Published in September 2007 Australian Longwall Magazine
Longwall mines in both states have been working hard to minimise risk by meeting all requirements of the new guidelines.
Of all longwall hydraulic incidents recorded by CMS Insurance over the past eight years, 62% have been caused by hose and-or fitting failure and resulted in 159 injuries - about 20 per year. A high force leak has the power to pierce the skin and can, in some cases, result in death.
"A pin-hole sized leak in a hose or pipe will cause a very fine jet of fluid that may be undetectable as a jet as it's not always noisy and not always wet, such as air. The very fine jet at high pressure will act like a hypodermic needle that may penetrate the skin, depositing some of the fluid. If a person is close to the leak or attempting to find a leak by hand, then there's a possibility of an injury," a Queensland Department of Mines and Energy spokesperson said.
Recently in New South Wales there was one fatality, and two serious injuries, involving high pressure fluids. In the first incident an employee sustained a hand injury (near miss hydraulic injection) while relieving stored hydraulic pressure through a bleed line adjacent to a longwall chock. In another incident an operator received minor injuries when the hydraulic hose for the bucket tilt function burst, allowing pressurised fluid to smash the front window screen of the front end loader he was operating.
A contractor was fatally injured while taking fluid samples from a large hydraulic system used to power longwall machinery. The fatal injuries were consistent with hydraulic injection.
The New South Wales Department of Primary Industries said response to MDG41, drafted in August 2006, had been positive.
"The reaction to the draft has been positive with many purchasers of substantial hydraulic equipment utilising either the total drafts or parts thereof in the purchasing specification," a spokesperson said.
"Mine personnel, suppliers of equipment, suppliers of hydraulic components, union representatives and consultant experts have contributed to MDG41. These people are very active and committed to improving hydraulic safety.
"Maintenance personnel are now utilising safety management systems as described in MDG41 for hydraulic assets at many mines."
The NSW DPI said mine operators found hydraulic system management and hose management to be challenging areas when looking at fluid power safety. However, compliance with MDG41 and the support of hose manufacturers was improving the safety on mines.
"Reaction from hose manufacturers is very positive, with most working toward meeting the requirements of the document where applicable," a spokesperson said.
In Queensland where mines are not required to comply with MDG41, the Queensland DME said because many hose manufacturers are starting to manufacture their products in compliance with MDG41, these mines were also seeing improved on-site safety.
"Hose manufacturers are supplying abrasion-resistant hosing, armoured hoses (wound externally with wire) and sheaths fitted around hoses; these measures are to reduce the possibility of pin holes or to contain the leak," the spokesperson said.
Queensland mine operators are also working with hose suppliers and holding regular meetings with workers to ensure they have up-to-date safety requirements.
"Operators also hold tool box talks, mainly with tradespeople but also with other staff to raise awareness of the risk posed by a fine, high pressure jet of fluid and specifically [warn them] not to search for [the jet] by hand," a spokesperson said.
A product which has proven itself in the field is Alfogomma's hose restraint and energy diffusion system. This year the product contained an intershield hose after a rotary coupling failure at the Ashton site in NSW's Hunter Valley. The restraint's primary function is to prevent any mechanical contact damage to personnel and-or equipment within strike range in the event of hose end or coupling failure. The product has been well received by mines, particularly those auditing against MDG41.
Treatment protocol
The management of high pressure fluid injection injuries may result in amputation of the affected limb or body part, or death, if not appropriately treated. Such protocol should contain, but not be limited to, at least the following, Queensland Mines Inspectorate's safety bulletin advises:
Treating all fluid injection injuries as serious or life threatening.
Training on-site first aid staff in appropriate response and treatment strategies.
Providing emergency transport to hospital.
Providing the attending medical professionals or institutions with Material Safety Data Sheets relating to the product suspected of being injected.
Providing the medical institution that will be treating the patient with documentation that describes the time, date, circumstances and symptoms observed on site.
Ensuring medical institutions and professionals equipped with the appropriate expertise have been identified and are used when a fluid injection injury occurs.
