SLIMANI YounesBENHAMIDA LyliaBOUSTILA Amir (Encadrant)2025-12-022025-12-022025http://dspace.ensti-annaba.dz:4000/handle/123456789/1030This thesis focuses on optimizing the underground ventilation system of Chaabet El-Hamra mine using a two-stage approach: passive and active techniques. Passive optimization included ometric improvements such as the lining of KO and YK galleries, which significantly reduced resistance and pressure loss. Active optimization involved the installation of a secondary fan in the KO branch, resulting in a local power reduction of over 30% and an overall system energy savings of 3.4 kW. The combined strategy improved airflow balance and energy efficiency across the network.enThesis