Development of effective data processing techniques for transient electromagnetic method (TEM) has become an important area in recent years for large-depth, high-resolution, and high-efficiency exploration of underground structures and resources. The finite memory quasi-Newton method (L-BFGS) for three-dimensional lateral constraint inversion(LCI) in TEM data processing was proposed, and satisfied results in the exploration for deeply buried coal seams in the Xinjie Yijing area of Ordos Basin, China has been obtained. Significant advantages of high resolution and reliability of this method was demonstrated by comparison with current one-dimensional methods. Thus, an effective theoretical and practical methodological techniques for the processing of areal electromagnetic exploration data was also provided. With integration of geological and drilling data, the sedimentary strata and coal seams with thicknesses of several tens of meters and depths of over a thousand meters were reliably identified and delineated by the proposed TEM-LCI method. The distribution range, bottom depth of concealed recoverable coal seams, as well as the distribution range of the Cretaceous Zhidan Group, Jurassic Zhiluo Group strata, coal seams, and water-bearing areas of resistivity anomalies within these strata and coal seams have been roughly outlined. Strong support for coal mining and safe production is then provided with the results of this study.