## 3 The Research Method Used
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Mine**} & \multicolumn{2}{c}{**Average Daily**} & \multicolumn{2}{c}{**Length of**} & \multirow{2}{*}{**Output per Meter**} & \multicolumn{2}{c}{**Intensity of**} & \multicolumn{2}{c}{**Number of Total**} & \multicolumn{2}{c}{**Average**} \\ \cline{2-5}  & **Output** & **Longwall Front** & **Pretary** & **Active Longwalls** & **Longwall Length** \\ \hline
1 & 6349 & 536 & 11.845 & 5 & 2.9 & 184.828 \\
2 & 6212 & 532 & 11.677 & 5.2 & 3 & 177.333 \\
3 & 6928 & 776 & 8.928 & 4.7 & 4.3 & 180.465 \\
4 & 5366 & 589 & 9.110 & 2.9 & 3 & 196.333 \\
10 & 5340 & 639 & 8.357 & 8.1 & 3.1 & 206.129 \\
17 & 6822 & 627 & 10.88 & 3.1 & 3.6 & 174.167 \\
20 & 8307 & 765 & 10.859 & 4.3 & 4.4 & 173.864 \\
23 & 3966 & 345 & 11.496 & 5.9 & 2.6 & 132.692 \\
24 & 9323 & 684 & 13.630 & 5.2 & 3 & 228.000 \\
25 & 8198 & 509 & 16.106 & 6.5 & 2.7 & 188.519 \\
27 & 4543 & 497 & 9.141 & 4.0 & 2 & 248.500 \\
30 & 7295 & 713 & 10.231 & 5.8 & 3.2 & 222.813 \\
36 & 8521 & 748 & 11.392 & 5.3 & 3.2 & 233.750 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Group 1 of mines. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Mine**} & \multicolumn{2}{c}{**Average Daily**} & \multicolumn{2}{c}{**Length of**} & \multirow{2}{*}{**Output per Meter**} & \multicolumn{2}{c}{**Intensity of**} & \multicolumn{2}{c}{**Number of Total**} & \multicolumn{2}{c}{**Average**} \\ \cline{2-5}  & **Output** & **Longwall Front** & **Pretary** & **Active Longwalls** & **Longwall Length** \\ \hline
1 & 6349 & 536 & 11.845 & 5 & 2.9 & 184.828 \\
2 & 6212 & 532 & 11.677 & 5.2 & 3 & 177.333 \\
3 & 6928 & 776 & 8.928 & 4.7 & 4.3 & 180.465 \\
4 & 5366 & 589 & 9.110 & 2.9 & 3 & 196.333 \\
10 & 5340 & 639 & 8.357 & 8.1 & 3.1 & 206.129 \\
17 & 6822 & 627 & 10.88 & 3.1 & 3.6 & 174.167 \\
20 & 8307 & 765 & 10.859 & 4.3 & 4.4 & 173.864 \\
23 & 3966 & 345 & 11.496 & 5.9 & 2.6 & 132.692 \\
24 & 9323 & 684 & 13.630 & 5.2 & 3 & 228.000 \\
25 & 8198 & 509 & 16.106 & 6.5 & 2.7 & 188.519 \\
27 & 4543 & 497 & 9.141 & 4.0 & 2 & 248.500 \\
30 & 7295 & 713 & 10.231 & 5.8 & 3.2 & 222.813 \\
36 & 8521 & 748 & 11.392 & 5.3 & 3.2 & 233.750 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Group 2 of mines. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Mine**} & \multicolumn{2}{c}{**Average Daily**} & \multicolumn{2}{c}{**Length of**} & \multirow{2}{*}{**Output per Meter**} & \multicolumn{2}{c}{**Intensity of**} & \multicolumn{2}{c}{**Number of Total**} & \multicolumn{2}{c}{**Average**} \\ \cline{2-5}  & **Output** & **Longwall Front** & **Pretary** & **Active Longwalls** & **Longwall Length** \\ \hline
5 & 6667 & 1041 & 6.404 & 3.4 & 3.9 & 266.923 \\
6 & 10,845 & 1027 & 10.56 & 4.1 & 4.2 & 244.524 \\
8 & 8585 & 851 & 10.088 & 3.2 & 3.5 & 243.143 \\
9 & 8059 & 984 & 8.190 & 4.1  
Further efforts to increase the effects of operations should be carried out for the designated four groups. The validity of this division is evidenced by the determined median unit cost of production for each of the diagnosed sets. The unit cost of production has a major impact on the profitability of mines. The amount of revenue is determined by the selling price of coal, over which mines have no influence, while the lowest possible production unit cost can be shaped by optimising production. Mines with the lowest cost are the leaders in production efficiency. The data in Table 6 were used to calculate the median cost, and the results of the calculations are summarised in Table 7 and Figure 3. Two of the four sets of mines group mines for which the median unit cost of production ranks below the median unit cost for all mines, while the next two sets are above the median. The result of this division can be used for further in-depth analysis and pro-efficiency measures.