## 3 Results and Discussion
### Quantitative Analysis
#### 3.2.2 Detailed Analysis  
The main objective of the analysis was to identify bunkers in which the receiving bins are most prone to failure. Therefore, durability analysis requires the receiving bins to be assigned to the individual bunkers. Figure 4 shows the locations of bunkers (1-15) within the structure of the ore transportation system, along with the indicated mining units (I-VI) and the ore-flow routes. Table 3 lists the repairs performed for bunkers 1-15 over the analyzed 30-month period. The last column in Table 3 contains number-based failure indicators per single receiving bin. The significant range of this indicator (1-17) results from different operating conditions, and justifies the durability analyses of the bin elements with respect to a particular receiving bin. The number-based failure indicator provides information on the frequency of repairs for the entire receiving bin. From the perspective of managing repairs and maintenance, or planning modifications, it is very important to know which elements of the receiving bin and in which bin become most frequently worn. Such analyses were possible owing to the listing of repairs and replacements by individual bin elements (in accordance with Figure 2). Over the investigated period, the majority of service works, i.e., 28, 23, and 22, were performed on bins 2, 10, 9, and 6, respectively (Figure 12). These bins have a capacity exceeding 1000 Mg of copper ore. The trough linings A were most frequently replaced in  
Figure 11: Histograms of time between repairs of (**A**–**C**) elements in mining unit named III. Figure 10: Histograms of time between repairs of (**A**–**C**) elements in mining unit named II. bunker 10, the vertical sealings B--in bunker 6, linings in the hopper C--in bunker 8, and front linings in the hopper D--in bunker 13. This is due to the operating characteristics of the particular type of the receiving bin. The design of the receiving bin determines the flow of the ore through its front part, and therefore the element A becomes more worn up to half its length. The case is similar for the elements B and C. The ore also passes down the front wall D towards the discharge opening. Therefore, the elements A, B, C, and D are most prone to abrasive wear. Repairs of the elements E, F, and G were sporadic. The lining on the back wall of the hopper H was replaced only three times in bunker 11. Analyses of the number of individual replacements together with the identified number-based failure indicator suggest that bunkers 3, 2, and 10 are most prone to failure. They show the highest number of repairs per one receiving bin. Importantly, the above-mentioned bunkers are located in the mining units in which the main haulage conveyors are also situated, and these have the highest daily capacities. The smallest value of the number-based failure indicator is observed for bunkers 7 and 14. In the case of bunker 14, this fact is due to its location in the transportation system, and the resulting smaller amount of the ore transported on the unit conveyors. Importantly, despite one of the highest amounts of the passing ore, bunker 7 showed a very low failure indicator, which directly results from the fact that it has as many as eight receiving bins. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & **A** & **B** & **C** & **D** & **E** & **F** & **G** & **H** & & \\ \hline
1 & 2  
An additional analysis, which was conducted separately for each of the mining units indicated in Figure 4, focused on the service works performed in order to repair the operating failures. The greatest number of service works on the receiving bin was performed in unit II, which receives the cumulative stream of ore transported on the main haulage conveyors (Figure 13). Unit IV also showed a significant number of repairs per one bin. This case can also be accounted for by the amount of the transported ore mass, but most importantly by a significantly variable lithology and high moisture content (Figure 14).