Lesson 2/Learning Event 2
Slightly Inclined Rocks. Where the rock mass contains parallel layers or fracture surfaces which are
slightly inclined, the quarry face should be oriented parallel to the strike of the rock. In this way work
may proceed up the dip of the sloping rock surfaces. The bedding or fracture planes can thus be used to
help maintain an even, well-drained quarry floor.
Steeply Inclined or Folded Rocks. Where rocks are folded or contain steeply-inclined layers or
fractures, the quarry face should be oriented at right angles to the strike of the rock structure. This eases
the problem of maintaining a vertical face and reduces drilling and safety hazards. If the quarry face is
oriented parallel to the strike of the rock (with rock layers or fractures inclined toward or away from the
face), problems with toes, overhangs, rock-falls, and rock sides will extend along the entire width of the
working area along the face (Figure 5).
Vertical Rocks. Where rock layers are essentially vertical, the quarry face may be worked either parallel
to strike (to aid in maintaining an even face) or perpendicular to strike (to aid in maintaining even quarry
walls). Blasting is more efficient when the face is parallel to strike.
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