## 4 Test Area in the Bw-4 and PW-1 Roadways  
Based on the results obtained from the numerical analysis and stability indicators, three test sections were designed in both roadways, with various support schemes applied. The support scheme for the first test section was, in both roadways, designed according to practical mine experience in maintaining the roadways behind the longwall face. The following two test sections were designed utilizing new support elements--Titan cable strand bolts with pre-tensioning (Figure 7a)-and the LPi steel arch support with a groove in the roof arch, which blocked the lower yoke and guided the frame arch sliding under their loading (Figure 7b). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{3}{*}{**Roadway**} & \multirow{3}{*}{**Chainage**} & \multicolumn{3}{c}{**Number of Cracks Is**} & \multicolumn{3}{c}{**Total Separationr**} & \multicolumn{3}{c}{**Range of Intensive**} & \multirow{3}{*}{\
\begin{tabular}{c} **Range of a** \\ **Crack Zone** \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} **ERMF** \\ **Class** \\ \end{tabular} } \\ \cline{3-10}  & & & **[-]** & & & & **[mm]** & & **[-]** & **[-]** \\ \hline \multirow{6}{*}{Bw-4} & 250 & 22 & III & 50 & III & 0.90 & II & 1.65 & III \\ \cline{2-10}  & 354 & 24 & III & 27 & II & 0.90 & II & 3.30 & II \\ \cline{2-10}  & 469 & 3 & I & 2 & I & 0 & I & 1.00 & I \\ \cline{2-10}  & 580 & 11 & II & 18 & II & 0.80 & II & 3.80 & II \\ \cline{2-10}  & 658 & 21 & III & 45 & III & 1.10 & II & 2.00 & III \\ \cline{2-10}  & 754 & 3 & I & 8 & I & 0.90 & II & 1.50 & I \\ \hline \multirow{3}{*}{PW-1} & 275 & 95 & VI & 976 & VI & 2.95 & IV & 10.30 & V \\ \cline{2-10}  & 358 & 89 & VI & 970 & VI & 1.90 & III & 10.35 & V \\ \cline{2-10}  & 570 & 34 & IV & 159 & VI & 2.50 & III & 10.25 & V \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Values of the ERMF index in tested roadways. Figure 7: New support elements: (**a**). Titan cable strand bolt (DSI Underground); (**b**). the LPi roof arch, with a groove blocking the lower yoke movement (on the right side—the zoom of element A), L—the lenght of the roof arch, R—the arch radius. Bw-4 had to be maintained, for ventilation reasons, behind the longwall face. The designed reinforcements were intended to ensure a required cross-section for the roadway during abutment pressures, and then goaf influence along the coal sidewall. The support schemes in Bw-4 for each test section consisted of a LP11/V32/4 steel yielding arch support (on test section III, the modified LP11/V32/4 type support with a groove was applied, L = 2.83 m--Figure 7b). The width of the roadway was 5.8 m, with a height of 4.025 m, and the frame spacing was 1 m. Additionally, the specific reinforcements on individual sections were as follows:  
* Test section I--two rows of hoisting joists V32-type (32 kg/m) fixed to the roof (every 1 m) by IR-6 cable strand bolts with a total length of 9 m; 3 Bullflex bags with a length of 1.5 m filled with cementitious material (Figure 8a);
* Test section II--two rows of hoisting joists V32-type with a length of 1.4 m fixed to the roof (every 2 m) by IR-5 injection cable strand bolts with a total length of 7 m; three steel rock bolts with a length of 2.5 m in each span between the arches; and a total of 3 Bullflex bags (Figure 8b);
* Test section III--two rows of hoisting joists V32-type with a length of 1.4 m fixed to the roof (every 2 m) by IR-5 injection cable strand bolts with a total length of 7 m; a total of three steel rock bolts with a length of 2.5 m in each span between the arches, with the outermost ones built every second span, depending on the presence of a cable strand bolt in the row; additional hoisting joist from the longwall side; rock lining (Figure 8c). A characteristic feature of the LP11/V32/4-type support applied in test section III is the modified method of the construction of the take-up device on the roof arch while maintaining the geometry of the LP11-type support.