Man overboard system ensures safety

Mining various materials has always presented a vast array of hazards. In many mines water, or more appropriately storing water and working in and around it, is one of those many hazards. Complacency with water is common, as we are generally quite comfortable with water. It plays a significant part in many recreational activities that many Australians enjoy. If you have asked someone involved with a quarry what they consider the hazards on-site to be, their answers would most likely be electricity, mobile equipment and the processing plant. You would rarely, if ever, hear them say ?water?.

What about when you work on this liquid landscape, day in, day out? Surely you are likely to fall in at some point? Falling into a pond with a life jacket on is no great issue because you can swim to a ladder and climb out, albeit rather wet and perhaps a little embarrassed. But what happens when the unimaginable occurs? What happens when a worker falls into the pond from an operational incident or unrelated medical incident, unconscious or incoherent?

Kurnell, on the southern peninsula of Botany Bay in New South Wales, is blessed with a magnificent fine sand resource suitable for the construction industry. Winning the material is most effectively achieved by a dredge operation pumping material through to a wash plant. Rocla Quarry Products has been dredging sand from the Kurnell Peninsula since 1985.

The process of dredging presents a few well known hazards, though up until recently, one particular risk has always relied on good faith and procedural soft controls. Ultimately, there are few cost-effective ways to completely mitigate all risks involved with working in and around a large pond. There will always be risks involved with dredging that cannot completely be removed, reasonably practical that it is.

?Our greatest fear is that someone will fall into the pond, unconscious and unnoticed. Hypothermia can be fatal!? said John Gardiner, the regional manager of Rocla Quarry Products, Kurnell.

Accessing the dredges at Kurnell is most often done by using a large barge, which is slow, steady and generally quite easy to operate. The risks associated with tying the barge off to the dredge to access the dredge or accessing the barge from the shore is minimal in good weather. Poor weather increases the risks. There are physical barriers (handrails) around both the barge and dredge. It is the human error of a misplaced foot, unanticipated movement or unforeseen incident that really cannot be ruled out.

If someone were to fall into the pond, unconscious, their mandatory life jacket would inflate and position the person in such a manner to ensure the airway is facing the correct way up (lying on their back) as this is what a personal flotation device (PFD1) is designed to do. Up until now there has been no failsafe way of recognising an individual has fallen into the pond other than visually, or the failure of the individual to respond to occasional radio communication. There is potential for a considerable delay for an alarm to be raised.

?By installing a man overboard alert system, we effectively removed the issue of not knowing if someone had fallen into the pond. We hope never to use the system, but I have confidence in knowing it is there,? explained Dan Bolton, the production manager of Rocla Quarry Products, Kurnell.

Rocla?s first approach in attempting to assess best practice was to consult with other industry players that operated dredges or worked with and around silt ponds. Surprisingly, at the time of investigation, there was little mention of a man overboard system. Marine workers or workers who are involved in public waterways have been using various man overboard systems since the early 1990s, but very few in quarrying.

The system selected is designed and manufactured by Sea Marshall in the UK. The workers are well used to wearing a life jacket (PFD1), which is an item of their mandatory personal protective equipment to be worn for any work (including transit to and from the dredges) on or around the pond. So, ideally, a unit that fitted into a life jacket (PFD1) would be most suitable. Most appropriately, Rocla?s employees could easily adopt it. If a safety system is not easy to use, then more often than not employees will not use it.

The basic operation of the system is quite simple. There is a ?base unit? which is located on-shore in the wash plant and programmed with phone numbers to call if it receives an SOS signal. The phone numbers in this case are that of the supervisor, production manager and the production superintendent. A worker wears a sender which is located in a purpose-made pocket of their (PFD1) life jacket and is ?armed? at all times when the worker is on the pond. If a worker falls into the pond or, more accurately, the sender is submersed in water for a designated period (five seconds), a radio signal will be sent and received by the ?base unit? and an alarm is automatically raised by sounding a siren and calling the designated phone numbers in ascending order. If an accidental signal is set off, the wearer can cancel it immediately by disarming the sender unit.

The system has been implemented so far with great success, that is, there have been no false alarms. An employee voluntarily taking a swim off one of the dredges has tested it. It has also become a part of Rocla Kurnell?s site emergency drills bringing realistic scenarios to its employees? training. All employees working on or around the pond have readily adopted the system and have no complaints about wearing the devices or raised any other unforeseen difficulty.

Hopefully, the system will never need to raise an alarm to indicate a worker has fallen into the pond, but it is an important step in the right direction towards minimising a significant hazard on-site.

Daniel Chojnacki is the quarry services manager at Rocla Quarry Products in Guildford, NSW.

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