The mineralogy and geochemistry of No. 9 coal seam within the Taiyuan Formation of the Hengcheng mining area, Ningdong coalfield, were studied to determine the distribution, occurrence, and enrichment characteristics of critical elements in coal and to evaluate its potential for comprehensive utilization. The results revealed that: ① No. 9 coal in the Hengcheng mining area is characterized by high vitrinite content, extremely low- low ash yield, and medium- high sulfur content. ② The dominant mineral in the coal is kaolinite, occurring as cell fillings, lenticular shapes, and thin layers. The coal seam floor mainly consists of quartz, kaolinite, and muscovite, which are mainly of clastic origin. ③ Major elements in the coal seam are mainly SiO2 and Al2O3. The coal exhibits slight enrichment in Li, Zr, Nb, Hf, Pb, and Th. Li, Pb, and Th are mainly hosted by kaolinite, Zr and Hf are found in zircon, and Nb is present in kaolinite and anatase. The No. 9 coal seam in this mining area formed in a tidal flat- lagoon environment affected by seawater. The lower part of the coal seam developed in a low swamp environment characterized by limited iron source supply, while the upper part formed in a high swamp environment with a severe iron source deficiency. This resulted in a distinct sulfur distribution: pyrite sulfur dominates the lower coal seam, whereas organic sulfur is prevalent in the upper part. The detrital material in the coal mainly originates from two sources: the Yinshan ancient land, which contributed Proterozoic terrigenous detrital material, and the Alashan block, which supplied detrital material from the early Carboniferous. The enrichment of critical elements such as Li, Zr, and Nb in the coal is mainly controlled by the input of alkali- peralkaline materials. Water/rock interactions also contribute to the activation, migration, and redistribution of these critical elements. The Li2O content in coal ash exceeds the cut- off grade, and REO, Ga, and Zr are close to the corresponding cut- off grade. Therefore, comprehensive development and utilization of Li- Ga- Zr- REY resources from this coal seam is a promising prospect.