What is the maximum underground development distance before mechanically operated fans are required?

The maximum underground development distance before mechanically operated fans are required is 200 feet. This regulation is in place to ensure adequate ventilation in underground mining operations. Beyond this distance, natural ventilation may not be sufficient to maintain air quality and remove harmful gases and dust, making the use of mechanically operated fans necessary to provide a consistent and reliable air supply to the workers. Proper ventilation is critical for safety and health in underground mines, as it helps prevent the buildup of toxic gases and provides fresh air to the workers, thereby reducing the risk of respiratory issues and improving overall working conditions.

In the context of this question, the other distances listed either fall short or exceed the regulatory requirement, which is specifically set at 200 feet. Maintaining adherence to this guideline is essential for the health and safety standards within the mining industry.