Milling is among the most energy-consuming technological stages of copper ore processing. It is performed in mills, which are machines of high rotational masses. The start of a mill filled to capacity requires appropriate solutions that mitigate the overloading. One method for increasing the energy efficiency of ball mills is to optimize their drive systems. This article looks at two variants of drive systems with efficiencies higher than the already existing solutions. The first variant is a low-speed synchronous motor with permanent magnets without a gearbox, and the second variant is an asynchronous high-efficiency motor with a gearbox and a fluid coupling. The energy performance analysis of the three solutions was based on the average energy consumption indicator per mass unit of the milled material and on the energy consumption per hour. The investigations required models of the drive systems and analyses with the use of the Monte Carlo methods. The highest energy efficiency is observed in the case of the solution based on the permanent magnet motor. However, the drive system with the high-speed motor offers a gentle start-up possibility owing to the fluid coupling.

The transverse vibration frequency of conveyor belts is an important parameter describing the dynamic characteristics of a belt conveyor. This parameter is most often identified from theoretical relationships, which are derived on the basis of an assumption that the belt is a stationary elastic string. Belt vibrations have a number of analogies to other tension member systems, such as, for example, power transmission belts. Some research findings suggest that in the case of a limited length of the belt section, a more accurate description of its vibration can be obtained with a beam model rather than with a string model. Experimental research has so far mostly revolved around measurements of stationary belts. This article presents the results of vibration measurements performed for a moving belt and obtained for various operating parameters of the conveyor, as well as for several configurations of the distance between idler supports. The analysis was conducted on a moving steel-cord belt. Belts of this type are commonly used in the majority of mines and industrial plants. The measurement results were compared with the model of a string and with the model of a beam in tension. Both of the theoretical models allowed for the belt speed, whose influence was demonstrated in both theoretical calculations and experimental tests to be negligible. On the other hand, the tensile force in the belt was observed to have a significant impact on the vibration frequency. Depending on the idler spacing, the measurement results are approximate to those of the beam model or of the string model. For spacing smaller than 1.6 m, the belt shows properties approximate to an elastic beam, while for spacing greater than 1.6 m, the belt behaviour can be better represented through a string model. A beam model is, therefore, more applicable in analyses of vibrations in the upper strand of the belt, while a string model is more useful in analyses of vibrations in the lower strand.

Belt mistracking is one of the most dangerous and costly failures of belt conveyors. This phenomenon can lead to complete damage to the conveyor belt, increased demand for electricity from the drive, accelerated wear of route elements, and poses a fire hazard. The article presents the most important causes and ways to detect belt mistracking. Based on the tests carried out at the laboratory test rig, the mechanical and operating parameters of the electric drive of conveyor operation burdened with the problem of lateral running off for the tested belt were compared. The mistracking causes a sudden, differentiated increase in the resistance to movement of the machine, which directly affects the recorded values of forces in the drive system and tensioning mechanism and increases the electrical energy consumption of the drive motor. Belt run monioring based on these parameters is not precise, because there are many other factors on the conveyor route, potentially responsible for the increase in recorded currents and forces. The paper presents an analysis of the possibility of using three, non-contact methods directly monitoring the lateral run-off of the belt, based on vibration measurements of conveyor pulley bearing, RGB images, thermal imaging and measuring the compressive force on the tensioning device.

In the material transfer area, the belt is exposed to considerable damage, the energy of falling material is lost, and there is significant dust and noise. One of the most common causes of failure is transfer chute blockage, when the flow of material in the free fall or loading zone is disturbed by oversized rock parts or other objects, e.g., rock bolts. The failure of a single transfer point may cause the entire transport route to be excluded from work and associated with costly breakdowns. For this reason, those places require continuous monitoring and special surveillance measures. The number of methods for monitoring this type of blockage is limited. The article presents the research results on the possibility of visual monitoring of the transfer operating status on an object in an underground copper ore mine. A standard industrial RGB camera was used to obtain the video material from the transfer point area, and the recorded frames were processed by a detection algorithm based on a neural network. The CNN autoencoder was taught to reconstruct the image of regular transfer operating conditions. A data set with the recorded transfer blockage state was used for validation.

This article performs a comparative analysis of noise generated by conveyor belts with different design parameters. The study was conducted for belts with the same tensile strength, differing in the physical parameters of the cover rubber. Noise emission measurements were performed on a laboratory belt conveyor. The test on the stand allowed for the determination of the noise emission as a function of variable operating parameters: the tensioning force and linear speed of the belt. Research results indicated a significant impact of speed on the emitted noise. The effect of belt tension on noise emission is small, and it is definitely less significant than the effect of linear speed. The results also show that it is possible to select a conveyor belt that emits less noise under the same operating conditions. The analysis of the results allowed us to determine the impact of the physical parameters of the belt covers on the emitted noise.

The transverse vibration of conveyor belts is a crucial aspect in their proper and safe design, as the correct determination of vibration frequencies is essential to avoid unsafe operating conditions and premature wear of components. This study presents the Moving Compressed Beam (MCB) transverse vibration model, that is based on the interpretation of a conveyor belt as a beam known from the literature. This approach allows you to include in the model the transverse flexural rigidity of a troughed belt-a parameter that is closely related to the belt geometry. While not commonly used in engineering practice, the MSB model was compared with other models during the laboratory tests based on changing of trough geometry. This study emphasizes the significance of considering the transverse flexural rigidity of conveyor belts during the design process, and the MCB model which offers a promising approach in aspect of vibration control.