## 6 Conclusions  
The article analyzes one of the most critical problems related to the daily operation of belt conveyors, which is the mistracking of the conveyor belt. A complete review of the causes of belt mistracking and the available but very limited methods for monitoring are provided. Experimental testing of the accuracy of new methods of detecting belt mistracking in real conditions is impossible due to the high risk of conveyor failure and belt damage, as well as the potential costs associated with them. For this purpose, a test rig was used to simulate the mistracking of the belt through an artificial, controlled difference in tension of the actuators of the tensioning device. By equipping the test rig with a set of sensors monitoring the basic operating parameters of the conveyor, the characteristics of normal and emergency operation were determined. Conveyor operation with lateral mistracking is characterized by increased electricity consumption, significant load on the drive units, additional forces in the station structure, and belt stresses and deformations as a result of friction of its edges. Using the available measuring devices (vibration sensors, thermal imaging camera, RGB camera and strain gauges on the belt tensioning actuators), characteristic data resulting from the mistracking of the belt were recorded--images in the visible and infrared bands as well as time signals. The recorded data was processed and analyzed in the context of developing a method for detecting and monitoring the mistracking of the belt with the greatest potential. Vibration monitoring of the conveyor pulley bearing housing detects lateral mistracking by analyzing the distortion of the vibration signal. At the moment of the mistracking of the belt, there is a sudden increase in vibration acceleration on one of the bearings as a result of asymmetric load. The detection may be based on detecting a sudden increase in the root mean square of the signal. The asymmetry of the bearing load is also a characteristic feature of the lateral mistracking. The method allows for the detection of potential failure conditions before the contact of the belt with the structure of the conveyor. However, the increase in the magnitude of the signal may be associated with other phenomena than belt mistracking, which makes the method ambiguous. Nevertheless, any increase in the recorded signal values is dangerous for the operation of the conveyor and should be immediately verified. The vision method based on RGB camera allows for monitoring of the position and displacement of the belt edge on the conveyor. Research has shown that thanks to the vision method, it is possible to detect changes in the belt edge position early, which completely eliminates the risk of belt damage. The great advantage of the method is its clearness, because only the mistracking is monitored, and other failure states of the components do not affect the result. The disadvantage of the solution is high sensitivity to image disturbances, which in mining conditions of conveyor operation result from significant dust, contamination of the belt and pulley, and acoustic vibrations. Figure 23: Eigenvalues of principal components. The thermal imaging method makes it possible to eliminate the disadvantages of the RGB vision method, because the image is analyzed only in the infrared range, and this partially reduces the impact associated with contamination and dust. The detection is based on measuring the rise in belt temperature caused by the friction phenomena on the conveyor belt structure. It does not allow for early detection of mistracking, but its result is a clear confirmation of the occurrence of this phenomenon. In addition, it allows monitoring of the sudden change in temperature of other elements within the pulley.