In an interview with International Longwall News, MSHA electrical safety division supervisor Dave Chirdon said the impetus for the Program Policy Letter (PPL) was to publicise additional approval guidelines being taken into consideration that are necessary for system designers in addressing new hazards coming into play with a new generation of technology.
“For example, the new communications and tracking systems that are being submitted for MSHA approval mostly all include larger batteries than we’ve ever seen on intrinsically safe equipment," said Chirdon.
“The new batteries are necessary to provide longer post-accident power capabilities.
“The introduction of these larger batteries introduces battery off-gassing hazards which have not previously been a concern with smaller batteries, hence the need for additional protection."
The guidelines impact all of those applications submitted for communications and tracking devices since the beginning of 2006, he added.
“It is quite possible that these new requirements may introduce delays to the approval process, but MSHA would not be doing its job if it didn’t acknowledge and address these new safety concerns," said Chirdon.
The agency plans to evaluate and approve each system independently and will not make one comprehensive announcement regarding the approval of them all, Chirdon said.
He added that MSHA will continue to prioritise the approval process for both types of units. It anticipates many of the 51 approval applications currently under review – each currently under various stages of investigation – will see their green lights throughout this calendar year and next.
“Some are nearing completion while others are only beginning the investigation process," said Chirdon, but noted that MSHA cannot speak specifically about individual applications.
He also told ILN that there are a number of obstacles in communications and tracking applications that are slowing the approval for many companies. One of the most significant is inadequate documentation.
“Many approval applicants are new to certification processes and specifically, MSHA’s approval process," he said.
“A high percentage of the applications that we receive do not include adequate documentation to allow expeditious processing [and] we spend significant time with these applicants in getting the documentation necessary to evaluate the design."
Another issue is unresolved design, as many of the applications received by the agency do not include finalised designs of the respective system.
“A lot of these approval applicants are taking off-the-shelf technology and attempting to adapt it to the underground mining environment, for which they are unfamiliar – so in many cases, we are seeing design changes being made during the approval process," said Chirdon.
Power supply design seems to be a sticking point for system applications, Chirdon added, as many companies are getting caught up with power supply specifications that will allow the respective system to be capable of delivering adequate backup power to be certified Intrinsically Safe (IS) by MSHA.
The final obstacle is the sheer level of applications the agency is receiving.
“MSHA’s Approval and Certification Center has never experienced such a high volume of intrinsic safety approval requests in such a short period of time,” said Chirdon.
“Although these applications have challenged our available resources, we have made significant adjustments to allow more expeditious processing of these applications."