Recent learnings

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Transcript Recent learnings

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Crane incidents in Western Australia –
Recent learnings
1. Power failure – testing runaways
Power failure – testing – learnings
• Emergency stop devices do not always sufficiently
simulate conditions under a power failure
• Depending on how the power failed, this can lead to
a voltage “spike”
• Persons performing crane load tests require
adequate testing criteria, and appropriate training to
apply these criteria
2. Deflection and/or alignment requirements –
Deflection and/or rail alignment requirements are as
defined by:
• AS 1418.18 section 5.13 for structural deflections
• AS 1418.1 table 7.20.9 for the rail alignment
DMP has identified mine sites with failed rails and rail
fixings, primarily associated with misalignment and
deflection incompatibility.
3. Wind loading
Uncontrolled movements of cranes due to wind load ‒
• Designs not considering correct loading or factors
specified in AS 1170.2
• Crane manufacturers not understanding design
• Sites not following the requirements of design
Wind runaways – requirements
AS 1170.2 , section 2.3 states:
AS 1418.1, section 2.2 states:
AS 1170.0 table F3
AS 1170.2 table 3.1
4. Electrical isolation issues
Regulation 5.29 Isolation of equipment
Each responsible person at a mine must ensure that –
electrical equipment at the mine is provided with full
current isolating devices capable of being secured in
the isolating position
Typical arrangement of electrical isolation
AS 1418, figure 8.10.2
Recommended actions for isolation
From AS 1418.1
… safety is frequently introduced by making the stop buttons latch
in the open state, mechanically and by requiring a reset by a start
button to re-establish the contactor independently of the reset of the
stop button contacts.
The system described may be characterised as fail-safe provided
that the probability that the contactor will open when commanded
(its intended service) is within the appropriate ranges….
Call these control switches rather than isolators – otherwise they
need to be lockable