## 5 Results  
Based on the numerical simulation analysis in Section 4.5, Optimization of Lateral and Vertical Weighting Factors, the optimal combination identified for inverting the measured data to investigate coal seam goals in the survey area is a vertical weighting factor of 0.1 and a horizontal weighting factor of 0.5. This study aims to delineate the distribution of underground coal seam goals within the industrial site of the Xiaolong Coal Mine. Three sections (L2, L5, and L8) were selected for analysis, representing the west, middle, and east sides of the industrial site, respectively. These sections span a profile length of 400 m with measurement points spaced 20 m apart, progressing from south to north. In the western section, L2, the resistivity inversion results exhibit a gradual increase with depth, revealing predominantly low-angle near-horizontal layered structures consistent with the geological data. A stable argillaceous siltstone and siltstone strata are observed near the surface (up to 50 m depth), indicating the presence of a near-horizontal low-resistance zone with resistivity around \(10\sim 75\)\(\Omega\cdot\)m. Between 130 m and 400 m horizontally, a middle resistance zone with resistivity around \(75\sim 150\)\(\Omega\cdot\)m is identified, which is distinctly different from the low-resistance strata above and suggests the presence of an unmined coal seam. Notably, a steep high-resistance \"bell-shaped\" area with resistivity around \(150\sim 180\)\(\Omega\cdot\)m is detected between 20 m and 90 m horizontally and 30 m to 75 m in depth, distinct from the surrounding medium-resistance strata. Based on the collected coal seam geological data and the fact that illegal mining has occurred in the area, this abnormal area should be a waterless void left behind after illegal mining of the coal seam. In the central section, L5, the inversion results mirror those of L2 in terms of the morphology and resistivity trends, with a similar gradual increase in resistivity with depth. The presence of a \"bell-shaped\" high-resistance region between 20 m and 90 m horizontally and a near-horizontal medium-resistance zone between 120 m and 400 m horizontally are consistent with the findings in L2. The differences in the contour line patterns reveal the potential  
Figure 14: Curve of fitting error decreasing with iteration times of high-resistivity fault valley model. Figure 13: Inversion results of high-resistivity fault valley model with lateral weighting factor of 0.5 and vertical weighting factor of 0.1.  
differences between the excavated and unexcavated coal seams. In the eastern section, L8, the vertical characteristics of the inversion results align with L2 and L5. However, notable differences include improved lateral continuity in the deep section and a northward displacement of the \"bell-shaped\" high-resistance area by approximately 20 m horizontal displacement to the north, with resistivity values around 150 \(\sim\) 380 \(\Omega\cdot\)m.  
In general, the inversion outcomes of the three surveyed lines exhibit overall similarity, yet nuanced discrepancies exist. The profile results of L2, L5 and L8 are shown in Figure 15. The primary distinction arises in the high-resistivity region located in the southern segment of the profile. Notably, while the high-resistivity zones of sections L2 and L5 bear a resemblance to each other, the high-resistivity region of section L8 displays both a horizontal displacement and a notably higher resistivity value. This variation is attributed to the presence of numerous intact coal pillars due to illegal mining activities along sections L2 and L5, resulting in a relatively limited mined-out area. Conversely, section L8 exhibits a higher degree of coal seam extraction, leading to a larger goat area and consequently yielding a higher resistivity value in the inversion results. To validate the accuracy of the detection findings, the drill hole ZK1 is positioned at a horizontal distance of 60 m on survey line L8.