钻孔瞬变电磁方法探测越界开采采空区的应用

煤矿井下越界开采扰乱煤炭资源开发秩序，同时存在巨大的安全隐患，准确探测越界开采采空区及其边界对安全采掘极为重要。常规的矿井瞬变电磁探测方法容易受到巷道中的金属和电磁信号干扰，探测精度有限，难以满足采空区边界精准解释的需求。为了解决这一问题，提出一种钻孔中收发信号的钻孔瞬变电磁方法和施工工艺，利用其远离巷道和靠近异常体的特点，提高异常信号在实测数据中的占比；并研究可行域约束的OCCAM反演算法，进一步减小体积效应影响，实现了对越界开采采空区的电阻率精细成像。结合山西某煤矿的工程实践，对该方法精准探测邻矿越界开采采空区规模、性质的实用性和有效性进行了检验。结果表明，钻孔瞬变电磁方法是矿井地球物理技术与钻探工艺技术的高效结合和有益补充，基于可行域约束的OCCAM反演算法能够有效应用于越界开采采空区的边界精确成像解释。 

Application of borehole transient electromagnetic method in detecting the cross-border mining goaf

Cross-border mining in underground coal mines disrupts the order of coal resource development, and has huge hidden safety danger. Accurate detection of goafs caused by cross-border mining and their boundaries is extremely important for safe mining. Conventional mine transient electromagnetic detection methods are susceptible to interference from metal and electromagnetic signals in the roadway, and its detection accuracy is limited, which makes it difficult to meet the needs of accurate interpretation of goaf boundary. For the purpose of solving this problem, a drilling transient electromagnetic method and construction technology for transmitting and receiving signals in drilling is proposed to increase the proportion of anomalous signals in the measured data. As its being far away from the roadway and close to anomalous objects, the feasible domain constraints of OCCAM inversion algorithm was studied to further reduce the volume effect and achieve the fine resistivity imaging of cross-border mining goaf. Combining with the engineering practice of a coal mine in Shanxi, the practicability and effectiveness of this method for accurately detecting the scale and nature of the adjacent mines cross-border mining goaf are tested. The results show that the borehole transient electromagnetic method is an efficient combination and beneficial supplement of mine geophysics and drilling technology. The OCCAM inversion algorithm based on feasible region constraint can be effectively applied to the accurate imaging interpretation of the boundary of the cross-border mining goaf.