What is a primary disadvantage of using line brattice in continuous miner operations?

Using line brattice in continuous miner operations has the primary disadvantage of not effectively conducting air to the face where it is needed. In underground mining, proper ventilation is critical to ensure that fresh air reaches the working face where miners are operating. Line brattice, while it serves the purpose of directing airflow, can sometimes be less effective in maintaining proper air flow due to its positioning and physical characteristics.

If the line brattice is not installed correctly or if it is damaged, it may not facilitate the necessary airflow, leading to inadequate ventilation. This can result in a buildup of harmful gases and insufficient oxygen for workers, thereby impacting safety and operational efficiency. Effective ventilation is essential for worker health and productivity, making this aspect of line brattice use particularly significant in continuous miner operations.

The other options highlight potential advantages of line brattice, such as ease of extension, increased airflow efficiency, and cost-effectiveness, but they do not address the critical challenge of ensuring that the air actually reaches the miners at the face, which is fundamental for safe mining operations.