Certain Carboniferous- Permian coal seams in North China possess significant concentrations of the strategic metal gallium. This study investigates the possibility of using reflected wave responses to interpret gallium content in a shallowly buried, ultra- thick coal seam. Using the No. 6 coal of the Heidaigou mine in the Jungar coalfield as a case study, this paper characterizes the vertical heterogeneities of the material composition, gallium content, host minerals, and elastic parameters in the coal seam. This characterization employed a comprehensive approach combining sample measurement, seismic rock physics modeling, principal component analysis, and other methods. Meanwhile, correlations between the kinematics, dynamics, and AVO responses of the reflected wave from the No. 6 coal seam and its distinct mineral enrichment types were examined through seismic forward simulation, seismic attribute analysis, and AVO analysis. The results show that the No. 6 coal seam can be divided into three sublayers according to the coal quality and the mineral enrichment. The middle and upper sublayers, characterized by their ultra- thickness, reveal boehmite as the main host mineral for gallium, exhibiting a strong, linear correlation with gallium content. Additionally, a positive correlation was observed between the sublayers elastic parameters, including P- wave impedance, and the contents of boehmite and gallium. Analysis indicates that when the fluid saturation state is known, a cross- plot of the two- way travel time difference between roof and floor reflected waves and seismic amplitude can effectively distinguish the mineral enrichment types. Moreover, the cross- plot of AVO intercept and gradient attributes derived from the coal seams roof and floor reflections enables the simultaneous discrimination of both the fluid saturation state and mineral enrichment type. This approach presents an effective method for interpreting gallium content in the coal seam. The research provides valuable insights and a practical methodological framework applicable to the exploration of gallium and other strategic metals in shallowly buried, ultra- thick coal seams.