What is the risk related to inadequate ventilation in coal mines?

Inadequate ventilation in coal mines significantly contributes to the risk of methane accumulation. Methane is a colorless, odorless gas that can be released during the mining process. If ventilation systems are insufficient, methane can build up in the mine, creating an explosive environment.

Effective ventilation is crucial not only to dilute methane concentrations but also to provide fresh air to miners. When proper airflow is not maintained, methane levels can reach dangerous thresholds, posing a serious safety risk of fires and explosions, which can have catastrophic consequences for both workers and the mine's infrastructure.

While dust inhalation is also a severe concern in mines, it primarily results from insufficient dust control measures rather than a lack of ventilation. Similarly, visibility issues may arise from dust but do not relate directly to ventilation quality. Rock falls can occur due to geological instability or poor engineering practices but are independent of the ventilation system. Thus, the primary risk connected to inadequate ventilation is the potential for methane accumulation, making it the correct answer.