OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 36 Mining

Section 599 Stopping

Subsection 599(1)(a)

A pull cord that stops a conveyor in an emergency is a very important and reliable safety device. In almost all conveyor galleries, whether on the surface or underground, workers are required to travel beside the running conveyor either to supervise, maintain, monitor or clean.

When working around moving equipment associated with a conveyor, there is always the potential that a worker will fall into or find their clothing caught in the conveyor system. The conveyor must therefore be capable of being stopped immediately to prevent serious injury. Accessible pull cords make this possible.

To ensure it remains effective, the pull cord system must be tested frequently and adjusted as necessary.

Subsection 599(1)(b)

The requirement to manually reset and restart a stopped conveyor ensures the conveyor is not restarted until the area where the pull cord was tripped has been visually inspected and remedial actions taken.

Subsection 599(2)

In mines where material is conveyed on a series of conveyors, a sequential control is installed to stop all affected belts before their individual continuation could cause problems by dumping material and perhaps burying transfer points. This process is triggered by the use of sensor switches. A minimum of two are required:

(i) Belt-slip switch – Friction caused by the slipping of a conveyor belt drive can generate heat that can contribute to fire and explosion hazards. This hazard is mitigated by application of a speed-sensitive “belt-slip” switch to shut down the conveyor when the belt suddenly slows to a predetermined speed.

(ii) Blocked chute – In a series of conveyors the transfer chute directing mineral from one belt to the next can become blocked, spilling coal over the surrounding area, working areas and possibly onto personnel. This hazard is mitigated by using blocked chute switches which detect an accumulation of mineral in the chute and automatically stop the delivery conveyor.