Functional safety in mining processes can be improved through the use of remote isolation systems. Such systems make isolations quicker and easier to perform, reducing the risk of human error and removing personnel from hazardous areas. They also allow for more effective maintenance during outages due to faster isolations. Remote isolation systems provide constant monitoring of isolation status to ensure reliability. While requiring upfront investment, the costs of these systems can be quickly offset through increased productivity and plant uptime.

1. Functional safety in mining
Remote isolation
Mark Spinks
Electrical Manager - FLSmidth

2. What is functional safety (FS)?
• Exida: “Freedom from unacceptable risk achieved through the safety lifecycle.”
• Wikipedia: “…the part of the overall safety of a system… that depends on the
system… operating correctly in response to its inputs, including the safe
management of likely operator errors, hardware failures and environmental
changes.”
• Marcus Punch: “Correct operation in response to inputs”.
• For us, it’s typically in relation to E/E/PS (Electrical, Electronic and Programmable Systems.)
• A way of managing the reliability of safety-related electrical systems.

3. Where is functional safety (FS)?
• It’s everywhere...
Image credit: IEC FS overview document

4. Remote Isolation: a great application for FS
• Some sobering reading: AS4024.3611 Appendix B
– While this only covers conveyor-related fatalities, there would no doubt be similar stories
on other machines.
• As history shows, while the site procedure may be clear, people take short
cuts and ‘push the limits’ of what’s acceptable.
• We can however take away one of the common reasons (excuses) people
take shortcuts – we can make isolation quick and easy.
• At the same time, we can make isolations more reliable.

5. Remote Isolation – why bother?!
• The big one: Human factors (discussed next)
• Removal of personnel from the line of fire during isolation.
– Consider just the arcflash risk reduction for some installations.
• Also, faster isolations can result in some welcome byproducts:
– More maintenance completed during an outage, or:
– A shorter outage (more plant uptime: more revenue*)
*System payback typically occurs within months.

6. Unsafe Acts
Unintended
Action
Slips
Attention
failures
Lapses
Memory
failures
Intended
Action
Violations
Routine or
exceptional
deviations
Mistakes
Rule or
knowledge-
based mistakes
Human Error
James Reason’s Model

7. Human Factors - SLIPS
Attention Failures – knowing what to do, but accidentally getting it wrong
• Failing to identify a necessary isolation point, despite being competent.
• Inadvertently turning an isolation point to on, rather than off.
• Knowing where to isolate, but operating the wrong handle. Image above: From Qld
DNRM safety alert# 163

8. Human Factors - LAPSES
Memory Failures – knowing what to do, but forgetting in that instance
• Forgetting to controlled-stop a process before isolating it
• Opening, but forgetting to rack-out a CB isolation point
• Forgetting to properly verify the isolation.

9. Human Factors – MISTAKES
‘But I thought…’ kind of issues
• Misunderstanding which isolation points should be isolated for a task.
• Not effectively verifying the isolation, due to lack of knowledge, or other challenges (for example, the belt
may have already been stopped for another reason, or isolated by another employee)
• Not effectively securing the isolation.
• Isolating correctly, but working on the wrong (un-isolated) equipment

10. Human Factors - VIOLATIONS
Deliberate deviation from procedure. May be routine,
or exceptional.
Not isolating correctly or fully due to:
• Time pressures (real or perceived).
• Belief that the belt will not start without all
permissives ready.
• The imbalance between perceived risk and the effort
or time required to isolate.

11. Common misconception #1:
“Conventional isolations are better. Remote
isolations are done through control systems and
therefore not as good”.

12. Reducing the risk of an isolation-related incident
An isolation-
related incident

13. Common misconception #2:
“Remote isolations are not WHOLE CURRENT
isolations, therefore no good”.
• Not true. Whole current isolations are performed, however these are initiated via a
control system.
• Verification of effectiveness is also inherent in the design (See image at right,
where REMSAFE’s lockout flap is not released by the system until after verification)
• Constant isolation status-monitoring is introduced and will take action if anything
changes.
• Again, consider the arcflash advantages of remotely switching whole-current
isolation points.
REMSAFE will not allow personnel
to apply a lock until the system
has verified the isolation.

14. Financial benefits
• Imagine being able to perform a fully effective isolation, in a few minutes.
• Particularly for common (ie regularly conducted) isolations, or complex
isolations (which take time to complete).
• Revenue increase can be very significant, particularly for bottleneck
processes.
• Also, means more ‘spanner time’ for skilled personnel
• Financial calculators available on the web

15. Can we design a system ourselves?
• Absolutely, but it’s challenging to do it well.
• Recommendations:
– Engage an expert supplier
– Engage a FSEng to assist (eg TUV certified)
– In any case, please don’t forget the ongoing
maintenance/proof-testing (discussed next).
– Also, consider in advance how to safely bypass the
system, should it fail.
Image courtesy of Marcus Punch

16. Testing
Image credit: Drager FS document

17. Testing(cont’d)
Image credit: E&H FS document

18. Remote Isolation - Summary
• Financial
– Cost of a system can be quickly offset by productivity increases
• Safety
– Makes isolations quick and easy (no excuses for not isolating)
– Less chance of human error
– Removes personnel from the line of fire
– Constant status-monitoring makes isolations more reliable