## 2 Cases of SCWIDs
### Details of SCWID in Working Face 322 of Qidong Coal Mine  
To further understand the detailed process of SCWID, the accident that occurred in 322 working face of Qidong coal mine is described below. 322 working face is the first mining face of Qidong Coal Mine. The starting and ending elevation of the working face is from \(-420\) m to \(-540\) m. The working face is 800 m long and 150 m wide. It is an inclined strip fully mechanized working face. The average thickness of the coal seam is 2.5 m and the average dip angle is \(10^{\circ}\). According to China's \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Working** & \begin{tabular}{c} **Width and** \\ **Mining Height** \\ **of Working Face** \\ **(m)** \\ \end{tabular} & **Supports Model** & \begin{tabular}{c} **Serial No.** \\ **and Time of** \\ **SCWID** \\ \end{tabular} & \
\begin{tabular}{c} **Bedrock** \\ **Thick-** \\ **ness** \\ **(m)** \\ \end{tabular} &
\begin{tabular}{c} **Water** \\ **Pres-** \\ **(MPa)** \\ \end{tabular} & **Disaster** & **Situation** \\ \hline
322 & 150/2.5 & ZZ4400-17/35 & 1/2001.11.25 & 66 & 3.7 & Dip advance &
\begin{tabular}{c} All supports \\ crushed, \\ 1520 m\({}^{3}\)/h \\ \end{tabular} \\ \hline
3221 & 150/2.5 & \begin{tabular}{c} Single Hydraulic \\ Prop \\ \end{tabular} & 2/2002.09.16 & 99 & 3.9 & \
\begin{tabular}{c} Dip advance \\ 71 m \\ \end{tabular} &
\begin{tabular}{c} 100 props crushed, \\ 239 m\({}^{3}\)/h \\ \end{tabular} \\ \hline
7114 & 174/2.6 & ZZ4400-17/35 & 4/2004.07.29 & 72 & 3.7 & \begin{tabular}{c} Dip advance \\ 44 m \\ \end{tabular} & \begin{tabular}{c} 116 supports \\ crushed, 71 m\({}^{3}\)/h \\ \end{tabular} \\ \cline{3-7}  & & 5/2005.01.16 & 80 & 3.7 & \
\begin{tabular}{c} Dip advance \\ 184 m \\ \end{tabular} &
\begin{tabular}{c} 22 supports \\ crushed, 169 m\({}^{3}\)/h \\ \end{tabular} \\ \hline
7112 & 85/2.6 & ZZ4400-17/35 & 6/2006.10.01 & 128 & 3.9 & \
\begin{tabular}{c} Dip advance \\ 244.5 m \\ \end{tabular} &
\begin{tabular}{c} 35 supports \\ crushed, 85 m\({}^{3}\)/h \\ \end{tabular} \\ \hline
7130 & 88-134/3.7 & ZY6000/18.5/38 & 7/2009.05.03 & 48 & 3.2 & \begin{tabular}{c} Strike advance \\ 150 m \\ \end{tabular} & \begin{tabular}{c} 23 props shrunk, \\ 91 m\({}^{3}\)/h \\ \end{tabular} \\ \cline{3-7}  & & 8/2009.06.07 & 43 & 3.2 & \begin{tabular}{c} Strike advance \\ 343 m \\ \end{tabular} & \begin{tabular}{c} 23 props shrunk, \\ 920 m\({}^{3}\)/h \\ \end{tabular} \\ \cline{3-7}  & & 9/2009.06.29 & 47 & 3.2 & \begin{tabular}{c} Strike advance \\ 450 m \\ \end{tabular} & \begin{tabular}{c} 30 props shrunk, \\ 260 m\({}^{3}\)/h \\ \end{tabular} \\ \cline{3-7}  & & 10/2009.08.29 & 44 & 3.2 & \
\begin{tabular}{c} Strike advance \\ 56 m \\ \end{tabular} &
\begin{tabular}{c} 6 props shrunk, \\ 850 m\({}^{3}\)/h \\ \end{tabular} \\ \hline
6130 & 126/1.67 & ZY4000-09/21 & 11/2009.09.13 & 45 & 3.2 & \begin{tabular}{c} Strike advance \\ 343 m \\ \end{tabular} & \begin{tabular}{c} 16 supports \\ crushed, 60 m\({}^{3}\)/h \\ \end{tabular} \\ \cline{3-7}  & & 12/2009.10.24 & 42.5 & 3.2 & \begin{tabular}{c} Strike advance \\ 397 m \\ \end{tabular} & \begin{tabular}{c} 2 supports \\ crushed, 24 m\({}^{3}\)/h \\ \end{tabular} \\ \cline{3-7}  & & 13/2009.11.14 & 43 & 3.2 & \begin{tabular}{c} Strike advance \\ 469 m \\ \end{tabular} & \begin{tabular}{c} 47 supports \\ crushed, 53 m\({}^{3}\)/h \\ \end{tabular} \\ \cline{3-7}  & & 14/2010.01.24 & 68.1 & 3.2 & \
\begin{tabular}{c} Strike advance \\ 571 m \\ \end{tabular} &
\begin{tabular}{c} 6 supports \\ crushed, 70 m\({}^{3}\)/h \\ \end{tabular} \\ \hline
7121 & 129/1.96 & ZY5000-13/28 & 15/2009.11.24 & 72 & 3.7 & \begin{tabular}{c} Strike advance \\ 358 m \\ \end{tabular} & \begin{tabular}{c} 40 supports \\ crushed, 50 m\({}^{3}\)/h \\ \end{tabular} \\ \cline{3-7}  & & 16/2010.07.24 & 113 & 3.7 & \
\begin{tabular}{c} Strike advance \\ 675 m \\ \end{tabular} &
\begin{tabular}{c} 8 supports \\ crushed, 30 m\({}^{3}\)/h \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}