling effect. A set of ultra-high water filling station can be laid at the wellhead， the filling hole can be drilled from the surface to the goaf after determining the filling position，and the slur⁃ ry is mixed and then lowered to the goaf by filling drilling.The practice results showed that the two major mined-out areas that affect the safety of the surface and the main shaft were filled in less than 2 months， the safety of surface structures and personnel were ensured.

Key words: goaf, three-dimensional laser scanning, ultra-high water filling