What factors determine the mine resistance?

The correct choice identifies a comprehensive set of factors that directly influence mine resistance. In mining operations, the resistance within airways, often referred to as airflow resistance, is largely determined by physical characteristics as well as airflow dynamics.

The area, perimeter, and length of airways are crucial because they define the geometry through which air will flow. Larger cross-sectional areas typically reduce resistance, while longer or more convoluted pathways increase it. Additionally, the velocity of the airflow impacts resistance; the faster the air moves through a given airway, the more friction it will encounter against the walls, affecting the overall resistance.

The coefficient of friction is also a key factor, as it quantifies how much resistance is generated from the interaction between the air and the surfaces of the airway. This coefficient can vary depending on the surface material of the airway, influencing the efficiency of airflow and the effectiveness of ventilation systems in the mine.

Together, these factors create a detailed picture of mine resistance, which is essential for effective ventilation management and ensuring safety and health standards are met within the mine environment.