To read part one of this article, click here.
For the Cooperative Research Centre for Mining, the future of longwall mining is all about consistency and process efficiency. “As the industry strives towards becoming a resources factory rather than quarry or pit, process consistency and sustainability are the driving paradigms,” CRCMining business and marketing manager David Haneman said.
“The most needed improvement in underground coal mining is consistency of process. This will be achieved by improved equipment reliability and system automation.”
According to CRCMining’s coal production program leader Dr Joe Cronin, to improve the reliability of process and equipment, accurate knowledge of the existing process, vision of the future process and a work program to eliminate the gaps is required.
“The old mantra of ‘what gets measured gets done’ applies to all industries,” Dr Cronin said, pointing to the development of their longwall downtime measurement software as one of a number of tools available to capture accurate downtime and process logging to ensure that production, maintenance and management are operating with “one version of the truth”.
Despite the changes, Dr Cronin believes the basic structure of longwall mining will not change a great deal in the next 10 years. “The major pieces of equipment; chocks, conveyors and shearers will still be there. The big difference will be in the integration of the equipment and the degree of autonomous operation,” he said.
The company’s technical director of engineering services Peter Lugg said: “More than ever, the next 10 years will see significantly increased production efficiency through process management and control. Certainly we will see greater focus on equipment working cooperatively.
“In development we will see a closed control loop from miner to conveyor where the conveyor, support and mining operations are controlled by a single system and are remotely monitored.
“In this way, we will see a significant decrease in scheduling delays and in delays caused by human induced inconsistency.
“We will see less people underground and a change in the skill set of those people working underground. Through increased consistency and with automatic fault detection, classification and prediction (DNA) we will see fewer breakdowns, and less requirement for breakdown-focused maintenance staff ... and an increase in reliability-centred approaches.
“Similarly, with greater emphasis on load and process monitoring (duty cycle meters, AFC tension monitoring), targeted preventative, condition monitoring and reliability-centred maintenance (asset management) will also increase both system availability and reliability.”
Looking at specific projects, CRCMining is working on Coil Tube drilling and tight radius drilling technology which will contribute to safe productivity of longwall mining, while the conversion of a shuttle car to fly-by-wire and assisted remote operation will enhance remote operation of continuous miners in outburst prone areas.
The future of longwall mining can’t be discussed without mentioning the issues that threaten its future. These have become evident over the past few years, especially in the Illawarra region. There has been a NSW Independent Inquiry into the impact of mining on significant natural features in the Southern Coalfield as environmental groups call for compulsory buffer zones.
Galvin has been involved in a number of public enquiries over the past few years related to subsidence impacts arising from mining. He said there were some real challenges facing longwall mining, particularly in respect of the effects on groundwater and natural surface features and mitigating the resulting impacts.
“The industry must develop a better understanding of sub-surface and surface response to longwall mining if it is to effectively manage subsidence-related risks and realise the full potential of technology developments in longwall mining in the future,” he said.
How the longwall industry addresses, handles and just as importantly, communicates changes it makes to address this issue will be critical to its future.
From a US researcher’s perspective, National Institute for Occupational Safety and Health (NIOSH) principal coal mining engineer Jürgen Brune said increased ventilation requirements was a major issue the industry would need to tackle as the faces got bigger and longer and equipment horsepower and sizes became bigger and beefier.
“All this requires more air to sweep it away, more methane is liberated and needs to be diluted ... that is the next hurdle to overcome and solutions found for,” Brune said.
He also pointed out if the S-MINER Act was picked up again in the US it was possible that the dust limit would be reduced and this would require even further ventilation requirements on the longwall face.
Brune also drew attention to the challenges the industry faced as it turned to more difficult seams. He said while industry was “picking at the raisins now”, in reference to an old German expression that you eat the raisins in the cake first, industry in the future would have to start eating the rest of the cake if it was to continue extracting coal.
“Our options will be reduced, it’s just a matter of when. We are now looking deeper for good seams, but then running into problems like bumps and seismic activity,” Brune said.
“We’re now in a very complex geotechnical environment, but we don’t have a handle yet on these issues, including with longwall mining.”
Brune said Crandall Canyon was a good example of showing industry that it had little solid knowledge of mining in deeper areas. In August 2007 nine people were killed at the Utah mine in a collapse followed by a cave-in 10 days later.
NIOSH research engineer Adam Smith sees a longwall future where miners no longer suffer hearing loss and impairment related to their time spent underground.
Starting this year, NIOSH is undertaking a five-year project to reduce noise generated by longwall mining systems.
Mine Safety and Health Administration data shows during 2006 hearing loss and impairment were the second-most reported cases of illness and disease in the longwall sector. Recent NIOSH studies noted 43% of underground workers surveyed were over the MSHA Permissible Exposure Level for noise.
Worse still, the occurrence of worker noise overexposure at the working face was even higher.
Smith said shearer operators could experience sound levels as high as 99 decibels and noise exposures that are 600% over the MSHA PEL.
This NIOSH project will examine how noise is generated by longwall mining systems and investigate controls to reduce levels experienced by workers underground. The number one target for reducing levels will be through engineering noise controls, followed by administrative controls such as switching the headgate and tailgate operators back and forth so one person doesn’t get all of the heavy noise exposure, and personal protective devices.
“The successes we’ve seen with continuous miners and roof bolters leads us to believe we can really make a contribution as far as longwalls go,” Smith said.
