3. Remediation of Goaf Areas for Resettlement in Yulin, Shaanxi Province, China

Mining of coal seams in the study area has created single-layer goafs of approximately 21,079 m². The underlying goafs of are in an unstable state, and subsidence or collapses may occur if no engineering measures are taken. The presence of the goafs has become one of the key factors restricting the land use of the area. The goafs are remediated to build a residential community for resettlement of residents. Three types of boreholes are drilled to remediate the potential subsidence area: hydrogeological investigation boreholes, grout curtain boreholes, and grouting boreholes. Two hundred fifty-two boreholes are completed with drilling footage of approximately 12,067 m. Approximately 55,327 m³ of grout were used to address the coal seam goafs.