Method for identifying the boundary of combustion metamorphic rocks in coalfields based on magnetic anomalies
GUO Junqi
WANG Peng
GU Jiling
GUO Peihong
XI Xingchao
LU Kai
Abstract：Combustion metamorphic rocks(CMR)are one of the main concealed disaster-causing factors in coal mines.Magnetic de-tection is the main method for delineating the distribution range of combustion metamorphic rocks,but accurately identifying the boundaries is a problem that needs to be solved.In order to accurately determine the boundaries of metamorphic rocks in coal fields using magnetic anomaly data,theoretical analysis,model calculation and field experiments were employed to conduct identification studies on the boundaries of single-layer and double-layer metamorphic rocks.Four boundary identification algorithms were selec-ted to process the positive evolution results of the single-layer model,and the boundary identification effects were compared and ana-lyzed;the secondary processing results of various combinations were analyzed,and the combination identification algorithms with better identification effects were selected;the two preferred combination identification algorithms were applied to the double-layer model to determine the optimal combination identification algorithm;the reliability of the boundary identification algorithms was verified through field experiments.The results show that the total horizontal derivative(THDR),vertical derivative(VDR),analytic-al signal amplitude(ASM),and gradient tilt angle(Tilt)based on the Reduction to the Pole magnetic anomaly(RTP)data can all dis-play the boundaries of the single-layer model to varying degrees.Among them,the total horizontal gradient modulus has higher clar-ity relying on using the maximum value for identification.The comparison of the results of multiple combinations of secondary pro-cessing shows that the result of RTP-THDR-Tilt can clearly identify the boundary of the single-layer and has good continuity of the recognition signal.Further tests on the double-layer model revealed that the results of various combinations of secondary treatment using RTP-THDR-Tilt could effectively determine the boundaries of the superimposed metamorphic rocks;the RTP-THDR-Tilt res-ults obtained from the on-site test data of the coal mine showed that the distribution of the boundary strips was in line with the geolo-gical characteristics of the mining area,and the two-layer boundaries of the metamorphic rocks determined by this method were con-sistent with the drilling and exposure results.
Keywords：magnetic anomalyMagnetic detectioncombustion metamorphic rocksboundary identificationconcealed disaster-causing factor
Publication Date：2025-11-20
Online Publishing Date：2025-11-25(First online date of this platform, not the publication date of the document)
Pages：9( 50-58 )