School of Earth Sciences and Resources, China University of Geosciences (Beijing)
School of Resources and Geosciences, China University of Mining and Technology
State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources, China University of Mining and Technology (Beijing)
School of Geosciences & Surveying Engineering, China University of Mining and Technology (Beijing)
School of Environment and Spatial Informatics, China University of Mining and Technology

煤自燃灾害是影响我国许多矿区发展的因素之一，带来严重的资源损失和环境污染。隐蔽火源定位及其分布范围识别是煤矿企业制定预防和治理措施的重要依据，也是煤火灾害领域内的研究热点和难点。合适的通风供氧通道是煤层自燃的必备条件，当煤体的氧化放热速率超过散热速率时，煤体温度不断上升直至引起煤层自燃，因此，找准火区燃烧中心并确定烧空区和垮落带是煤火探测的主要任务。以内蒙古乌海市公乌素露天矿为研究对象，在煤层电阻率与温度关联分析的基础上，采用地质雷达和圆锥型瞬变电磁法开展了着火点及分布范围探测，结合地面冒烟区位置获得了火区地下通道的地球物理特征，进而确定了研究区着火通道的分布范围。研究结果表明：原岩区和烧结区的物性稳定性较为连续，其顶界面在雷达影像中呈现出较为明显的反射同相轴，在圆锥型瞬变电磁成果中则体现为横向连续的电阻率分布。地下隐蔽着火通道由孔洞裂隙发育、岩体破碎等因素造成，在地质雷达剖面中反映为同相回波弱且不连续，在瞬变电磁拟断面中出现电阻率等值线在横向上下凹或错段。测线方向上高程落差不同处视电阻率范围不同，需要在测区整体电性规律的基础上，分区研究测线局部范围内的物性变化，以界定原岩中物探异常的分布规律。综合圆锥型瞬变电磁和地质雷达两种方法，可对潜在自燃着火点位置及着火范围进行有效识别，为着火区范围的圈定以及着火规律的分析提供依据。

Spontaneous combustion in coal seams, a factor influencing the development of many mining areas in China, can cause severe coal resource loss and environmental pollution. The positioning and distribution identification of hidden fire sources can provide an important basis for coal mine enterprises to prepare prevention and control measures. They are also a hot research topic and challenge in the field of coal fire disasters. Suitable channels for ventilation and oxygen supply are necessary for spontaneous combustion in coal seams. When the oxidative heat release rate of coals exceeds the heat dissipation rate, coal temperature will rise until the occurrence of spontaneous combustion in coal seams. Therefore, the primary task for coal fire surveys is to pinpoint the combustion centers of coal fire zones and identify the burning-out areas and caving zones. This study investigated the Gongwusu open-pit coal mine in Wuhai City, Inner Mongolia. Based on the correlation analysis of coal seam resistivity and temperature, this study conducted surveys of the coal fire locations and their distribution range using the ground penetrating radar (GPR) and conical source-based transient electromagnetic (CSTEM) methods. Then, by combining the surface smoking positions, this study acquired the geophysical characteristics of the underground channels of the fire zones and further ascertained the distribution range of the coal fire channels. The results indicate that: (1) Both the protolith and sintering zones exhibited relatively consistent physical stability, with their top boundaries present as distinct reflection events in radar images and as transversely continuous resistivity distribution in the CSTEM outcomes. (2) The underground hidden fire channels, caused by factors like rock fragmentation and the presence of pores and fissures, exhibited weak, discontinuous in-phase echoes in the GPR profiles. In contrast, they show transverse concaves or dislocations of resistivity contours in the CSTEM pseudosections. (3) Along the survey lines, the apparent resistivity range varied with the elevation drop. Therefore, to determine the distribution patterns of geophysical anomalies in the protoliths, it is necessary to delve into the localized changes in physical property along survey lines based on the analysis of overall resistivity across the study area. As indicated by these results, potential spontaneous combustion in coal seams and its distribution range can be pinpointed by integrating the CSTEM and GPR methods, thus providing a basis for delineating coal fire zones and analyzing coal fire patterns.

国家重点研发计划课题(2022YFF1303305)；国家自然科学基金项目(42374082，41974086)

马子钧，杨海燕，李文宇，等. 煤层自燃区隐蔽火源的综合地球物理探测应用[J]. 煤田地质与勘探，2023，51(12)：131−137.

MA Zijun，YANG Haiyan，LI Wenyu，et al. Application of integrated geophysical surveys in the identification of hidden fire sources in spontaneous combustion zones in coal seams[J]. Coal Geology & Exploration，2023，51(12)：131−137.