Which class applies to mines employing not less than 25 underground and 50 surface personnel, to not more than 50 underground and 75 surface?

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

Answer: (C)

Classification of a mine is determined by the number of people working underground and on the surface. This approach uses specific thresholds to group mines by size, guiding safety programs and regulatory considerations. The range described—at least 25 underground and 50 surface, up to 50 underground and 75 surface—fits a mid-size category. This designation is Class C. Mines in this band are neither the smallest nor the largest, so they receive a middle-ground set of requirements appropriate for that workforce level. If a mine employs fewer people than the lower limits, it would fall into the smaller categories; if it employs more than the upper limits, it would be placed in the larger category. Therefore, this range corresponds to Class C.