Asymmetric evolution of overburden fractures and roof water-hazard zoning during sequential mining of closely spaced coal seams
Year: 2026
Type: article
Abstract: Sequential mining of closely spaced coal seams creates complex relations among residual fractures, cumulative damage, current loading, and roof water hazards. Panels 11,201, 11,200, and 22,201 at Hujia-ta Coal Mine were investigated in their actual sequence using empirical calculation, physical simulation, abutment-pressure and microseismic monitoring, 3DEC, TEM surveys, and drainage drilling. After adjacent extraction of panels 11,201 and 11,200, visible fracture height increased from 55.3 to 56.2 m (1.6%), whereas the boundary-angle difference increased from 0° to 7°, showing a clearer response of boundary geometry. After repeated extraction of panel 22,201, the maximum fracture-height ratio between the 11,200 and 11,201 zones was K H = 1.65, while the right-to-left abutment-pressure peak ratio was K P = 1.93, indicating spatial non-coincidence between the cumulative visible-damage extreme and current load peak. At a mean burial depth of 254.3 m and an interburden thickness of 44 m, the empirical damage height was 110.2 m. Integrated evidence delineated Class I coupled priority zones and Class III anomaly target zones; no Class II target was identified, only interpretable areas not assigned to Classes I–III were classified as Class IV background zones, and the 1520–1940 m equipment-interference section was left unclassified. Two drainage stages completed 8 drill sites, 27 boreholes, 2450 m of drilling, and 15,024 m 3 of drainage. All 21 Stage−2 boreholes reached the target goafs; maximum inflow and water pressure were 22 m 3 /h and 0.32 MPa. After drainage, the goaf-water-related low-resistivity response was not detected under comparable surveys, and roof-aquifer anomalies decreased from three to one. Mechanical damage, electrical response, and hydraulic connectivity should be treated as distinct but complementary evidence layers for drilling targets and drainage priorities.
Institution: Xi'an University of Science and Technology
Language: English
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,890
OpenAlex ID: W7223473780
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