## Appendix A  
Figure A9: Some original samples and processed samples. (**a**) Original samples of the Jurassic sandstone collected from the borehole J3-1 of the Anju coal mine, with a diameter of 50 mm. (**b**) Original samples of the Shanxi Formation sandstone collected from the No. 12 mining area of the Tangkou coal mine, with a diameter of 50 mm. (**c**) Standard plunger rock samples of Jurassic sandstone with a diameter of 25.4 mm and heights of 25.4–50.8 mm, for porosity and permeability tests (From Anju coal mine). (**d**) Standard plunger rock samples of Shihezi Formation sandstone with a diameter of 25.4 mm and heights of 25.4–50.8 mm, for porosity and permeability tests (From Longyun coal mine). (**e**) Standard plunger rock samples of Shanxi Formation sandstone with a diameter of 25.4 mm and heights of 25.4–50.8 mm, for porosity and permeability tests (From Tangkou coal mine). (**f**) Standard plunger rock samples of Shanxi Formation sandstone with a diameter of 25.4 mm and heights of 25.4–50.8 mm, for porosity and permeability tests (From Anju coal mine).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample No.** & \(\mathbf{\Phi_{0}}\) **(\%)** & \(\mathbf{C_{1}}\) **(\%)** & \(\mathbf{C_{2}}\) **(\%)** & \(\mathbf{C_{3}}\) **(\%)** & \(\mathbf{C}\) **(\%)** \\ \hline Z30 & 40.1537 & 63.89 & 55.17 & 12.89 & 4.47 \\ Z25 & 40.1537 & 75.10 & 50.00 & 15.24 & 4.68 \\ Z32 & 40.6514 & 79.09 & 70.59 & 8.17 & 2.87 \\ Z46 & 39.1135 & 87.22 & 40.00 & 8.31 & 3.09 \\ Z11 & 37.3493 & 58.50 & 70.97 & 19.45 & 3.38 \\ Z41 & 39.2007 & 88.52 & 44.44 & 26.46 & 2.85 \\ Z42 & 39.2154 & 88.52 & 44.44 & 7.11 & 3.69 \\ Z13 & 39.5582 & 66.88 & 68.70 & 31.04 & 5.11 \\ X9-1 & 33.5619 & 64.25 & 83.33 & 42.37 & 1.67 \\ A0 & 32.6476 & 66.31 & 81.82 & 91.01 & 2.23 \\ X3 & 32.7753 & 67.96 & 85.71 & 49.87 & 1.79 \\ A4 & 34.2240 & 83.93 & 90.91 & 39.12 & 1.73 \\ A1 & 36.6514 & 79.09 & 58.82 & 41.87 & 2.16 \\ T8 & 33.4237 & 73.07 & 77.78 & 35.42 & 1.74 \\ S12 & 35.2225 & 75.87 & 94.12 & 105.20 & 1.78 \\ S18 & 35.5895 & 74.71 & 88.89 & 64.40 & 1.96 \\ S22 & 35.9758 & 81.93 & 92.31 & 72.18 & 1.63 \\ A5 & 34.9591 & 84.27 & 90.91 & 25.07 & 1.64 \\ S16 & 35.8773 & 83.28 & 83.33 & 57.33 & 1.63 \\ S10 & 35.4960 & 76.90 & 97.56 & 17.91 & 1.58 \\ S11 & 35.5895 & 76.68 & 96.39 & 27.62 & 1.60 \\ S17 & 36.4882 & 82.19 & 92.31 & 80.65 & 1.92 \\ S19 & 35.7801 & 79.04 & 93.33 & 81.86 & 1.83 \\ S15 & 35.6842 & 74.78 & 77.78 & 90.63 & 1.58 \\ S20 & 35.5895 & 76.12 & 82.35 & 56.45 & 1.46 \\ T4 & 29.5613 & 72.94 & 100.00 & 58.82 & 0.33 \\ T3 & 32.2131 & 71.75 & 98.90 & 23.12 & 0.70 \\ T13 & 33.0909 & 87.91 & 100.00 & 37.36 & 1.52 \\ T2 & 32.6056 & 71.48 & 96.77 & 86.21 & 0.48 \\ T21 & 34.9591 & 91.42 & 100.00 & 30.40 & 1.37 \\ A9 & 34.9505 & 85.69 & 100.00 & 14.76 & 1.38 \\ A7 & 35.5053 & 71.27 & 98.04 & 12.45 & 1.31 \\ H11 & 35.8773 & 91.64 & 100.00 & 98.21 & 0.41 \\ H6-2 & 36.0756 & 91.68 & 100.00 & 80.81 & 0.40 \\ \hline \hline \end{tabular} \(\Phi_{0}\)—Initial porosity (%); C\({}_{1}\)—Visual compaction rate (%); C\({}_{2}\)—Visual cementation rate (%); C\({}_{3}\)—Visual dissolution rate (%); C—Comprehensive diagetic coefficient (%).  
\end{table}
Table 4: The content of clay matrix, the sorting coefficients and grain sizes of deep-mine sand-stone.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline