Published in the June 2010 Australian Longwall Magazine

To address these two issues and pave a new way forward, Industry & Investment NSW held a full-house workshop in mid-May with plenty of check inspectors, maintenance managers and mechanical technicians in attendance.

Dust control measures are of particular concern to Hunter Valley operations as regulator testing of inhalable coal dust in March found 50 of the 95 longwall samples from the region failed the upper limit of 10 milligrams per cubic metre.

At the workshop Coal Services offered the services of its occupational hygiene personnel to the industry.

Coal Services occupational hygiene services manager Gary Mace said they would look at operating procedures, control measures and help the mines to improve dust control at minimum cost.

In many cases the higher dust output comes from not correctly applying existing procedures or control measures.

“The 10 milligram per cubic metre upper limit is a practically achievable standard – in fact it has been an international standard since the 1970s,” Chief Inspector of Coal Mines Rob Regan said.

Mace does not see any change to the main factors at play.

He said these were operator positioning, ventilation standards and the use of water, whether it was correct operation of sprays, water pressure, or the judicious use of the water and how it was applied and where.

But Coal Services is also looking into newer approaches. These include mounting sprays on powered roof supports to contain dust closer to the face line or even on the roof to keep dust down when the chocks move forward.

The effectiveness of shearer clearers can also come under their audits along with control measures around the BSL and crusher systems, where the sealing of gaps between equipment can make a difference.

Mace said there were a lot of simple measures as well, such as hosing down chocks during maintenance, to remove excess dust that can re-enter the atmosphere.

Yet the actual seams often determine the amount of control required and there is a consensus that Hunter coal tends to be drier while Lithgow area mines get a better compliance rate due to damper seams.

Regan noted the Southern Coalfields seams were still damper than in the Hunter despite a lot of gas drainage activity.

“The Hunter appears to be dry overall, so that means in the Hunter area people really have to pay greater attention to their spray technologies and also positioning of people, because they are the key issues that allow people to be able to achieve the 10 milligram or better result,” Regan said.

While Coal Services could potentially go down the path of issuing notices to mines for failures in any dust sampling standards, better results are expected from working with the industry.

“It’s not a big stick approach. The approach that both the regulator and Coal Services have always found effective with industry is to provide the right sort of information so that people can actually address the problems and address them properly,” Regan said.

As Coal Services looks forward to getting occupational hygiene staff onto occupational health and safety committees and onsite task committees at mines throughout the state, issues with diesel-engine systems will be countered by upcoming mandatory training requirements.

Safemine Engineering trainer and assessor Phil Berriman said the work required to develop formal Australian competencies for a Certificate III in Diesel Engine Systems and a Diploma of Diesel Engine Systems was well advanced.

Developed in consultation with national industry skills council, SkillsDMC, Berriman expects the competencies to go national around the end of August as part of a new coal training package to be released at this time.

He added that part three of the Australian Standard (AS/NZS 3584.3: 2010) was being rewritten, with publication expected in October.

Upcoming changes associated with recent government guidelines include the introduction of improved maintenance management systems.

Berriman said these included a structure for Recognised Service Facilities and requirements for a Competent Person to take responsibility for the ongoing compliance and safety of diesel engine systems.

The Diploma of DES will give technicians the Competent Persons status in this regard and will be delivered through registered training organisations such as Safemine.

“Qualifications are made up of a number of competencies, and the issue is not whether or not you have sat in a room for x number of hours, the issue is can you demonstrate you have the competencies?” Berriman emphasised.

“And that can be done by the recognition of prior learning process.”

Regan added that many maintenance people currently underground will have about 95% of the competencies already, with only refresher training required.

Berriman summarised the recent government changes as a multi-pronged approach to improve maintenance in underground mines, improve maintenance facilities, and to build on competence and design and implementation standards in relation to DES equipment.

These developments follow some grim statistics of failure rates.

“We’ve got registered something like 1080 DES systems in NSW, when analysed there are 465 actual failures of the explosion-protected properties of DES which basically means having a failure every two to three days of at least one,” Regan said.

The majority of failures relate to inadequate maintenance of shutdown circuits although equipment design was also a cause.

“Failures appear to be in line with the number of units in service, so it really is a systematic problem in the design and maintenance of the equipment,” Regan said.

“Not that any one manufacturer’s design or manufacture is worse than another but in terms of this equipment we know the design for many of these equipment systems dates back to the 1980s, or prior to the 1980s, and the maintenance systems are built around that as well.”

While electronically managed engine systems solve many of the issues present with DES and are becoming more common in diesel vehicles underground, Berriman said mines will be forced to adopt this technology by mandate within three years.

In the meantime, there is recognition that there are plenty of old machines in use.

“That’s why the focus is on site maintenance, and also the competence of workshops, we as the regulator will be moving more towards an accredited workshop system,” Regan said.

On the potential for upgrading the explosion-protected DES in older vehicles, Berriman said it was not that probable on a commercial or technical basis in many cases.

“But there will be some replacement of diesel engine systems in machines and vehicles,” he said.

“For example on the south coast there is still a lot of rail transportand rail-operated personnel carrier cars – they have geriatric engine technology systems – but the machine itself is actually fine and the probability is that they will get new engine systems and that’s entirely appropriate.”

Overall, Regan said the 150-strong attendance of the recent workshop in Eastern Creek was very heartening along with the industry discussions after the presentations.

He said he wanted to make sure the mines knew that individual events or failures with the two discussed issues were not isolated.

“There is a situation in the industry where a number of mines need to put in place these control mechanisms and maintain them in place.”

Berriman said he had an impression that all the stakeholders in the state’s coal industry were cooperatively working together to make it better.

“That’s a damn good thing and it doesn’t happen in all industries.”