## 3 Results
### Structural Equation Model  
The grouped data in the form of three databases (the database resulting from the survey on working conditions, the database resulting from the collection of data on safety and health factors at work, and the database on downtimes/failures of machines), which  
Figure 1: A structural equation model that includes ergonomic and contextual factors affecting the risks of mining machinery. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Technical** & **Electrical** & **Management** & **Organizational** & **Level of** \\  & **Downtimes** & **Downtime** & **(Misuse)** & **Downtime** & **Danger** \\ \hline Number of & & & & & \\ downtimes & & & & & \\ (some of the & & & & & \\ downtimes & & & & & \\ had one or & & & & & \\ more causes at & & & & & \\ the same time & & & & & \\ \hline Sum (minutes) & 259,250 & 39,510 & 44,225 & 57,380 & 57,647 \\ \hline Average & 31.67379 & 55.96317 & 170.7529 & 74.32642 & 6.154922 \\ \hline Median & 5 & 30 & 60 & 30 & 6 \\ \hline Maximum & 1200 & 480 & 600 & 7000 & 10 \\ \hline Minimum & 0 & 5 & 5 & 5 & 1 \\ \hline Standard error & 90.5483 & 48.16778 & 218.7768 & 338.8762 & 1.580656 \\ \hline Variance & 8198.994 & 2320.135 & 47.863.29 & 114,837.1 & 2.498474 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Descriptive statistics for mining machine downtimes. were described in the previous chapter, the structural equation modelling method was carried out to establish the cause-and-effect relationships between the observed variables (the SPSS AMOS ver 21 software package was used). Firstly, a correlation matrix was performed for each data group; these matrices are provided in Supplementary Materials. For further analyses, only the variables with significant correlation coefficients were used. Secondly, three individual models were developed in structural equations: one for working conditions (verified in [67]), one for safety and health at work, and one for the machine downtime causes. Finally, all three models were joined into one model. The construct EO (ergonomic characteristics of the system, operator-workplace) represents the group of constructs that are related to the ergonomic adjustment of operator workplace adjustments. The construct SHW (safety and health at work) represents the group of constructs that are related to the contextual factors originating from the safety climate in the organization. Constructs RM1 and RM2 are related to the risk of possible mining machine failure. The cause-and-effect relation between these four constructs was the subject of plenty of testing and searching for a structure that finally provided satisfactory results (parameters \(\chi^{2}\), df, GFI, AGFI, NFI, CFI, TLI, RMSEA). These results are given in Supplementary Materials (Supplementary Materials--Figure S1: Analysis summary, esimates and model fit), where, for the final model, there was significance (\(p\)-value) between constructs. The final structural equation model was obtained by SEM analysis, as shown in Figure 1, where the labels have the following meanings from constructs and indicators. Constructs and their indicators in the model are as follows:  
ES--Ergonomic adjustments of the seat of the mining machine:  
Q1 Rating of the height adjustability of the mining machine operator's seat;  
Q2 Rating of the horizontal adjustability of the mining machine operator's seat;  
Q3 Assessment of the ergonomic suitability of the seat according to the height of the mining machine. EC--Ergonomic adaptations of the control organs of the mining machine:  
Q4 Assessment of the adjustability of the location of the control organs of the mining machine;  
Q5 Evaluation of the controllability of the mining machine's control organs;  
Q6 Evaluation of the possibility of easily reaching the controls or levers;  
EE--Ergonomic evaluation of the working conditions of the mining machine.