Rapid growth of mining, construction and industrial activities is supported by automated high-performance machineries with sophisticated mechanism like hydraulic excavators. In this research paper, studies and researches have been carried out on the boom-arm-bucket robot system of a hydraulic excavator used especially on industrial, construction and mining sites. These studies provide general information about the technical specifications of this system. In order to improve the system's performances, finite elements stress analyses have been carried out. The studies begin with the design of the system using CAD (Computer Aided Design) software. Then a static force analysis of each component has been performed to determine the forces applied on them. The drawings were transferred to the finite element stress analysis software and all required steps for the analysis have been executed. The results obtained from the finite elements analysis revealed that the designed components were safe and subject to stress far below the assigned material's yield strength. However, the components were heavy and their weight could have been a disadvantage to their use. Design modifications have been performed in order lighten the components and at the same time to decrease their fabrication cost by decreasing the components thickness and changing the assigned material. These modifications also helped to improve their mobility.

The suspension system is an important component of a truck. It provides stability to the vehicle, maneuverability, and comfort. A lot of energy is dissipated through this system. In order to scavenge this dissipated energy, piezoelectric stacks can be installed in the system. One of the factors which significantly impacts the harvested power voltage is the location and connection type of the piezoelectric stack in the suspension system. The series connection between the suspension spring and the piezoelectric material has been preferred in this study for it will not affect the mechanical properties and performances of the system. The equivalent system stiffness is increased and the ride comfort is negatively affected in case of a parallel connection between the suspension spring and the piezoelectric stack. The equations of motion of the truck were derived. Harmonic excitation simulations have been run in the MATLAB Simulink software in order to assess the potential of the energy harvesting from truck suspension systems through piezoelectric stacks.

This research work is about the maintenance performances analysis and improvement of miscellaneous mining machinery and equipment used at the NORDGOLD SOMITA mining plant. The study started with a brief introduction to the mining activity. Then a general presentation of the TAPARKO mining site and its history was performed. Moreover, an overview of the equipment which is used on the mining site and its mechanical applications and utility was carried out. The maintenance plays a vital and essential role in the mining sector. A good maintenance management provides the plant with safe and effective equipment. One of the main issues in maintenance planning is to make sure that the planned maintenance tasks have positively influenced the productivity of the plant as expected. In order to achieve the desired performance at an optimal cost, the maintenance department has to keep monitoring the maintenance performances. This will help the company to reach the maximum profitability. Some maintenance key performance indicators exist and they allow the maintenance planners to monitor the maintenance effectiveness in a defined interval of time. Thus, a decrease of maintenance performances can be quickly detected and prompt corrective measures can be taken. Therefore, the necessary data was collected and an analysis of those indicators was accomplished. The obtained results revealed that. Last but not least, through a thorough examination of these results, some suggestions have been made in order to improve the mechanical maintenance practices in the mining sector.