$6.$ You have been hired as a ventilation engineer by YYY Mining Ltd$.,$ a company that operates several underground mines extracting valuable minerals. Recently, the management team has raised concerns about the increasing operational costs associated with the mine's ventilation system. They are looking for ways to optimize the ventilation costs while maintaining or improving safety standards and operational efficiency. Your task is to perform an economic analysis of the current ventilation system, identify cost$-$saving opportunities, and propose a detailed plan to achieve these savings without compromising on air quality and safety.