Which class applies to mines employing a total of not more than 25 underground and 50 surface personnel?

• A. Class A
• B. Class B
• C. Class C
• D. Class D

Answer: (D)

Mines are grouped by how many people work there, so the safety rules match the size of the operation. When an operation stays at or below 25 underground workers and at or below 50 surface workers, it falls into the smallest class. This means it’s subject to the lighter requirements of that class rather than the stricter rules that apply to larger operations. The important point is that both limits must be met—if either the underground count or the surface count goes above its limit, the mine moves into a higher class with tougher safety and regulatory demands. So a mine with not more than 25 underground and not more than 50 surface personnel fits the smallest-class criterion.