When advancing toward a suspected water pocket, boreholes must be drilled at least eight meters ahead of a face in which direction?

• A. Longitudinal
• B. Lateral
• C. Vertical
• D. Diagonal

Answer: (B)

The main concept is to detect water pockets before the face is advanced by probing the rock to the sides of the heading. Boreholes are drilled in the lateral direction, meaning to the side of the heading, at least eight meters ahead of the face. This orientation gives a cross-sectional check of conditions ahead and to the sides, so you can locate any potential water and establish drainage or other controls before breaking into the pocket. The eight-meter lead provides a safety margin to implement changes—such as stopping, dewatering, or stabilizing measures—before water can enter the working area. Drilling in other directions isn’t as effective: a longitudinal borehole would chase water along the face but might miss pockets off to the sides; a vertical borehole tests rock above or below rather than the forward path; a diagonal borehole blends the tests and may not reliably reveal a pocket ahead.