OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 36 Mining

Section 541 Mine walls

Subsection 541(1)

The proper design and control of pit walls significantly affects worker safety and the ability of workers to extract ore. Consequently, any design or related operating procedure used to maintain pit walls must be certified by a professional engineer. Section 8 of the OHS Regulation requires procedures to be in writing and available to workers.

Subsection 541(2)

To minimize the risk of injury in a mine, the employer must ensure that

(a) undermining is prohibited since undermining of unconsolidated material can cause the material to collapse;

(b) working faces receive a good cleaning before being left to stand. Bench heights are designed and excavated to be less than 1.5 metres above the maximum height the excavation equipment can reach. It becomes difficult above this height to clean loose materials that can contribute to an overhang;

(c) the horizontal flat bench area within 2 metres of the working face crest must be kept clear of unconsolidated material. The height and stability of the bench above could dictate more than this specified 2 metre horizontal separation from the crest of the next lower working bench;

(d) unconsolidated material lying more than 2 metres from the crest of the horizontal bench is stabilized to prevent it from falling onto workers below; and

(e) safety berms are established at certain intervals along the height of the pit wall to catch rocks loosened from the face by weathering or vibration from blasting.