In mining terminology, what is a rib?

• A. The floor boundary of a mine opening.
• B. The sidewall of a mine opening along the coal seam.
• C. The roof of a mine opening.
• D. A ventilation duct along the seam.

Answer: (B)

Rib refers to the sidewall of a mine opening that runs along the coal seam. When roadways are driven parallel to the seam, the material forming the boundary on each side—the wall next to the coal and rock—is called the rib. This is different from the floor, which is the bottom boundary, and the roof, which is the top boundary above the seam. A ventilation duct along the seam would be a separate feature used for air movement, not the rib. Ensuring proper rib support helps prevent rib falls as miners advance along the seam.