| MSHA's Accident Prevention Program
Working Near the Edge
Beware of Soft Areas;
Recent accidents show the need for extra care when working near the edge of a highwall or slope.
|Accident No. 1: A drill toppled over a highwall, crushing the driller, when the support jack near the edge of the highwall sank into soft, unconsolidated material as the tower was being raised.|
|Accident No. 2: A dragline toppled into the pit when the soft soil it was sitting on gave way as the operator swung a load of material.|
When operating equipment near the edge of a slope, keep the following points in mind:
- Before setting up, check the top
and face of the slope for indications - such as rutting, cracking,
sliding, or slumping - that the material near the edge may be too weak
to support the equipment.
- Be especially alert when ground
conditions change to a softer or weaker material. Uncompacted or cast
spoil, for example, may be loose and contain voids.
- Position equipment perpendicular to
the edge of the slope to provide better stability should a portion of
the edge give way.
- Be alert for signs of movement or
inadequate bearing as the equipment is being positioned and during
operation. Check level sensors frequently.
- Use bearing pads or blocking to provide adequate bearing-area when the ground is soft. Make sure blocking is readily available wherever soft conditions may be encountered.
- Check the pads for excessive penetration into the ground as the load is applied;
- Extend the jacks just enough to level the equipment, keeping the equipment as low to the ground as possible; and
- Avoid using the jacks in their fully-extended position.
|MSHA Video Clip|
Working Near the Edge - Beware of Soft Areas; Stay Perpendicular"
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